63 lines
1.0 KiB
Python
63 lines
1.0 KiB
Python
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from hy.errors import HyError
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WHITESPACE = [" ", "\t", "\n", "\r"]
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class LexException(HyError):
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pass
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class State(object):
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__slots__ = ("machine",)
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def __init__(self, machine):
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self.machine = machine
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def enter(self):
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pass
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def exit(self):
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pass
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class Expression(State):
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def enter(self):
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self.nodes = []
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self.buf = ""
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def commit(self):
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self.nodes.append(self.buf)
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self.buf = ""
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def exit(self):
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self.commit()
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self.machine.nodes.append(self.nodes)
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def process(self, char):
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if char == ")":
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return Idle
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if char == "(":
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return Expression
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if char in WHITESPACE:
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self.commit()
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return
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self.buf += char
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class Idle(State):
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def process(self, char):
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table = {
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"(": Expression
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}
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if char in table:
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return table[char]
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if char in WHITESPACE:
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return
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raise LexException("Unknown char: %s" % (char))
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