435 lines
14 KiB
Nim
435 lines
14 KiB
Nim
# SPDX-FileCopyrightText: ☭ 2021 Emery Hemingway
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# SPDX-License-Identifier: Unlicense
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import std/[sequtils, tables, typetraits]
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import preserves
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import ./protocols/dataspacePatterns
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from ./actors import Ref
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export dataspacePatterns.`$`, PatternKind, DCompoundKind, AnyAtomKind
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type
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Assertion = Preserve[Ref]
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AnyAtom* = dataspacePatterns.AnyAtom[Ref]
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DBind* = dataspacePatterns.DBind[Ref]
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DCompound* = dataspacePatterns.DCompound[Ref]
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DCompoundArr* = dataspacePatterns.DCompoundArr[Ref]
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DCompoundDict* = dataspacePatterns.DCompoundDict[Ref]
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DCompoundRec* = dataspacePatterns.DCompoundRec[Ref]
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DLit* = dataspacePatterns.DLit[Ref]
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Pattern* = dataspacePatterns.Pattern[Ref]
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proc `?`*(d: sink DBind): Pattern =
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Pattern(orKind: PatternKind.DBind, dbind: d)
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proc `?`*(d: sink DLit): Pattern =
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Pattern(orKind: PatternKind.DLit, dlit: d)
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proc `?`*(aa: sink AnyAtom): Pattern =
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?DLit(value: aa)
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proc `?`*(d: sink DCompound): Pattern =
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Pattern(orKind: PatternKind.DCompound, dcompound: d)
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proc `?`*(d: sink DCompoundRec): Pattern =
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?DCompound(orKind: DCompoundKind.rec, rec: d)
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proc `?`*(d: sink DCompoundArr): Pattern =
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?DCompound(orKind: DCompoundKind.arr, arr: d)
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proc `?`*(d: sink DCompoundDict): Pattern =
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?DCompound(orKind: DCompoundKind.dict, dict: d)
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proc `?`*(x: bool): Pattern =
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?AnyAtom(orKind: AnyAtomKind.`bool`, bool: x)
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proc `?`*(x: float32): Pattern =
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?AnyAtom(orKind: AnyAtomKind.`float`, float: x)
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proc `?`*(x: float64): Pattern =
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?AnyAtom(orKind: AnyAtomKind.`double`, double: x)
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proc `?`*(x: int): Pattern =
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?AnyAtom(orKind: AnyAtomKind.`int`, int: x)
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proc `?`*(s: sink string): Pattern =
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?AnyAtom(orKind: AnyAtomKind.`string`, string: s)
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proc `?`*(x: sink seq[byte]): Pattern =
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?AnyAtom(orKind: AnyAtomKind.`bytes`, bytes: x)
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proc `?`*(x: sink Symbol): Pattern =
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?AnyAtom(orKind: AnyAtomKind.`symbol`, symbol: x)
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proc `?`*[T](pr: Preserve[T]): Pattern =
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## Convert a `Preserve` value to a `Pattern`.
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assert not pr.embedded
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case pr.kind
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of pkBoolean: ?pr.bool
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of pkFloat: ?pr.float
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of pkDouble: ?pr.double
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of pkSignedInteger: ?(int pr.int) # TODO: overflow!
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of pkString: ?pr.string
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of pkByteString: ?pr.bytes
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of pkSymbol: ?pr.symbol
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of pkRecord:
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?DCompoundRec(
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label: pr.label,
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fields: map[Preserve[T], Pattern](pr.fields, `?`))
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of pkSequence:
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?DCompoundArr(items: map(pr.sequence, `?`))
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of pkSet: raise newException(
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ValueError, "cannot construct a pattern over a set literal")
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of pkDictionary:
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var dict = DCompoundDict()
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for key, val in pr.pairs: dict.entries[key] = ?val
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?dict
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of pkEmbedded:
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raiseAssert "cannot construct a pattern over a embedded literal"
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proc drop*(): Pattern = Pattern(orKind: PatternKind.DDiscard)
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## Create a pattern to match any value without capture.
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proc grab*(): Pattern = ?DBind(pattern: drop())
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## Create a pattern to capture any value.
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proc `?`*[A, B](table: TableRef[A,B]): Pattern =
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raiseAssert "not implemented"
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#[
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proc `?`*(pat: sink Pattern): Pattern =
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## Construct a `Pattern` that matches a `Pattern`.
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case pat.orKind
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of PatternKind.DDiscard: result = pat
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of PatternKind.DBind: result = drop()
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of PatternKind.DLit: result = ?pat.toPreserve(Ref)
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of PatternKind.DCompound:
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case pat.dcompound.orKind:
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of DCompoundKind.rec:
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var fields = move pat.dcompound.rec.fields
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for f in fields.mitems: f = ?(move f)
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result = ?pat.toPreserve(Ref)
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# echo "need to stuff fields into ", result, " at ", result.dcompound.rec.fields[1].dcompound.arr.items
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result.dcompound.rec.fields[1].dcompound.arr.items = fields
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#[
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of DCompoundKind.arr
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pat.dcompound.arr
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of DCompoundKind.dict
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pat.dcompound.dict
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]#
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else: raiseAssert "`?` not implemented for pattern " & $pat
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]#
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#[
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proc `?`*(patterns: openArray[Pattern]): Pattern =
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raiseAssert "got it in the right place"
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#[
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result = DCompoundArr()
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for e in val:
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if i > arr.items.high: arr.items.setLen(succ i)
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arr.items[i] = pat
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for pat in arr.items.mitems:
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if pat.isNil: pat = drop()
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result = ?DCompound(
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orKind: DCompoundKind.arr,
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arr: arr)
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]#
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]#
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proc `?`*[T](val: sink T): Pattern =
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## Construct a `Pattern` from value of type `T`.
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#[
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when T is Pattern:
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case val.orKind
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of PatternKind.DDiscard, PatternKind.DBind: result = val
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of PatternKind.DLit: result = ?val.toPreserve(Ref)
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of PatternKind.DCompound:
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case val.dcompound.orKind:
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of DCompoundKind.rec:
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var fields = move val.dcompound.rec.fields
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for f in fields.mitems: f = ?(move f)
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result = ?val.toPreserve(Ref)
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# echo "need to stuff fields into ", result, " at ", result.dcompound.rec.fields[1].dcompound.arr.items
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result.dcompound.rec.fields[1].dcompound.arr.items = fields
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#[
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of DCompoundKind.arr
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val.dcompound.arr
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of DCompoundKind.dict
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val.dcompound.dict
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]#
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else: raiseAssert "`?` not implemented for pattern " & $val
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]#
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when T is Ref:
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result = Pattern(orKind: PatternKind.DLit, dlit: DLit(
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value: AnyAtom(
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orKind: AnyAtomKind.embedded,
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embedded: embed(val))))
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elif T is ptr | ref:
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if system.`==`(val, nil): result = ?(Symbol "null")
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else: result = ?(val[])
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elif T is bool:
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result = Pattern(orKind: PatternKind.DLit, dlit: DLit(
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value: AnyAtom(
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orKind: AnyAtomKind.bool,
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bool: val)))
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elif T is float32:
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result = Pattern(orKind: PatternKind.DLit, dlit: DLit(
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value: AnyAtom(
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orKind: AnyAtomKind.float,
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float: val)))
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elif T is float64:
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result = Pattern(orKind: PatternKind.DLit, dlit: DLit(
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value: AnyAtom(
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orKind: AnyAtomKind.double,
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double: val)))
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elif T is SomeInteger:
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result = Pattern(orKind: PatternKind.DLit, dlit: DLit(
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value: AnyAtom(
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orKind: AnyAtomKind.int,
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int: AnyAtomInt val)))
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elif T is string:
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result = Pattern(orKind: PatternKind.DLit, dlit: DLit(
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value: AnyAtom(
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orKind: AnyAtomKind.string,
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string: val)))
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elif T is seq[byte]:
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result = Pattern(orKind: PatternKind.DLit, dlit: DLit(
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value: AnyAtom(
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orKind: AnyAtomKind.bytes,
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bytes: val)))
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elif T is array | seq:
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let arr = DCompoundArr(items: newSeq[Pattern](val.len))
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for i, e in val.mitems: arr.items[i] = ?(move e)
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result = ?arr
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elif T is Symbol:
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result = Pattern(orKind: PatternKind.DLit, dlit: DLit(
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value: AnyAtom(
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orKind: AnyAtomKind.symbol,
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symbol: Symbol $val)))
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elif T.hasPreservesRecordPragma:
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var
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label = T.recordLabel.tosymbol(Ref)
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fields = newSeq[Pattern]()
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for f in fields(val):
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fields.add ?f
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result = ?DCompound(
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orKind: DCompoundKind.rec,
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rec: DCompoundRec(
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label: label, fields: fields))
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else:
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?(toPreserve(val, Ref))
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proc `?`*(T: static typedesc): Pattern =
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## Derive a `Pattern` from type `T`.
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## This works for `tuple` and `object` types but in the
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## general case will return a wildcard binding.
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runnableExamples:
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import preserves
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type Point = tuple[x: int; y: int]
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assert $(?Point) == "<arr [<bind <_>> <bind <_>>]>"
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type Rect {.preservesRecord: "rect".} = tuple[a: Point; B: Point]
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assert $(?Rect) == "<rec rect [<arr [<bind <_>> <bind <_>>]> <arr [<bind <_>> <bind <_>>]>]>"
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type ColoredRect {.preservesDictionary.} = tuple[color: string; rect: Rect]
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assert $(?ColoredRect) == "<dict {color: <bind <_>>, rect: <rec rect [<arr [<bind <_>> <bind <_>>]> <arr [<bind <_>> <bind <_>>]>]>}>"
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when T is Pattern:
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raiseAssert "? for pattern"
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elif T is ref:
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?pointerBase(T)
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elif T is array:
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var arr = DCompoundArr(items: newSeq[Pattern](len(T)))
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for p in arr.items.mitems: p = grab()
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result = ?arr
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elif T.hasPreservesRecordPragma:
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var
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label = T.recordLabel.tosymbol(Ref)
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fields = newSeq[Pattern]()
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for key, val in fieldPairs(default T):
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when typeOf(val) is Pattern:
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fields.add drop()
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else:
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fields.add ?(typeOf val)
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result = ?DCompound(
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orKind: DCompoundKind.rec,
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rec: DCompoundRec(
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label: label, fields: fields))
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elif T.hasPreservesDictionaryPragma:
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var dict = DCompoundDict()
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for key, val in fieldPairs(default T):
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dict.entries[key.toSymbol(Ref)] = ?(typeOf val)
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?DCompound(
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orKind: DCompoundKind.dict,
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dict: dict)
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elif T.hasPreservesTuplePragma or T is tuple:
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raiseAssert "got a tuple"
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var arr = DCompoundArr()
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for key, val in fieldPairs(default T):
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arr.items.add ?(typeOf val)
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?DCompound(
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orKind: DCompoundKind.arr,
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arr: arr)
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else:
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grab() # otherwise an abritrary capture
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proc fieldCount(T: typedesc): int =
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for _, _ in fieldPairs(default T):
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inc result
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proc `?`*(T: static typedesc; bindings: sink openArray[(int, Pattern)]): Pattern =
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## Construct a `Pattern` from type `T` that selectively captures fields.
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runnableExamples:
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import preserves
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type Point = tuple[x: int; y: int; z: int]
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assert $(Point ? { 2: grab() }) == "<arr [<_> <_> <bind <_>>]>"
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when T is ref:
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`?`(pointerBase(T), bindings)
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elif T.hasPreservesRecordPragma:
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var
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label = T.recordLabel.tosymbol(Ref)
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fields = newSeq[Pattern](fieldCount T)
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for (i, pat) in bindings:
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fields[i] = pat
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for pat in fields.mitems:
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if pat.isNil: pat = drop()
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result = ?DCompound(
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orKind: DCompoundKind.rec,
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rec: DCompoundRec(
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label: label, fields: fields))
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elif T is tuple:
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var arr = DCompoundArr()
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for (i, pat) in bindings:
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if i > arr.items.high: arr.items.setLen(succ i)
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arr.items[i] = pat
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for pat in arr.items.mitems:
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if pat.isNil: pat = drop()
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result = ?DCompound(
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orKind: DCompoundKind.arr,
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arr: arr)
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else:
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raiseAssert("no preserves pragma on " & $T)
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#[
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proc `?`*(pat: sink Pattern; bindings: sink openArray[(int, Pattern)]): Pattern =
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## Construct a `Pattern` from `pat` with overrides from `bindings`.
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result = pat
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assert not result.isNil
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case result.orKind
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of PatternKind.DDiscard, PatternKind.DBind: discard
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of PatternKind.DCompound:
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case result.dcompound.orKind
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of `rec`:
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echo "need to override record fields ", result.dcompound.rec.fields, " with ", bindings
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var foo = result.dcompound.rec.fields[1] ? bindings
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echo "recursing into fields returned ", foo
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result.dcompound.rec.fields[1] = foo
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of `arr`:
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echo "need to override array items ", result.dcompound.arr.items, " with ", bindings
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for i in result.dcompound.arr.items.mitems:
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i = drop()
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for (i, pat) in bindings:
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result.dcompound.arr.items[i] = pat
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else:
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raiseAssert $result.dcompound.orKind
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else:
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raiseAssert $result.orKind
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]#
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proc `??`*(pat: sink Pattern; bindings: sink openArray[(int, Pattern)]): Pattern =
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## Create a `Pattern` that matches or captures from a `Pattern` over `pat`.
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runnableExamples:
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import preserves
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type Point* {.preservesRecord: "point".} = object
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x, y: int
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assert $(?Point) == "<rec point [<bind <_>> <bind <_>>]>"
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# Capture two values from a value of `Point`.
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assert $(?Point ?? { 0: ?DLit }) == "<rec rec [<lit point> <arr [<rec lit [<bind <_>>]> <_>]>]>"
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# Match a pattern of `Point` with a literal value set in the first field and capture that value.
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assert $(?tuple[x: int, y: int] ?? { 1: ?DLit }) == "<rec arr [<arr [<_> <rec lit [<bind <_>>]>]>]>"
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# Match a pattern over a tuple with a literal value set in the second field and capture that value.
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case pat.orKind
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of PatternKind.DCompound:
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case pat.dcompound.orKind:
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of DCompoundKind.rec:
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let fieldsLen = pat.dcompound.rec.fields.len
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pat.dcompound.rec.fields.setLen 0
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result = ?pat
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result.dcompound.rec.fields[1].dcompound.arr.items.setLen fieldsLen
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for (i, p) in bindings:
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result.dcompound.rec.fields[1].dcompound.arr.items[i] = p
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for e in result.dcompound.rec.fields[1].dcompound.arr.items.mitems:
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if e.isNil: e = drop()
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of DCompoundKind.arr:
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let itemsLen = pat.dcompound.arr.items.len
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pat.dcompound.arr.items.setLen 0
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result = ?pat
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echo "override ", result.dcompound.rec.fields[0].dcompound.arr.items
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result.dcompound.rec.fields[0].dcompound.arr.items.setLen itemsLen
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for (i, p) in bindings:
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result.dcompound.rec.fields[0].dcompound.arr.items[i] = p
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for e in result.dcompound.rec.fields[0].dcompound.arr.items.mitems:
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if e.isNil: e = drop()
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of DCompoundKind.dict:
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let keys = pat.dcompound.dict.entries.keys.toSeq
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clear pat.dcompound.dict.entries
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result = ?pat
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else:
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raiseAssert "cannot override " & $pat
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proc recordPattern*(label: Preserve[Ref], fields: varargs[Pattern]): Pattern =
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?DCompoundRec(label: label, fields: fields.toSeq)
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type
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Value = Preserve[Ref]
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Path = seq[Value]
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Analysis* = tuple
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constPaths: seq[Path]
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constValues: seq[Value]
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capturePaths: seq[Path]
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func walk(result: var Analysis; path: var Path; p: Pattern)
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func walk(result: var Analysis; path: var Path; key: int|Value; pat: Pattern) =
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path.add(key.toPreserve(Ref))
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walk(result, path, pat)
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discard path.pop
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func walk(result: var Analysis; path: var Path; p: Pattern) =
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case p.orKind
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of PatternKind.DCompound:
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case p.dcompound.orKind
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of DCompoundKind.rec:
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for k, e in p.dcompound.rec.fields: walk(result, path, k, e)
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of DCompoundKind.arr:
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for k, e in p.dcompound.arr.items: walk(result, path, k, e)
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of DCompoundKind.dict:
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for k, e in p.dcompound.dict.entries: walk(result, path, k, e)
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of PatternKind.DBind:
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result.capturePaths.add(path)
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walk(result, path, p.dbind.pattern)
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of PatternKind.DDiscard: discard
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of PatternKind.DLit:
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result.constPaths.add(path)
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result.constValues.add(p.dlit.value.toPreserve(Ref))
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func analyse*(p: Pattern): Analysis =
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var path: Path
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walk(result, path, p)
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