def parse_expr(self):
""" Expression ::= primary-Expression (Operator primary-Expression)* """
token = self.token_current()
token_lookahead = self.token_lookahead()
if token_lookahead.type == scanner.TK_LPAREN:
""" Identifier '(' Param ')' """
ident = token.val # save ident name
self.token_accept(scanner.TK_IDENTIFIER) # scan the token
self.token_accept(scanner.TK_LPAREN) # accept left paren
expr = self.parse_param_expr()
self.token_accept(scanner.TK_RPAREN)
e1 = ast.CallCommand(ident, expr)
else:
e1 = self.parse_secexpr()
token = self.token_current()
while token.type == scanner.TK_OPERATOR and token.val in [
'+', '-', '<', '>', '='
]:
oper = token.val
self.token_accept_any()
e2 = self.parse_secexpr()
e1 = ast.BinaryExpression(e1, oper, e2)
token = self.token_current()
return e1
def parse_add_expression(self):
e1 = self.parse_mul_expression()
token = self.token_current()
while token.type == scanner.TK_OPERATOR and token.val in ['+', '-']:
oper = token.val
self.token_accept_any()
e2 = self.parse_mul_expression()
token = self.token_current()
e1 = ast.BinaryExpression(e1, oper, e2)
return e1
def p_expression_math(self, p):
"""
expression : expression PLUS expression
| expression MINUS expression
| expression TIMES expression
| expression DIVIDE expression
| expression MPLUS expression
| expression MMINUS expression
| expression MTIMES expression
| expression MDIVIDE expression
"""
p[0] = ast.BinaryExpression(p[1], p[2], p[3], p.lexer.lexer.lineno)
def parse_tertiary_expression(self):
""" Sec-Expression ( Oper-Sec Sec-Expression )* """
e1 = self.parse_secondary_expression()
token = self.token_current()
while token.type == scanner.TK_OPERATOR and token.val in ['+', '-']:
oper = token.val
self.token_accept_any()
e2 = self.parse_secondary_expression()
token = self.token_current()
e1 = ast.BinaryExpression(e1, oper, e2)
return e1
def parse_expr(self):
""" Expression ::= primary-Expression (operator primary-Expression)* """
e1 = self.parse_pri_expr()
token = self.token_current()
while (token.type == scanner.TK_OPERATOR):
op = token.val
self.token_accept(scanner.TK_OPERATOR)
e2 = self.parse_pri_expr()
token = self.token_current()
e1 = ast.BinaryExpression(e1, op, e2)
return e1
def parse_secexpr(self):
""" SecExpr :== PriExpr (OPER_PRI PriExpr)*"""
e1 = self.parse_priexpr()
token = self.token_current()
while token.type == scanner.TK_OPERATOR and token.val in [
'*', '/', '\\'
]:
oper = token.val
self.token_accept_any()
e2 = self.parse_priexpr()
token = self.token_current()
e1 = ast.BinaryExpression(e1, oper, e2)
return e1
def parse_expression(self):
""" Expression ::= primary-Expression (Operator primary-Expression)* """
e1 = self.parse_add_expression()
token = self.token_current()
while token.type == scanner.TK_OPERATOR and token.val in [
'<', '=', '>'
]:
oper = token.val
self.token_accept_any()
e2 = self.parse_add_expression()
token = self.token_current()
e1 = ast.BinaryExpression(e1, oper, e2)
return e1
def parse_secondary_expression(self):
""" Pri-Expression ( Oper-Pri Pri-Expression )* """
e1 = self.parse_primary_expression()
token = self.token_current()
while token.type == scanner.TK_OPERATOR and token.val in [
'*', '/', ''
]:
oper = token.val
self.token_accept_any()
e2 = self.parse_primary_expression()
token = self.token_current()
e1 = ast.BinaryExpression(e1, oper, e2)
return e1
def p_relation(self, p):
"""relation : expression comparison_operator expression"""
p[0] = ast.BinaryExpression(p[1], p[2], p[3], p.lexer.lexer.lineno)