syndicate-nim/src/syndicate/patterns.nim

154 lines
4.6 KiB
Nim

# SPDX-FileCopyrightText: ☭ 2021 Emery Hemingway
# SPDX-License-Identifier: Unlicense
import std/[tables, typetraits]
import preserves
import ./protocols/dataspacePatterns
from ./actors import Ref
export dataspacePatterns.`$`, PatternKind, DCompoundKind
type
AnyAtom* = dataspacePatterns.AnyAtom[Ref]
DBind = dataspacePatterns.DBind[Ref]
DCompound = dataspacePatterns.DCompound[Ref]
DCompoundArr = dataspacePatterns.DCompoundArr[Ref]
DCompoundDict = dataspacePatterns.DCompoundDict[Ref]
DCompoundRec = dataspacePatterns.DCompoundRec[Ref]
DLit = dataspacePatterns.DLit[Ref]
Pattern* = dataspacePatterns.Pattern[Ref]
proc `?`*(d: DBind): Pattern =
Pattern(orKind: PatternKind.DBind, dbind: d)
proc `?`*(d: DLit): Pattern =
Pattern(orKind: PatternKind.DLit, dlit: d)
proc `?`*(d: DCompound): Pattern =
Pattern(orKind: PatternKind.DCompound, dcompound: d)
proc `?`*(x: bool): Pattern =
?DLit(value: AnyAtom(orKind: AnyAtomKind.`bool`, bool: x))
proc `?`*(x: float32): Pattern =
?DLit(value: AnyAtom(orKind: AnyAtomKind.`float`, float: x))
proc `?`*(x: float64): Pattern =
?DLit(value: AnyAtom(orKind: AnyAtomKind.`double`, double: x))
proc `?`*(x: int): Pattern =
?DLit(value: AnyAtom(orKind: AnyAtomKind.`int`, int: x))
proc `?`*(s: string): Pattern =
?DLit(value: AnyAtom(orKind: AnyAtomKind.`string`, string: s))
proc `?`*(x: seq[byte]): Pattern =
?DLit(value: AnyAtom(orKind: AnyAtomKind.`bytes`, bytes: x))
proc `?`*(x: Symbol): Pattern =
?DLit(value: AnyAtom(orKind: AnyAtomKind.`symbol`, symbol: x))
proc drop*(): Pattern = Pattern(orKind: PatternKind.DDiscard)
proc grab*(): Pattern = ?DBind(pattern: drop())
proc `?_`*(): Pattern = drop()
proc `?*`*(): Pattern = grab()
proc `?`*(T: typedesc; bindings: sink openArray[(int, Pattern)]): Pattern =
## Pattern constructor operator.
# TODO: get a pattern for T and then replace the inner patterns with bindings.
when T.hasPreservesRecordPragma:
var
label = T.recordLabel.tosymbol(Ref)
fields = newSeq[Pattern]()
for (i, pat) in bindings:
if i > fields.high: fields.setLen(succ i)
fields[i] = pat
result = ?DCompound(
orKind: DCompoundKind.rec,
rec: DCompoundRec(
label: label, fields: fields))
elif T is ref:
`?`(pointerBase(T), bindings)
else:
{.error: "no preserves pragma on " & $T.}
proc `?`*(T: static typedesc): Pattern =
## Derive a `Pattern` from type `T`.
## This works for `tuple` and `object` types but in the
## general case will return a wildcard binding.
when T is ref:
?pointerBase(T)
elif T is Preserve: grab()
elif T.hasPreservesRecordPragma:
var
label = T.recordLabel.tosymbol(Ref)
fields = newSeq[Pattern]()
for key, val in fieldPairs(default T):
fields.add ?(typeOf val)
result = ?DCompound(
orKind: DCompoundKind.rec,
rec: DCompoundRec(
label: label, fields: fields))
elif T.hasPreservesTuplePragma:
var arr = DCompoundArr()
for key, val in fieldPairs(default T):
arr.items.add grab()
?DCompound(
orKind: DCompoundKind.arr,
arr: arr)
elif T.hasPreservesDictionaryPragma:
var dict = DCompoundDict()
for key, val in fieldPairs(default T):
dict.entries[key.toSymbol(Ref)] = ?(typeOf val)
?DCompound(
orKind: DCompoundKind.dict,
dict: dict)
elif T is tuple:
var arr = DCompoundArr()
for key, val in fieldPairs(default T):
arr.items.add ?(typeOf val)
result = ?DCompound(
orKind: DCompoundKind.arr,
arr: arr)
else:
grab() # capture any value
type
Value = Preserve[Ref]
Path = seq[Value]
Analysis* = tuple
constPaths: seq[Path]
constValues: seq[Value]
capturePaths: seq[Path]
func walk(result: var Analysis; path: var Path; p: Pattern)
func walk(result: var Analysis; path: var Path; key: int|Value; pat: Pattern) =
path.add(key.toPreserve(Ref))
walk(result, path, pat)
discard path.pop
func walk(result: var Analysis; path: var Path; p: Pattern) =
case p.orKind
of PatternKind.DCompound:
case p.dcompound.orKind
of DCompoundKind.rec:
for k, e in p.dcompound.rec.fields: walk(result, path, k, e)
of DCompoundKind.arr:
for k, e in p.dcompound.arr.items: walk(result, path, k, e)
of DCompoundKind.dict:
for k, e in p.dcompound.dict.entries: walk(result, path, k, e)
of PatternKind.DBind:
result.capturePaths.add(path)
walk(result, path, p.dbind.pattern)
of PatternKind.DDiscard: discard
of PatternKind.DLit:
result.constPaths.add(path)
result.constValues.add(p.dlit.value.toPreserve(Ref))
func analyse*(p: Pattern): Analysis =
var path: Path
walk(result, path, p)