def _function_definition(self):
"""Function definition rule.
function_definition -> 'def' ID '(' (ID (',' ID)*)? ')' slist
"""
self._match(tokens.DEF)
node = AST(tokens.FUNC_DEF)
id_token = self._lookahead_token(0)
node.add_child(AST(id_token))
func_symbol = FunctionSymbol(id_token.text, self.current_scope)
func_symbol.scope = self.current_scope
self.current_scope.define(func_symbol)
self.current_scope = func_symbol
self._match(tokens.ID)
self._match(tokens.LPAREN)
if self._lookahead_type(0) == tokens.ID:
node.add_child(AST(self._lookahead_token(0)))
variable_symbol = VariableSymbol(self._lookahead_token(0).text)
variable_symbol.scope = self.current_scope
self.current_scope.define(variable_symbol)
self._match(tokens.ID)
while self._lookahead_type(0) == tokens.COMMA:
self._match(tokens.COMMA)
node.add_child(AST(self._lookahead_token(0)))
variable_symbol = VariableSymbol(self._lookahead_token(0).text)
self.current_scope.define(variable_symbol)
variable_symbol.scope = self.current_scope
self._match(tokens.ID)
self._match(tokens.RPAREN)
self.current_scope = LocalScope(self.current_scope)
block_ast = self._slist()
func_symbol.block_ast = block_ast
node.add_child(block_ast)
# pop LocalScope
self.current_scope = self.current_scope.get_enclosing_scope()
# pop FunctionSymbol
self.current_scope = self.current_scope.get_enclosing_scope()
return node
def _function_definition(self):
"""Function definition rule.
function_definition -> 'def' ID '(' (ID (',' ID)*)? ')' slist
"""
self._match(tokens.DEF)
node = AST(tokens.FUNC_DEF)
id_token = self._lookahead_token(0)
node.add_child(AST(id_token))
func_symbol = FunctionSymbol(id_token.text, self.current_scope)
func_symbol.scope = self.current_scope
self.current_scope.define(func_symbol)
self.current_scope = func_symbol
self._match(tokens.ID)
self._match(tokens.LPAREN)
if self._lookahead_type(0) == tokens.ID:
node.add_child(AST(self._lookahead_token(0)))
variable_symbol = VariableSymbol(self._lookahead_token(0).text)
variable_symbol.scope = self.current_scope
self.current_scope.define(variable_symbol)
self._match(tokens.ID)
while self._lookahead_type(0) == tokens.COMMA:
self._match(tokens.COMMA)
node.add_child(AST(self._lookahead_token(0)))
variable_symbol = VariableSymbol(self._lookahead_token(0).text)
self.current_scope.define(variable_symbol)
variable_symbol.scope = self.current_scope
self._match(tokens.ID)
self._match(tokens.RPAREN)
self.current_scope = LocalScope(self.current_scope)
block_ast = self._slist()
func_symbol.block_ast = block_ast
node.add_child(block_ast)
# pop LocalScope
self.current_scope = self.current_scope.get_enclosing_scope()
# pop FunctionSymbol
self.current_scope = self.current_scope.get_enclosing_scope()
return node
class Parser(BaseParser):
"""TinyPie Parser"""
def __init__(self, lexer, lookahead_limit=2, interpreter=None):
self.lexer = lexer
self.lookahead = [None] * lookahead_limit
self.lookahead_limit = lookahead_limit
self.pos = 0
self._init_lookahead()
self.root = AST(tokens.BLOCK)
self.current_node = self.root
self.interpreter = interpreter
self.current_scope = interpreter.global_scope
def parse(self):
node = AST(tokens.BLOCK)
while self._lookahead_type(0) != tokens.EOF:
token_type = self._lookahead_type(0)
if token_type == tokens.DEF:
node.add_child(self._function_definition())
else:
st_node = self._statement()
if st_node is not None:
node.add_child(st_node)
self.root = node
def _function_definition(self):
"""Function definition rule.
function_definition -> 'def' ID '(' (ID (',' ID)*)? ')' slist
"""
self._match(tokens.DEF)
node = AST(tokens.FUNC_DEF)
id_token = self._lookahead_token(0)
node.add_child(AST(id_token))
func_symbol = FunctionSymbol(id_token.text, self.current_scope)
func_symbol.scope = self.current_scope
self.current_scope.define(func_symbol)
self.current_scope = func_symbol
self._match(tokens.ID)
self._match(tokens.LPAREN)
if self._lookahead_type(0) == tokens.ID:
node.add_child(AST(self._lookahead_token(0)))
variable_symbol = VariableSymbol(self._lookahead_token(0).text)
variable_symbol.scope = self.current_scope
self.current_scope.define(variable_symbol)
self._match(tokens.ID)
while self._lookahead_type(0) == tokens.COMMA:
self._match(tokens.COMMA)
node.add_child(AST(self._lookahead_token(0)))
variable_symbol = VariableSymbol(self._lookahead_token(0).text)
self.current_scope.define(variable_symbol)
variable_symbol.scope = self.current_scope
self._match(tokens.ID)
self._match(tokens.RPAREN)
self.current_scope = LocalScope(self.current_scope)
block_ast = self._slist()
func_symbol.block_ast = block_ast
node.add_child(block_ast)
# pop LocalScope
self.current_scope = self.current_scope.get_enclosing_scope()
# pop FunctionSymbol
self.current_scope = self.current_scope.get_enclosing_scope()
return node
def _slist(self):
"""Statement list rule.
slist -> ':' NL statement+ '.' NL
| statement
"""
node = AST(tokens.BLOCK)
if self._lookahead_type(0) == tokens.COLON:
self._match(tokens.COLON)
self._match(tokens.NL)
while not (self._lookahead_type(0) == tokens.DOT and
self._lookahead_type(1) == tokens.NL):
st_node = self._statement()
if st_node is not None:
node.add_child(st_node)
self._match(tokens.DOT)
self._match(tokens.NL)
else:
st_node = self._statement()
if st_node is not None:
node.add_child(st_node)
return node
def _statement(self):
"""Statement rule.
statement -> 'print' expr NL
| 'return' expr NL
| call NL
| assign NL
| 'if' expr slist ('else' slist)?
| 'while' expr slist
| NL
"""
if self._lookahead_type(0) == tokens.PRINT:
node = AST(self._lookahead_token(0))
self._match(tokens.PRINT)
node.add_child(self._expr())
self._match(tokens.NL)
return node
elif self._lookahead_type(0) == tokens.RETURN:
node = AST(self._lookahead_token(0))
self._match(tokens.RETURN)
node.add_child(self._expr())
self._match(tokens.NL)
return node
elif self._lookahead_type(0) == tokens.NL:
self._match(tokens.NL)
elif (self._lookahead_type(0) == tokens.ID and
self._lookahead_type(1) == tokens.LPAREN
):
return self._call()
elif self._lookahead_type(0) == tokens.IF:
node = AST(self._lookahead_token(0))
self._match(tokens.IF)
node.add_child(self._expr())
node.add_child(self._slist())
if self._lookahead_type(0) == tokens.ELSE:
self._match(tokens.ELSE)
node.add_child(self._slist())
return node
elif self._lookahead_type(0) == tokens.WHILE:
node = AST(self._lookahead_token(0))
self._match(tokens.WHILE)
node.add_child(self._expr())
node.add_child(self._slist())
return node
else:
return self._assign()
def _expr(self):
"""Expression rule.
expr -> add_expr (('<' | '==') add_expr)?
"""
left_node = self._add_expr()
if self._lookahead_type(0) in (tokens.LT, tokens.EQ):
node = AST(self._lookahead_token(0))
node.add_child(left_node)
self._match(self._lookahead_type(0))
node.add_child(self._add_expr())
left_node = node
return left_node
def _add_expr(self):
"""Add expression rule.
add_expr -> mult_expr (('+' | '-') mult_expr)*
"""
left_node = self._mult_expr()
while self._lookahead_type(0) in (tokens.ADD, tokens.SUB):
node = AST(self._lookahead_token(0))
node.add_child(left_node)
self._match(self._lookahead_type(0))
node.add_child(self._mult_expr())
left_node = node
return left_node
def _mult_expr(self):
"""Multiply expression rule.
mult_expr -> atom ('*' atom)*
"""
result_node = self._atom()
while self._lookahead_type(0) == tokens.MUL:
node = AST(self._lookahead_token(0))
node.add_child(result_node)
self._match(tokens.MUL)
node.add_child(self._atom())
result_node = node
return result_node
def _assign(self):
"""Assign rule.
assign -> ID '=' expr
"""
node = AST(tokens.ASSIGN)
node.add_child(AST(self._lookahead_token(0)))
variable_symbol = VariableSymbol(self._lookahead_token(0).text)
variable_symbol.scope = self.current_scope
self.current_scope.define(variable_symbol)
self._match(tokens.ID)
self._match(tokens.ASSIGN)
node.add_child(self._expr())
return node
def _call(self):
"""Call rule.
call -> ID '(' (expr (',' expr)*)? ')'
"""
node = AST(tokens.CALL)
node.scope = self.current_scope
node.add_child(AST(self._lookahead_token(0)))
self._match(tokens.ID)
self._match(tokens.LPAREN)
result_node = self._expr()
if result_node is not None:
node.add_child(result_node)
while self._lookahead_type(0) == tokens.COMMA:
self._match(tokens.COMMA)
node.add_child(self._expr())
self._match(tokens.RPAREN)
return node
def _atom(self):
"""Atom rule.
atom -> ID | INT | STRING | call | '(' expr ')'
"""
if (self._lookahead_type(0) == tokens.ID and
self._lookahead_type(1) == tokens.LPAREN
):
return self._call()
elif self._lookahead_type(0) == tokens.ID:
node = AST(self._lookahead_token(0))
self._match(tokens.ID)
return node
elif self._lookahead_type(0) == tokens.INT:
node = AST(self._lookahead_token(0))
self._match(tokens.INT)
return node
elif self._lookahead_type(0) == tokens.STRING:
# strip single quote around the string
token = self._lookahead_token(0)
token.text = token.text.strip("'")
node = AST(token)
self._match(tokens.STRING)
return node
elif self._lookahead_type(0) == tokens.LPAREN:
self._match(tokens.LPAREN)
node = self._expr()
self._match(tokens.RPAREN)
return node
class Parser(BaseParser):
"""TinyPie Parser"""
def __init__(self, lexer, lookahead_limit=2, interpreter=None):
self.lexer = lexer
self.lookahead = [None] * lookahead_limit
self.lookahead_limit = lookahead_limit
self.pos = 0
self._init_lookahead()
self.root = AST(tokens.BLOCK)
self.current_node = self.root
self.interpreter = interpreter
self.current_scope = interpreter.global_scope
def parse(self):
node = AST(tokens.BLOCK)
while self._lookahead_type(0) != tokens.EOF:
token_type = self._lookahead_type(0)
if token_type == tokens.DEF:
node.add_child(self._function_definition())
else:
st_node = self._statement()
if st_node is not None:
node.add_child(st_node)
self.root = node
def _function_definition(self):
"""Function definition rule.
function_definition -> 'def' ID '(' (ID (',' ID)*)? ')' slist
"""
self._match(tokens.DEF)
node = AST(tokens.FUNC_DEF)
id_token = self._lookahead_token(0)
node.add_child(AST(id_token))
func_symbol = FunctionSymbol(id_token.text, self.current_scope)
func_symbol.scope = self.current_scope
self.current_scope.define(func_symbol)
self.current_scope = func_symbol
self._match(tokens.ID)
self._match(tokens.LPAREN)
if self._lookahead_type(0) == tokens.ID:
node.add_child(AST(self._lookahead_token(0)))
variable_symbol = VariableSymbol(self._lookahead_token(0).text)
variable_symbol.scope = self.current_scope
self.current_scope.define(variable_symbol)
self._match(tokens.ID)
while self._lookahead_type(0) == tokens.COMMA:
self._match(tokens.COMMA)
node.add_child(AST(self._lookahead_token(0)))
variable_symbol = VariableSymbol(self._lookahead_token(0).text)
self.current_scope.define(variable_symbol)
variable_symbol.scope = self.current_scope
self._match(tokens.ID)
self._match(tokens.RPAREN)
self.current_scope = LocalScope(self.current_scope)
block_ast = self._slist()
func_symbol.block_ast = block_ast
node.add_child(block_ast)
# pop LocalScope
self.current_scope = self.current_scope.get_enclosing_scope()
# pop FunctionSymbol
self.current_scope = self.current_scope.get_enclosing_scope()
return node
def _slist(self):
"""Statement list rule.
slist -> ':' NL statement+ '.' NL
| statement
"""
node = AST(tokens.BLOCK)
if self._lookahead_type(0) == tokens.COLON:
self._match(tokens.COLON)
self._match(tokens.NL)
while not (self._lookahead_type(0) == tokens.DOT
and self._lookahead_type(1) == tokens.NL):
st_node = self._statement()
if st_node is not None:
node.add_child(st_node)
self._match(tokens.DOT)
self._match(tokens.NL)
else:
st_node = self._statement()
if st_node is not None:
node.add_child(st_node)
return node
def _statement(self):
"""Statement rule.
statement -> 'print' expr NL
| 'return' expr NL
| call NL
| assign NL
| 'if' expr slist ('else' slist)?
| 'while' expr slist
| NL
"""
if self._lookahead_type(0) == tokens.PRINT:
node = AST(self._lookahead_token(0))
self._match(tokens.PRINT)
node.add_child(self._expr())
self._match(tokens.NL)
return node
elif self._lookahead_type(0) == tokens.RETURN:
node = AST(self._lookahead_token(0))
self._match(tokens.RETURN)
node.add_child(self._expr())
self._match(tokens.NL)
return node
elif self._lookahead_type(0) == tokens.NL:
self._match(tokens.NL)
elif (self._lookahead_type(0) == tokens.ID
and self._lookahead_type(1) == tokens.LPAREN):
return self._call()
elif self._lookahead_type(0) == tokens.IF:
node = AST(self._lookahead_token(0))
self._match(tokens.IF)
node.add_child(self._expr())
node.add_child(self._slist())
if self._lookahead_type(0) == tokens.ELSE:
self._match(tokens.ELSE)
node.add_child(self._slist())
return node
elif self._lookahead_type(0) == tokens.WHILE:
node = AST(self._lookahead_token(0))
self._match(tokens.WHILE)
node.add_child(self._expr())
node.add_child(self._slist())
return node
else:
return self._assign()
def _expr(self):
"""Expression rule.
expr -> add_expr (('<' | '==') add_expr)?
"""
left_node = self._add_expr()
if self._lookahead_type(0) in (tokens.LT, tokens.EQ):
node = AST(self._lookahead_token(0))
node.add_child(left_node)
self._match(self._lookahead_type(0))
node.add_child(self._add_expr())
left_node = node
return left_node
def _add_expr(self):
"""Add expression rule.
add_expr -> mult_expr (('+' | '-') mult_expr)*
"""
left_node = self._mult_expr()
while self._lookahead_type(0) in (tokens.ADD, tokens.SUB):
node = AST(self._lookahead_token(0))
node.add_child(left_node)
self._match(self._lookahead_type(0))
node.add_child(self._mult_expr())
left_node = node
return left_node
def _mult_expr(self):
"""Multiply expression rule.
mult_expr -> atom ('*' atom)*
"""
result_node = self._atom()
while self._lookahead_type(0) == tokens.MUL:
node = AST(self._lookahead_token(0))
node.add_child(result_node)
self._match(tokens.MUL)
node.add_child(self._atom())
result_node = node
return result_node
def _assign(self):
"""Assign rule.
assign -> ID '=' expr
"""
node = AST(tokens.ASSIGN)
node.add_child(AST(self._lookahead_token(0)))
variable_symbol = VariableSymbol(self._lookahead_token(0).text)
variable_symbol.scope = self.current_scope
self.current_scope.define(variable_symbol)
self._match(tokens.ID)
self._match(tokens.ASSIGN)
node.add_child(self._expr())
return node
def _call(self):
"""Call rule.
call -> ID '(' (expr (',' expr)*)? ')'
"""
node = AST(tokens.CALL)
node.scope = self.current_scope
node.add_child(AST(self._lookahead_token(0)))
self._match(tokens.ID)
self._match(tokens.LPAREN)
result_node = self._expr()
if result_node is not None:
node.add_child(result_node)
while self._lookahead_type(0) == tokens.COMMA:
self._match(tokens.COMMA)
node.add_child(self._expr())
self._match(tokens.RPAREN)
return node
def _atom(self):
"""Atom rule.
atom -> ID | INT | STRING | call | '(' expr ')'
"""
if (self._lookahead_type(0) == tokens.ID
and self._lookahead_type(1) == tokens.LPAREN):
return self._call()
elif self._lookahead_type(0) == tokens.ID:
node = AST(self._lookahead_token(0))
self._match(tokens.ID)
return node
elif self._lookahead_type(0) == tokens.INT:
node = AST(self._lookahead_token(0))
self._match(tokens.INT)
return node
elif self._lookahead_type(0) == tokens.STRING:
# strip single quote around the string
token = self._lookahead_token(0)
token.text = token.text.strip("'")
node = AST(token)
self._match(tokens.STRING)
return node
elif self._lookahead_type(0) == tokens.LPAREN:
self._match(tokens.LPAREN)
node = self._expr()
self._match(tokens.RPAREN)
return node
