1126 lines
35 KiB
Nim
1126 lines
35 KiB
Nim
# SPDX-FileCopyrightText: 2021 ☭ Emery Hemingway
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# SPDX-License-Identifier: Unlicense
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import bigints
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import std/[base64, endians, hashes, options, sets, sequtils, streams, tables, typetraits]
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from std/json import escapeJson, escapeJsonUnquoted
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from std/macros import hasCustomPragma, getCustomPragmaVal
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import ./preserves/private/dot
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from std/strutils import parseEnum
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when defined(tracePreserves):
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template trace(args: varargs[untyped]) =
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echo args
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else:
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template trace(args: varargs[untyped]) = discard
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type
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PreserveKind* = enum
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pkBoolean, pkFloat, pkDouble, pkSignedInteger, pkBigInteger, pkString, pkByteString, pkSymbol,
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pkRecord, pkSequence, pkSet, pkDictionary, pkEmbedded
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const
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atomKinds* = {pkBoolean, pkFloat, pkDouble, pkSignedInteger, pkBigInteger, pkString, pkByteString, pkSymbol}
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compoundKinds* = {pkRecord, pkSequence, pkSet, pkDictionary}
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type
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Preserve*[E = void] = object
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case kind*: PreserveKind
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of pkBoolean:
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bool*: bool
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of pkFloat:
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float*: float32
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of pkDouble:
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double*: float64
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of pkSignedInteger:
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int*: BiggestInt
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of pkBigInteger:
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bigint*: BigInt
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of pkString:
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string*: string
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of pkByteString:
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bytes*: seq[byte]
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of pkSymbol:
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symbol*: string
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of pkRecord:
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record*: seq[Preserve[E]] # label is last
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of pkSequence:
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sequence*: seq[Preserve[E]]
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of pkSet:
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set*: seq[Preserve[E]]
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# TODO: HashSet
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of pkDictionary:
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dict*: seq[DictEntry[E]]
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# TODO: Tables
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of pkEmbedded:
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embed*: E
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embedded*: bool
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## Flag to mark embedded Preserves
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DictEntry[E] = tuple[key: Preserve[E], val: Preserve[E]]
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proc `==`*[A, B](x: Preserve[A]; y: Preserve[B]): bool =
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## Check `x` and `y` for equivalence.
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if x.kind == y.kind and x.embedded == y.embedded:
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case x.kind
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of pkBoolean:
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result = x.bool == y.bool
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of pkFloat:
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result = x.float == y.float
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of pkDouble:
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result = x.double == y.double
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of pkSignedInteger:
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result = x.int == y.int
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of pkBigInteger:
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result = x.bigint == y.bigint
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of pkString:
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result = x.string == y.string
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of pkByteString:
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result = x.bytes == y.bytes
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of pkSymbol:
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result = x.symbol == y.symbol
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of pkRecord:
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result = x.record.len == y.record.len
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for i in 0..x.record.high:
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if not result: break
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result = result and (x.record[i] == y.record[i])
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of pkSequence:
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for i, val in x.sequence:
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if y.sequence[i] != val: return false
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result = true
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of pkSet:
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result = x.set.len == y.set.len
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for i in 0..x.set.high:
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if not result: break
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result = result and (x.set[i] == y.set[i])
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of pkDictionary:
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result = x.dict.len == y.dict.len
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for i in 0..x.dict.high:
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if not result: break
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result = result and
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(x.dict[i].key == y.dict[i].key) and
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(x.dict[i].val == y.dict[i].val)
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of pkEmbedded:
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when A is B:
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when A is void:
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result = true
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else:
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result = x.embed == y.embed
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proc `<`(x, y: string | seq[byte]): bool =
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for i in 0 .. min(x.high, y.high):
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if x[i] < y[i]: return true
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if x[i] != y[i]: return false
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x.len < y.len
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proc `<`*[A, B](x: Preserve[A]; y: Preserve[B]): bool =
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## Preserves have a total order over values. Check if `x` is ordered before `y`.
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if x.embedded != y.embedded:
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result = y.embedded
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elif x.kind != y.kind:
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if x.kind == pkSignedInteger and y.kind == pkBigInteger:
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result = x.int.initBigInt < y.bigint
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elif x.kind == pkBigInteger and y.kind == pkSignedInteger:
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result = x.bigint < y.int.initBigInt
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else:
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result = x.kind < y.kind
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else:
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case x.kind
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of pkBoolean:
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result = (not x.bool) and y.bool
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of pkFloat:
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result = x.float < y.float
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of pkDouble:
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result = x.double < y.double
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of pkSignedInteger:
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result = x.int < y.int
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of pkBigInteger:
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result = x.bigint < y.bigint
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of pkString:
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result = x.string < y.string
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of pkByteString:
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result = x.bytes < y.bytes
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of pkSymbol:
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result = x.symbol < y.symbol
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of pkRecord:
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if x.record[x.record.high] < y.record[y.record.high]: return true
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for i in 0..<min(x.record.high, y.record.high):
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if x.record[i] < y.record[i]: return true
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if x.record[i] == y.record[i]: return false
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result = x.record.len < y.record.len
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of pkSequence:
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for i in 0..min(x.sequence.high, y.sequence.high):
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if x.sequence[i] < y.sequence[i]: return true
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if x.sequence[i] != y.sequence[i]: return false
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result = x.sequence.len < y.sequence.len
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of pkSet:
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for i in 0..min(x.set.high, y.set.high):
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if x.set[i] < y.set[i]: return true
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if x.set[i] != y.set[i]: return false
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result = x.set.len < y.set.len
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of pkDictionary:
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for i in 0..min(x.dict.high, y.dict.high):
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if x.dict[i].key < y.dict[i].key: return true
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if x.dict[i].key == y.dict[i].key:
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if x.dict[i].val < y.dict[i].val: return true
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if x.dict[i].val != y.dict[i].val: return false
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result = x.dict.len < y.dict.len
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of pkEmbedded:
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when (not A is void) and (A is B):
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result = x.embed < y.embed
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proc hash*(pr: Preserve): Hash =
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## Produce a `Hash` of `pr` for use with a `HashSet` or `Table`.
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var h = hash(pr.kind.int) !& hash(pr.embedded)
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case pr.kind
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of pkBoolean:
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h = h !& hash(pr.bool)
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of pkFloat:
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h = h !& hash(pr.float)
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of pkDouble:
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h = h !& hash(pr.double)
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of pkSignedInteger:
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h = h !& hash(pr.int)
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of pkBigInteger:
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h = h !& hash(pr.bigint.flags)
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h = h !& hash(pr.bigint)
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of pkString:
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h = h !& hash(pr.string)
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of pkByteString:
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h = h !& hash(pr.bytes)
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of pkSymbol:
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h = h !& hash(pr.symbol)
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of pkRecord:
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for val in pr.record:
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h = h !& hash(val)
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of pkSequence:
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for val in pr.sequence:
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h = h !& hash(val)
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of pkSet:
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for val in pr.set.items:
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h = h !& hash(val)
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of pkDictionary:
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for (key, val) in pr.dict.items:
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h = h !& hash(key) !& hash(val)
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of pkEmbedded:
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h = h !& hash(pr.embed)
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!$h
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proc `[]`*(pr: Preserve; i: int): Preserve =
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## Select an indexed value from ``pr``.
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## Only valid for records and sequences.
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case pr.kind
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of pkRecord: pr.record[i]
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of pkSequence: pr.sequence[i]
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else:
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raise newException(ValueError, "`Preserves value is not indexable")
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proc `[]`*(pr, key: Preserve): Preserve =
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## Select a dictionary value from ``pr``.
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if pr.kind == pkDictionary:
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for (k, v) in pr.dict:
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if key == k: return v
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raise newException(KeyError, "Key not in Preserves dictionary")
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else:
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raise newException(ValueError, "`[]` is not valid for " & $pr.kind)
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proc getOrDefault(pr: Preserve; key: Preserve): Preserve =
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## Retrieves the value of `pr[key]` if `pr` is a dictionary containing `key`
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## or returns the `#f` Preserves value.
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if pr.kind == pkDictionary:
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for (k, v) in pr.dict:
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if key == k:
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result = v
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break
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proc incl*(pr: var Preserve; key: Preserve) =
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## Include `key` in the Preserves set `pr`.
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for i in 0..pr.set.high:
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if key < pr.set[i]:
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insert(pr.set, [key], i)
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return
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pr.set.add(key)
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proc excl*(pr: var Preserve; key: Preserve) =
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## Exclude `key` from the Preserves set `pr`.
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for i in 0..pr.set.high:
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if pr.set[i] == key:
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delete(pr.set, i, i)
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break
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proc `[]`*(pr: var Preserve; key: Preserve): Preserve =
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## Select a value by `key` from the Preserves dictionary `pr`.
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for (k, v) in pr.dict.items:
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if k == key: return v
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raise newException(KeyError, "value not in Preserves dictionary")
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proc `[]=`*(pr: var Preserve; key, val: Preserve) =
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## Insert `val` by `key` in the Preserves dictionary `pr`.
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for i in 0..pr.dict.high:
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if key < pr.dict[i].key:
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insert(pr.dict, [(key, val, )], i)
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return
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elif key == pr.dict[i].key:
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pr.dict[i].val = val
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return
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pr.dict.add((key, val, ))
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proc toSymbol*(s: sink string; E = void): Preserve[E] {.inline.} =
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## Create a Preserves symbol value.
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Preserve[E](kind: pkSymbol, symbol: s)
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proc initRecord*[E](label: Preserve[E]; arity: Natural = 0): Preserve[E] =
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## Create a Preserves record value.
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result = Preserve[E](kind: pkRecord, record: newSeq[Preserve[E]](arity.succ))
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result.record[arity] = label
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proc initRecord*[E](label: Preserve[E]; args: varargs[Preserve[E]]): Preserve[E] =
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## Create a Preserves record value.
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result = Preserve[E](kind: pkRecord,
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record: newSeqOfCap[Preserve[E]](1+args.len))
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for arg in args:
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result.record.add(arg)
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result.record.add(label)
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proc initSequence*[E](len: Natural = 0): Preserve[E] =
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## Create a Preserves sequence value.
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Preserve[E](kind: pkSequence, sequence: newSeq[Preserve[E]](len))
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proc initSet*[E](): Preserve[E] = Preserve[E](kind: pkSet)
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## Create a Preserves set value.
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proc initDictionary*[E](): Preserve[E] = Preserve[E](kind: pkDictionary)
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## Create a Preserves dictionary value.
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proc embed*[E](pr: sink Preserve[E]): Preserve[E] =
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## Create a Preserves value that embeds ``e``.
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result = pr
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result.embedded = true
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proc embed*[E](e: sink E): Preserve[E] =
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## Create a Preserves value that embeds ``e``.
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Preserve[E](kind: pkEmbedded, embed: e)
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proc len*(pr: Preserve): int =
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## Return the shallow count of values in ``pr``, that is the number of
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## fields in a record, items in a sequence, items in a set, or key-value pairs
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## in a dictionary.
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case pr.kind
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of pkRecord: pr.record.len.pred
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of pkSequence: pr.sequence.len
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of pkSet: pr.set.len
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of pkDictionary: pr.dict.len
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else: 0
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iterator items*(pr: Preserve): Preserve =
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## Shallow iterator over `pr`, yield the fields in a record,
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## the items of a sequence, the items of a set, or the pairs
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## of a dictionary.
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case pr.kind
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of pkRecord:
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for i in 0..pr.record.high.pred:
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yield pr.record[i]
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of pkSequence:
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for e in pr.sequence.items: yield e
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of pkSet:
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for e in pr.set.items: yield e
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of pkDictionary:
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for (k, v) in pr.dict.items:
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yield k # key can be an arbitrary Preserve
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yield v
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else: discard
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func isBoolean*(pr: Preserve): bool {.inline.} = pr.kind == pkBoolean
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## Check if ``pr`` is a Preserve boolean.
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func isFalse*(pr: Preserve): bool {.inline.} =
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## Check if ``pr`` is equivalent to the zero-initialized ``Preserve``.
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pr.kind == pkBoolean and pr.bool == false
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func isFloat*(pr: Preserve): bool {.inline.} = pr.kind == pkFloat
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## Check if ``pr`` is a Preserve float.
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func isDouble*(pr: Preserve): bool {.inline.} = pr.kind == pkDouble
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## Check if ``pr`` is a Preserve double.
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func isInteger*(pr: Preserve): bool {.inline.} = pr.kind in {pkSignedInteger, pkBigInteger}
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## Check if ``pr`` is a Preserve double.
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func isString*(pr: Preserve): bool {.inline.} = pr.kind == pkString
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## Check if ``pr`` is a Preserve text string.
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func isByteString*(pr: Preserve): bool {.inline.} = pr.kind == pkByteString
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## Check if ``pr`` is a Preserves byte string.
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func isSymbol*(pr: Preserve): bool {.inline.} = pr.kind == pkSymbol
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## Check if `pr` is a Preserves symbol.
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func isSymbol*(pr: Preserve; sym: string): bool {.inline.} =
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## Check if ``pr`` is a Preserves symbol of ``sym``.
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(pr.kind == pkSymbol) and (pr.symbol == sym)
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func isRecord*(pr: Preserve): bool {.inline.} = (pr.kind == pkRecord) and (pr.record.len > 0)
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## Check if ``pr`` is a Preserves record.
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proc isSequence*(pr: Preserve): bool {.inline.} = pr.kind == pkSequence
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## Check if ``pr`` is a Preserves sequence.
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proc isSet*(pr: Preserve): bool {.inline.} = pr.kind == pkSet
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## Check if ``pr`` is a Preserves set.
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proc isDictionary*(pr: Preserve): bool {.inline.} = pr.kind == pkDictionary
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## Check if ``pr`` is a Preserves dictionary.
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func isEmbedded*[E](pr: Preserve[E]): bool {.inline.} =
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## Check if ``pr`` is an embedded value.
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when E is void: pr.embedded # embedded Preserves
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else: pr.kind == pkEmbedded # embedded Nim
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proc label*(pr: Preserve): Preserve {.inline.} =
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## Return the label of record value.
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pr.record[pr.record.high]
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proc arity*(pr: Preserve): int {.inline.} =
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## Return the number of fields in record `pr`.
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pred(pr.record.len)
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proc fields*(pr: Preserve): seq[Preserve] {.inline.} =
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## Return the fields of a record value.
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pr.record[0..pr.record.high.pred]
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iterator fields*(pr: Preserve): Preserve =
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## Iterate the fields of a record value.
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for i in 0..<pr.record.high: yield pr.record[i]
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proc unembed*[E](pr: Preserve[E]): E =
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## Unembed an `E` value from a `Preserve[E]` value.
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if pr.kind != pkEmbedded:
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raise newException(ValueError, "not an embedded value")
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pr.embed
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proc writeVarint(s: Stream; n: int) =
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var n = n
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while true:
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let c = int8(n and 0x7f)
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n = n shr 7
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if n == 0:
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s.write((char)c.char)
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break
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else:
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s.write((char)c or 0x80)
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proc readVarint(s: Stream): int =
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var shift: int
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while shift < (9*8):
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let c = s.readChar.int
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result = result or ((c and 0x7f) shl shift)
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if (c and 0x80) == 0:
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break
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shift.inc 7
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proc write*[E](str: Stream; pr: Preserve[E]) =
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## Write the binary-encoding of a Preserves value to a stream.
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if pr.embedded: str.write(0x86'u8)
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case pr.kind:
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of pkBoolean:
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case pr.bool
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of false: str.write(0x80'u8)
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of true: str.write(0x81'u8)
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of pkFloat:
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str.write(0x82'u8)
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when system.cpuEndian == bigEndian:
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str.write(pr.float)
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else:
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var be: float32
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swapEndian32(be.addr, pr.float.unsafeAddr)
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str.write(be)
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of pkDouble:
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str.write(0x83'u8)
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when system.cpuEndian == bigEndian:
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str.write(pr.double)
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else:
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var be: float64
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swapEndian64(be.addr, pr.double.unsafeAddr)
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str.write(be)
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of pkSignedInteger:
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if (-3 <= pr.int) and (pr.int <= 12):
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str.write(0x90'i8 or int8(if pr.int < 0: pr.int + 16 else: pr.int))
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else:
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var bitCount = 1'u8
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if pr.int < 0:
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while ((not pr.int) shr bitCount) != 0:
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inc(bitCount)
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else:
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while (pr.int shr bitCount) != 0:
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inc(bitCount)
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var byteCount = (bitCount + 8) div 8
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str.write(0xa0'u8 or (byteCount - 1))
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proc write(n: uint8; i: BiggestInt) =
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if n > 0:
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write(n.pred, i shr 8)
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str.write(i.uint8)
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write(byteCount, pr.int)
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of pkBigInteger:
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doAssert(Negative notin pr.bigint.flags, "negative big integers not implemented")
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var bytes = newSeqOfCap[uint8](pr.bigint.limbs.len * 4)
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var begun = false
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for i in countdown(pr.bigint.limbs.high, 0):
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let limb = pr.bigint.limbs[i]
|
|
for j in countdown(24, 0, 8):
|
|
let b = uint8(limb shr j)
|
|
begun = begun or (b != 0)
|
|
if begun:
|
|
bytes.add(b)
|
|
if bytes.len <= 16:
|
|
str.write(0xa0'u8 or bytes.high.uint8)
|
|
else:
|
|
str.write(0xb0'u8)
|
|
str.writeVarint(bytes.len)
|
|
str.write(cast[string](bytes))
|
|
of pkString:
|
|
str.write(0xb1'u8)
|
|
str.writeVarint(pr.string.len)
|
|
str.write(pr.string)
|
|
of pkByteString:
|
|
str.write(0xb2'u8)
|
|
str.writeVarint(pr.bytes.len)
|
|
str.write(cast[string](pr.bytes))
|
|
of pkSymbol:
|
|
str.write(0xb3'u8)
|
|
str.writeVarint(pr.symbol.len)
|
|
str.write(pr.symbol)
|
|
of pkRecord:
|
|
assert(pr.record.len > 0)
|
|
str.write(0xb4'u8)
|
|
str.write(pr.record[pr.record.high])
|
|
for i in 0..<pr.record.high:
|
|
str.write(pr.record[i])
|
|
str.write(0x84'u8)
|
|
of pkSequence:
|
|
str.write(0xb5'u8)
|
|
for e in pr.sequence:
|
|
str.write(e)
|
|
str.write(0x84'u8)
|
|
of pkSet:
|
|
str.write(0xb6'u8)
|
|
for val in pr.set.items:
|
|
str.write(val)
|
|
str.write(0x84'u8)
|
|
of pkDictionary:
|
|
str.write(0xb7'u8)
|
|
for (key, value) in pr.dict.items:
|
|
str.write(key)
|
|
str.write(value)
|
|
str.write(0x84'u8)
|
|
of pkEmbedded:
|
|
when not E is void:
|
|
str.write(0x86'u8)
|
|
str.write(pr.embed.toPreserve)
|
|
|
|
proc encode*[E](pr: Preserve[E]): seq[byte] =
|
|
## Return the binary-encoding of a Preserves value.
|
|
let s = newStringStream()
|
|
s.write pr
|
|
s.setPosition 0
|
|
result = cast[seq[byte]](s.readAll)
|
|
|
|
proc decodePreserves*(s: Stream; E = void): Preserve[E] =
|
|
## Decode a Preserves value from a binary-encoded stream.
|
|
proc assertStream(check: bool) =
|
|
if not check:
|
|
raise newException(ValueError, "invalid Preserves stream")
|
|
const endMarker = 0x84
|
|
let tag = s.readUint8()
|
|
case tag
|
|
of 0x80: result = Preserve[E](kind: pkBoolean, bool: false)
|
|
of 0x81: result = Preserve[E](kind: pkBoolean, bool: true)
|
|
of 0x82:
|
|
when system.cpuEndian == bigEndian:
|
|
result = Preserve[E](kind: pkFloat, float: s.readFloat32())
|
|
else:
|
|
result = Preserve[E](kind: pkFloat)
|
|
var be = s.readFloat32()
|
|
swapEndian32(result.float.addr, be.addr)
|
|
of 0x83:
|
|
when system.cpuEndian == bigEndian:
|
|
result = Preserve[E](kind: pkDouble, double: s.readFloat64())
|
|
else:
|
|
result = Preserve[E](kind: pkDouble)
|
|
var be = s.readFloat64()
|
|
swapEndian64(result.double.addr, be.addr)
|
|
of 0x86:
|
|
result = decodePreserves(s, E)
|
|
result.embedded = true
|
|
of 0xb1:
|
|
result = Preserve[E](kind: pkString)
|
|
let len = s.readVarint()
|
|
result.string = s.readStr(len)
|
|
of 0xb2:
|
|
result = Preserve[E](kind: pkByteString)
|
|
let len = s.readVarint()
|
|
result.bytes = cast[seq[byte]](s.readStr(len))
|
|
of 0xb3:
|
|
let len = s.readVarint()
|
|
result = Preserve[E](kind: pkSymbol, symbol: s.readStr(len))
|
|
of 0xb4:
|
|
result = Preserve[E](kind: pkRecord)
|
|
var label = decodePreserves(s, E)
|
|
while s.peekUint8() != endMarker:
|
|
result.record.add decodePreserves(s, E)
|
|
result.record.add(move label)
|
|
discard s.readUint8()
|
|
of 0xb5:
|
|
result = Preserve[E](kind: pkSequence)
|
|
while s.peekUint8() != endMarker:
|
|
result.sequence.add decodePreserves(s, E)
|
|
discard s.readUint8()
|
|
of 0xb6:
|
|
result = Preserve[E](kind: pkSet)
|
|
while s.peekUint8() != endMarker:
|
|
incl(result, decodePreserves(s, E))
|
|
discard s.readUint8()
|
|
of 0xb7:
|
|
result = Preserve[E](kind: pkDictionary)
|
|
while s.peekUint8() != endMarker:
|
|
result[decodePreserves(s, E)] = decodePreserves(s, E)
|
|
discard s.readUint8()
|
|
of 0xb0:
|
|
let len = s.readVarint()
|
|
result = Preserve[E](kind: pkBigInteger, bigint: initBigint 0)
|
|
for _ in 1..len:
|
|
result.bigint = (result.bigint shl 8) + s.readUint8().int32
|
|
of endMarker:
|
|
assertStream(false)
|
|
else:
|
|
case 0xf0 and tag
|
|
of 0x90:
|
|
var n = tag.BiggestInt
|
|
result = Preserve[E](kind: pkSignedInteger,
|
|
int: n - (if n > 0x9c: 0xa0 else: 0x90))
|
|
of 0xa0:
|
|
let len = (tag.int and 0x0f) + 1
|
|
if len <= 8:
|
|
result = Preserve[E](kind: pkSignedInteger, int: s.readUint8().BiggestInt)
|
|
if (result.int and 0x80) != 0: result.int.dec(0x100)
|
|
for i in 1..<len:
|
|
result.int = (result.int shl 8) or s.readUint8().BiggestInt
|
|
else:
|
|
result = Preserve[E](kind: pkBigInteger)
|
|
for i in 0..<len:
|
|
result.bigint = (result.bigint shl 8) + s.readUint8().int32
|
|
else:
|
|
assertStream(false)
|
|
|
|
proc decodePreserves*(s: string; E = void): Preserve[E] =
|
|
## Decode a string of binary-encoded Preserves.
|
|
decodePreserves(s.newStringStream, E)
|
|
|
|
proc decodePreserves*(s: seq[byte]; E = void): Preserve[E] =
|
|
## Decode a byte-string of binary-encoded Preserves.
|
|
decodePreserves(cast[string](s), E)
|
|
|
|
template preservesRecord*(label: string) {.pragma.}
|
|
## Serialize this object or tuple as a record.
|
|
## See ``toPreserve``.
|
|
|
|
template preservesTuple*() {.pragma.}
|
|
## Serialize this object or tuple as a tuple.
|
|
## See ``toPreserve``.
|
|
|
|
template preservesTupleTail*() {.pragma.}
|
|
## Serialize this object field to the end of its containing tuple.
|
|
## See ``toPreserve``.
|
|
|
|
template preservesDictionary*() {.pragma.}
|
|
## Serialize this object or tuple as a dictionary.
|
|
## See ``toPreserve``.
|
|
|
|
template preservesSymbol*() {.pragma.}
|
|
## Serialize this string as a symbol.
|
|
## See ``toPreserve``.
|
|
|
|
template preservesOr*() {.pragma.}
|
|
## Serialize this object as an ``or`` alternative.
|
|
## See ``toPreserve``.
|
|
|
|
template preservesLiteral*(value: typed) {.pragma.}
|
|
## Serialize a Preserves literal within this object.
|
|
## See ``toPreserve``.
|
|
|
|
template unpreservable*() {.pragma.}
|
|
## Pragma to forbid a type from being converted by ``toPreserve``.
|
|
## Useful for preventing an embeded type from being encoded
|
|
## as its native type.
|
|
## Unpreservability is asserted at runtime.
|
|
|
|
proc toPreserve*[T](x: T; E = void): Preserve[E] =
|
|
## Serializes ``x`` to Preserves. Can be customized by defining
|
|
## ``toPreserveHook(x: T; E: typedesc)`` in the calling scope.
|
|
## Any ``toPreserveHook`` that does not compile will be discarded;
|
|
## *Write tests for your hooks!*
|
|
##
|
|
## When `tracePreserves` is defined (`-d:tracePreserves`) a diagnostic
|
|
## trace is printing during `toPreserve`.
|
|
when (T is Preserve[E]): result = x
|
|
elif T is E: result = embed(x)
|
|
elif compiles(toPreserveHook(x, E)):
|
|
result = toPreserveHook(x, E)
|
|
elif T is distinct:
|
|
result = toPreserve(x.distinctBase, E)
|
|
elif T is enum:
|
|
result = toSymbol($x, E)
|
|
elif T is Bigint:
|
|
result = Preserve[E](kind: pkBigInteger, bigint: x)
|
|
elif T is seq[byte]:
|
|
result = Preserve[E](kind: pkByteString, bytes: x)
|
|
elif T is array | seq:
|
|
result = Preserve[E](kind: pkSequence, sequence: newSeqOfCap[Preserve[E]](x.len))
|
|
for v in x.items: result.sequence.add(toPreserve(v, E))
|
|
elif T is bool:
|
|
result = Preserve[E](kind: pkBoolean, bool: x)
|
|
elif T is float:
|
|
result = Preserve[E](kind: pkFloat, float: x)
|
|
elif T is float64:
|
|
result = Preserve[E](kind: pkDouble, double: x)
|
|
elif T is tuple:
|
|
result = Preserve[E](kind: pkSequence,
|
|
sequence: newSeqOfCap[Preserve[E]](tupleLen(T)))
|
|
for xf in fields(x):
|
|
result.sequence.add(toPreserve(xf, E))
|
|
elif T is Ordinal:
|
|
result = Preserve[E](kind: pkSignedInteger, int: x.ord.BiggestInt)
|
|
elif T is ptr | ref:
|
|
if system.`==`(x, nil): result = toSymbol("null", E)
|
|
else: result = toPreserve(x[], E)
|
|
elif T is string:
|
|
result = Preserve[E](kind: pkString, string: x)
|
|
elif T is SomeInteger:
|
|
result = Preserve[E](kind: pkSignedInteger, int: x.BiggestInt)
|
|
elif T is object:
|
|
template fieldToPreserve(key: string; val: typed): Preserve {.used.} =
|
|
when x.dot(key).hasCustomPragma(preservesSymbol):
|
|
toSymbol(val, E)
|
|
elif x.dot(key).hasCustomPragma(preservesLiteral):
|
|
const lit = parsePreserves(x.dot(key).getCustomPragmaVal(preservesLiteral))
|
|
cast[Preserve[E]](lit)
|
|
else:
|
|
toPreserve(val, E)
|
|
when T.hasCustomPragma(unpreservable):
|
|
raiseAssert($T & " is unpreservable")
|
|
elif T.hasCustomPragma(preservesOr):
|
|
var hasKind, hasVariant: bool
|
|
for k, v in x.fieldPairs:
|
|
if k == "orKind":
|
|
assert(not hasKind)
|
|
hasKind = true
|
|
else:
|
|
assert(hasKind and not hasVariant)
|
|
result = fieldToPreserve(k, v)
|
|
hasVariant = true
|
|
elif T.hasCustomPragma(preservesRecord):
|
|
result = Preserve[E](kind: pkRecord)
|
|
for k, v in x.fieldPairs:
|
|
result.record.add(fieldToPreserve(k, v))
|
|
result.record.add(tosymbol(T.getCustomPragmaVal(preservesRecord), E))
|
|
elif T.hasCustomPragma(preservesTuple):
|
|
result = initSequence[E]()
|
|
for label, field in x.fieldPairs:
|
|
when x.dot(label).hasCustomPragma(preservesTupleTail):
|
|
for y in field.items:
|
|
result.sequence.add(toPreserve(y, E))
|
|
# TODO: what if there are fields after the tail?
|
|
else:
|
|
result.sequence.add(fieldToPreserve(label, field))
|
|
elif T.hasCustomPragma(preservesDictionary):
|
|
result = initDictionary[E]()
|
|
for key, val in x.fieldPairs:
|
|
result[toSymbol(key, E)] = fieldToPreserve(key, val)
|
|
else: result = toPreserveHook(x, E)
|
|
else: result = toPreserveHook(x, E)
|
|
# the hook doesn't compile but produces a useful error
|
|
trace T, " -> ", result
|
|
|
|
proc toPreserveHook*[A](pr: Preserve[A]; E: typedesc): Preserve[E] =
|
|
## Hook for converting ``Preserve`` values with different embedded types.
|
|
if pr.kind == pkEmbedded:
|
|
when E is void:
|
|
result = toPreserve(pr.embed, E)
|
|
else:
|
|
result = Preserve[E](pk: pr.kind, embed: (E)pr.embed)
|
|
else:
|
|
result = cast[Preserve[E]](pr)
|
|
|
|
proc toPreserveHook*[T](set: HashSet[T]; E: typedesc): Preserve[E] =
|
|
## Hook for preserving ``HashSet``.
|
|
result = Preserve[E](kind: pkSet, set: newSeqOfCap[Preserve[E]](set.len))
|
|
for e in set: result.incl toPreserve(e, E)
|
|
|
|
#[
|
|
when isMainModule:
|
|
var h: HashSet[string]
|
|
var pr = h.toPreserveHook(void)
|
|
assert fromPreserveHook(h, pr)
|
|
]#
|
|
|
|
proc toPreserveHook*[A, B](table: Table[A, B]|TableRef[A, B], E: typedesc): Preserve[E] =
|
|
## Hook for preserving ``Table``.
|
|
result = initDictionary[E]()
|
|
for k, v in table.pairs:
|
|
when A is string:
|
|
result[toSymbol(k, E)] = toPreserve(v, E)
|
|
else:
|
|
result[toPreserve(k, E)] = toPreserve(v, E)
|
|
|
|
proc fromPreserve*[T, E](v: var T; pr: Preserve[E]): bool =
|
|
## Inplace version of `preserveTo`. Returns ``true`` on
|
|
## a complete match, otherwise returns ``false``.
|
|
## Can be customized with `fromPreserveHook[E](x: T; var pr: Preserve[E]): bool`.
|
|
## Any ``fromPreserveHook`` that does not compile will be discarded;
|
|
## *Write tests for your hooks!*
|
|
##
|
|
## When `tracePreserves` is defined (`-d:tracePreserves`) a diagnostic
|
|
## trace is printing during `fromPreserve`.
|
|
# TODO: {.raises: [].}
|
|
runnableExamples:
|
|
import preserves, preserves/parse
|
|
type Foo {.preservesRecord: "foo".} = object
|
|
x, y: int
|
|
var foo: Foo
|
|
assert(fromPreserve(foo, parsePreserves("""<foo 1 2>""")))
|
|
assert(foo.x == 1)
|
|
assert(foo.y == 2)
|
|
when T is Preserve[E]:
|
|
v = pr
|
|
result = true
|
|
elif T is E:
|
|
if pr.kind == pkEmbedded:
|
|
v = pr.embed
|
|
result = true
|
|
elif compiles(fromPreserveHook(v, pr)):
|
|
result = fromPreserveHook(v, pr)
|
|
elif T is distinct:
|
|
result = fromPreserve(result.distinctBase, pr)
|
|
elif T is enum:
|
|
if pr.isSymbol:
|
|
try:
|
|
v = parseEnum[T](pr.symbol)
|
|
result = true
|
|
except ValueError: discard
|
|
elif T is Bigint:
|
|
case pr.kind
|
|
of pkSignedInteger:
|
|
v = initBigint(pr.int)
|
|
result = true
|
|
of pkBigInteger:
|
|
v = pr.bigint
|
|
result = true
|
|
else: disard
|
|
elif T is bool:
|
|
if pr.kind == pkBoolean:
|
|
v = pr.bool
|
|
result = true
|
|
elif T is SomeInteger:
|
|
if pr.kind == pkSignedInteger:
|
|
v = T(pr.int)
|
|
result = true
|
|
elif T is float:
|
|
if pr.kind == pkFloat:
|
|
v = pr.float
|
|
result = true
|
|
elif T is seq[byte]:
|
|
if pr.kind == pkByteString:
|
|
v = pr.bytes
|
|
result = true
|
|
elif T is seq:
|
|
if pr.kind == pkSequence:
|
|
v.setLen(pr.len)
|
|
result = true
|
|
for i, e in pr.sequence:
|
|
result = result and fromPreserve(v[i], e)
|
|
if not result:
|
|
v.setLen 0
|
|
break
|
|
elif T is float64:
|
|
case pr.kind
|
|
of pkFloat:
|
|
v = pr.float
|
|
result = true
|
|
of pkDouble:
|
|
v = pr.double
|
|
result = true
|
|
elif T is Ordinal | SomeInteger:
|
|
if pr.kind == pkSignedInteger:
|
|
v = (T)pr.int
|
|
result = true
|
|
elif T is string:
|
|
case pr.kind
|
|
of pkString:
|
|
v = pr.string
|
|
result = true
|
|
of pkSymbol:
|
|
v = pr.symbol
|
|
result = true
|
|
else: discard
|
|
elif T is tuple:
|
|
case pr.kind
|
|
of pkRecord, pkSequence:
|
|
if pr.len <= tupleLen(T):
|
|
result = true
|
|
var i: int
|
|
for f in fields(v):
|
|
if result and i < pr.len:
|
|
result = result and fromPreserve(f, pr[i])
|
|
inc i
|
|
of pkDictionary:
|
|
if tupleLen(T) == pr.len:
|
|
result = true
|
|
for key, val in fieldPairs(v):
|
|
if result:
|
|
result = result and fromPreserve(val, pr[toSymbol(key, E)])
|
|
else: discard
|
|
elif T is ref:
|
|
if isNil(v): new(v)
|
|
result = fromPreserve(v[], pr)
|
|
elif T is object:
|
|
template fieldFromPreserve(key: string; val: typed; pr: Preserve[E]): bool {.used.} =
|
|
when v.dot(key).hasCustomPragma(preservesSymbol):
|
|
if pr.isSymbol:
|
|
fromPreserve(val, pr)
|
|
else:
|
|
false
|
|
elif v.dot(key).hasCustomPragma(preservesLiteral):
|
|
const lit = parsePreserves(v.dot(key).getCustomPragmaVal(preservesLiteral))
|
|
pr == lit
|
|
else:
|
|
fromPreserve(val, pr)
|
|
when T.hasCustomPragma(unpreservable):
|
|
raiseAssert($T & " is unpreservable")
|
|
elif T.hasCustomPragma(preservesRecord):
|
|
if pr.isRecord and pr.label.isSymbol(T.getCustomPragmaVal(preservesRecord)):
|
|
result = true
|
|
var i: int
|
|
for key, val in fieldPairs(v):
|
|
if result and i <= pr.len:
|
|
result = result and fieldFromPreserve(key, val, pr.record[i])
|
|
inc i
|
|
result = result and (i == pr.len)
|
|
elif T.hasCustomPragma(preservesTuple):
|
|
if pr.isSequence:
|
|
result = true
|
|
var i: int
|
|
for name, field in fieldPairs(v):
|
|
when v.dot(name).hasCustomPragma(preservesTupleTail):
|
|
setLen(v.dot(name), pr.len - i)
|
|
var j: int
|
|
while result and i < pr.len:
|
|
result = result and fieldFromPreserve(name, v.dot(name)[j], pr.sequence[i])
|
|
inc i
|
|
inc j
|
|
else:
|
|
if result and i < pr.len:
|
|
result = result and fieldFromPreserve(name, field, pr.sequence[i])
|
|
inc i
|
|
result = result and (i == pr.len)
|
|
elif T.hasCustomPragma(preservesDictionary):
|
|
if pr.isDictionary:
|
|
result = true
|
|
var i: int
|
|
for key, _ in fieldPairs(v):
|
|
let val = pr.getOrDefault(toSymbol(key, E))
|
|
result = result and fieldFromPreserve(
|
|
key, v.dot(key), val)
|
|
if not result: break
|
|
inc i
|
|
result = result and (i == pr.len)
|
|
elif T.hasCustomPragma(preservesOr):
|
|
for kind in typeof(T.orKind):
|
|
v = T(orKind: kind)
|
|
var fieldWasFound = false
|
|
for key, val in fieldPairs(v):
|
|
when key != "orKind": # fieldPairs unwraps early
|
|
result = fieldFromPreserve(key, v.dot(key), pr)
|
|
fieldWasFound = true
|
|
break
|
|
if not fieldWasFound:
|
|
# hopefully a `discard` of-branch, so discard `pr`
|
|
result = true
|
|
if result: break
|
|
else: result = fromPreserveHook(v, pr)
|
|
else: result = fromPreserveHook(v, pr)
|
|
# the hook doesn't compile but produces a useful error
|
|
if not result:
|
|
trace T, " !- ", pr
|
|
else:
|
|
trace T, " <- ", pr
|
|
|
|
proc preserveTo*(pr: Preserve; T: typedesc): Option[T] =
|
|
## Reverse of `toPreserve`.
|
|
# TODO: {.raises: [].}
|
|
runnableExamples:
|
|
import std/options, preserves, preserves/parse
|
|
type Foo {.preservesRecord: "foo".} = object
|
|
x, y: int
|
|
|
|
assert(parsePreserves("""<foo "abc">""").preserveTo(Foo).isNone)
|
|
assert(parsePreserves("""<bar 1 2>""").preserveTo(Foo).isNone)
|
|
assert(parsePreserves("""<foo 1 2>""").preserveTo(Foo).isSome)
|
|
var v: T
|
|
if fromPreserve(v, pr):
|
|
result = some(move v)
|
|
|
|
proc fromPreserveHook*[T, E](set: var HashSet[T]; pr: Preserve[E]): bool =
|
|
## Hook for preserving ``HashSet``.
|
|
if pr.kind == pkSet:
|
|
result = true
|
|
set.init(pr.set.len)
|
|
var e: T
|
|
for pe in pr.set:
|
|
result = fromPreserve(e, pe)
|
|
if not result: break
|
|
set.incl(move e)
|
|
|
|
proc fromPreserveHook*[A,B,E](t: var (Table[A,B]|TableRef[A,B]); pr: Preserve[E]): bool =
|
|
if pr.isDictionary:
|
|
result = true
|
|
var a: A
|
|
var b: B
|
|
for (k, v) in pr.dict.items:
|
|
result = fromPreserve(a, k) and fromPreserve(b, v)
|
|
if not result:
|
|
clear t
|
|
break
|
|
t[move a] = move b
|
|
|
|
when isMainModule:
|
|
var t: Table[int, string]
|
|
var pr = t.toPreserveHook(void)
|
|
assert fromPreserveHook(t, pr)
|
|
|
|
proc mapEmbeds*(pr: sink Preserve[void]; E: typedesc): Preserve[E] =
|
|
## Convert `Preserve[void]` to `Preserve[E]` using `fromPreserve` for `E`.
|
|
when E is void: {.error: "E cannot be void".}
|
|
if pr.embedded:
|
|
pr.embedded = false
|
|
result = Preserve[E](kind: pkEmbedded)
|
|
if not fromPreserve(result.embed, pr):
|
|
raise newException(ValueError, "failed to convert " & $E & " from " & $pr)
|
|
else:
|
|
case pr.kind
|
|
of pkBoolean, pkFloat, pkDouble, pkSignedInteger, pkBigInteger, pkString, pkByteString, pkSymbol:
|
|
result = cast[Preserve[E]](pr)
|
|
of pkRecord:
|
|
result = Preserve[E](kind: pr.kind)
|
|
result.record = map(pr.record) do (x: Preserve[void]) -> Preserve[E]:
|
|
mapEmbeds(x, E)
|
|
of pkSequence:
|
|
result = Preserve[E](kind: pr.kind)
|
|
result.sequence = map(pr.sequence) do (x: Preserve[void]) -> Preserve[E]:
|
|
mapEmbeds(x, E)
|
|
of pkSet:
|
|
result = Preserve[E](kind: pr.kind)
|
|
result.set = map(pr.set) do (x: Preserve[void]) -> Preserve[E]:
|
|
mapEmbeds(x, E)
|
|
of pkDictionary:
|
|
result = Preserve[E](kind: pr.kind)
|
|
result.dict = map(pr.dict) do (e: DictEntry[void]) -> DictEntry[E]:
|
|
(mapEmbeds(e.key, E), mapEmbeds(e.val, E))
|
|
of pkEmbedded:
|
|
assert false
|
|
|
|
proc mapEmbeds*[A, B](pr: sink Preserve[A]; op: proc (v: A): B): Preserve[B] =
|
|
## Convert `Preserve[A]` to `Preserve[B]` using an `A → B` procedure.
|
|
case pr.kind
|
|
of pkBoolean, pkFloat, pkDouble, pkSignedInteger, pkBigInteger, pkString, pkByteString, pkSymbol:
|
|
result = cast[Preserve[B]](pr)
|
|
of pkRecord:
|
|
result = Preserve[B](kind: pr.kind)
|
|
result.record = map(pr.record) do (x: Preserve[A]) -> Preserve[B]:
|
|
mapEmbeds(x, op)
|
|
of pkSequence:
|
|
result = Preserve[B](kind: pr.kind)
|
|
result.sequence = map(pr.sequence) do (x: Preserve[A]) -> Preserve[B]:
|
|
mapEmbeds(x, op)
|
|
of pkSet:
|
|
result = Preserve[B](kind: pr.kind)
|
|
result.set = map(pr.set) do (x: Preserve[A]) -> Preserve[B]:
|
|
mapEmbeds(x, op)
|
|
of pkDictionary:
|
|
result = Preserve[B](kind: pr.kind)
|
|
result.dict = map(pr.dict) do (e: DictEntry[A]) -> DictEntry[B]:
|
|
(mapEmbeds(e.key, op), mapEmbeds(e.val, op))
|
|
of pkEmbedded:
|
|
result = embed op(pr.embed)
|
|
|
|
proc concat[E](result: var string; pr: Preserve[E]) =
|
|
if pr.embedded: result.add("#!")
|
|
case pr.kind:
|
|
of pkBoolean:
|
|
case pr.bool
|
|
of false: result.add "#f"
|
|
of true: result.add "#t"
|
|
of pkFloat:
|
|
result.add($pr.float & "f")
|
|
of pkDouble:
|
|
result.add $pr.double
|
|
of pkSignedInteger:
|
|
result.add $pr.int
|
|
of pkBigInteger:
|
|
result.add $pr.bigint
|
|
of pkString:
|
|
result.add escapeJson(pr.string)
|
|
of pkByteString:
|
|
for b in pr.bytes:
|
|
if b.char notin {'\20'..'\21', '#'..'[', ']'..'~'}:
|
|
result.add("#[") #]#
|
|
result.add(base64.encode(pr.bytes))
|
|
result.add(']')
|
|
return
|
|
result.add("#\"")
|
|
result.add(cast[string](pr.bytes))
|
|
result.add('"')
|
|
of pkSymbol:
|
|
result.add(escapeJsonUnquoted(pr.symbol))
|
|
of pkRecord:
|
|
assert(pr.record.len > 0)
|
|
result.add('<')
|
|
result.concat(pr.record[pr.record.high])
|
|
for i in 0..<pr.record.high:
|
|
result.add(' ')
|
|
result.concat(pr.record[i])
|
|
result.add('>')
|
|
of pkSequence:
|
|
result.add('[')
|
|
for i, val in pr.sequence:
|
|
if i > 0:
|
|
result.add(", ")
|
|
result.concat(val)
|
|
result.add(']')
|
|
of pkSet:
|
|
result.add("#{")
|
|
for val in pr.set.items:
|
|
result.concat(val)
|
|
result.add(' ')
|
|
if pr.set.len > 1:
|
|
result.setLen(result.high)
|
|
result.add('}')
|
|
of pkDictionary:
|
|
result.add('{')
|
|
var i = 0
|
|
for (key, value) in pr.dict.items:
|
|
if i > 0:
|
|
result.add(' ')
|
|
result.concat(key)
|
|
result.add(": ")
|
|
result.concat(value)
|
|
if i < pr.dict.high:
|
|
result.add(',')
|
|
inc i
|
|
result.add('}')
|
|
of pkEmbedded:
|
|
result.add("#!")
|
|
result.add($pr.embed)
|
|
|
|
proc `$`*(pr: Preserve): string = concat(result, pr)
|
|
## Generate the textual representation of ``pr``.
|