def main():
"""Drives the Jack-to-VM translation process"""
file_name = sys.argv[1]
tokenizers = []
output_files = []
abs_path = os.path.abspath(file_name)
if '.jack' in file_name and file_name[-5:] == '.jack':
tokenizer = JackTokenizer(abs_path)
tokenizers.append(tokenizer)
output_path = os.path.splitext(abs_path)[0] + '.xml'
output_files.append(output_path)
else:
for walk_obj in os.walk(abs_path):
for jack_file in walk_obj[2]:
if '.jack' in jack_file and jack_file[-5:] == '.jack':
tokenizer = JackTokenizer(abs_path + '/' + jack_file)
tokenizers.append(tokenizer)
output_path = abs_path + '/' + jack_file[:-5] + '.xml'
output_files.append(output_path)
for tokenizer in tokenizers:
while tokenizer.has_more_tokens():
tokenizer.advance()
token_type = tokenizer.token_type()
if token_type == 'KEYWORD':
keyword = tokenizer.keyword()
elif token_type == 'SYMBOL':
symbol = tokenizer.symbol()
elif token_type == 'IDENTIFIER':
identifier = tokenizer.identifier()
elif token_type == 'INT_CONST':
int_val = tokenizer.int_val()
elif token_type == 'STRING_CONST':
string_val = tokenizer.string_val()
def test_advance(self):
"""Tests all parts of the tokenizer using this Jack code:
/** Multi-line comment for
some class. */
class A{
// Single-line comment
let x = -4;
do Output.printString("Ring Constants!");
}
"""
tokenizer = JackTokenizer("test.jack")
tokenizer.advance()
self.assertEqual(tokenizer.keyword(), CLASS)
self.assertEqual(tokenizer.token_type(), KEYWORD)
tokenizer.advance()
self.assertEqual(tokenizer.identifier(), 'A')
self.assertEqual(tokenizer.token_type(), IDENTIFIER)
tokenizer.advance()
self.assertEqual(tokenizer.symbol(), '{')
self.assertEqual(tokenizer.token_type(), SYMBOL)
tokenizer.advance()
self.assertEqual(tokenizer.keyword(), LET)
self.assertEqual(tokenizer.token_type(), KEYWORD)
tokenizer.advance()
self.assertEqual(tokenizer.identifier(), 'x')
self.assertEqual(tokenizer.token_type(), IDENTIFIER)
tokenizer.advance()
self.assertEqual(tokenizer.symbol(), '=')
self.assertEqual(tokenizer.token_type(), SYMBOL)
tokenizer.advance()
self.assertEqual(tokenizer.symbol(), '-')
self.assertEqual(tokenizer.token_type(), SYMBOL)
tokenizer.advance()
self.assertEqual(tokenizer.int_val(), 4)
self.assertEqual(tokenizer.token_type(), INT_CONST)
tokenizer.advance()
self.assertEqual(tokenizer.symbol(), ';')
self.assertEqual(tokenizer.token_type(), SYMBOL)
tokenizer.advance()
self.assertEqual(tokenizer.keyword(), DO)
self.assertEqual(tokenizer.token_type(), KEYWORD)
tokenizer.advance()
self.assertEqual(tokenizer.identifier(), 'Output')
self.assertEqual(tokenizer.token_type(), IDENTIFIER)
tokenizer.advance()
self.assertEqual(tokenizer.symbol(), '.')
self.assertEqual(tokenizer.token_type(), SYMBOL)
tokenizer.advance()
self.assertEqual(tokenizer.identifier(), 'printString')
self.assertEqual(tokenizer.token_type(), IDENTIFIER)
tokenizer.advance()
self.assertEqual(tokenizer.symbol(), '(')
self.assertEqual(tokenizer.token_type(), SYMBOL)
tokenizer.advance()
self.assertEqual(tokenizer.string_val(), 'Ring Constants!')
self.assertEqual(tokenizer.token_type(), STRING_CONST)
tokenizer.advance()
self.assertEqual(tokenizer.symbol(), ')')
self.assertEqual(tokenizer.token_type(), SYMBOL)
tokenizer.advance()
self.assertEqual(tokenizer.symbol(), ';')
self.assertEqual(tokenizer.token_type(), SYMBOL)
tokenizer.advance()
self.assertEqual(tokenizer.symbol(), '}')
self.assertEqual(tokenizer.token_type(), SYMBOL)
class CompilationEngine:
###############
# CONSTRUCTOR #
###############
def __init__(self, in_filename, in_file, out_xml, out_vm):
"""
Creates a new compilation engine with the given input and output.
The next routine called must be compileClass().
:param in_file: Open source Jack file.
:param out_xml: Open XML file.
:param out_vm: Open VM file.
"""
self.__in_filename = in_filename
self.__in_file, self.__out_xml = in_file, out_xml
self.__tokenizer = JackTokenizer(in_file)
self.__symbolTable = SymbolTable()
self.__vmWriter = VMWriter(in_filename, out_vm)
self.__stack = list()
self.__tokenizer.advance()
self.__resetUniqueLabels()
###################
# PRIVATE METHODS #
###################
def __resetUniqueLabels(self):
self.__unique_id_if = 0
self.__unique_id_while = 0
def __uniqueWhileLabels(self):
"""
Return (IF_TRUE, IF_FALSE, IF_END) labels carrying a unique id to
prevent collisions with other labels carrying the same name.
Example:
while_exp, while_end = __uniqueWhileLabels()
-->
while_exp = "WHILE_EXP123"
while_end = "WHILE_END123"
"""
unique_labels = []
for label in [WHILE_EXP, WHILE_END]:
unique_labels.append("{}{}{}".format(label, UNIQUE_DELIMITER,
self.__unique_id_while))
self.__unique_id_while += 1
return unique_labels
def __uniqueIfLabels(self):
"""
Return (IF_TRUE, IF_FALSE, IF_END) labels carrying a unique id to
prevent collisions with other labels carrying the same name.
Example:
if_true, if_false, if_end = __uniqueIfLabels()
-->
if_true = "IF_TRUE123"
if_false = "IF_FALSE123"
if_end = "IF_END123"
"""
unique_labels = []
for label in [IF_TRUE, IF_FALSE, IF_END]:
unique_labels.append("{}{}{}".format(label, UNIQUE_DELIMITER,
self.__unique_id_if))
self.__unique_id_if += 1
return unique_labels
def __writeToken(self, token, token_type):
"""
Writes the given token as an xml tag to the output.
:param token:
:param token_type:
:return:
"""
tag = self.__getIndentedTag("<{0}>{1}{2}{1}</{0}>\n".format(
token_type, XML_DELIM_TERMINAL, token))
self.__out_xml.write(tag)
def __writeTokenAndAdvance(self, token, token_type):
"""
Writes the given token as an xml tag to the output and extracts the
next token from the code.
:param token: token tag value
:param token_type: token tag type
"""
# Build XML tag
self.__writeToken(token, token_type)
self.__tokenizer.advance()
def __getIndentedTag(self, tag):
"""
Return the given tag with trailing tabs according to current
indentation level.
:param tag: tag to indent
:return: tag indented with trailing tabs.
"""
return XML_INDENT_CHAR * len(self.__stack) + tag
def __openTag(self, tagName):
"""
Open an XML tag with the given name.
All following tags will be written as inner tags until __closeTag()
is called.
:param tagName: name of the tag to open
"""
tag = self.__getIndentedTag("<{}>\n".format(tagName))
self.__out_xml.write(tag)
self.__stack.append(tagName)
def __closeTag(self):
"""
Close the current open XML tag.
All following tags will be written as outer tags in the previous
indentation level.
"""
tagName = self.__stack.pop()
tag = self.__getIndentedTag("</{}>\n".format(tagName))
self.__out_xml.write(tag)
def __compileKeyWord(self):
"""
Compile a keyword token
"""
keyword = self.__tokenizer.keyWord()
self.__writeTokenAndAdvance(keyword, TOKEN_TYPE_KEYWORD)
return keyword
def __compileSymbol(self):
"""
Compile a symbol token
"""
symbol = self.__tokenizer.symbol()
self.__writeTokenAndAdvance(symbol, TOKEN_TYPE_SYMBOL)
return symbol
def __compileIdentifier(self,
category,
status,
kind=KIND_NONE,
index=INDEX_NONE):
"""
Compile an identifier token
"""
info = "{} {}".format(category, status)
if kind != KIND_NONE:
info += " " + KIND_2_SEGMENT[kind]
if index != INDEX_NONE:
info += " " + str(index)
info = "[{}] ".format(info)
identifier = self.__tokenizer.identifier()
self.__writeTokenAndAdvance(info + identifier, TOKEN_TYPE_IDENTIFIER)
return identifier
def __compileIntVal(self):
"""
Compile an intVal token
"""
intval = self.__tokenizer.intVal()
self.__writeTokenAndAdvance(intval, TOKEN_TYPE_INTEGER)
self.__vmWriter.writePush(VM_SEGMENT_CONSTANT, intval)
return intval
def __compileStringVal(self):
"""
Compile a stringVal token
"""
string = self.__tokenizer.stringVal()
self.__writeTokenAndAdvance(string, TOKEN_TYPE_STRING)
corrected = self.__correctString(string)
self.__vmWriter.writePush(VM_SEGMENT_CONSTANT, len(corrected))
self.__vmWriter.writeCall(OS_STRING_NEW, 1)
for char in corrected:
self.__vmWriter.writePush(VM_SEGMENT_CONSTANT, ord(char))
self.__vmWriter.writeCall(OS_STRING_APPEND_CHAR, 2)
def __compileClassName(self, status):
"""
Compiles a variable name.
"""
return self.__compileIdentifier(CATEGORY_CLASS, status)
def __compileSubroutineName(self, status):
"""
Compiles a variable name.
"""
return self.__compileIdentifier(CATEGORY_SUBROUTINE, status)
def __compileSubroutineCall(self):
"""
Compiles a subroutine call.
Syntax:
( className | varName) '.' subroutineName '(' expressionList ')' |
subroutineName '(' expressionList ')'
"""
# Compile XML
callName = ""
exp_count = 0
if self.__tokenizer.lookahead() == RE_DOT: # className | varName
# extract var\class name
callName = self.__tokenizer.peek()
# className or varName?
kind = self.__symbolTable.kindOf(callName)
if (kind != KIND_NONE): # varName
# Use class name instead of object name
varName = callName
callName = self.__symbolTable.typeOf(callName)
# Push variable (this) and call class method
index = self.__symbolTable.indexOf(varName)
segment = self.__symbolTable.segmentOf(varName)
self.__vmWriter.writePush(segment, index)
# Include self as argument 0
exp_count += 1
self.__compileIdentifier(kind, STATUS_USE, kind, index)
else: # className
self.__compileIdentifier(CATEGORY_CLASS, STATUS_USE)
callName += self.__compileSymbol() # '.'
else: # subroutineName
# Subroutine -> className.Subroutine
self.__vmWriter.writePush(VM_SEGMENT_POINTER, 0)
callName += self.__className + FUNC_NAME_DELIMITER
exp_count += 1
callName += self.__compileSubroutineName(STATUS_USE)
self.__compileSymbol() # '('
exp_count += self.CompileExpressionList() # expressionList
self.__compileSymbol() # ')'
# Compile VM
self.__vmWriter.writeCall(callName, exp_count)
def __compileVarName(self, status):
"""
Compiles a variable name.
"""
name = self.__tokenizer.peek()
index = INDEX_NONE
if status != STATUS_DEFINE:
index = self.__symbolTable.indexOf(name)
varName = self.__compileIdentifier(CATEGORY_VAR, status, KIND_VAR,
index)
return varName
def __compileType(self):
"""
Compiles a type.
Syntax:
'int' | 'char' | 'boolean' | className
"""
# 'int' | 'char' | 'boolean'
if self.__tokenizer.peek() in {RE_INT, RE_CHAR, RE_BOOLEAN}:
type = self.__compileKeyWord()
# className
else:
type = self.__compileClassName(STATUS_USE)
return type
def __compileSubroutineBody(self, funcType, name):
"""
Compiles a subroutine body.
Syntax:
'{' varDec* statements '}'
"""
self.__openTag('subroutineBody') # <subroutineBody>
self.__compileSymbol() # '{'
# varDec*
while self.__tokenizer.peek() == RE_VAR:
self.compileVarDec() # varDec*
vars = self.__symbolTable.varCount(KIND_VAR)
self.__vmWriter.writeFunction(name, vars)
if funcType == RE_METHOD:
# Hold self at pointer
self.__vmWriter.writePush(VM_SEGMENT_ARGUMENT, 0)
self.__vmWriter.writePop(VM_SEGMENT_POINTER, 0)
if funcType == RE_CONSTRUCTOR:
# Allocate memory for all fields
fields = self.__symbolTable.varCount(KIND_FIELD)
self.__vmWriter.writePush(VM_SEGMENT_CONSTANT, fields)
self.__vmWriter.writeCall(OS_MEMORY_ALLOC, 1)
# Hold allocated memory at pointer
self.__vmWriter.writePop(VM_SEGMENT_POINTER, 0)
self.compileStatements() # statements
self.__compileSymbol() # '}'
self.__closeTag() # </subroutineBody>
return vars
##################
# PUBLIC METHODS #
##################
def compileClass(self):
"""
Compiles a complete class.
Syntax:
'class' className '{' classVarDec* subroutineDec* '}'
"""
self.__openTag('class') # <class>
self.__compileKeyWord() # 'class'
className = self.__compileClassName( # className
STATUS_DEFINE)
self.__className = className
self.__compileSymbol() # '{'
# classVarDec*
while self.__tokenizer.peek() in {RE_STATIC, RE_FIELD}:
self.CompileClassVarDec()
# subroutineDec*
while self.__tokenizer.peek() in {
RE_CONSTRUCTOR, RE_FUNCTION, RE_METHOD
}:
self.CompileSubroutine()
self.__compileSymbol() # '}'
self.__closeTag() # </class>
def CompileClassVarDec(self):
"""
Compiles a static declaration or a field declaration.
Syntax:
('static' | 'field') type varName (',' varName)* ';'
"""
self.__openTag('classVarDec') # <classVarDec>
kind = self.__compileKeyWord() # ('static' | 'field')
type = self.__compileType() # type
moreVars = True
while moreVars: # (',' varName)*
name = self.__compileVarName( # varName
STATUS_DEFINE)
self.__symbolTable.define(name, type, kind)
if self.__tokenizer.peek() != RE_COMMA:
moreVars = False
else:
self.__compileSymbol() # ','
self.__compileSymbol() # ';'
self.__closeTag() # </classVarDec>
def CompileSubroutine(self):
"""
Compiles a complete method, function, or constructor.
Syntax:
('constructor' | 'function' | 'method') ('void' | type)
subroutineName '(' parameterList ')' subroutineBody
"""
# Start subroutine in symbol table
self.__resetUniqueLabels()
self.__symbolTable.startSubroutine()
# Compile XML
self.__openTag('subroutineDec') # <subroutineDec>
funcType = self.__compileKeyWord() # ('constructor' |
# 'function' | 'method')
if funcType in {RE_METHOD}:
# +1 var count for this method (+1 for self)
self.__symbolTable.define(VM_SELF, self.__className, KIND_ARG)
if self.__tokenizer.peek() == RE_VOID:
type = self.__compileKeyWord() # 'void'
else:
type = self.__compileType() # type
subName = self.__compileSubroutineName( # soubroutineName
STATUS_DEFINE)
name = self.__className + FUNC_NAME_DELIMITER + subName
self.__compileSymbol() # '('
self.compileParameterList() # parameterList
self.__compileSymbol() # ')'
self.__compileSubroutineBody(funcType, name) # subroutineBody
self.__closeTag() # </subroutineDec>
def compileParameterList(self):
"""
Compiles a (possibly empty) parameter list, not including the
enclosing "()".
Syntax:
( (type varName) (',' type varName)*)?
"""
parameters = 0 # no parameters?
self.__openTag('parameterList') # <parameterList>
if self.__tokenizer.peek() != RE_BRACKETS_RIGHT:
moreVars = True
while moreVars:
parameters += 1 # yes parameters!
type = self.__compileType() # type
name = self.__compileVarName( # varName
STATUS_DEFINE)
self.__symbolTable.define(name, type, KIND_ARG)
if self.__tokenizer.peek() == RE_COMMA:
self.__compileSymbol() # ','
else:
moreVars = False
self.__closeTag() # </parametersList>
return parameters
def compileVarDec(self):
"""
Compiles a var declaration.
Syntax:
'var' type varName (',' varName)* ';'
"""
self.__openTag('varDec') # <varDec>
moreVars = True
self.__compileKeyWord() # 'var'
type = self.__compileType() # type
while moreVars:
name = self.__tokenizer.peek() # varName
self.__symbolTable.define(name, type, KIND_VAR)
self.__compileVarName(STATUS_DEFINE)
if self.__tokenizer.peek() == RE_COMMA:
self.__compileSymbol() # ','
else:
moreVars = False
self.__compileSymbol() # ';'
self.__closeTag() # </varDec>
def compileStatements(self):
"""
Compiles a sequence of statements, not including the enclosing "{}".
Syntax:
statement*
where statement is in:
letStatement | ifStatement | whileStatement | doStatement | returnStatement
"""
self.__openTag('statements') # <statements>
statement = self.__tokenizer.peek()
while statement in {
RE_LET, RE_IF, RE_WHILE, RE_DO, RE_RETURN_NOTHING,
RE_RETURN_SOMETHING
}:
if statement == RE_LET:
self.compileLet()
elif statement == RE_IF:
self.compileIf()
elif statement == RE_WHILE:
self.compileWhile()
elif statement == RE_DO:
self.compileDo()
elif statement == RE_RETURN_NOTHING:
self.compileReturnNothing()
elif statement == RE_RETURN_SOMETHING:
self.compileReturnSomething()
statement = self.__tokenizer.peek()
self.__closeTag() # </statements>
def compileDo(self):
"""
Compiles a do statement.
Syntax:
'do' subroutineCall ';'
"""
self.__openTag('doStatement') # <doStatement>
self.__compileKeyWord() # 'do'
self.__compileSubroutineCall() # subroutineCall
self.__vmWriter.writePop(VM_SEGMENT_TEMP, 0)
self.__compileSymbol() # ';'
self.__closeTag() # </doStatement>
def compileLet(self):
"""
Compiles a let statement.
Syntax:
'let' varName ('[' expression ']')? '=' expression ';'
"""
isArray = False
self.__openTag('letStatement') # <letStatement>
self.__compileKeyWord() # 'let'
varName = self.__tokenizer.peek()
index = self.__symbolTable.indexOf(varName)
segment = self.__symbolTable.segmentOf(varName)
self.__compileVarName(STATUS_USE) # varName
if self.__tokenizer.peek() == RE_BRACKETS_SQUARE_LEFT:
isArray = True
self.__compileSymbol() # '['
self.CompileExpression() # expression
self.__compileSymbol() # ']'
# Add the offset to the variable address
self.__vmWriter.writePush(segment, index)
self.__vmWriter.writeArithmetic(RE_PLUS, True)
# Address of array element is at stack top
self.__compileSymbol() # '='
self.CompileExpression() # expression
self.__compileSymbol() # ';'
self.__closeTag() # </letStatement>
if isArray:
# Pop rh-expression to temp
self.__vmWriter.writePop(VM_SEGMENT_TEMP, 0)
# Get address of array element
self.__vmWriter.writePop(VM_SEGMENT_POINTER, 1)
# Push rh-expression to stack
self.__vmWriter.writePush(VM_SEGMENT_TEMP, 0)
# Pop rh-expression to address of element
self.__vmWriter.writePop(VM_SEGMENT_THAT, 0)
else:
# Compile only if the varName was defined
# (unlike class name of subroutine name)
# if segment != KIND_NONE: # varName was defined
index = self.__symbolTable.indexOf(varName)
self.__vmWriter.writePop(segment, index)
def compileWhile(self):
"""
Compiles a while statement.
Syntax:
'while' '(' expression ')' '{' statements '}'
"""
LABEL_EXP, LABEL_END = self.__uniqueWhileLabels()
self.__openTag('whileStatement') # <whileStatement>
self.__compileKeyWord() # 'while'
self.__compileSymbol() # '('
self.__vmWriter.writeLabel( # label WHILE_EXP
LABEL_EXP)
self.CompileExpression() # expression
# Negate the expression
# (jump out of while if *NOT* expression)
self.__vmWriter.writeArithmetic(RE_TILDA, False)
self.__compileSymbol() # ')'
self.__vmWriter.writeIf(LABEL_END) # if-goto WHILE_END
self.__compileSymbol() # '{'
self.compileStatements() # statements
self.__compileSymbol() # '}'
self.__vmWriter.writeGoto(LABEL_EXP) # goto WHILE_EXP
self.__vmWriter.writeLabel(LABEL_END) # lable WHILE_END
self.__closeTag() # </whileStatement>
def compileReturnNothing(self):
"""
Compiles a 'return;' statement.
Syntax:
'return;'
"""
# Compile XML
self.__openTag('returnStatement') # <returnStatement>
self.__writeToken(
'return', # 'return'
TOKEN_TYPE_KEYWORD)
self.__writeTokenAndAdvance(
';', # ';'
TOKEN_TYPE_SYMBOL)
self.__vmWriter.writeReturn(True)
self.__closeTag() # </returnStatement>
def compileReturnSomething(self):
"""
Compiles a return statement.
Syntax:
'return' expression? ';'
"""
# Compile XML
self.__openTag('returnStatement') # <returnStatement>
self.__writeTokenAndAdvance(
'return', # 'return'
TOKEN_TYPE_KEYWORD)
self.CompileExpression() # expression
self.__compileSymbol() # ';'
self.__vmWriter.writeReturn()
self.__closeTag() # </returnStatement>
def compileIf(self):
"""
Compiles an if statement, possibly with a trailing else clause.
Syntax:
'if' '(' expression ')' '{' statements '}' ( 'else' '{' statements
'}' )?
"""
LABEL_TRUE, LABEL_FALSE, LABEL_END = self.__uniqueIfLabels()
self.__openTag('ifStatement') # <ifStatement>
self.__compileKeyWord() # 'if'
self.__compileSymbol() # '('
# VM Code for computing ~(cond)
self.CompileExpression() # expression
self.__compileSymbol() # ')'
self.__vmWriter.writeIf(LABEL_TRUE) # if-goto LABEL_TRUE
self.__vmWriter.writeGoto(LABEL_FALSE) # goto LABEL_FALSE
self.__vmWriter.writeLabel(LABEL_TRUE) # label LABEL_TRUE
self.__compileSymbol() # '{'
# VM Code for executing TRUE
self.compileStatements() # statements
self.__compileSymbol() # '}'
if self.__tokenizer.peek() == RE_ELSE: #
self.__vmWriter.writeGoto(LABEL_END) # goto LABEL_END
self.__vmWriter.writeLabel( # label LABEL_FALSE
LABEL_FALSE)
self.__compileKeyWord() # 'else'
self.__compileSymbol() # '{'
# VM Code for executing ELSE
self.compileStatements() # statements
self.__compileSymbol() # '}'
self.__vmWriter.writeLabel( # label END
LABEL_END)
else:
self.__vmWriter.writeLabel( # label FALSE
LABEL_FALSE)
self.__closeTag() # </ifStatement>
def CompileExpression(self):
"""
Compiles an expression.
Syntax:
term (op term)*
"""
self.__openTag('expression') # <expression>
self.CompileTerm() # term
while self.__tokenizer.peek() in {
RE_PLUS, RE_BAR, RE_ASTERISK, RE_SLASH, RE_AMPERSAND, RE_VBAR,
RE_LT, RE_GT, RE_EQ
}:
symbol = self.__compileSymbol() # op
self.CompileTerm() # term
self.__vmWriter.writeSymbol(symbol)
self.__closeTag() # </expression>
def __correctString(self, string):
"""
Convert escape characters in a string to valid chars
:param string: string to correct
:return: corrected strings with escaped characters corrected
"""
correct = string.replace('\t', '\\t')
correct = correct.replace('\n', '\\n')
correct = correct.replace('\r', '\\r')
return correct
def CompileTerm(self):
"""
Compiles a term.
This routine is faced with a slight difficulty when trying to decide
between some of the alternative parsing rules.
Specifically, if the current token is an identifier, the routine
must distinguish between a variable, an array entry, and a subroutine
call. A single look-ahead token, which may be one
of "[", "(", or "." suffices to distinguish between the three
possibilities. Any other token is not part of this term and should
not be advanced over.
Syntax:
integerConstant | stringConstant | keywordConstant | varName |
varName '[' expression ']' | subroutineCall | '(' expression ')' |
unaryOp term
"""
self.__openTag('term') # <term>
lookahead = self.__tokenizer.lookahead()
if self.__tokenizer.peek() == RE_BRACKETS_LEFT:
self.__compileSymbol() # '('
self.CompileExpression() # expression
self.__compileSymbol() # ')'
elif self.__tokenizer.peek() in {RE_TILDA, RE_BAR}:
symbol = self.__compileSymbol() # unaryOp
self.CompileTerm() # term
self.__vmWriter.writeArithmetic(symbol, False)
elif lookahead == RE_BRACKETS_SQUARE_LEFT:
varName = self.__tokenizer.peek()
self.__compileVarName(STATUS_USE) # varName
self.__compileSymbol() # '['
self.CompileExpression() # expression
self.__compileSymbol() # ']'
# Compile array indexing
kind = self.__symbolTable.kindOf(varName)
index = self.__symbolTable.indexOf(varName)
segment = KIND_2_SEGMENT[kind]
self.__vmWriter.writePush(segment, index)
self.__vmWriter.writeArithmetic(RE_PLUS, True)
self.__vmWriter.writePop(VM_SEGMENT_POINTER, 1)
self.__vmWriter.writePush(VM_SEGMENT_THAT, 0)
elif lookahead in {RE_BRACKETS_LEFT, RE_DOT}:
self.__compileSubroutineCall() # subroutineCall |
# (varName | className) '.' subroutineCall
else:
if self.__tokenizer.tokenType() == TOKEN_TYPE_INTEGER:
self.__compileIntVal() # integerConstant
elif self.__tokenizer.tokenType() == TOKEN_TYPE_STRING:
self.__compileStringVal() # stringConstant
elif self.__tokenizer.tokenType() == TOKEN_TYPE_KEYWORD:
# true | false | null | this
# true | false | null - pushed to stack as constants
keyword = self.__tokenizer.peek()
if keyword in {RE_FALSE, RE_NULL, RE_TRUE}:
self.__vmWriter.writePush(VM_SEGMENT_CONSTANT, 0)
if keyword == RE_TRUE:
self.__vmWriter.writeArithmetic(RE_TILDA, False)
# this - pushes pointer
elif keyword == RE_THIS:
self.__vmWriter.writePush(VM_SEGMENT_POINTER, 0)
self.__compileKeyWord() # keywordConstant
elif self.__tokenizer.tokenType() == TOKEN_TYPE_IDENTIFIER:
name = self.__tokenizer.peek()
kind = self.__symbolTable.kindOf(name)
index = self.__symbolTable.indexOf(name)
segment = self.__symbolTable.segmentOf(name)
self.__compileIdentifier(kind, STATUS_USE, kind, index)
self.__vmWriter.writePush(segment, index)
self.__closeTag() # </term>
def CompileExpressionList(self):
"""
Compiles a (possibly empty) comma-separated list of expressions.
Syntax:
(expression (',' expression)* )?
"""
exp_count = 0
self.__openTag('expressionList') # <expressionList>
if self.__tokenizer.peek() != RE_BRACKETS_RIGHT:
self.CompileExpression()
exp_count += 1 # expression
while self.__tokenizer.peek() == RE_COMMA:
self.__compileSymbol() # ','
self.CompileExpression()
exp_count += 1
self.__closeTag() # </expressionList>
return exp_count
class CompilationEngine:
def __init__(self, input_path, output_path):
"""
creates a new compilation engine with the given input and output. the next routine called must be compileClass()
:param input_path: input stream/file
:param output_path: output stream/file
"""
self._root = None
self._current_node = None
self.tokenizer = JackTokenizer(input_path)
self.CompileClass()
for elem in self._root.iter():
if elem.tag == 'expressionList' or elem.tag == 'parameterList':
if "/>" in str(ET.tostring(elem)):
elem.text = '\n'
p = ET.XMLParser(remove_blank_text=True)
tree = ET.ElementTree(self._root, parser=p)
tree.write(output_path, method='xml', pretty_print=True)
def CompileClass(self):
"""
Compiles a complete class.
"""
self._root = ET.Element('class')
self.tokenizer.advance()
self._write_line(self._root, self.tokenizer.keyWord())
self.tokenizer.advance()
self._write_line(self._root, self.tokenizer.identifier())
self.tokenizer.advance()
self._write_line(self._root, self.tokenizer.symbol())
self.CompileClassVarDec()
self.CompileSubroutine()
self.tokenizer.advance()
self._write_line(self._root, self.tokenizer.symbol())
def _write_line(self, node, name):
"""
writes the current node to the output file
:param name: the name of the node
"""
_ = ET.SubElement(node, TYPES[self.tokenizer.tokenType()])
_.text = ' ' + name + ' '
def CompileClassVarDec(self):
"""
Compiles a static declaration or a field declaration.
"""
peek = self.tokenizer.peek()
if 'static' in peek or 'field' in peek:
_classVarNode = ET.SubElement(self._root, 'classVarDec')
while 'static' in peek or 'field' in peek:
self.tokenizer.advance()
self._write_line(_classVarNode,
self.tokenizer.keyWord()) # field/static
self.tokenizer.advance()
self._write_line(_classVarNode, self.tokenizer.keyWord()) # type
self.tokenizer.advance()
self._write_line(_classVarNode,
self.tokenizer.identifier()) # name
self.tokenizer.advance()
while self.tokenizer.symbol() == ',':
self._write_line(_classVarNode, self.tokenizer.symbol()) # ,
self.tokenizer.advance()
self._write_line(_classVarNode,
self.tokenizer.identifier()) # name
self.tokenizer.advance()
self._write_line(_classVarNode, self.tokenizer.symbol()) # ;
peek = self.tokenizer.peek()
if 'static' in peek or 'field' in peek:
_classVarNode = ET.SubElement(self._root, 'classVarDec')
def CompileSubroutine(self):
"""
Compiles a complete method, function, or constructor.
"""
_last_node = self._current_node
_subroutineNode = ET.SubElement(self._root, 'subroutineDec')
self._current_node = _subroutineNode
peek = self.tokenizer.peek()
while 'function' in peek or 'constructor' in peek or 'method' in peek:
self.tokenizer.advance()
self._write_line(_subroutineNode,
self.tokenizer.keyWord()) # const/func/method
self.tokenizer.advance()
self._write_line(_subroutineNode,
self.tokenizer.current_token) # void/type
self.tokenizer.advance()
self._write_line(_subroutineNode,
self.tokenizer.identifier()) # name
self.tokenizer.advance()
self._write_line(_subroutineNode, self.tokenizer.symbol()) # '('
self.CompileParameterList()
self.tokenizer.advance()
self._write_line(_subroutineNode, self.tokenizer.symbol()) # ')'
self.tokenizer.advance()
self._current_node = ET.SubElement(_subroutineNode,
'subroutineBody')
self._write_line(self._current_node,
self.tokenizer.symbol()) # '{'
peek = self.tokenizer.peek()
if 'var' in peek:
self.CompileVarDec()
self.CompileStatements()
self.tokenizer.advance()
self._write_line(self._current_node,
self.tokenizer.symbol()) # '}'
peek = self.tokenizer.peek()
if 'function' in peek or 'constructor' in peek or 'method' in peek:
_subroutineNode = ET.SubElement(self._root, 'subroutineDec')
self._current_node = _subroutineNode
def CompileParameterList(self):
"""
Compiles a (possibly empty) parameter list, not including the enclosing ()
"""
param_list = ET.SubElement(self._current_node, 'parameterList')
peek = self.tokenizer.peek()
if peek != ')':
self.tokenizer.advance()
self._write_line(param_list, self.tokenizer.keyWord()) # type
self.tokenizer.advance()
self._write_line(param_list, self.tokenizer.identifier()) # name
peek = self.tokenizer.peek()
while peek == ',':
self.tokenizer.advance()
self._write_line(param_list, self.tokenizer.symbol()) # ','
self.tokenizer.advance()
self._write_line(param_list, self.tokenizer.keyWord()) # type
self.tokenizer.advance()
self._write_line(param_list, self.tokenizer.identifier()) # name
peek = self.tokenizer.peek()
# if not param_list.text:
# param_list.text = '\n'
def CompileVarDec(self):
"""
Compiles a var declaration.
"""
_varDecNode = ET.SubElement(self._current_node, 'varDec')
peek = self.tokenizer.peek()
while 'var' in peek:
self.tokenizer.advance()
self._write_line(_varDecNode, self.tokenizer.keyWord())
self.tokenizer.advance()
self._write_line(_varDecNode, self.tokenizer.keyWord())
self.tokenizer.advance()
self._write_line(_varDecNode, self.tokenizer.identifier())
self.tokenizer.advance()
while self.tokenizer.symbol() == ',':
self._write_line(_varDecNode, self.tokenizer.symbol()) # ,
self.tokenizer.advance()
self._write_line(_varDecNode,
self.tokenizer.identifier()) # name
self.tokenizer.advance()
self._write_line(_varDecNode, self.tokenizer.symbol()) # ;
peek = self.tokenizer.peek()
if peek == 'var':
_varDecNode = ET.SubElement(self._current_node, 'varDec')
def CompileStatements(self):
"""
Compiles a sequence of statements, not including the enclosing "{}"
"""
peek = self.tokenizer.peek()
_parent = self._current_node
self._current_node = ET.SubElement(self._current_node, 'statements')
while 'let' in peek or 'if' in peek or 'while' in peek or 'do' in peek or 'return' in peek:
if 'let' in peek:
self.CompileLet()
elif 'if' in peek:
self.CompileIf()
elif 'while' in peek:
self.CompileWhile()
elif 'do' in peek:
self.CompileDo()
elif 'return' in peek:
self.CompileReturn()
peek = self.tokenizer.peek()
self._current_node = _parent
def CompileDo(self):
"""
Compiles a do statement.
"""
_last_node = self._current_node
_statement = ET.SubElement(self._current_node, 'doStatement')
self._current_node = _statement
self.tokenizer.advance()
self._write_line(_statement, self.tokenizer.keyWord())
self.tokenizer.advance()
self._write_line(_statement, self.tokenizer.identifier())
peek = self.tokenizer.peek()
while peek == '.':
self.tokenizer.advance()
self._write_line(_statement, self.tokenizer.symbol())
self.tokenizer.advance()
self._write_line(_statement, self.tokenizer.identifier())
peek = self.tokenizer.peek()
self.tokenizer.advance()
self._write_line(_statement, self.tokenizer.symbol()) # '('
self.CompileExpressionList()
self.tokenizer.advance()
self._write_line(_statement, self.tokenizer.symbol()) # ')'
self.tokenizer.advance()
self._write_line(_statement, self.tokenizer.symbol()) # ';'
self._current_node = _last_node
def CompileLet(self):
"""
Compiles a let statement.
"""
_last_node = self._current_node
_statement = ET.SubElement(self._current_node, 'letStatement')
self._current_node = _statement
self.tokenizer.advance()
self._write_line(_statement, self.tokenizer.keyWord())
self.tokenizer.advance()
self._write_line(_statement, self.tokenizer.identifier())
peek = self.tokenizer.peek()
if peek == '[':
self.tokenizer.advance()
self._write_line(_statement, self.tokenizer.symbol()) # '['
self.tokenizer.advance()
self.CompileExpression()
self.tokenizer.advance()
self._write_line(_statement, self.tokenizer.symbol()) # ']'
self.tokenizer.advance()
self._write_line(_statement, self.tokenizer.symbol()) # '='
self.tokenizer.advance()
self.CompileExpression()
self.tokenizer.advance()
self._write_line(_statement, self.tokenizer.symbol()) # ';'
self._current_node = _last_node
def CompileWhile(self):
"""
Compiles a while statement.
"""
_last_node = self._current_node
_statement = ET.SubElement(self._current_node, 'whileStatement')
self._current_node = _statement
self.tokenizer.advance()
self._write_line(_statement, self.tokenizer.keyWord()) # while
self.tokenizer.advance()
self._write_line(_statement, self.tokenizer.symbol()) # '('
self.tokenizer.advance()
self.CompileExpression()
self.tokenizer.advance()
self._write_line(_statement, self.tokenizer.symbol()) # ')'
self.tokenizer.advance()
self._write_line(_statement, self.tokenizer.symbol()) # '{'
self.CompileStatements()
self.tokenizer.advance()
self._write_line(_statement, self.tokenizer.symbol()) # '}'
self._current_node = _last_node
def CompileReturn(self):
"""
Compiles a return statement.
"""
_last_node = self._current_node
_statement = ET.SubElement(self._current_node, 'returnStatement')
self._current_node = _statement
self.tokenizer.advance()
self._write_line(_statement, self.tokenizer.keyWord()) # return
peek = self.tokenizer.peek()
if peek != ';':
self.tokenizer.advance()
self.CompileExpression()
self.tokenizer.advance()
else:
self.tokenizer.advance()
self._write_line(self._current_node, self.tokenizer.symbol()) # ';'
self._current_node = _last_node
def CompileIf(self):
"""
Compiles an if statement, possibly with a trailing else clause.
"""
_last_node = self._current_node
_statement = ET.SubElement(self._current_node, 'ifStatement')
self._current_node = _statement
self.tokenizer.advance()
self._write_line(_statement, self.tokenizer.keyWord()) # if
self.tokenizer.advance()
self._write_line(_statement, self.tokenizer.symbol()) # '('
self.tokenizer.advance()
self.CompileExpression()
self.tokenizer.advance()
self._write_line(_statement, self.tokenizer.symbol()) # ')'
self.tokenizer.advance()
self._write_line(_statement, self.tokenizer.symbol()) # '{'
self.CompileStatements()
self.tokenizer.advance()
self._write_line(_statement, self.tokenizer.symbol()) # '}'
peek = self.tokenizer.peek()
if peek == 'else':
self.tokenizer.advance()
self._write_line(_statement, self.tokenizer.keyWord()) # else
self.tokenizer.advance()
self._write_line(_statement, self.tokenizer.symbol()) # '{'
self.CompileStatements()
self.tokenizer.advance()
self._write_line(_statement, self.tokenizer.symbol()) # '}'
self._current_node = _last_node
def CompileExpression(self):
"""
Compiles an expression.
"""
_last_node = self._current_node
self._current_node = ET.SubElement(self._current_node, 'expression')
self.CompileTerm()
peek = self.tokenizer.peek()
while peek in OPS:
self.tokenizer.advance()
self._write_line(self._current_node, self.tokenizer.symbol())
self.tokenizer.advance()
self.CompileTerm()
peek = self.tokenizer.peek()
self._current_node = _last_node
def CompileTerm(self):
"""
Compiles a term. This routine is faced with a slight difficulty when trying to decide between some of the
alternative parsing rules. Specifically, if the current token is an identifier, the routine must distinguish
between a variable, an array entry, and a subroutine call. A single look-ahead token, which may be one
of [, (, or . suffices to distinguish between the three possibilities. Any other token is not
part of this term and should not be advanced over.
"""
term_branch = ET.SubElement(self._current_node, 'term')
# self.tokenizer.advance()
if self.tokenizer.tokenType(
) == 'INT_CONST' or self.tokenizer.tokenType() == 'KEYWORD':
self._write_line(term_branch, self.tokenizer.current_token)
elif self.tokenizer.tokenType() == 'STRING_CONST':
self._write_line(term_branch, self.tokenizer.stringVal())
elif self.tokenizer.current_token in UNARY_OP:
self._write_line(term_branch, self.tokenizer.symbol())
last_node = self._current_node
self._current_node = term_branch
self.tokenizer.advance()
self.CompileTerm()
self._current_node = last_node
elif self.tokenizer.current_token in SYMBOLS:
self._write_line(term_branch, self.tokenizer.symbol())
self.tokenizer.advance()
last_node = self._current_node
self._current_node = term_branch
self.CompileExpression()
self._current_node = last_node
self.tokenizer.advance()
self._write_line(term_branch, self.tokenizer.symbol())
else:
self._write_line(term_branch, self.tokenizer.identifier())
peek = self.tokenizer.peek()
if '[' in peek or '(' in peek:
self.tokenizer.advance()
self._write_line(term_branch, self.tokenizer.symbol())
self.tokenizer.advance()
last_node = self._current_node
self._current_node = term_branch
self.CompileExpression()
self._current_node = last_node
self.tokenizer.advance()
self._write_line(term_branch, self.tokenizer.symbol())
elif '.' in peek:
self.tokenizer.advance()
self._write_line(term_branch, self.tokenizer.symbol())
self.tokenizer.advance()
self._write_line(term_branch, self.tokenizer.identifier())
self.tokenizer.advance()
self._write_line(term_branch, self.tokenizer.symbol())
last_node = self._current_node
self._current_node = term_branch
self.CompileExpressionList()
self._current_node = last_node
self.tokenizer.advance()
self._write_line(term_branch, self.tokenizer.symbol())
def CompileExpressionList(self):
"""
Compiles a (possibly empty) comma-separated list of expressions.
"""
last_node = self._current_node
self._current_node = ET.SubElement(self._current_node,
'expressionList')
peek = self.tokenizer.peek()
while peek != ')':
self.tokenizer.advance()
if peek == ',':
self._write_line(self._current_node, self.tokenizer.symbol())
self.tokenizer.advance()
self.CompileExpression()
peek = self.tokenizer.peek()
self._current_node = last_node
class CompilationEngine:
def __init__(self, filename):
self.tokenizer = JackTokenizer(filename)
def compile(self, filename):
input_stream = initialize(filename)
compileClass()
def xml_print_el(self):
xmlprint(self.tokenizer.token_type, self.tokenizer.token)
def advanceSymbol(self, symbol):
if self.tokenizer.hasMoreTokens():
self.tokenizer.advance()
else:
raise SyntaxError('Symbol expected:' + symbol +
', found end of stream')
if self.tokenizer.symbol() != symbol:
raise SyntaxError('Symbol expected:' + symbol)
def advanceKeyword(self, keyword):
if self.tokenizer.hasMoreTokens():
self.tokenizer.advance()
else:
raise SyntaxError('Keyword expected:' + keyword +
', found end of stream')
if self.tokenizer.keyword() != keyword:
raise SyntaxError('Keyword expected:' + keyword)
def advanceTokenType(self, tokenType):
if self.tokenizer.hasMoreTokens():
self.tokenizer.advance()
else:
raise SyntaxError('Identifier expected, found end of stream')
if self.tokenizer.token_type != 'identifier':
raise SyntaxError('Identifier expected')
def advanceKeywords(self, *args):
if self.tokenizer.hasMoreTokens():
self.tokenizer.advance()
else:
raise SyntaxError('Keywords expected:' + args +
', found end of stream')
if self.tokenizer.keyword() != keyword:
raise SyntaxError('Keywords expected:' + args)
def advanceAndGetType(self):
if self.tokenizer.hasMoreTokens():
self.tokenizer.advance()
else:
raise SyntaxError('type expected, found end of stream')
if self.is_type():
return self.tokenizer.token
else:
raise SyntaxError('type expected')
def is_type(self):
return self.tokenizer.keyword() in [
'int', 'char', 'boolean'
] or self.tokenizer.token_type == 'identifier'
def advanceAndGetReturnType(self):
self.advance()
if self.is_type() or self.tokenizer.keyword() == 'void':
return self.tokenizer.token
else:
raise SyntaxError('type expected')
def advanceToClassName(self):
self.advanceTokenType('identifier')
return self.tokenizer.identifier()
def advanceToVarName(self):
self.advanceTokenType('identifier')
return self.tokenizer.identifier()
def advanceToSubroutineName(self):
self.advanceTokenType('identifier')
return self.tokenizer.identifier()
def hasClassVarDec(self):
pass
def advance(self):
if self.tokenizer.hasMoreTokens():
self.tokenizer.advance()
else:
raise SyntaxError('found end of stream!')
def compileClass(self):
# 'class' className '{' classVarDec* subroutineDec* '}'
print('<class>')
self.advanceKeyword('class')
self.xml_print_el()
# classname
self.advanceToClassName()
className = self.tokenizer.identifier()
self.xml_print_el()
# {
self.advanceSymbol('{')
self.xml_print_el()
self.advance()
# classVarDec*
while (self.tokenizer.keyword() in ['static', 'field']):
self.compileClassVarDec()
# subroutineDec*
while (self.tokenizer.keyword()
in ['constructor', 'function', 'method']):
self.compileSubroutine()
# }
self.advanceSymbol('}')
self.xml_print_el()
print('</class>')
def compileClassVarDec(self):
# ('static'|'field') type varName (',' varName)* ';'
print('<classVarDec>')
# ('static'|'field')
self.xml_print_el()
# type
type = self.advanceAndGetType()
self.xml_print_el()
# varName
varName = self.advanceToVarName()
self.xml_print_el()
# ;
self.advanceSymbol(';')
self.xml_print_el()
print('</classVarDec>')
self.advance()
def compileSubroutine(self):
print('<subroutineDec>')
kind = self.tokenizer.keyword()
self.xml_print_el()
# ( 'void' | type )
return_type = self.advanceAndGetReturnType()
self.xml_print_el()
# subroutineName
name = self.advanceToSubroutineName()
self.xml_print_el()
# (
self.advanceSymbol('(')
self.xml_print_el()
# TODO parameterList
self.compileParameterList()
# (
self.advanceSymbol(')')
self.xml_print_el()
# subroutineBody
self.compileSubroutineBody()
print('</subroutineDec>')
self.advance()
pass
def compileSubroutineBody(self):
print('<subroutineBody>')
# {
self.advanceSymbol('{')
self.xml_print_el()
# varDec*
#TODO a structure to represent the *
self.varDec()
# statementes
self.compileStatements()
# }
self.advanceSymbol('}')
self.xml_print_el()
print('</subroutineBody>')
def compileParameterList(self):
print('<parameterList>')
print('</parameterList>')
def compileVarDec(self):
pass
def compileStatements(self):
pass
def compileDo():
pass
def compileLet():
pass
def compileWhile():
pass
def compileReturn():
pass
def compileIf():
pass
def compileExpression():
pass
# if identifier: variable, array entry, subroutine call
def compileTerm():
# single lookahead token - can be [ ( or .
pass
# comma separated list of expressions
def compileExpressionList():
pass
class CompilationEngine:
"""
The compilation engine compile the jack code given in the input file
into an xml code saved in the out_file
"""
def __init__(self, in_file, out_file):
"""
A compilation engine constructor
:param in_file: the file we are currently compiling
:param out_file: the file where we save the output
"""
self.tokenizer = JackTokenizer(in_file)
self.out_file = open(out_file, 'w')
self._indent_count = 0
def compile_class(self):
"""
compiles a class according to the grammar
"""
self._write_outer_tag(CLASS_TAG)
self.tokenizer.advance()
if self.tokenizer.key_word() != CLASS_TAG:
print(COMPILE_CLASS_ERROR)
sys.exit()
self._write_token(self.tokenizer.token_type())
self._check_write_name()
self._check_write_symbol("{")
# there may be multiple variable declarations
while self._check_if_var_dec():
self.compile_class_var_dec()
# there may be multiple subroutine declarations
while self._check_subroutine_dec():
self.compile_subroutine_dec()
self._check_write_symbol("}")
self._write_outer_tag(CLASS_TAG, IS_ENDING_TAG)
def compile_class_var_dec(self):
"""
compiles the class's variables declarations
"""
self._write_outer_tag(CLASS_VAR_DEC_TAG)
# we only come in the function if the current token is correct so we
# can just write it
self._write_token(self.tokenizer.token_type())
self._check_write_type()
self._check_write_name()
while self._check_if_comma(): # there are more variables
self._check_write_symbol(",")
self._check_write_name()
self._check_write_symbol(";")
self._write_outer_tag(CLASS_VAR_DEC_TAG, IS_ENDING_TAG)
def compile_subroutine_dec(self):
"""
compiles the class's subroutine (methods and functions) declarations
"""
self._write_outer_tag(SUBROUTINE_DEC_TAG)
# we only come in the function if the current token is correct so we
# can just write it
self._write_token(self.tokenizer.token_type())
# the function is either void or has a type
if self.tokenizer.key_word() == 'void':
self._write_token(self.tokenizer.token_type())
else:
self._check_write_type()
self._check_write_name()
self._check_write_symbol("(")
self.compile_parameter_list()
self._check_write_symbol(")")
self.compile_subroutine_body()
self._write_outer_tag(SUBROUTINE_DEC_TAG, IS_ENDING_TAG)
def compile_parameter_list(self):
"""
compiles the parameter list for the subroutines
"""
self._write_outer_tag(PARAMETER_LIST_TAG)
# if curr_token is ')' it means the param list is empty
if self.tokenizer.symbol() != ')':
self._check_write_type()
self._check_write_name()
while self._check_if_comma(): # there are more params
self._check_write_symbol(",")
self._check_write_type()
self._check_write_name()
self._write_outer_tag(PARAMETER_LIST_TAG, IS_ENDING_TAG)
def compile_subroutine_body(self):
"""
compiles the body of the subroutine
"""
self._write_outer_tag(SUBROUTINE_BODY_TAG)
self._check_write_symbol("{")
# there may be multiple variable declarations at the beginning of
# the subroutine
while self.tokenizer.key_word() == 'var':
self.compile_var_dec()
self.compile_statements()
self._check_write_symbol("}")
self._write_outer_tag(SUBROUTINE_BODY_TAG, IS_ENDING_TAG)
def compile_var_dec(self):
"""
compiles the variable declarations
"""
self._write_outer_tag(VAR_DEC_TAG)
self._write_token(self.tokenizer.token_type())
self._check_write_type()
self._check_write_name()
# there may be multiple variable names in the dec
while self._check_if_comma():
self._check_write_symbol(",")
self._check_write_name()
self._check_write_symbol(";")
self._write_outer_tag(VAR_DEC_TAG, IS_ENDING_TAG)
def compile_statements(self):
"""
compiles the statements (0 or more statements)
"""
self._write_outer_tag(STATEMENTS_TAG)
while self._check_if_statement():
if self.tokenizer.key_word() == 'let':
self.compile_let()
elif self.tokenizer.key_word() == 'if':
self.compile_if()
elif self.tokenizer.key_word() == 'while':
self.compile_while()
elif self.tokenizer.key_word() == 'do':
self.compile_do()
elif self.tokenizer.key_word() == 'return':
self.compile_return()
self._write_outer_tag(STATEMENTS_TAG, IS_ENDING_TAG)
def compile_do(self):
"""
compiles the do statement
"""
self._write_outer_tag(DO_STATEMENT_TAG)
self._write_token(self.tokenizer.token_type())
self.compile_subroutine_call()
self._check_write_symbol(";")
self._write_outer_tag(DO_STATEMENT_TAG, IS_ENDING_TAG)
def compile_let(self):
"""
compiles the let statement
"""
self._write_outer_tag(LET_STATEMENT_TAG)
self._write_token(self.tokenizer.token_type())
self._check_write_name()
if self.tokenizer.symbol() == '[': # if there is an array
self._check_write_symbol("[")
self.compile_expression()
self._check_write_symbol("]")
self._check_write_symbol("=")
self.compile_expression()
self._check_write_symbol(";")
self._write_outer_tag(LET_STATEMENT_TAG, IS_ENDING_TAG)
def compile_if(self):
"""
compiles the if statements
"""
self._write_outer_tag(IF_STATEMENT_TAG)
self._write_token(self.tokenizer.token_type())
self._check_write_symbol("(")
self.compile_expression()
self._check_write_symbol(")")
self._check_write_symbol("{")
self.compile_statements()
self._check_write_symbol("}")
# there can also be an if else scenario
if self.tokenizer.key_word() == 'else':
self._write_token(self.tokenizer.token_type())
self._check_write_symbol("{")
self.compile_statements()
self._check_write_symbol("}")
self._write_outer_tag(IF_STATEMENT_TAG, IS_ENDING_TAG)
def compile_while(self):
"""
compiles the while statements
"""
self._write_outer_tag("whileStatement")
self._write_token(self.tokenizer.token_type())
self._check_write_symbol("(")
self.compile_expression()
self._check_write_symbol(")")
self._check_write_symbol("{")
self.compile_statements()
self._check_write_symbol("}")
self._write_outer_tag("whileStatement", IS_ENDING_TAG)
def compile_return(self):
"""
compiles the return statements
"""
self._write_outer_tag(RETURN_STATEMENT_TAG)
self._write_token(self.tokenizer.token_type())
# if cur token is ; we return nothing, otherwise we return something
if not self.tokenizer.symbol() == ';':
self.compile_expression()
self._check_write_symbol(";")
self._write_outer_tag(RETURN_STATEMENT_TAG, IS_ENDING_TAG)
def compile_subroutine_call(self):
"""
compiles the subroutine calls ( when we actually call a subroutine
as opposed to declaring it)
"""
self._check_write_name()
# there may be a '.' if it is a foo.bar() scenario (or Foo.bar())
if self.tokenizer.symbol() == ".":
self._check_write_symbol(".")
self._check_write_name()
self._check_write_symbol("(")
self.compile_expression_list()
self._check_write_symbol(")")
def compile_expression(self):
"""
compiles expressions which are terms and possibly operators and more
terms
"""
self._write_outer_tag(EXPRESSION_TAG)
self.compile_term()
# there may be a few operators in one expression
while self.tokenizer.symbol() in OPERATIONS:
self._write_op()
self.compile_term()
self._write_outer_tag(EXPRESSION_TAG, IS_ENDING_TAG)
def compile_term(self):
"""
compiles terms according to the grammar
"""
self._write_outer_tag(TERM_TAG)
cur_type = self.tokenizer.token_type()
# either a string/int constant
if self.tokenizer.token_type() in ["INT_CONST", "STRING_CONST"]:
self._write_token(cur_type)
# or a constant keyword (true, false, null, this)
elif self.tokenizer.key_word() in KEYWORD_CONST:
self._write_token(cur_type)
# or an expression within brown brackets
elif self.tokenizer.symbol() == '(':
self._write_token(cur_type)
self.compile_expression()
self._check_write_symbol(")")
# or a unary op and then a term
elif self.tokenizer.symbol() in UNARY_OPS:
self._write_op()
self.compile_term()
# or it is an identifier which could be:
elif self.tokenizer.identifier():
self._compile_term_identifier()
else:
print(COMPILE_TERM_ERROR)
sys.exit()
self._write_outer_tag(TERM_TAG, IS_ENDING_TAG)
def _compile_term_identifier(self):
"""
compiles terms in case of identifier token
"""
# an array
if self.tokenizer.get_next_token() == '[':
self._check_write_name()
self._check_write_symbol("[")
self.compile_expression()
self._check_write_symbol("]")
# or a subroutine call
elif self.tokenizer.get_next_token() in [".", "("]:
self.compile_subroutine_call()
else:
self._check_write_name() # or just a variable name
def compile_expression_list(self):
"""
compiles the expression lists
"""
self._write_outer_tag(EXPRESSION_LIST_TAG)
# if it is ')' then the expression list is empty
if self.tokenizer.symbol() != ')':
self.compile_expression()
while self._check_if_comma(): # while there are more expressions
self._write_token(self.tokenizer.token_type())
self.compile_expression()
self._write_outer_tag(EXPRESSION_LIST_TAG, IS_ENDING_TAG)
def _check_if_var_dec(self):
"""
check if we are currently compiling a variable declaration
:return: true iff the current token is either 'static' or 'field'
"""
return self.tokenizer.key_word() in CLASS_VAR_KEYWORDS
def _check_subroutine_dec(self):
"""
checks if we are currently compiling a subroutine declaration
:return: true iff the current token is either 'constructor' or
'function' or 'method'
"""
return self.tokenizer.key_word() in SUBROUTINE
def _check_if_comma(self):
"""
checks if current token is a comma
:return: true iff the current token is a ','
"""
return self.tokenizer.symbol() == ','
def _check_if_statement(self):
"""
checks if we are currently compiling a statement
:return: true iff the current token
is in ['let', 'if', 'while', 'do', 'return']
"""
return self.tokenizer.key_word() in STATEMENTS
def _check_write_type(self):
"""
checks if the current token is a valid type and if so, it writes it
to the output file
"""
if self.tokenizer.key_word() in TYPE_KEYWORDS:
self._write_token(self.tokenizer.token_type())
else:
self._check_write_name()
def _check_write_symbol(self, expected_symbol):
"""
checks if the current token is the expected symbol, if so it write
it to the output file
:param expected_symbol: the symbol we are validating is the current
token
:return: prints illegal statement error if it is not the expected
symbol and exits the program
"""
if self.tokenizer.symbol() != expected_symbol:
print(ILLEGAL_STATEMENT_ERROR)
sys.exit()
self._write_token(self.tokenizer.token_type())
def _check_write_name(self):
"""
checks the current token is a name (identifier), and if so, write
it to the output file
:return: prints illegal statement error if it is not a name and
exits the program
"""
if self.tokenizer.identifier():
self._write_token("IDENTIFIER")
else:
print(ILLEGAL_STATEMENT_ERROR)
sys.exit()
def _write_outer_tag(self, tag_str, end=False):
"""
writes the outer tags of the different sections we are compiling
:param tag_str: the string of the current section we are compiling
:param end: true iff it is an end tag
"""
if end: # we decrease the indent count before the closing tag
self._indent_count -= 1
self.out_file.write("\t" * self._indent_count)
self.out_file.write("</" + tag_str + ">\n")
else: # we increase the indent count after the opening tag
self.out_file.write("\t" * self._indent_count)
self.out_file.write("<" + tag_str + ">\n")
self._indent_count += 1
def _write_op(self):
"""
writes an op symbol to the out file
"""
self.out_file.write("\t" * self._indent_count)
self.out_file.write("<symbol> ")
if self.tokenizer.symbol() == '<':
self.out_file.write("<")
elif self.tokenizer.symbol() == '>':
self.out_file.write(">")
elif self.tokenizer.symbol() == '&':
self.out_file.write("&")
elif self.tokenizer.symbol() == '\"':
self.out_file.write(""")
else:
self.out_file.write(self.tokenizer.symbol())
self.out_file.write(" </symbol>\n")
self.tokenizer.advance()
def _write_token(self, cur_type):
"""
writes the current token to the output file
:param cur_type: the type of the current token
"""
self.out_file.write("\t" * self._indent_count)
self.out_file.write("<" + TOKEN_TYPE_STR[cur_type] + "> ")
self.out_file.write(str(self.tokenizer.get_token_str()))
self.out_file.write(" </" + TOKEN_TYPE_STR[cur_type] + ">\n")
self.tokenizer.advance()
class CompilationEngine:
def __init__(self, input_file, output_file):
self.tokenizer = JackTokenizer(input_file)
self.symbol_table = SymbolTable()
self.vm_writer = VMWriter(output_file)
self.current_sub_name = None
self.class_name = None
self.func_counter = 0
self.while_counter = 0
self.if_counter = 0
# starts the process
self.tokenizer.advance()
self.compile_class()
self.vm_writer.close()
def compile_class(self):
"""
compiles the class function
:return: none
"""
# advances a single step to get the class name
self.tokenizer.advance()
# set class's name
self.class_name = self.tokenizer.current_token
# moves to the symbol {
self.tokenizer.advance()
# move to the next symbol and check what it is
self.tokenizer.advance()
# compiles class variable
while KEY_WORDS.get(self.tokenizer.current_token) == STATIC or \
KEY_WORDS.get(self.tokenizer.current_token) == FIELD:
self.compile_class_var_dec()
# compiles subroutine
while KEY_WORDS.get(self.tokenizer.current_token) == CONSTRUCTOR or \
KEY_WORDS.get(self.tokenizer.current_token) == METHOD or \
KEY_WORDS.get(self.tokenizer.current_token) == FUNCTION:
self.compile_sub_routine()
# we are now at the <symbol> } <symbol> which closes the class
def compile_class_var_dec(self):
"""
compiles a var dec
:return: none
"""
var_kind = self.tokenizer.key_word()
# advances the token to the var's type
self.tokenizer.advance()
if self.tokenizer.token_type() == KEY_WORD:
var_type = self.tokenizer.key_word()
else:
var_type = self.tokenizer.identifier()
# advances the token to the var's identifier
self.tokenizer.advance()
if self.tokenizer.token_type() == KEY_WORD:
var_name = self.tokenizer.key_word()
else:
var_name = self.tokenizer.identifier()
# update symbol table
self.symbol_table.define(var_name, var_type, var_kind)
# advance to next token, and check if there are more var_names
self.tokenizer.advance()
while self.tokenizer.current_token != ";":
# token is <symbol> , <symbol>
# advance to var's identifier
self.tokenizer.advance()
var_name = self.tokenizer.current_token
# update symbol table
self.symbol_table.define(var_name, var_type, var_kind)
self.tokenizer.advance()
# the current token is <symbol> ; <symbol>, advance to next
self.tokenizer.advance()
def compile_sub_routine(self):
"""
compiles a single sub routine
:return: none
"""
# start new subroutine symbol table
self.symbol_table.start_subroutine()
# get subroutine type (method/construction/function)
sub_type = self.tokenizer.key_word()
# advances the token to what the subroutine returns
self.tokenizer.advance()
# updates the return type
if self.tokenizer.token_type() == KEY_WORD:
return_type = self.tokenizer.key_word()
else:
return_type = self.tokenizer.identifier()
# advances the token to <identifier> sub_name <identifier>
self.tokenizer.advance()
# update the subroutine name
subroutine_name = self.tokenizer.identifier()
self.current_sub_name = subroutine_name
# advance to <symbol> ( <symbol>
self.tokenizer.advance()
# if subroutine is a method, add 'this' to the symbol table as argument 0
if sub_type == METHOD:
self.symbol_table.define("this", self.class_name, "ARG")
# compiles the parameter list
self.compile_parameter_list()
# we are at <symbol> ) <symbol>
# advance to subroutine body, and compile it
self.tokenizer.advance()
self.compile_subroutine_body(sub_type)
def compile_subroutine_body(self, sub_type):
"""
the method compiles the subroutine body
:return: none
"""
# we are at bracket {, advance
self.tokenizer.advance()
# compile var dec
while KEY_WORDS.get(self.tokenizer.current_token) == VAR:
self.compile_var_dec()
# write function label
self.vm_writer.write_function(
self.class_name + '.' + self.current_sub_name,
self.symbol_table.var_count("VAR"))
# if is method, update THIS to the object
if sub_type == METHOD:
self.vm_writer.write_push(ARG, 0)
self.vm_writer.write_pop("POINTER", 0)
# if is constructor, allocate memory, and put in this
if sub_type == CONSTRUCTOR:
self.vm_writer.write_push("CONST",
self.symbol_table.var_count("FIELD"))
self.vm_writer.write_call("Memory.alloc", 1)
self.vm_writer.write_pop("POINTER", 0)
if self.tokenizer.current_token != "}":
self.compile_statements()
# we are at bracket }, advance
self.tokenizer.advance()
def compile_parameter_list(self):
"""
compiles a parameter list
:return: none
"""
# advance to first parameter
self.tokenizer.advance()
# while there are more parameters
while self.tokenizer.current_token != ')':
# tests what to put as the type of the object
if self.tokenizer.token_type() == KEY_WORD:
var_type = self.tokenizer.key_word()
else:
var_type = self.tokenizer.identifier()
# advance to variables name <identifier> var_name <identifier>
self.tokenizer.advance()
var_name = self.tokenizer.identifier()
# define new variable
self.symbol_table.define(var_name, var_type, "ARG")
# gets the next token
self.tokenizer.advance()
# advance to next token if we are at ','
if self.tokenizer.current_token == ",":
self.tokenizer.advance()
def compile_var_dec(self):
"""
compiles a declaration of a variable
:return: none
"""
# we are at <keyword> var <keyword>
# advance to variable type
self.tokenizer.advance()
if self.tokenizer.token_type() == KEY_WORD:
var_type = self.tokenizer.key_word()
else:
var_type = self.tokenizer.identifier()
# advance to the variables name
self.tokenizer.advance()
while self.tokenizer.current_token != ';':
# we are at <identifier> var_name <identifier>
var_name = self.tokenizer.identifier()
# define variable in symbol table
self.symbol_table.define(var_name, var_type, "VAR")
# advance to next token
self.tokenizer.advance()
# tests what to put as the type of the object
if self.tokenizer.current_token == ",":
self.tokenizer.advance()
# we are at <symbol> ; <symbol>
# advance to next token
self.tokenizer.advance()
def compile_statements(self):
"""
the method compiles statements
:return: none
"""
# while there are more statements, deal with each one
while self.tokenizer.current_token != '}':
statement_type = self.tokenizer.key_word()
if statement_type == LET:
self.compile_let()
elif statement_type == IF:
self.compile_if()
elif statement_type == WHILE:
self.compile_while()
elif statement_type == DO:
self.compile_do()
elif statement_type == RETURN:
self.compile_return()
def compile_do(self):
"""
the method compiles a do command
:return: none
"""
# we are at <keyword> do <keyword>
# advance to next token <identifier> name_of_func <identifier>
self.tokenizer.advance()
func_name = self.tokenizer.identifier()
self.tokenizer.advance()
# compile the subroutine call
self.compile_subroutine_call(func_name)
# pop the result from the function into temp
self.vm_writer.write_pop("TEMP", 0)
# we are at <symbol> ; <symbol>, advance to next token
self.tokenizer.advance()
def compile_let(self):
"""
the method compiles a let statement
:return: none
"""
# we are at <keyword> let <keyword>
# advance to next token (var_name)
self.tokenizer.advance()
# we are at <identifier> var_name <identifier>
var_name = self.tokenizer.identifier()
# get variable data
var_index = self.symbol_table.index_of(var_name)
var_kind = TYPE_DICT.get(self.symbol_table.kind_of(var_name))
# advance to next token ('[' | '=')
self.tokenizer.advance()
is_array = False
if self.tokenizer.current_token == '[':
is_array = True
# push arr
self.vm_writer.write_push(var_kind, var_index)
# advance to expression and compile it
self.tokenizer.advance()
self.compile_expression()
# we are at <symbol> ] <symbol>, advance to next token
self.tokenizer.advance()
# add the index of array and the expression to get the correct location
self.vm_writer.write_arithmetic("ADD")
# we are at <symbol> = <symbol>
# advance to expression and compile it
self.tokenizer.advance()
self.compile_expression()
# if var is an array
if is_array:
self.vm_writer.write_pop("TEMP", 0)
self.vm_writer.write_pop("POINTER", 1)
self.vm_writer.write_push("TEMP", 0)
self.vm_writer.write_pop("THAT", 0)
# if var is not an array
else:
self.vm_writer.write_pop(var_kind, var_index)
# we are at <symbol> ; <symbol>, advance to next
self.tokenizer.advance()
return
def compile_while(self):
"""
the method compiles a while statement
:return: none
"""
while_counter = str(self.while_counter)
# update the while counter
self.while_counter += 1
# create new label for the start of the while
self.vm_writer.write_label("While_" + while_counter)
# we are at <keyword> while <keyword>, advance to next token
self.tokenizer.advance()
# we are at <symbol> ( <symbol>, advance to next token
self.tokenizer.advance()
self.compile_expression()
# we are at <symbol> ) <symbol>, advance to next token
self.tokenizer.advance()
# negate expression
self.vm_writer.write_arithmetic("NOT")
# if condition is not met, go to the end of the while
self.vm_writer.write_if("End_While_" + while_counter)
# we are at <symbol> { <symbol>, advance to next token
self.tokenizer.advance()
# compile statements
self.compile_statements()
# go back to the start of the while
self.vm_writer.write_goto("While_" + while_counter)
# create new label for the end of the while
self.vm_writer.write_label("End_While_" + while_counter)
# we are at <symbol> } <symbol>, advance to next token
self.tokenizer.advance()
return
def compile_return(self):
"""
the method compiles a return statement
:return: none
"""
# we are at <keyword> return <keyword>, advance to next token
self.tokenizer.advance()
if self.tokenizer.current_token != ';':
self.compile_expression()
else:
# if function is void, push const 0 to the stack
self.vm_writer.write_push("CONST", 0)
# we are at <symbol> ; <symbol>, advance to next token
self.tokenizer.advance()
self.vm_writer.write_return()
return
def compile_if(self):
"""
the method compiles an if statement
:return: none
"""
if_count = str(self.if_counter)
# update if counter
self.if_counter += 1
# we are at <keyword> if <keyword>, advance to next token
self.tokenizer.advance()
# we are at <symbol> ( <symbol>, advance to next token
self.tokenizer.advance()
# compile expression
self.compile_expression()
# negate the expression
self.vm_writer.write_arithmetic("NOT")
# check if condition is met
self.vm_writer.write_if("ELSE_" + if_count)
# we are at <symbol> ) <symbol>, advance to next token
self.tokenizer.advance()
# we are at <symbol> { <symbol>, advance to next token
self.tokenizer.advance()
self.compile_statements()
# jump to the end of the if
self.vm_writer.write_goto("END_IF_" + if_count)
# we are at <symbol> } <symbol>, advance to next token
self.tokenizer.advance()
# create else label (which may be empty)
self.vm_writer.write_label("ELSE_" + if_count)
if self.tokenizer.current_token == 'else':
# we are at <keyword> else <keyword>, advance
self.tokenizer.advance()
# we are at <symbol> { <symbol>, advance
self.tokenizer.advance()
self.compile_statements()
# we are at <symbol> } <symbol>, advance
self.tokenizer.advance()
# create new label
self.vm_writer.write_label("END_IF_" + if_count)
return
def compile_expression(self):
"""
the method compiles an expression
:return:
"""
# compile the term
self.compile_term()
while self.tokenizer.current_token in OP_LST:
call_math = False
# we are at <symbol> op <symbol>
op = OP_DICT.get(self.tokenizer.current_token)
# check if operator needs to call math
if self.tokenizer.current_token == '*' or self.tokenizer.current_token == '/':
call_math = True
# advance to next term and compile term
self.tokenizer.advance()
self.compile_term()
# output the operator
if call_math:
self.vm_writer.write_call(op[0], op[1])
else:
self.vm_writer.write_arithmetic(op)
return
def compile_term(self):
"""
the method compiles a term
:return: none
"""
token_type = self.tokenizer.token_type()
if token_type == INT_CONST:
# push the const int
self.vm_writer.write_push("CONST", self.tokenizer.int_val())
self.tokenizer.advance()
elif token_type == STRING_CONST:
# write without the ""
string_val = self.tokenizer.string_val()
# push the len of the string and call the string constructor
self.vm_writer.write_push("CONST", len(string_val))
self.vm_writer.write_call("String.new", 1)
# update new string
for char in string_val:
self.vm_writer.write_push("CONST", ord(char))
self.vm_writer.write_call("String.appendChar", 2)
self.tokenizer.advance()
elif self.tokenizer.current_token in KEY_WORD_CONST:
segment, idx = KEY_WORD_CONST.get(self.tokenizer.current_token)
self.vm_writer.write_push(segment, idx)
if self.tokenizer.current_token == 'true':
self.vm_writer.write_arithmetic('NOT')
self.tokenizer.advance()
elif self.tokenizer.current_token == '(':
# we are at <symbol> ( <symbol>, advance to next token
self.tokenizer.advance()
self.compile_expression()
# we are at <symbol> ) <symbol>, advance to next token
self.tokenizer.advance()
elif self.tokenizer.current_token in UNARY_OP:
op_command = UNARY_OP.get(self.tokenizer.current_token)
self.tokenizer.advance()
self.compile_term()
self.vm_writer.write_arithmetic(op_command)
# var/var[expression]/subroutine_call
else:
# we are at <identifier> var_name <identifier>
var_name = self.tokenizer.identifier()
self.tokenizer.advance()
# if is var_name[expression]
if self.tokenizer.current_token == '[':
var_kind = TYPE_DICT.get(self.symbol_table.kind_of(var_name))
var_index = self.symbol_table.index_of(var_name)
# push arr
self.vm_writer.write_push(var_kind, var_index)
# we are at <symbol> [ <symbol>, advance to expression and compile it
self.tokenizer.advance()
self.compile_expression()
# add the index of array and the expression to get the correct location
self.vm_writer.write_arithmetic("ADD")
# set the that pointer
self.vm_writer.write_pop("POINTER", 1)
# push to the stack what is in the arr[i]
self.vm_writer.write_push("THAT", 0)
# we are at <symbol> ] <symbol>, advance
self.tokenizer.advance()
# if is a subroutine call
elif self.tokenizer.current_token == '(' or self.tokenizer.current_token == '.':
self.compile_subroutine_call(var_name)
else:
# if is just 'var'
var_kind = TYPE_DICT.get(self.symbol_table.kind_of(var_name))
var_index = self.symbol_table.index_of(var_name)
self.vm_writer.write_push(var_kind, var_index)
return
def compile_expression_list(self):
"""
the method compiles a list of expressions
:return: amount of arguments in the expression list
"""
expression_counter = 0
# check that list is not empty
if self.tokenizer.current_token != ')':
expression_counter += 1
# compile first expression
self.compile_expression()
# if there are more expressions, compile them
while self.tokenizer.current_token == ',':
expression_counter += 1
# we are at <symbol> , <symbol>, advance
self.tokenizer.advance()
# compile expression
self.compile_expression()
return expression_counter
def compile_subroutine_call(self, identifier):
"""
the method compiles a subroutine call (not including the subroutine
first varName
:return: none
"""
func_name = self.class_name + "." + identifier
num_of_arguments = 0
if self.tokenizer.current_token == '.':
# change func name to its class name
if self.symbol_table.type_of(identifier) is not None:
func_name = self.symbol_table.type_of(identifier)
# we are at <symbol> . <symbol>, advance
self.tokenizer.advance()
# we are at <identifier> sub_name <identifier>
func_name = func_name + "." + self.tokenizer.identifier()
self.tokenizer.advance()
# push the object to the stack
segment = TYPE_DICT.get(self.symbol_table.kind_of(identifier))
idx = self.symbol_table.index_of(identifier)
self.vm_writer.write_push(segment, idx)
num_of_arguments += 1
else:
# we are at <symbol> . <symbol>, advance
self.tokenizer.advance()
# we are at <identifier> sub_name <identifier>
func_name = identifier + "." + self.tokenizer.identifier()
self.tokenizer.advance()
else:
self.vm_writer.write_push("POINTER", 0)
num_of_arguments += 1
# we are at <symbol> ( <symbol>, advance
self.tokenizer.advance()
num_of_arguments += self.compile_expression_list()
# we are at <symbol> ) <symbol>, advance
self.tokenizer.advance()
self.vm_writer.write_call(func_name, num_of_arguments)
return
class CompilationEngine:
def __init__(self, input_path, output_path):
"""
creates a new compilation engine with the given input and output. the next routine called must be compileClass()
:param input_path: input stream/file
:param output_path: output stream/file
"""
self.labels = 0
self.jack_class = None
self.class_subroutine = None
self.tokenizer = JackTokenizer(input_path)
self._writer = VMWriter(output_path)
self.CompileClass()
def CompileClass(self):
"""
Compiles a complete class.
"""
self.tokenizer.advance()
self.tokenizer.advance()
self.jack_class = JackClass(self.tokenizer.current_token)
self.tokenizer.advance()
self.CompileClassVarDec()
self.CompileSubroutine()
self.tokenizer.advance()
def CompileClassVarDec(self):
"""
Compiles a static declaration or a field declaration.
"""
peek = self.tokenizer.peek()
while 'static' in peek or 'field' in peek:
self.tokenizer.advance()
kind = self.tokenizer.keyWord() # field/static
self.tokenizer.advance()
type = self.tokenizer.keyWord() # type
self.tokenizer.advance()
name = self.tokenizer.identifier() # name
self.tokenizer.advance()
self.jack_class.add_var(name, type, kind)
while self.tokenizer.symbol() == ',':
self.tokenizer.advance()
name = self.tokenizer.identifier()
self.tokenizer.advance()
self.jack_class.add_var(name, type, kind)
peek = self.tokenizer.peek()
def CompileSubroutine(self):
"""
Compiles a complete method, function, or constructor.
"""
peek = self.tokenizer.peek()
while 'function' in peek or 'constructor' in peek or 'method' in peek:
self.tokenizer.advance()
kind = self.tokenizer.keyWord() # const/func/method
self.tokenizer.advance()
type = self.tokenizer.current_token # void/type
self.tokenizer.advance()
name = self.tokenizer.identifier() # name
self.tokenizer.advance()
self.class_subroutine = JackSubroutine(name, kind, type,
self.jack_class)
self.CompileParameterList()
self.tokenizer.advance()
self.tokenizer.advance()
peek = self.tokenizer.peek()
if 'var' in peek:
self.CompileVarDec()
full_name = '{}.{}'.format(self.jack_class.class_name,
self.class_subroutine.name)
self._writer.write_function(full_name, self.class_subroutine.var_c)
if kind == 'constructor':
fields = self.jack_class.counters[0]
self._writer.push('constant', str(fields))
self._writer.write_call('Memory.alloc', '1')
self._writer.pop('pointer', '0')
elif kind == 'method':
self._writer.push('argument', '0')
self._writer.pop('pointer', '0')
self.CompileStatements()
self.tokenizer.advance()
peek = self.tokenizer.peek()
def CompileParameterList(self):
"""
Compiles a (possibly empty) parameter list, not including the enclosing ()
"""
peek = self.tokenizer.peek()
if peek != ')':
self.tokenizer.advance()
type = self.tokenizer.keyWord() # type
self.tokenizer.advance()
name = self.tokenizer.identifier() # name
peek = self.tokenizer.peek()
self.class_subroutine.add_arg(name, type)
while peek == ',':
self.tokenizer.advance()
self.tokenizer.advance()
type = self.tokenizer.keyWord() # type
self.tokenizer.advance()
name = self.tokenizer.identifier() # name
self.class_subroutine.add_arg(name, type)
peek = self.tokenizer.peek()
def CompileVarDec(self):
"""
Compiles a var declaration.
"""
peek = self.tokenizer.peek()
while 'var' in peek:
self.tokenizer.advance()
self.tokenizer.advance()
type = self.tokenizer.keyWord()
self.tokenizer.advance()
name = self.tokenizer.identifier()
self.class_subroutine.add_var(name, type)
self.tokenizer.advance()
while self.tokenizer.symbol() == ',':
self.tokenizer.advance()
name = self.tokenizer.identifier() # name
self.class_subroutine.add_var(name, type)
self.tokenizer.advance()
peek = self.tokenizer.peek()
def CompileStatements(self):
"""
Compiles a sequence of statements, not including the enclosing "{}"
"""
peek = self.tokenizer.peek()
while 'let' in peek or 'if' in peek or 'while' in peek or 'do' in peek or 'return' in peek:
if 'let' in peek:
self.CompileLet()
elif 'if' in peek:
self.CompileIf()
elif 'while' in peek:
self.CompileWhile()
elif 'do' in peek:
self.CompileDo()
elif 'return' in peek:
self.CompileReturn()
peek = self.tokenizer.peek()
def CompileDo(self):
"""
Compiles a do statement.
"""
self.tokenizer.advance() # do
self.tokenizer.advance() # do
self.CompileTerm()
self._writer.pop('temp', '0')
self.tokenizer.advance() # ;
if self.tokenizer.current_token != ';':
self.tokenizer.advance()
def CompileLet(self):
"""
Compiles a let statement.
"""
self.tokenizer.advance() # let
self.tokenizer.advance()
name = self.tokenizer.identifier()
symbol = self.class_subroutine.get_symbol(name)
peek = self.tokenizer.peek()
if peek == '[':
self.tokenizer.advance() # [
self.tokenizer.advance()
self.CompileExpression()
self.tokenizer.advance() # ]
self.tokenizer.advance() # =
self._writer.push(symbol)
self._writer.write_cmd('add')
self.tokenizer.advance()
self.CompileExpression()
self._writer.pop('temp', '0')
self._writer.pop('pointer', '1')
self._writer.push('temp', '0')
self._writer.pop('that', '0')
else:
self.tokenizer.advance() # =
self.tokenizer.advance()
self.CompileExpression()
self._writer.pop(symbol)
self.tokenizer.advance() # ;
def CompileWhile(self):
"""
Compiles a while statement.
"""
label_c = self.labels
self.tokenizer.advance() # while
self.tokenizer.advance() # (
self.tokenizer.advance()
self._writer.write_label(LABEL_FORMAT.format('WHILE_EXP', label_c))
self.CompileExpression()
self.tokenizer.advance() # )
self.tokenizer.advance() # {
self._writer.write_if(LABEL_FORMAT.format('WHILE_END', label_c))
self.CompileStatements()
self._writer.write_goto(LABEL_FORMAT.format('WHILE_END', label_c))
self._writer.write_label(LABEL_FORMAT.format('WHILE_EXP', label_c))
self.tokenizer.advance() # }
def CompileReturn(self):
"""
Compiles a return statement.
"""
self.tokenizer.advance() # return
peek = self.tokenizer.peek()
if peek != ';':
self.tokenizer.advance()
self.CompileExpression()
self.tokenizer.advance()
else:
self._writer.push('constant', '0')
self.tokenizer.advance()
self._writer.write_return()
def CompileIf(self):
"""
Compiles an if statement, possibly with a trailing else clause.
"""
label_c = self.labels
self.tokenizer.advance() # if
self.tokenizer.advance()
self.tokenizer.advance() # (
self.CompileExpression()
self.tokenizer.advance() # )
self.tokenizer.advance() # {
self._writer.write_if(LABEL_FORMAT.format('IF_TRUE', label_c))
self._writer.write_goto(LABEL_FORMAT.format('IF_FALSE', label_c))
self._writer.write_label(LABEL_FORMAT.format('IF_TRUE', label_c))
self.labels += 1
self.CompileStatements()
self.tokenizer.advance() # }
peek = self.tokenizer.peek()
if peek == 'else':
self._writer.write_goto(LABEL_FORMAT.format('IF_END', label_c))
self._writer.write_label(LABEL_FORMAT.format('IF_FALSE', label_c))
self.tokenizer.advance() # else
self.tokenizer.advance() # {
self.CompileStatements()
self.tokenizer.advance() # }
self._writer.write_label(LABEL_FORMAT.format('IF_END', label_c))
else:
self._writer.write_label(LABEL_FORMAT.format('IF_FALSE', label_c))
def CompileExpression(self):
"""
Compiles an expression.
"""
self.CompileTerm()
peek = self.tokenizer.peek()
while peek in OPS:
self.tokenizer.advance()
op = self.tokenizer.symbol()
self.tokenizer.advance()
self.CompileTerm()
self._writer.write_cmd(OP_DIC[op])
peek = self.tokenizer.peek()
def CompileTerm(self):
"""
Compiles a term. This routine is faced with a slight difficulty when trying to decide between some of the
alternative parsing rules. Specifically, if the current token is an identifier, the routine must distinguish
between a variable, an array entry, and a subroutine call. A single look-ahead token, which may be one
of [, (, or . suffices to distinguish between the three possibilities. Any other token is not
part of this term and should not be advanced over.
"""
if self.tokenizer.current_token in UNARY_OP:
self._writer.write_cmd(UNARY_DIC[self.tokenizer.current_token])
self.tokenizer.advance()
self.CompileTerm()
elif self.tokenizer.current_token == '(':
self.tokenizer.advance()
self.CompileExpression()
self.tokenizer.advance() # )
elif self.tokenizer.tokenType() == 'INT_CONST':
self._writer.push('constant', self.tokenizer.current_token)
elif self.tokenizer.tokenType() == 'STRING_CONST':
str = self.tokenizer.stringVal()
self._writer.push('constant', len(str))
self._writer.write_call('String.new', '1')
for char in str:
self._writer.push('constant', ord(char))
self._writer.write_call('String.appendChar', '2')
elif self.tokenizer.tokenType() == 'KEYWORD':
if self.tokenizer.current_token == 'this':
self._writer.push('pointer', '0')
else:
self._writer.push('constant', '0')
if self.tokenizer.current_token == 'true':
self._writer.write('not')
elif self.tokenizer.tokenType() == 'IDENTIFIER':
value = self.tokenizer.identifier()
var = self.class_subroutine.get_symbol(value)
peek = self.tokenizer.peek()
if peek == '[':
self.tokenizer.advance()
self.tokenizer.advance() # [
self.CompileExpression()
self._writer.push(var)
self._writer.write_cmd('add')
self._writer.pop('pointer', '1')
self._writer.push('that', '0')
self.tokenizer.advance() # ]
else:
function_name = value
functions_class = self.class_subroutine.jack_class
is_default = True
args = 0
if peek == '.':
is_default = False
self.tokenizer.advance()
self.tokenizer.advance()
function_object = self.class_subroutine.get_symbol(
function_name)
function_name = self.tokenizer.current_token
if function_object:
functions_class = var.type
args = 1
self._writer.push(var)
else:
functions_class = value
peek = self.tokenizer.peek()
if peek == '(':
if is_default:
args = 1
self._writer.push('pointer', '0')
self.tokenizer.advance() # (
args += self.CompileExpressionList()
if type(functions_class) != type(''):
functions_class = functions_class.class_name
full_name = '{}.{}'.format(functions_class, function_name)
self._writer.write_call(full_name, args)
if self.tokenizer.current_token != ')':
self.tokenizer.advance() # ')'
elif var:
self._writer.push(var)
def CompileExpressionList(self):
"""
Compiles a (possibly empty) comma-separated list of expressions.
"""
expressions_counter = 0
peek = self.tokenizer.peek()
while peek != ')' and peek != ';':
self.tokenizer.advance()
expressions_counter += 1
if self.tokenizer.current_token == ',':
self.tokenizer.advance()
self.CompileExpression()
peek = self.tokenizer.peek()
return expressions_counter
class CompilationEngine:
"""
The compilation engine compile the jack code given in the input file
into an xml code saved in the out_file
"""
def __init__(self, in_file, out_file):
"""
A compilation engine constructor
:param in_file: the file we are currently compiling
:param out_file: the file where we save the output
"""
self._tokenizer = JackTokenizer(in_file)
self._class_table = SymbolTable()
self._method_table = SymbolTable()
self._cur_class_name = ""
self._vm_writer = VMWriter(out_file)
self._label_count_while = 0
self._label_count_if = 0
def compile_class(self):
"""
compiles a class according to the grammar
"""
self._class_table.start_subroutine()
self._tokenizer.advance()
# check if the current keyword is the right class tag
if self._tokenizer.key_word() != CLASS_TAG:
print(COMPILE_CLASS_ERROR)
sys.exit()
self._tokenizer.advance()
self._cur_class_name = self.get_cur_token()
self._tokenizer.advance()
self._check_symbol("{")
# there may be multiple variable declarations
while self._check_if_var_dec():
self.compile_class_var_dec()
# there may be multiple subroutine declarations
while self._check_subroutine_dec():
self.compile_subroutine_dec()
self._check_symbol("}")
def compile_class_var_dec(self):
"""
compiles the class's variables declarations
"""
cur_kind = self.get_cur_token()
self._tokenizer.advance()
cur_type = self.get_cur_token()
self._check_type()
cur_name = self.get_cur_token()
self._check_name()
self._class_table.define(cur_name, cur_type, cur_kind)
while self._check_if_comma(): # there are more variables
self._tokenizer.advance()
cur_name = self.get_cur_token()
self._check_name()
self._class_table.define(cur_name, cur_type, cur_kind)
self._check_symbol(";")
def get_cur_token(self):
return self._tokenizer.get_token_str()
def compile_subroutine_dec(self):
"""
compiles the class's subroutine (methods and functions) declarations
"""
# re-initialize the method symbol table
self._method_table.start_subroutine()
key_word = self._tokenizer.key_word()
self._tokenizer.advance()
self._tokenizer.advance()
cur_name = self.get_cur_token()
self._tokenizer.advance()
# method get the as argument the base address of the current object
if key_word == "method":
self._method_table.define("this", self._cur_class_name, "argument")
self._check_symbol("(")
self.compile_parameter_list()
self._check_symbol(")")
subroutine_path = self._cur_class_name + '.' + cur_name
# the function is either void or has a type
self.compile_subroutine_body(subroutine_path, key_word)
def compile_parameter_list(self):
"""
compiles the parameter list for the subroutines
"""
# if curr_token is ')' it means the param list is empty
if self._tokenizer.symbol() == ')':
return
cur_type = self.get_cur_token()
self._check_type()
cur_name = self.get_cur_token()
self._check_name()
self._method_table.define(cur_name, cur_type, "argument")
while self._check_if_comma(): # there are more params
self._tokenizer.advance()
cur_type = self.get_cur_token()
self._check_type()
cur_name = self.get_cur_token()
self._check_name()
self._method_table.define(cur_name, cur_type, "argument")
def compile_subroutine_body(self, subroutine_name, subroutine_kind):
"""
compiles the body of the subroutine
"""
self._check_symbol("{")
# there may be multiple variable declarations at the beginning of
# the subroutine
while self._tokenizer.key_word() == 'var':
self.compile_var_dec()
# define the subroutine
n_locals = self._method_table.var_count("local")
self._vm_writer.write_function(subroutine_name, n_locals)
if subroutine_kind == "constructor":
# allocating memory for the object's fields
num_of_fields = self._class_table.var_count("field")
self._vm_writer.write_push("constant", num_of_fields)
self._vm_writer.write_call("Memory.alloc", 1)
# make 'this' to point to address returned by Memory.alloc
self._vm_writer.write_pop("pointer", 0)
if subroutine_kind == "method":
# assign pointer[0] to the object's base address in order to
# get access to 'this' segment
self._vm_writer.write_push("argument", 0)
self._vm_writer.write_pop("pointer", 0)
self.compile_statements()
self._check_symbol("}")
def compile_var_dec(self):
"""
compiles the variable declarations
"""
self._tokenizer.advance()
cur_type = self.get_cur_token()
self._check_type()
cur_name = self.get_cur_token()
self._check_name()
self._method_table.define(cur_name, cur_type, "local")
# there may be multiple variable names in the dec
while self._check_if_comma():
self._tokenizer.advance()
self._method_table.define(self.get_cur_token(), cur_type, "local")
self._check_name()
self._check_symbol(";")
def compile_statements(self):
"""
compiles the statements (0 or more statements)
"""
while self._check_if_statement():
if self._tokenizer.key_word() == 'let':
self.compile_let()
elif self._tokenizer.key_word() == 'if':
self.compile_if()
elif self._tokenizer.key_word() == 'while':
self.compile_while()
elif self._tokenizer.key_word() == 'do':
self.compile_do()
elif self._tokenizer.key_word() == 'return':
self.compile_return()
def compile_do(self):
"""
compiles the do statement
"""
self._tokenizer.advance()
self.compile_subroutine_call()
self._check_symbol(";")
self._vm_writer.write_pop("temp", 0)
def compile_let(self):
"""
compiles the let statement
"""
self._tokenizer.advance()
name = self.get_cur_token()
info = self._get_symbol_info(name)
self._check_if_declared(info)
s_type, s_kind, s_id = info
seg = self._get_segment(s_kind)
is_and_array = False
if self._tokenizer.get_next_token() == '[': # if there is an array
is_and_array = True
self.compile_term()
else:
self._tokenizer.advance()
self._check_symbol("=")
self.compile_expression()
if is_and_array:
# save the value created after compiling the expression which
# appears right after '=' in temp[0]
self._vm_writer.write_pop("temp", 0)
# now the top of the stack should be the address of the right cell
# in the array so we assign it to pointer[1]
self._vm_writer.write_pop("pointer", 1)
# re-pushing the value we saved in temp[0]
self._vm_writer.write_push("temp", 0)
# the value of the array is located in that[0]
seg = "that"
s_id = 0
# execute the assignment
self._vm_writer.write_pop(seg, s_id)
self._check_symbol(";")
@staticmethod
def _check_if_declared(info):
if info is None:
print("Unknown Symbol")
sys.exit()
def compile_if(self):
"""
compiles the if statements
"""
false_label = self._get_if_label()
end_label = self._get_if_label()
self._tokenizer.advance()
self._check_symbol("(")
self.compile_expression()
self._check_symbol(")")
self._check_symbol("{")
self._vm_writer.write_arithmetic("not")
self._vm_writer.write_if_goto(false_label)
self.compile_statements()
self._check_symbol("}")
# there can also be an if else scenario
self._vm_writer.write_goto(end_label)
self._vm_writer.write_label(false_label)
if self._tokenizer.key_word() == 'else':
self._tokenizer.advance()
self._check_symbol("{")
self.compile_statements()
self._check_symbol("}")
self._vm_writer.write_label(end_label)
def compile_while(self):
"""
compiles the while statements
"""
self._tokenizer.advance()
first_label = self._get_while_label()
second_label = self._get_while_label(END_WHILE)
self._check_symbol("(")
self._vm_writer.write_label(first_label)
self.compile_expression()
self._vm_writer.write_arithmetic("not")
self._vm_writer.write_if_goto(second_label)
self._check_symbol(")")
self._check_symbol("{")
self.compile_statements()
self._vm_writer.write_goto(first_label)
self._vm_writer.write_label(second_label)
self._check_symbol("}")
def compile_return(self):
"""
compiles the return statements
"""
self._tokenizer.advance()
# if cur token is ; we return nothing, otherwise we return something
if not self._tokenizer.symbol() == ';':
self.compile_expression()
else:
self._vm_writer.write_push("constant", 0)
self._check_symbol(";")
self._vm_writer.write_return()
def compile_subroutine_call(self):
"""
compiles the subroutine calls ( when we actually call a subroutine
as opposed to declaring it)
"""
method_name = self.get_cur_token()
self._check_name()
num_of_args = 0
# there may be a '.' if it is a foo.bar() scenario (or Foo.bar())
if self._tokenizer.symbol() == ".":
self._tokenizer.advance()
class_name = method_name
method_name = self.get_cur_token()
self._check_name()
symbol_info = self._get_symbol_info(class_name)
if symbol_info is None:
cur_name = class_name + '.' + method_name
else:
type_of, kind_of, id_of = symbol_info
num_of_args += 1
self._vm_writer.write_push(self._get_segment(kind_of), id_of)
cur_name = type_of + '.' + method_name
else:
cur_name = self._cur_class_name + '.' + method_name
num_of_args += 1
self._vm_writer.write_push("pointer", 0)
self._check_symbol("(")
num_of_args += self.compile_expression_list()
self._check_symbol(")")
self._vm_writer.write_call(cur_name, num_of_args)
def compile_expression(self):
"""
compiles expressions which are terms and possibly operators and more
terms
"""
symbol = self._tokenizer.symbol()
self.compile_term()
# write the 'not' operator if necessary
if symbol == '~':
self._vm_writer.write_arithmetic("not")
# there may be a few operators in one expression
while self._tokenizer.symbol() in OPERATIONS:
symbol = self._tokenizer.symbol()
self.compile_term()
# executing operators after handling the the operands
# in order to evaluate the current expression as postfix expression
op = self._get_op(symbol)
self._vm_writer.write_arithmetic(op)
def compile_term(self):
"""
compiles terms according to the grammar
"""
cur_type = self._tokenizer.token_type()
key_word = self._tokenizer.key_word()
cur_token = self.get_cur_token()
# either a string/int constant
if cur_type in ["INT_CONST", "STRING_CONST"]:
self._compile_string_int_term(cur_token, cur_type)
# or a constant keyword (true, false, null, this)
elif key_word in KEYWORD_CONST:
self._compile_const_keyword_term(key_word)
# or an expression within brown brackets
elif self._tokenizer.symbol() == '(':
self._tokenizer.advance()
self.compile_expression()
self._check_symbol(")")
# or a unary op and then a term
elif self._tokenizer.symbol() in OPERATIONS:
self._tokenizer.advance()
self.compile_term()
# or it is an identifier which could be:
elif self._tokenizer.identifier():
self._compile_term_identifier()
else:
print(COMPILE_TERM_ERROR)
sys.exit()
def _compile_const_keyword_term(self, key_word):
"""
compile term in case the current token type is constant keyword
:param key_word: string from {'true', 'false', 'null', 'this'}
"""
if key_word == "this":
self._vm_writer.write_push("pointer", 0)
else:
self._vm_writer.write_push("constant", 0)
if key_word == "true":
self._vm_writer.write_arithmetic("not")
self._tokenizer.advance()
def _compile_string_int_term(self, cur_token, cur_type):
"""
compile term in case the given token type is constant string
or constant integer
:param cur_token: the current token as a string
:param cur_type: the type of the current token
"""
if cur_type == "INT_CONST":
self._vm_writer.write_push("constant", cur_token)
else: # is string
n = len(cur_token)
self._vm_writer.write_push("constant", n)
self._vm_writer.write_call("String.new", 1)
for c in cur_token:
self._vm_writer.write_push("constant", ord(c))
self._vm_writer.write_call("String.appendChar", 2)
self._tokenizer.advance()
def _compile_term_identifier(self):
"""
compiles terms in case of identifier token
"""
cur_token = self.get_cur_token()
info = self._get_symbol_info(cur_token)
next_token = self._tokenizer.get_next_token()
if info is not None and next_token not in [".", "("]:
type_of, kind_of, id_of = info
seg = self._get_segment(kind_of)
self._vm_writer.write_push(seg, id_of)
# an array
if next_token == '[':
self._check_name()
self._check_symbol("[")
self.compile_expression()
self._check_symbol("]")
self._vm_writer.write_arithmetic("add")
if self._tokenizer.symbol() != '=':
self._vm_writer.write_pop("pointer", 1)
self._vm_writer.write_push("that", 0)
# or a subroutine call
elif next_token in [".", "("]:
self.compile_subroutine_call()
else:
self._tokenizer.advance()
def compile_expression_list(self):
"""
compiles the expression lists
"""
# if it is ')' then the expression list is empty
if self._tokenizer.symbol() == ')':
return 0
num_of_args = 1 # at least one argument
self.compile_expression()
# while there are more expressions
while self._check_if_comma():
self._tokenizer.advance()
cur_symbol = self._tokenizer.symbol()
self.compile_expression()
if cur_symbol == '-': # negative int
self._vm_writer.write_arithmetic("neg")
num_of_args += 1
return num_of_args
def _check_if_var_dec(self):
"""
check if we are currently compiling a variable declaration
:return: true iff the current token is either 'static' or 'field'
"""
return self._tokenizer.key_word() in CLASS_VAR_KEYWORDS
def _check_subroutine_dec(self):
"""
checks if we are currently compiling a subroutine declaration
:return: true iff the current token is either 'constructor' or
'function' or 'method'
"""
return self._tokenizer.key_word() in SUBROUTINE
def _check_if_comma(self):
"""
checks if current token is a comma
:return: true iff the current token is a ','
"""
return self._tokenizer.symbol() == ','
def _check_if_statement(self):
"""
checks if we are currently compiling a statement
:return: true iff the current token
is in ['let', 'if', 'while', 'do', 'return']
"""
return self._tokenizer.key_word() in STATEMENTS
def _check_type(self):
"""
checks if the current token is a valid type and if so, it writes it
to the output file
"""
if not self._tokenizer.key_word() in TYPE_KEYWORDS:
self._check_name()
else:
self._tokenizer.advance()
def _check_symbol(self, expected_symbol):
"""
checks if the current token is the expected symbol, if so it write
it to the output file
:param expected_symbol: the symbol we are validating is the current
token
:return: prints illegal statement error if it is not the expected
symbol and exits the program
"""
if self._tokenizer.symbol() != expected_symbol:
print(ILLEGAL_STATEMENT_ERROR)
sys.exit()
self._tokenizer.advance()
def _check_name(self):
"""
checks the current token is a name (identifier), and if so, write
it to the output file
:return: prints illegal statement error if it is not a name and
exits the program
"""
if not self._tokenizer.identifier():
print(ILLEGAL_STATEMENT_ERROR)
sys.exit()
self._tokenizer.advance()
@staticmethod
def _get_op(symbol):
"""
writes an op symbol to the out file
"""
if symbol == '<':
return "lt"
elif symbol == '>':
return "gt"
elif symbol == '=':
return "eq"
elif symbol == '&':
return "and"
elif symbol == '|':
return "or"
elif symbol == '+':
return "add"
elif symbol == '-':
return "sub"
elif symbol == '~':
return "not"
elif symbol == "*":
return "call Math.multiply 2"
elif symbol == "/":
return "call Math.divide 2"
def _get_symbol_info(self, symbol_name):
"""
first checks if the given symbol in the method symbol table
if the method table contains the symbol it returns it's information:
(type,kind,id)
otherwise check if the class symbol table contains the symbol
if it does it return the symbol information from the class table
else returns None
:param symbol_name: string
"""
info = self._method_table.get_info(symbol_name)
if info is None:
info = self._class_table.get_info(symbol_name)
return info
@staticmethod
def _get_segment(cur_kind):
"""
:param cur_kind: Jack kind - from the list:
["var", "argument", "field", "class", "subroutine", "local", "static"]
:return: if the given kind is "field" it returns 'this'
otherwise returns the given kind
"""
if cur_kind == "field":
return "this"
else:
return cur_kind
def _get_if_label(self):
"""
create new if label and increment the if label counter
:return: if unused label
"""
curr_counter = str(self._label_count_if)
self._label_count_if += 1
return "IF" + curr_counter
def _get_while_label(self, is_end_while=False):
"""
creates label according to the given flag, if the method creates
end while label it increments the while label counter
:param is_end_while: if true creates end while label
otherwise creates while label
:return: unused while label or end while label according to the flag
"""
curr_counter = str(self._label_count_while)
if is_end_while:
self._label_count_while += 1
return "WHILE_END" + curr_counter
return "WHILE" + curr_counter
