55 lines
1.4 KiB
Python
55 lines
1.4 KiB
Python
from typing import Any
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from assembler.lexer import TT
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class ParserError(Exception):
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pass
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class BaseParser:
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def __init__(self, tokens: list[Any]):
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self.current_ix = 0
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self.tokens = tokens
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def peek(self, offset=0):
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token = self.tokens[self.current_ix + offset]
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return token
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def at_end_p(self):
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return self.peek().type == TT.eof
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def advance(self):
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token = self.peek()
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self.current_ix += 1
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return token
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def match(self, token_type, offset=0):
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token = self.peek(offset)
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return token.type == token_type
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def match_keyword(self, keyword):
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if self.match(TT.keyword):
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token = self.peek()
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return token.keyword == keyword
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else:
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return False
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def consume(self, token_type, message):
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token = self.advance()
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if token.type != token_type:
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raise ParserError(message, token)
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return token
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def consume_either(self, token_type1, token_type2, message):
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token = self.advance()
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if token.type != token_type1 and token.type != token_type2:
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raise ParserError(message, token)
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return token
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def consume_keyword(self, keyword, message):
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if self.match_keyword(keyword):
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token = self.advance()
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return token
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else:
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token = self.advance()
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raise ParserError(message, token)
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