class CompilationEngine:
def __init__(self, source, destination):
self.src = source
self.dst = destination
self.writer = VMWriter(destination)
self.iter = Lookahead(tokenizor.newTokenizor(self.src))
self._symbol_table = SymbolTable()
def compile(self):
root = self._compileClass()
return root
def _compileClass(self):
classE = Element(ELEMENTS.CLASS)
self._readKeyword(classE, ELEMENTS.CLASS)
self.className = self._readIdentifier(classE)
self._readSymbol(classE, _SYMBOLS.BRACKET_CURLY_OPEN)
self._compileClassVarDec(classE)
self._compileSubroutine(classE)
self._readSymbol(classE, _SYMBOLS.BRACKET_CURLY_CLOSE)
return classE
def _compileClassVarDec(self, parent):
while self.nextTok.type == tokenizor.KEYWORD and self.nextTok.value in _CLASSVARDEC.FIELD_TYPES:
classVarDecE = Element(ELEMENTS.CLASSVARDEC)
self._readKeyword(classVarDecE)
self._readType(classVarDecE)
self._readIdentifier(classVarDecE)
while self._readSymbolOptional(classVarDecE, _SYMBOLS.COMMA):
self._readIdentifier(classVarDecE)
self._readSymbol(classVarDecE, _SYMBOLS.SEMI_COLON)
parent.append(classVarDecE)
def _compileSubroutine(self, parent):
while self.nextTok and self.nextTok.type == tokenizor.KEYWORD and self.nextTok.value in _SUBROUTINEDEC.TYPES:
subroutineDecE = Element(ELEMENTS.SUBROUTINEDEC)
function_type = self._readKeyword(subroutineDecE)
self._readReturnType(subroutineDecE)
self.methodName = self._readIdentifier(subroutineDecE)
self._symbol_table.startSubroutine(self.className, self.methodName)
if function_type == _SUBROUTINEDEC.METHOD:
self._symbol_table.define("this", self.className, SYM_KINDS.ARG)
self._uid = -1
self._readSymbol(subroutineDecE, _SYMBOLS.PARENTHESES_OPEN)
self._compileParameters(subroutineDecE)
self._readSymbol(subroutineDecE, _SYMBOLS.PARENTHESES_CLOSE)
self._compileSubroutineBody(subroutineDecE, function_type)
parent.append(subroutineDecE)
def _gen_label(self, type_):
self._uid += 1
return "%s.%s.%s.%d" % (self.className, self.methodName, type_, self._uid)
def _gen_labels(self, *parts):
self._uid += 1
return ["%s.%s.%s.%d" % (self.className, self.methodName, part, self._uid) for part in parts]
def _compileSubroutineBody(self, parent, function_type):
bodyE = Element(ELEMENTS.SUBROUTINEBODY)
self._readSymbol(bodyE, _SYMBOLS.BRACKET_CURLY_OPEN)
nArgs = self._compileVarDec(bodyE)
function_name = parent[2].text
function_full_name = "%s.%s" % (self.className, function_name)
self.writer.writeFunction(function_full_name, nArgs)
if function_type == _SUBROUTINEDEC.CONSTRUCTOR:
field_count = self._symbol_table.varCount(SYM_KINDS.FIELD)
self.writer.writePush(SEGMENT.CONST, field_count)
self.writer.writeCall("Memory.alloc", 1)
self.writer.writePop(SEGMENT.POINTER, 0)
elif function_type == _SUBROUTINEDEC.METHOD:
self.writer.writePush(SEGMENT.ARG, 0)
self.writer.writePop(SEGMENT.POINTER, 0)
self._compileStatements(bodyE)
self._readSymbol(bodyE, _SYMBOLS.BRACKET_CURLY_CLOSE)
parent.append(bodyE)
def _compileStatements(self, parent):
statementsE = Element(ELEMENTS.STATEMENTS)
while self.nextTok.type == tokenizor.KEYWORD and self.nextTok.value in _STATEMENTS.TYPE_NAMES:
if self.nextTok.value == _STATEMENTS.LET:
statementE = Element(ELEMENTS.STATEMENT_LET)
self._readKeyword(statementE)
identifier = self._readIdentifier(statementE)
is_array = False
if self._readSymbolOptional(statementE, _SYMBOLS.BRACKET_OPEN):
is_array = True
self._compileExpression(statementE)
self.writer.writePush(*self._identifier_data(identifier))
self.writer.writeArithmetic("add")
self._readSymbol(statementE, _SYMBOLS.BRACKET_CLOSE)
self._readSymbol(statementE, _SYMBOLS.EQUAL)
self._compileExpression(statementE)
self._readSymbol(statementE, _SYMBOLS.SEMI_COLON)
if is_array:
self.writer.writePop(SEGMENT.TEMP, 0)
self.writer.writePop(SEGMENT.POINTER, 1)
self.writer.writePush(SEGMENT.TEMP, 0)
self.writer.writePop(SEGMENT.THAT, 0)
else:
self.writer.writePop(*self._identifier_data(identifier))
statementsE.append(statementE)
elif self.nextTok.value == _STATEMENTS.IF:
label_else, label_end = self._gen_labels("if.else", "if.end")
statementE = Element(ELEMENTS.STATEMENT_IF)
self._readKeyword(statementE)
self._readSymbol(statementE, _SYMBOLS.PARENTHESES_OPEN)
self._compileExpression(statementE)
self._readSymbol(statementE, _SYMBOLS.PARENTHESES_CLOSE)
self.writer.writeArithmetic("not")
self.writer.writeIf(label_else)
self._readSymbol(statementE, _SYMBOLS.BRACKET_CURLY_OPEN)
self._compileStatements(statementE)
self._readSymbol(statementE, _SYMBOLS.BRACKET_CURLY_CLOSE)
self.writer.writeGoto(label_end)
self.writer.writeLabel(label_else)
if self._readKeywordOptional(statementE, _KEYWORDS.ELSE):
self._readSymbol(statementE, _SYMBOLS.BRACKET_CURLY_OPEN)
self._compileStatements(statementE)
self._readSymbol(statementE, _SYMBOLS.BRACKET_CURLY_CLOSE)
self.writer.writeLabel(label_end)
statementsE.append(statementE)
elif self.nextTok.value == _STATEMENTS.WHILE:
label_start, label_end = self._gen_labels("while.start", "while.end")
self.writer.writeLabel(label_start)
statementE = Element(ELEMENTS.STATEMENT_WHILE)
self._readKeyword(statementE)
self._readSymbol(statementE, _SYMBOLS.PARENTHESES_OPEN)
self._compileExpression(statementE)
self._readSymbol(statementE, _SYMBOLS.PARENTHESES_CLOSE)
self.writer.writeArithmetic("not")
self.writer.writeIf(label_end)
self._readSymbol(statementE, _SYMBOLS.BRACKET_CURLY_OPEN)
self._compileStatements(statementE)
self._readSymbol(statementE, _SYMBOLS.BRACKET_CURLY_CLOSE)
statementsE.append(statementE)
self.writer.writeGoto(label_start)
self.writer.writeLabel(label_end)
elif self.nextTok.value == _STATEMENTS.DO:
self._compileDo(statementsE)
elif self.nextTok.value == _STATEMENTS.RETURN:
statementE = Element(ELEMENTS.STATEMENT_RETURN)
self._readKeyword(statementE)
if not (self.nextTok.type == tokenizor.SYMBOL and self.nextTok.value == _SYMBOLS.SEMI_COLON):
self._compileExpression(statementE)
else:
self.writer.writePush(SEGMENT.CONST, 0)
self._readSymbol(statementE, _SYMBOLS.SEMI_COLON)
self.writer.writeReturn()
statementsE.append(statementE)
if len(statementsE) == 0:
statementsE.text = "\n"
parent.append(statementsE)
def _compileExpression(self, parent):
expressionE = Element(ELEMENTS.EXPRESSION)
self._readTerm(expressionE)
while self.nextTok.type == tokenizor.SYMBOL and self.nextTok.value in _SYMBOLS.OPERATORS:
symbol = self._readSymbol(expressionE)
self._readTerm(expressionE)
self.writer.writeArithmetic(symbol)
parent.append(expressionE)
def _compileExpressionList(self, parent):
self._readSymbol(parent, _SYMBOLS.PARENTHESES_OPEN)
expListE = Element(ELEMENTS.EXPRESSION_LIST)
nArgs = 0
while not (self.nextTok.type == tokenizor.SYMBOL and self.nextTok.value == _SYMBOLS.PARENTHESES_CLOSE):
self._compileExpression(expListE)
self._readSymbolOptional(expListE, _SYMBOLS.COMMA)
nArgs += 1
# hack for TextComparer
if len(expListE) == 0:
expListE.text = "\n"
parent.append(expListE)
self._readSymbol(parent, _SYMBOLS.PARENTHESES_CLOSE)
return nArgs
def _compileDo(self, parent):
statementE = Element(ELEMENTS.STATEMENT_DO)
self._readKeyword(statementE, _STATEMENTS.DO)
identifier = self._readIdentifier(statementE)
nArgs = 0
if self._readSymbolOptional(statementE, _SYMBOLS.DOT):
type_ = self._symbol_table.typeOf(identifier)
if type_:
segment, index = self._identifier_data(identifier)
self.writer.writePush(segment, index)
nArgs += 1
identifier = "%s.%s" % (type_, self._readIdentifier(statementE))
else:
identifier = "%s.%s" % (identifier, self._readIdentifier(statementE))
else:
identifier = "%s.%s" % (self.className, identifier)
self.writer.writePush(SEGMENT.POINTER, 0)
nArgs += 1
nArgs += self._compileExpressionList(statementE)
self._readSymbol(statementE, _SYMBOLS.SEMI_COLON)
self.writer.writeCall(identifier, nArgs)
self.writer.writePop(SEGMENT.TEMP, 0)
parent.append(statementE)
def _compileVarDec(self, parent):
nArgs = 0
while self.nextTok.type == tokenizor.KEYWORD and self.nextTok.value == _KEYWORDS.VAR:
varDecE = Element(ELEMENTS.VAR_DEC)
self._readKeyword(varDecE, _KEYWORDS.VAR)
self._readType(varDecE)
self._readIdentifier(varDecE)
nArgs += 1
while self._readSymbolOptional(varDecE, _SYMBOLS.COMMA):
self._readIdentifier(varDecE)
nArgs += 1
self._readSymbol(varDecE, _SYMBOLS.SEMI_COLON)
parent.append(varDecE)
return nArgs
def _compileParameters(self, parent):
paramListE = Element(ELEMENTS.PARAM_LIST)
while (self.nextTok.type == tokenizor.KEYWORD and self.nextTok.value in _CLASSVARDEC.VAR_TYPES) or self.nextTok.type == tokenizor.IDENTIFIER:
self._readType(paramListE)
self._readIdentifier(paramListE)
self._readSymbolOptional(paramListE, _SYMBOLS.COMMA)
if len(paramListE) == 0:
paramListE.text = "\n"
parent.append(paramListE)
##############################
########## READ ##############
##############################
def _readTerm(self, parent):
termE = Element(ELEMENTS.TERM)
if self.nextTok.type == tokenizor.INTEGER:
self.next()
termE.append(_leafElement(ELEMENTS.INTEGER_CONSTANT, self.tok.value))
self.writer.writePush(SEGMENT.CONST, self.tok.value)
elif self.nextTok.type == tokenizor.STRING:
self.next()
termE.append(_leafElement(ELEMENTS.STRING_CONSTANT, self.tok.value))
string_value = self.tok.value
self.writer.writePush(SEGMENT.CONST, len(string_value))
self.writer.writeCall("String.new", 1)
for char in string_value:
self.writer.writePush(SEGMENT.CONST, ord(char))
self.writer.writeCall("String.appendChar", 2)
elif self.nextTok.type == tokenizor.KEYWORD and self.nextTok.value in _KEYWORDS.CONSTANTS:
self.next()
termE.append(_leafElement(ELEMENTS.KEYWORD, self.tok.value))
_KW_CONT_WRITE[self.tok.value](self.writer)
elif self.nextTok.type == tokenizor.IDENTIFIER:
identifier = self._readIdentifier(termE)
nArgs = 0
if self._readSymbolOptional(termE, _SYMBOLS.BRACKET_OPEN):
self._compileExpression(termE)
self.writer.writePush(*self._identifier_data(identifier))
self.writer.writeArithmetic("add")
self.writer.writePop(SEGMENT.POINTER, 1)
self.writer.writePush(SEGMENT.THAT, 0)
self._readSymbol(termE, _SYMBOLS.BRACKET_CLOSE)
elif self.nextTok.type == tokenizor.SYMBOL and self.nextTok.value == _SYMBOLS.PARENTHESES_OPEN:
nArgs = self._compileExpressionList(termE)
self._readSymbol(termE, _SYMBOLS.PARENTHESES_CLOSE)
self.writer.writeCall(identifier, nArgs)
elif self._readSymbolOptional(termE, _SYMBOLS.DOT):
type_ = self._symbol_table.typeOf(identifier)
if type_:
segment, index = self._identifier_data(identifier)
self.writer.writePush(segment, index)
nArgs += 1
identifier = "%s.%s" % (type_, self._readIdentifier(termE))
else:
identifier = "%s.%s" % (identifier, self._readIdentifier(termE))
nArgs += self._compileExpressionList(termE)
self.writer.writeCall(identifier, nArgs)
else:
self.writer.writePush(*self._identifier_data(identifier))
elif self.nextTok.type == tokenizor.SYMBOL and self.nextTok.value == _SYMBOLS.PARENTHESES_OPEN:
self.next()
termE.append(_leafElement(ELEMENTS.SYMBOL, self.tok.value))
self._compileExpression(termE)
self._readSymbol(termE, _SYMBOLS.PARENTHESES_CLOSE)
elif self.nextTok.type == tokenizor.SYMBOL and self.nextTok.value in _SYMBOLS.UNARY_OPARTORS:
self.next()
sym = self.tok.value
termE.append(_leafElement(ELEMENTS.SYMBOL, self.tok.value))
self._readTerm(termE)
self.writer.writeArithmeticUnary(sym)
else:
raise self._syntaxError("Unexpected %s." % self.tok.value)
parent.append(termE)
def _identifier_data(self, identifier):
return _SEG_TRANSLATE[self._symbol_table.kindOf(identifier)], self._symbol_table.indexOf(identifier)
def _readIdentifier(self, parent):
self.next()
self._assertToken(self.tok, ELEMENTS.IDENTIFIER, type_=tokenizor.IDENTIFIER)
name = self.tok.value
element = _leafElement(ELEMENTS.IDENTIFIER, name)
type_ = self._symbol_table.typeOf(name)
kind = None
index = None
if type_ is None:
if parent.tag in (ELEMENTS.CLASSVARDEC, ELEMENTS.VAR_DEC) and len(parent) > 1:
type_ = parent[1].text
kind = _SYM_KIND_MAP[parent[0].text]
elif parent.tag == ELEMENTS.PARAM_LIST and len(parent) > 0:
type_ = parent[-1].text
kind = SYM_KINDS.ARG
if kind is not None:
index = self._symbol_table.define(name, type_, kind)
else:
type_ = self._symbol_table.typeOf(name)
kind = self._symbol_table.kindOf(name)
index = self._symbol_table.indexOf(name)
if kind is not None:
element.set("type", type_)
element.set("kind", str(kind))
element.set("index", str(index))
parent.append(element)
return name
def _readType(self, parent):
if self.nextTok.type == tokenizor.KEYWORD and self.nextTok.value in _CLASSVARDEC.VAR_TYPES:
self.next()
parent.append(_leafElement(ELEMENTS.KEYWORD, self.tok.value))
else:
self._readIdentifier(parent)
def _readReturnType(self, parent):
if self.nextTok.type == tokenizor.KEYWORD and self.nextTok.value in _SUBROUTINEDEC.RETURN_TYPES:
self.next()
parent.append(_leafElement(ELEMENTS.KEYWORD, self.tok.value))
else:
self._readIdentifier(parent)
def _readSymbol(self, parent, expected = None):
self.next()
expectedStr = expected if expected is not None else ELEMENTS.SYMBOL
self._assertToken(self.tok, expectedStr, type_=tokenizor.SYMBOL)
if expected is not None:
self._assertToken(self.tok, expected, value_=expected)
parent.append(_leafElement(ELEMENTS.SYMBOL, self.tok.value))
return self.tok.value
def _readKeyword(self, parent, expected = None):
self.next()
expectedStr = expected if expected is not None else ELEMENTS.KEYWORD
self._assertToken(self.tok, expectedStr, type_=tokenizor.KEYWORD)
if expected is not None:
self._assertToken(self.tok, expected, value_=expected)
parent.append(_leafElement(ELEMENTS.KEYWORD, self.tok.value))
return self.tok.value
def _readSymbolOptional(self, parent, expected):
if self.nextTok.type == tokenizor.SYMBOL and self.nextTok.value == expected:
self.next()
parent.append(_leafElement(ELEMENTS.SYMBOL, self.tok.value))
return True
return False
def _readKeywordOptional(self, parent, expected):
if self.nextTok.type == tokenizor.KEYWORD and self.nextTok.value == expected:
self.next()
parent.append(_leafElement(ELEMENTS.KEYWORD, self.tok.value))
return True
return False
def next(self):
self.tok = self.iter.next()
self.nextTok = self.iter.lookahead()
def _assertToken(self, tok, expected_str, type_ = None, value_ = None):
if (type_ != None and tok.type != type_) or (value_ != None and tok.value != value_):
raise self._syntaxError("Expected %s but found %s" % (expected_str, tok.value), tok)
def _syntaxError(self, msg, tok = None):
if tok is None:
tok = self.tok
return SyntaxError(msg, (None, tok.srow, tok.scol, tok.line))
class CompilationEngine:
def __init__(self, source, destination):
self.src = source
self.dst = destination
self.writer = VMWriter(destination)
self.iter = Lookahead(tokenizor.newTokenizor(self.src))
self._symbol_table = SymbolTable()
def compile(self):
root = self._compileClass()
return root
def _compileClass(self):
classE = Element(ELEMENTS.CLASS)
self._readKeyword(classE, ELEMENTS.CLASS)
self.className = self._readIdentifier(classE)
self._readSymbol(classE, _SYMBOLS.BRACKET_CURLY_OPEN)
self._compileClassVarDec(classE)
self._compileSubroutine(classE)
self._readSymbol(classE, _SYMBOLS.BRACKET_CURLY_CLOSE)
return classE
def _compileClassVarDec(self, parent):
while self.nextTok.type == tokenizor.KEYWORD and self.nextTok.value in _CLASSVARDEC.FIELD_TYPES:
classVarDecE = Element(ELEMENTS.CLASSVARDEC)
self._readKeyword(classVarDecE)
self._readType(classVarDecE)
self._readIdentifier(classVarDecE)
while self._readSymbolOptional(classVarDecE, _SYMBOLS.COMMA):
self._readIdentifier(classVarDecE)
self._readSymbol(classVarDecE, _SYMBOLS.SEMI_COLON)
parent.append(classVarDecE)
def _compileSubroutine(self, parent):
while self.nextTok and self.nextTok.type == tokenizor.KEYWORD and self.nextTok.value in _SUBROUTINEDEC.TYPES:
subroutineDecE = Element(ELEMENTS.SUBROUTINEDEC)
function_type = self._readKeyword(subroutineDecE)
self._readReturnType(subroutineDecE)
self.methodName = self._readIdentifier(subroutineDecE)
self._symbol_table.startSubroutine(self.className, self.methodName)
if function_type == _SUBROUTINEDEC.METHOD:
self._symbol_table.define("this", self.className,
SYM_KINDS.ARG)
self._uid = -1
self._readSymbol(subroutineDecE, _SYMBOLS.PARENTHESES_OPEN)
self._compileParameters(subroutineDecE)
self._readSymbol(subroutineDecE, _SYMBOLS.PARENTHESES_CLOSE)
self._compileSubroutineBody(subroutineDecE, function_type)
parent.append(subroutineDecE)
def _gen_label(self, type_):
self._uid += 1
return "%s.%s.%s.%d" % (self.className, self.methodName, type_,
self._uid)
def _gen_labels(self, *parts):
self._uid += 1
return [
"%s.%s.%s.%d" % (self.className, self.methodName, part, self._uid)
for part in parts
]
def _compileSubroutineBody(self, parent, function_type):
bodyE = Element(ELEMENTS.SUBROUTINEBODY)
self._readSymbol(bodyE, _SYMBOLS.BRACKET_CURLY_OPEN)
nArgs = self._compileVarDec(bodyE)
function_name = parent[2].text
function_full_name = "%s.%s" % (self.className, function_name)
self.writer.writeFunction(function_full_name, nArgs)
if function_type == _SUBROUTINEDEC.CONSTRUCTOR:
field_count = self._symbol_table.varCount(SYM_KINDS.FIELD)
self.writer.writePush(SEGMENT.CONST, field_count)
self.writer.writeCall("Memory.alloc", 1)
self.writer.writePop(SEGMENT.POINTER, 0)
elif function_type == _SUBROUTINEDEC.METHOD:
self.writer.writePush(SEGMENT.ARG, 0)
self.writer.writePop(SEGMENT.POINTER, 0)
self._compileStatements(bodyE)
self._readSymbol(bodyE, _SYMBOLS.BRACKET_CURLY_CLOSE)
parent.append(bodyE)
def _compileStatements(self, parent):
statementsE = Element(ELEMENTS.STATEMENTS)
while self.nextTok.type == tokenizor.KEYWORD and self.nextTok.value in _STATEMENTS.TYPE_NAMES:
if self.nextTok.value == _STATEMENTS.LET:
statementE = Element(ELEMENTS.STATEMENT_LET)
self._readKeyword(statementE)
identifier = self._readIdentifier(statementE)
is_array = False
if self._readSymbolOptional(statementE, _SYMBOLS.BRACKET_OPEN):
is_array = True
self._compileExpression(statementE)
self.writer.writePush(*self._identifier_data(identifier))
self.writer.writeArithmetic("add")
self._readSymbol(statementE, _SYMBOLS.BRACKET_CLOSE)
self._readSymbol(statementE, _SYMBOLS.EQUAL)
self._compileExpression(statementE)
self._readSymbol(statementE, _SYMBOLS.SEMI_COLON)
if is_array:
self.writer.writePop(SEGMENT.TEMP, 0)
self.writer.writePop(SEGMENT.POINTER, 1)
self.writer.writePush(SEGMENT.TEMP, 0)
self.writer.writePop(SEGMENT.THAT, 0)
else:
self.writer.writePop(*self._identifier_data(identifier))
statementsE.append(statementE)
elif self.nextTok.value == _STATEMENTS.IF:
label_else, label_end = self._gen_labels("if.else", "if.end")
statementE = Element(ELEMENTS.STATEMENT_IF)
self._readKeyword(statementE)
self._readSymbol(statementE, _SYMBOLS.PARENTHESES_OPEN)
self._compileExpression(statementE)
self._readSymbol(statementE, _SYMBOLS.PARENTHESES_CLOSE)
self.writer.writeArithmetic("not")
self.writer.writeIf(label_else)
self._readSymbol(statementE, _SYMBOLS.BRACKET_CURLY_OPEN)
self._compileStatements(statementE)
self._readSymbol(statementE, _SYMBOLS.BRACKET_CURLY_CLOSE)
self.writer.writeGoto(label_end)
self.writer.writeLabel(label_else)
if self._readKeywordOptional(statementE, _KEYWORDS.ELSE):
self._readSymbol(statementE, _SYMBOLS.BRACKET_CURLY_OPEN)
self._compileStatements(statementE)
self._readSymbol(statementE, _SYMBOLS.BRACKET_CURLY_CLOSE)
self.writer.writeLabel(label_end)
statementsE.append(statementE)
elif self.nextTok.value == _STATEMENTS.WHILE:
label_start, label_end = self._gen_labels(
"while.start", "while.end")
self.writer.writeLabel(label_start)
statementE = Element(ELEMENTS.STATEMENT_WHILE)
self._readKeyword(statementE)
self._readSymbol(statementE, _SYMBOLS.PARENTHESES_OPEN)
self._compileExpression(statementE)
self._readSymbol(statementE, _SYMBOLS.PARENTHESES_CLOSE)
self.writer.writeArithmetic("not")
self.writer.writeIf(label_end)
self._readSymbol(statementE, _SYMBOLS.BRACKET_CURLY_OPEN)
self._compileStatements(statementE)
self._readSymbol(statementE, _SYMBOLS.BRACKET_CURLY_CLOSE)
statementsE.append(statementE)
self.writer.writeGoto(label_start)
self.writer.writeLabel(label_end)
elif self.nextTok.value == _STATEMENTS.DO:
self._compileDo(statementsE)
elif self.nextTok.value == _STATEMENTS.RETURN:
statementE = Element(ELEMENTS.STATEMENT_RETURN)
self._readKeyword(statementE)
if not (self.nextTok.type == tokenizor.SYMBOL
and self.nextTok.value == _SYMBOLS.SEMI_COLON):
self._compileExpression(statementE)
else:
self.writer.writePush(SEGMENT.CONST, 0)
self._readSymbol(statementE, _SYMBOLS.SEMI_COLON)
self.writer.writeReturn()
statementsE.append(statementE)
if len(statementsE) == 0:
statementsE.text = "\n"
parent.append(statementsE)
def _compileExpression(self, parent):
expressionE = Element(ELEMENTS.EXPRESSION)
self._readTerm(expressionE)
while self.nextTok.type == tokenizor.SYMBOL and self.nextTok.value in _SYMBOLS.OPERATORS:
symbol = self._readSymbol(expressionE)
self._readTerm(expressionE)
self.writer.writeArithmetic(symbol)
parent.append(expressionE)
def _compileExpressionList(self, parent):
self._readSymbol(parent, _SYMBOLS.PARENTHESES_OPEN)
expListE = Element(ELEMENTS.EXPRESSION_LIST)
nArgs = 0
while not (self.nextTok.type == tokenizor.SYMBOL
and self.nextTok.value == _SYMBOLS.PARENTHESES_CLOSE):
self._compileExpression(expListE)
self._readSymbolOptional(expListE, _SYMBOLS.COMMA)
nArgs += 1
# hack for TextComparer
if len(expListE) == 0:
expListE.text = "\n"
parent.append(expListE)
self._readSymbol(parent, _SYMBOLS.PARENTHESES_CLOSE)
return nArgs
def _compileDo(self, parent):
statementE = Element(ELEMENTS.STATEMENT_DO)
self._readKeyword(statementE, _STATEMENTS.DO)
identifier = self._readIdentifier(statementE)
nArgs = 0
if self._readSymbolOptional(statementE, _SYMBOLS.DOT):
type_ = self._symbol_table.typeOf(identifier)
if type_:
segment, index = self._identifier_data(identifier)
self.writer.writePush(segment, index)
nArgs += 1
identifier = "%s.%s" % (type_,
self._readIdentifier(statementE))
else:
identifier = "%s.%s" % (identifier,
self._readIdentifier(statementE))
else:
identifier = "%s.%s" % (self.className, identifier)
self.writer.writePush(SEGMENT.POINTER, 0)
nArgs += 1
nArgs += self._compileExpressionList(statementE)
self._readSymbol(statementE, _SYMBOLS.SEMI_COLON)
self.writer.writeCall(identifier, nArgs)
self.writer.writePop(SEGMENT.TEMP, 0)
parent.append(statementE)
def _compileVarDec(self, parent):
nArgs = 0
while self.nextTok.type == tokenizor.KEYWORD and self.nextTok.value == _KEYWORDS.VAR:
varDecE = Element(ELEMENTS.VAR_DEC)
self._readKeyword(varDecE, _KEYWORDS.VAR)
self._readType(varDecE)
self._readIdentifier(varDecE)
nArgs += 1
while self._readSymbolOptional(varDecE, _SYMBOLS.COMMA):
self._readIdentifier(varDecE)
nArgs += 1
self._readSymbol(varDecE, _SYMBOLS.SEMI_COLON)
parent.append(varDecE)
return nArgs
def _compileParameters(self, parent):
paramListE = Element(ELEMENTS.PARAM_LIST)
while (self.nextTok.type == tokenizor.KEYWORD
and self.nextTok.value in _CLASSVARDEC.VAR_TYPES
) or self.nextTok.type == tokenizor.IDENTIFIER:
self._readType(paramListE)
self._readIdentifier(paramListE)
self._readSymbolOptional(paramListE, _SYMBOLS.COMMA)
if len(paramListE) == 0:
paramListE.text = "\n"
parent.append(paramListE)
##############################
########## READ ##############
##############################
def _readTerm(self, parent):
termE = Element(ELEMENTS.TERM)
if self.nextTok.type == tokenizor.INTEGER:
self.next()
termE.append(
_leafElement(ELEMENTS.INTEGER_CONSTANT, self.tok.value))
self.writer.writePush(SEGMENT.CONST, self.tok.value)
elif self.nextTok.type == tokenizor.STRING:
self.next()
termE.append(_leafElement(ELEMENTS.STRING_CONSTANT,
self.tok.value))
string_value = self.tok.value
self.writer.writePush(SEGMENT.CONST, len(string_value))
self.writer.writeCall("String.new", 1)
for char in string_value:
self.writer.writePush(SEGMENT.CONST, ord(char))
self.writer.writeCall("String.appendChar", 2)
elif self.nextTok.type == tokenizor.KEYWORD and self.nextTok.value in _KEYWORDS.CONSTANTS:
self.next()
termE.append(_leafElement(ELEMENTS.KEYWORD, self.tok.value))
_KW_CONT_WRITE[self.tok.value](self.writer)
elif self.nextTok.type == tokenizor.IDENTIFIER:
identifier = self._readIdentifier(termE)
nArgs = 0
if self._readSymbolOptional(termE, _SYMBOLS.BRACKET_OPEN):
self._compileExpression(termE)
self.writer.writePush(*self._identifier_data(identifier))
self.writer.writeArithmetic("add")
self.writer.writePop(SEGMENT.POINTER, 1)
self.writer.writePush(SEGMENT.THAT, 0)
self._readSymbol(termE, _SYMBOLS.BRACKET_CLOSE)
elif self.nextTok.type == tokenizor.SYMBOL and self.nextTok.value == _SYMBOLS.PARENTHESES_OPEN:
nArgs = self._compileExpressionList(termE)
self._readSymbol(termE, _SYMBOLS.PARENTHESES_CLOSE)
self.writer.writeCall(identifier, nArgs)
elif self._readSymbolOptional(termE, _SYMBOLS.DOT):
type_ = self._symbol_table.typeOf(identifier)
if type_:
segment, index = self._identifier_data(identifier)
self.writer.writePush(segment, index)
nArgs += 1
identifier = "%s.%s" % (type_, self._readIdentifier(termE))
else:
identifier = "%s.%s" % (identifier,
self._readIdentifier(termE))
nArgs += self._compileExpressionList(termE)
self.writer.writeCall(identifier, nArgs)
else:
self.writer.writePush(*self._identifier_data(identifier))
elif self.nextTok.type == tokenizor.SYMBOL and self.nextTok.value == _SYMBOLS.PARENTHESES_OPEN:
self.next()
termE.append(_leafElement(ELEMENTS.SYMBOL, self.tok.value))
self._compileExpression(termE)
self._readSymbol(termE, _SYMBOLS.PARENTHESES_CLOSE)
elif self.nextTok.type == tokenizor.SYMBOL and self.nextTok.value in _SYMBOLS.UNARY_OPARTORS:
self.next()
sym = self.tok.value
termE.append(_leafElement(ELEMENTS.SYMBOL, self.tok.value))
self._readTerm(termE)
self.writer.writeArithmeticUnary(sym)
else:
raise self._syntaxError("Unexpected %s." % self.tok.value)
parent.append(termE)
def _identifier_data(self, identifier):
return _SEG_TRANSLATE[self._symbol_table.kindOf(
identifier)], self._symbol_table.indexOf(identifier)
def _readIdentifier(self, parent):
self.next()
self._assertToken(self.tok,
ELEMENTS.IDENTIFIER,
type_=tokenizor.IDENTIFIER)
name = self.tok.value
element = _leafElement(ELEMENTS.IDENTIFIER, name)
type_ = self._symbol_table.typeOf(name)
kind = None
index = None
if type_ is None:
if parent.tag in (ELEMENTS.CLASSVARDEC,
ELEMENTS.VAR_DEC) and len(parent) > 1:
type_ = parent[1].text
kind = _SYM_KIND_MAP[parent[0].text]
elif parent.tag == ELEMENTS.PARAM_LIST and len(parent) > 0:
type_ = parent[-1].text
kind = SYM_KINDS.ARG
if kind is not None:
index = self._symbol_table.define(name, type_, kind)
else:
type_ = self._symbol_table.typeOf(name)
kind = self._symbol_table.kindOf(name)
index = self._symbol_table.indexOf(name)
if kind is not None:
element.set("type", type_)
element.set("kind", str(kind))
element.set("index", str(index))
parent.append(element)
return name
def _readType(self, parent):
if self.nextTok.type == tokenizor.KEYWORD and self.nextTok.value in _CLASSVARDEC.VAR_TYPES:
self.next()
parent.append(_leafElement(ELEMENTS.KEYWORD, self.tok.value))
else:
self._readIdentifier(parent)
def _readReturnType(self, parent):
if self.nextTok.type == tokenizor.KEYWORD and self.nextTok.value in _SUBROUTINEDEC.RETURN_TYPES:
self.next()
parent.append(_leafElement(ELEMENTS.KEYWORD, self.tok.value))
else:
self._readIdentifier(parent)
def _readSymbol(self, parent, expected=None):
self.next()
expectedStr = expected if expected is not None else ELEMENTS.SYMBOL
self._assertToken(self.tok, expectedStr, type_=tokenizor.SYMBOL)
if expected is not None:
self._assertToken(self.tok, expected, value_=expected)
parent.append(_leafElement(ELEMENTS.SYMBOL, self.tok.value))
return self.tok.value
def _readKeyword(self, parent, expected=None):
self.next()
expectedStr = expected if expected is not None else ELEMENTS.KEYWORD
self._assertToken(self.tok, expectedStr, type_=tokenizor.KEYWORD)
if expected is not None:
self._assertToken(self.tok, expected, value_=expected)
parent.append(_leafElement(ELEMENTS.KEYWORD, self.tok.value))
return self.tok.value
def _readSymbolOptional(self, parent, expected):
if self.nextTok.type == tokenizor.SYMBOL and self.nextTok.value == expected:
self.next()
parent.append(_leafElement(ELEMENTS.SYMBOL, self.tok.value))
return True
return False
def _readKeywordOptional(self, parent, expected):
if self.nextTok.type == tokenizor.KEYWORD and self.nextTok.value == expected:
self.next()
parent.append(_leafElement(ELEMENTS.KEYWORD, self.tok.value))
return True
return False
def next(self):
self.tok = self.iter.next()
self.nextTok = self.iter.lookahead()
def _assertToken(self, tok, expected_str, type_=None, value_=None):
if (type_ != None and tok.type != type_) or (value_ != None
and tok.value != value_):
raise self._syntaxError(
"Expected %s but found %s" % (expected_str, tok.value), tok)
def _syntaxError(self, msg, tok=None):
if tok is None:
tok = self.tok
return SyntaxError(msg, (None, tok.srow, tok.scol, tok.line))