380 lines
9.7 KiB
Python
Executable File
380 lines
9.7 KiB
Python
Executable File
# -*- encoding: utf-8 -*-
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# Copyright 2018 the authors.
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# This file is part of Hy, which is free software licensed under the Expat
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# license. See the LICENSE.
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from __future__ import unicode_literals
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from functools import wraps
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import string, re, unicodedata
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from rply import ParserGenerator
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from hy._compat import PY3, str_type, isidentifier
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from hy.models import (HyBytes, HyComplex, HyCons, HyDict, HyExpression,
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HyFloat, HyInteger, HyKeyword, HyList, HySet, HyString,
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HySymbol)
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from .lexer import lexer
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from .exceptions import LexException, PrematureEndOfInput
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pg = ParserGenerator(
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[rule.name for rule in lexer.rules] + ['$end'],
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cache_id="hy_parser"
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)
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mangle_delim = 'Δ' if PY3 else 'X'
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def mangle(s):
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"""Stringify the argument and convert it to a valid Python identifier
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according to Hy's mangling rules."""
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assert s
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s = str_type(s)
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s = s.replace("-", "_")
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s2 = s.lstrip('_')
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leading_underscores = '_' * (len(s) - len(s2))
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s = s2
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if s.endswith("?"):
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s = 'is_' + s[:-1]
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if not isidentifier(leading_underscores + s):
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# Replace illegal characters with their Unicode character
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# names, or hexadecimal if they don't have one.
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s = 'hyx_' + ''.join(
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c
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if c != mangle_delim and isidentifier('S' + c)
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# We prepend the "S" because some characters aren't
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# allowed at the start of an identifier.
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else '{0}{1}{0}'.format(mangle_delim,
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unicodedata.name(c, '').lower().replace('-', 'H').replace(' ', '_')
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or 'U{:x}'.format(ord(c)))
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for c in s)
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s = leading_underscores + s
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assert isidentifier(s)
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return s
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def unmangle(s):
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"""Stringify the argument and try to convert it to a pretty unmangled
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form. This may not round-trip, because different Hy symbol names can
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mangle to the same Python identifier."""
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s = str_type(s)
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s2 = s.lstrip('_')
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leading_underscores = len(s) - len(s2)
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s = s2
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if s.startswith('hyx_'):
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s = re.sub('{0}(U)?([_a-z0-9H]+?){0}'.format(mangle_delim),
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lambda mo:
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chr(int(mo.group(2), base=16))
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if mo.group(1)
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else unicodedata.lookup(
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mo.group(2).replace('_', ' ').replace('H', '-').upper()),
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s[len('hyx_'):])
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if s.startswith('is_'):
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s = s[len("is_"):] + "?"
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s = s.replace('_', '-')
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return '-' * leading_underscores + s
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def set_boundaries(fun):
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@wraps(fun)
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def wrapped(p):
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start = p[0].source_pos
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end = p[-1].source_pos
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ret = fun(p)
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ret.start_line = start.lineno
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ret.start_column = start.colno
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if start is not end:
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ret.end_line = end.lineno
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ret.end_column = end.colno
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else:
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ret.end_line = start.lineno
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ret.end_column = start.colno + len(p[0].value)
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return ret
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return wrapped
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def set_quote_boundaries(fun):
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@wraps(fun)
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def wrapped(p):
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start = p[0].source_pos
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ret = fun(p)
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ret.start_line = start.lineno
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ret.start_column = start.colno
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ret.end_line = p[-1].end_line
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ret.end_column = p[-1].end_column
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return ret
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return wrapped
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@pg.production("main : list_contents")
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def main(p):
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return p[0]
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@pg.production("main : $end")
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def main_empty(p):
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return []
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def reject_spurious_dots(*items):
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"Reject the spurious dots from items"
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for list in items:
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for tok in list:
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if tok == "." and type(tok) == HySymbol:
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raise LexException("Malformed dotted list",
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tok.start_line, tok.start_column)
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@pg.production("paren : LPAREN list_contents RPAREN")
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@set_boundaries
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def paren(p):
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cont = p[1]
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# Dotted lists are expressions of the form
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# (a b c . d)
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# that evaluate to nested cons cells of the form
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# (a . (b . (c . d)))
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if len(cont) >= 3 and isinstance(cont[-2], HySymbol) and cont[-2] == ".":
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reject_spurious_dots(cont[:-2], cont[-1:])
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if len(cont) == 3:
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# Two-item dotted list: return the cons cell directly
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return HyCons(cont[0], cont[2])
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else:
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# Return a nested cons cell
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return HyCons(cont[0], paren([p[0], cont[1:], p[2]]))
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# Warn preemptively on a malformed dotted list.
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# Only check for dots after the first item to allow for a potential
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# attribute accessor shorthand
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reject_spurious_dots(cont[1:])
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return HyExpression(p[1])
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@pg.production("paren : LPAREN RPAREN")
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@set_boundaries
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def empty_paren(p):
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return HyExpression([])
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@pg.production("list_contents : term list_contents")
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def list_contents(p):
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return [p[0]] + p[1]
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@pg.production("list_contents : term")
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def list_contents_single(p):
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return [p[0]]
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@pg.production("list_contents : DISCARD term discarded_list_contents")
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def list_contents_empty(p):
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return []
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@pg.production("discarded_list_contents : DISCARD term discarded_list_contents")
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@pg.production("discarded_list_contents :")
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def discarded_list_contents(p):
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pass
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@pg.production("term : identifier")
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@pg.production("term : paren")
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@pg.production("term : dict")
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@pg.production("term : list")
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@pg.production("term : set")
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@pg.production("term : string")
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def term(p):
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return p[0]
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@pg.production("term : DISCARD term term")
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def term_discard(p):
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return p[2]
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@pg.production("term : QUOTE term")
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@set_quote_boundaries
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def term_quote(p):
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return HyExpression([HySymbol("quote"), p[1]])
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@pg.production("term : QUASIQUOTE term")
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@set_quote_boundaries
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def term_quasiquote(p):
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return HyExpression([HySymbol("quasiquote"), p[1]])
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@pg.production("term : UNQUOTE term")
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@set_quote_boundaries
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def term_unquote(p):
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return HyExpression([HySymbol("unquote"), p[1]])
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@pg.production("term : UNQUOTESPLICE term")
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@set_quote_boundaries
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def term_unquote_splice(p):
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return HyExpression([HySymbol("unquote-splice"), p[1]])
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@pg.production("term : HASHSTARS term")
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@set_quote_boundaries
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def term_hashstars(p):
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n_stars = len(p[0].getstr()[1:])
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if n_stars == 1:
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sym = "unpack-iterable"
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elif n_stars == 2:
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sym = "unpack-mapping"
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else:
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raise LexException(
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"Too many stars in `#*` construct (if you want to unpack a symbol "
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"beginning with a star, separate it with whitespace)",
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p[0].source_pos.lineno, p[0].source_pos.colno)
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return HyExpression([HySymbol(sym), p[1]])
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@pg.production("term : HASHOTHER term")
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@set_quote_boundaries
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def hash_other(p):
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# p == [(Token('HASHOTHER', '#foo'), bar)]
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st = p[0].getstr()[1:]
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str_object = HyString(st)
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expr = p[1]
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return HyExpression([HySymbol("dispatch-tag-macro"), str_object, expr])
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@pg.production("set : HLCURLY list_contents RCURLY")
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@set_boundaries
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def t_set(p):
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return HySet(p[1])
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@pg.production("set : HLCURLY RCURLY")
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@set_boundaries
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def empty_set(p):
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return HySet([])
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@pg.production("dict : LCURLY list_contents RCURLY")
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@set_boundaries
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def t_dict(p):
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return HyDict(p[1])
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@pg.production("dict : LCURLY RCURLY")
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@set_boundaries
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def empty_dict(p):
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return HyDict([])
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@pg.production("list : LBRACKET list_contents RBRACKET")
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@set_boundaries
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def t_list(p):
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return HyList(p[1])
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@pg.production("list : LBRACKET RBRACKET")
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@set_boundaries
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def t_empty_list(p):
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return HyList([])
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@pg.production("string : STRING")
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@set_boundaries
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def t_string(p):
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# Replace the single double quotes with triple double quotes to allow
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# embedded newlines.
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s = eval(p[0].value.replace('"', '"""', 1)[:-1] + '"""')
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return (HyString if isinstance(s, str_type) else HyBytes)(s)
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@pg.production("string : PARTIAL_STRING")
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def t_partial_string(p):
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# Any unterminated string requires more input
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raise PrematureEndOfInput("Premature end of input")
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bracket_string_re = next(r.re for r in lexer.rules if r.name == 'BRACKETSTRING')
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@pg.production("string : BRACKETSTRING")
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@set_boundaries
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def t_bracket_string(p):
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m = bracket_string_re.match(p[0].value)
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delim, content = m.groups()
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return HyString(content, brackets=delim)
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@pg.production("identifier : IDENTIFIER")
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@set_boundaries
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def t_identifier(p):
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obj = p[0].value
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val = symbol_like(obj)
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if val is not None:
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return val
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if "." in obj and symbol_like(obj.split(".", 1)[0]) is not None:
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# E.g., `5.attr` or `:foo.attr`
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raise LexException(
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'Cannot access attribute on anything other than a name (in '
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'order to get attributes of expressions, use '
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'`(. <expression> <attr>)` or `(.<attr> <expression>)`)',
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p[0].source_pos.lineno, p[0].source_pos.colno)
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return HySymbol(obj)
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def symbol_like(obj):
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"Try to interpret `obj` as a number or keyword."
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try:
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return HyInteger(obj)
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except ValueError:
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pass
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if '/' in obj:
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try:
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lhs, rhs = obj.split('/')
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return HyExpression([HySymbol('fraction'), HyInteger(lhs),
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HyInteger(rhs)])
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except ValueError:
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pass
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try:
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return HyFloat(obj)
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except ValueError:
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pass
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if obj != 'j':
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try:
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return HyComplex(obj)
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except ValueError:
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pass
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if obj.startswith(":") and "." not in obj:
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return HyKeyword(obj)
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@pg.error
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def error_handler(token):
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tokentype = token.gettokentype()
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if tokentype == '$end':
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raise PrematureEndOfInput("Premature end of input")
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else:
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raise LexException(
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"Ran into a %s where it wasn't expected." % tokentype,
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token.source_pos.lineno, token.source_pos.colno)
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parser = pg.build()
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