61 lines
2.0 KiB
Python
61 lines
2.0 KiB
Python
from .schema import dataspacePatterns as P
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from . import Symbol, Record
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from preserves import preserve
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_dict = dict ## we're about to shadow the builtin
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_ = P.Pattern.DDiscard(P.DDiscard())
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def bind(p):
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return P.Pattern.DBind(P.DBind(p))
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CAPTURE = bind(_)
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class unquote:
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def __init__(self, pattern):
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self.pattern = pattern
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# Simple, stupid single-level quasiquotation.
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def quote(p):
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if isinstance(p, unquote):
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return p.pattern
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if p.VARIANT == P.Pattern.DDiscard.VARIANT:
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return lit(preserve(p))
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if p.VARIANT == P.Pattern.DBind.VARIANT:
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return rec('bind', quote(p.value.pattern))
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if p.VARIANT == P.Pattern.DLit.VARIANT:
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return lit(preserve(p))
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if p.VARIANT == P.Pattern.DCompound.VARIANT:
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p = p.value
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if p.VARIANT == P.DCompound.rec.VARIANT:
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return rec('rec', lit(p.label), arr(*map(quote, p.fields)))
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if p.VARIANT == P.DCompound.arr.VARIANT:
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return rec('arr', arr(*map(quote, p.items)))
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if p.VARIANT == P.DCompound.dict.VARIANT:
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return rec('dict', dict(*map(lambda kv: (kv[0], quote(kv[1])), p.entries.items())))
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raise Exception(f'Unhandled case in quote: {repr(p)}')
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def lit(v):
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if isinstance(v, list) or isinstance(v, tuple):
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return arr(*map(lit, v))
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elif isinstance(v, set) or isinstance(v, frozenset):
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raise Exception('Cannot represent literal set in dataspace pattern')
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elif isinstance(v, _dict):
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return dict(*((k, lit(vv)) for (k, vv) in v.items()))
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elif isinstance(v, Record):
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return _rec(v.key, *map(lit, v.fields))
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else:
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return P.Pattern.DLit(P.DLit(P.AnyAtom.decode(v)))
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def rec(labelstr, *members):
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return _rec(Symbol(labelstr), *members)
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def _rec(label, *members):
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return P.Pattern.DCompound(P.DCompound.rec(label, members))
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def arr(*members):
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return P.Pattern.DCompound(P.DCompound.arr(members))
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def dict(*kvs):
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return P.Pattern.DCompound(P.DCompound.dict(_dict(kvs)))
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