Created
June 21, 2018 15:52
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from rply import ParserGenerator | |
from ast import Number, Sum, Sub, Print | |
class Parser(): | |
def __init__(self, module, builder, printf): | |
self.pg = ParserGenerator( | |
# A list of all token names accepted by the parser. | |
['NUMBER', 'PRINT', 'OPEN_PAREN', 'CLOSE_PAREN', | |
'SEMI_COLON', 'SUM', 'SUB'] | |
) | |
self.module = module | |
self.builder = builder | |
self.printf = printf | |
def parse(self): | |
@self.pg.production('program : PRINT OPEN_PAREN expression CLOSE_PAREN SEMI_COLON') | |
def program(p): | |
return Print(self.builder, self.module, self.printf, p[2]) | |
@self.pg.production('expression : expression SUM expression') | |
@self.pg.production('expression : expression SUB expression') | |
def expression(p): | |
left = p[0] | |
right = p[2] | |
operator = p[1] | |
if operator.gettokentype() == 'SUM': | |
return Sum(self.builder, self.module, left, right) | |
elif operator.gettokentype() == 'SUB': | |
return Sub(self.builder, self.module, left, right) | |
@self.pg.production('expression : NUMBER') | |
def number(p): | |
return Number(self.builder, self.module, p[0].value) | |
@self.pg.error | |
def error_handle(token): | |
raise ValueError(token) | |
def get_parser(self): | |
return self.pg.build() |
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