etc404
62 lines
1.7 KiB
Python
62 lines
1.7 KiB
Python
import re
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import lisp
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class Reader:
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tokens: list[str]
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def __init__(self):
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self.tokens = []
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self.interpreter = lisp.Lisp()
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def run(self):
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while self.peek() != "":
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self.interpreter.evaluate(self.read_expression())
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self.consume()
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def tokenize(self, expression: str):
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self.tokens += re.findall(r"""[\s,]*[;.*]*([()']|"(?:\\.|[^\\"])*"?|[^\s()'",;]*)""", expression)
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def peek(self):
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return self.tokens[0]
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def consume(self):
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token = self.tokens[0]
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self.tokens = self.tokens[1:]
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return token
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def read_expression(self):
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if len(self.tokens) == 0:
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return None
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if self.peek() == "(":
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self.consume()
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atomlist = []
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token = self.peek()
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while token != ")":
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atomlist.append(self.read_expression())
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while self.peek() == "":
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self.consume()
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expression: str = input("... ")
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self.tokenize(expression)
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token = self.peek()
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self.consume()
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return atomlist
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elif self.peek() == "'":
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# Expand the quote macro!
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self.consume()
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return ["quote", self.read_expression()]
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else:
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return self.read_atom()
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def read_atom(self):
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token = self.consume()
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if token.upper() == "T":
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return True
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elif token.upper() == "NIL":
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return False
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try:
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return int(token)
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except ValueError:
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try:
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return float(token)
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except ValueError:
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return token |