58 lines
1.4 KiB
Python
58 lines
1.4 KiB
Python
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import sys
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import ply.yacc as yacc
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from Lexer import Lexer
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from nodes import *
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class Parser(object):
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def __init__(self, input):
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self.input = input
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self.lexer = Lexer()
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self.tokens = self.lexer.tokens
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self.parser = yacc.yacc(module = self)
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self.saw_error = False
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def p_unit(self, p):
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'unit : unit_items'
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if self.saw_error:
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p[0] = None
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else:
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p[0] = UnitNode(p[1].children)
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def p_unit_items(self, p):
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'unit_items : unit_item unit_items'
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p[0] = Node([p[1]] + p[2].children)
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def p_unit_items_empty(self, p):
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'unit_items : empty'
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p[0] = p[1]
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def p_unit_item_c_stmt(self, p):
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'unit_item : c_expr SEMICOLON'
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p[0] = p[1]
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def p_statement(self, p):
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'statement : expr SEMICOLON'
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p[0] = StatementNode([p[1]])
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def p_expr(self, p):
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'expr : c_expr'
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p[0] = p[1]
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def p_c_expr(self, p):
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'c_expr : C LPAREN STRING RPAREN'
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p[0] = CExprNode(p[3])
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def p_empty(self, p):
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'empty :'
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p[0] = Node()
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def p_error(self, p):
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self.saw_error = True
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col = p.lexpos - max(0, self.input.rfind('\n', 0, p.lexpos))
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sys.stdout.write('Error: Unexpected %s at line %d, col %d\n' % (
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p.type, p.lineno, col))
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def parse(self):
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return self.parser.parse(self.input, lexer = self.lexer)
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