diff options
Diffstat (limited to 'lib/std/jsonutils.nim')
| -rw-r--r-- | lib/std/jsonutils.nim | 119 |
1 files changed, 58 insertions, 61 deletions
diff --git a/lib/std/jsonutils.nim b/lib/std/jsonutils.nim index 722ea49b5..2d28748ce 100644 --- a/lib/std/jsonutils.nim +++ b/lib/std/jsonutils.nim @@ -1,5 +1,5 @@ ##[ -This module implements a hookable (de)serialization for arbitrary types. +This module implements a hookable (de)serialization for arbitrary types using JSON. Design goal: avoid importing modules where a custom serialization is needed; see strtabs.fromJsonHook,toJsonHook for an example. ]## @@ -16,7 +16,7 @@ runnableExamples: assert 0.0.toJson.kind == JFloat assert Inf.toJson.kind == JString -import json, strutils, tables, sets, strtabs, options +import std/[json, strutils, tables, sets, strtabs, options, strformat] #[ Future directions: @@ -30,29 +30,15 @@ add a way to customize serialization, for e.g.: objects. ]# -import macros -from enumutils import symbolName -from typetraits import OrdinalEnum +import std/macros +from std/enumutils import symbolName +from std/typetraits import OrdinalEnum, tupleLen when defined(nimPreviewSlimSystem): import std/assertions -when not defined(nimFixedForwardGeneric): - # xxx remove pending csources_v1 update >= 1.2.0 - proc to[T](node: JsonNode, t: typedesc[T]): T = - when T is string: node.getStr - elif T is bool: node.getBool - else: static: doAssert false, $T # support as needed (only needed during bootstrap) - proc isNamedTuple(T: typedesc): bool = # old implementation - when T isnot tuple: result = false - else: - var t: T - for name, _ in t.fieldPairs: - when name == "Field0": return compiles(t.Field0) - else: return true - return false -else: - proc isNamedTuple(T: typedesc): bool {.magic: "TypeTrait".} + +proc isNamedTuple(T: typedesc): bool {.magic: "TypeTrait".} type Joptions* = object # xxx rename FromJsonOptions @@ -92,19 +78,24 @@ macro getDiscriminants(a: typedesc): seq[string] = let sym = a[1] let t = sym.getTypeImpl let t2 = t[2] - doAssert t2.kind == nnkRecList - result = newTree(nnkBracket) - for ti in t2: - if ti.kind == nnkRecCase: - let key = ti[0][0] - let typ = ti[0][1] - result.add newLit key.strVal - if result.len > 0: + case t2.kind + of nnkEmpty: # allow empty objects result = quote do: - @`result` + seq[string].default + of nnkRecList: + result = newTree(nnkBracket) + for ti in t2: + if ti.kind == nnkRecCase: + let key = ti[0][0] + result.add newLit key.strVal + if result.len > 0: + result = quote do: + @`result` + else: + result = quote do: + seq[string].default else: - result = quote do: - seq[string].default + raiseAssert "unexpected kind: " & $t2.kind macro initCaseObject(T: typedesc, fun: untyped): untyped = ## does the minimum to construct a valid case object, only initializing @@ -118,7 +109,7 @@ macro initCaseObject(T: typedesc, fun: untyped): untyped = case t.kind of nnkObjectTy: t2 = t[2] of nnkRefTy: t2 = t[0].getTypeImpl[2] - else: doAssert false, $t.kind # xxx `nnkPtrTy` could be handled too + else: raiseAssert $t.kind # xxx `nnkPtrTy` could be handled too doAssert t2.kind == nnkRecList result = newTree(nnkObjConstr) result.add sym @@ -168,7 +159,7 @@ template fromJsonFields(newObj, oldObj, json, discKeys, opt) = if discKeys.len == 0 or hasField(oldObj, key): val = accessField(oldObj, key) else: - checkJson false, $($T, key, json) + checkJson false, "key '$1' for $2 not in $3" % [key, $T, json.pretty()] else: if json.hasKey key: numMatched.inc @@ -187,7 +178,7 @@ template fromJsonFields(newObj, oldObj, json, discKeys, opt) = else: json.len == num and num == numMatched - checkJson ok, $(json.len, num, numMatched, $T, json) + checkJson ok, "There were $1 keys (expecting $2) for $3 with $4" % [$json.len, $num, $T, json.pretty()] proc fromJson*[T](a: var T, b: JsonNode, opt = Joptions()) @@ -220,28 +211,24 @@ proc fromJson*[T](a: var T, b: JsonNode, opt = Joptions()) = adding "json path" leading to `b` can be added in future work. ]# checkJson b != nil, $($T, b) - when compiles(fromJsonHook(a, b)): fromJsonHook(a, b) + when compiles(fromJsonHook(a, b, opt)): fromJsonHook(a, b, opt) + elif compiles(fromJsonHook(a, b)): fromJsonHook(a, b) elif T is bool: a = to(b,T) elif T is enum: case b.kind of JInt: a = T(b.getBiggestInt()) of JString: a = parseEnum[T](b.getStr()) - else: checkJson false, $($T, " ", b) + else: checkJson false, fmt"Expecting int/string for {$T} got {b.pretty()}" elif T is uint|uint64: a = T(to(b, uint64)) elif T is Ordinal: a = cast[T](to(b, int)) elif T is pointer: a = cast[pointer](to(b, int)) - elif T is distinct: - when nimvm: - # bug, potentially related to https://github.com/nim-lang/Nim/issues/12282 - a = T(jsonTo(b, distinctBase(T))) - else: - a.distinctBase.fromJson(b) + elif T is distinct: a.distinctBase.fromJson(b) elif T is string|SomeNumber: a = to(b,T) elif T is cstring: case b.kind of JNull: a = nil of JString: a = b.str - else: checkJson false, $($T, " ", b) + else: checkJson false, fmt"Expecting null/string for {$T} got {b.pretty()}" elif T is JsonNode: a = b elif T is ref | ptr: if b.kind == JNull: a = nil @@ -249,7 +236,7 @@ proc fromJson*[T](a: var T, b: JsonNode, opt = Joptions()) = a = T() fromJson(a[], b, opt) elif T is array: - checkJson a.len == b.len, $(a.len, b.len, $T) + checkJson a.len == b.len, fmt"Json array size doesn't match for {$T}" var i = 0 for ai in mitems(a): fromJson(ai, b[i], opt) @@ -285,14 +272,24 @@ proc fromJson*[T](a: var T, b: JsonNode, opt = Joptions()) = fromJsonFields(a, nil, b, seq[string].default, opt) else: checkJson b.kind == JArray, $(b.kind) # we could customize whether to allow JNull + + when compiles(tupleLen(T)): + let tupleSize = tupleLen(T) + else: + # Tuple len isn't in csources_v1 so using tupleLen would fail. + # Else branch basically never runs (tupleLen added in 1.1 and jsonutils in 1.4), but here for consistency + var tupleSize = 0 + for val in fields(a): + tupleSize.inc + + checkJson b.len == tupleSize, fmt"Json doesn't match expected length of {tupleSize}, got {b.pretty()}" var i = 0 for val in fields(a): fromJson(val, b[i], opt) i.inc - checkJson b.len == i, $(b.len, i, $T, b) # could customize else: # checkJson not appropriate here - static: doAssert false, "not yet implemented: " & $T + static: raiseAssert "not yet implemented: " & $T proc jsonTo*(b: JsonNode, T: typedesc, opt = Joptions()): T = ## reverse of `toJson` @@ -305,7 +302,8 @@ proc toJson*[T](a: T, opt = initToJsonOptions()): JsonNode = ## .. note:: With `-d:nimPreviewJsonutilsHoleyEnum`, `toJson` now can ## serialize/deserialize holey enums as regular enums (via `ord`) instead of as strings. ## It is expected that this behavior becomes the new default in upcoming versions. - when compiles(toJsonHook(a)): result = toJsonHook(a) + when compiles(toJsonHook(a, opt)): result = toJsonHook(a, opt) + elif compiles(toJsonHook(a)): result = toJsonHook(a) elif T is object | tuple: when T is object or isNamedTuple(T): result = newJObject() @@ -348,7 +346,7 @@ proc toJson*[T](a: T, opt = initToJsonOptions()): JsonNode = else: result = %a proc fromJsonHook*[K: string|cstring, V](t: var (Table[K, V] | OrderedTable[K, V]), - jsonNode: JsonNode) = + jsonNode: JsonNode, opt = Joptions()) = ## Enables `fromJson` for `Table` and `OrderedTable` types. ## ## See also: @@ -366,14 +364,13 @@ proc fromJsonHook*[K: string|cstring, V](t: var (Table[K, V] | OrderedTable[K, V "type is `" & $jsonNode.kind & "`." clear(t) for k, v in jsonNode: - t[k] = jsonTo(v, V) + t[k] = jsonTo(v, V, opt) -proc toJsonHook*[K: string|cstring, V](t: (Table[K, V] | OrderedTable[K, V])): JsonNode = +proc toJsonHook*[K: string|cstring, V](t: (Table[K, V] | OrderedTable[K, V]), opt = initToJsonOptions()): JsonNode = ## Enables `toJson` for `Table` and `OrderedTable` types. ## ## See also: ## * `fromJsonHook proc<#fromJsonHook,,JsonNode>`_ - # pending PR #9217 use: toSeq(a) instead of `collect` in `runnableExamples`. runnableExamples: import std/[tables, json, sugar] let foo = ( @@ -388,9 +385,9 @@ proc toJsonHook*[K: string|cstring, V](t: (Table[K, V] | OrderedTable[K, V])): J result = newJObject() for k, v in pairs(t): # not sure if $k has overhead for string - result[(when K is string: k else: $k)] = toJson(v) + result[(when K is string: k else: $k)] = toJson(v, opt) -proc fromJsonHook*[A](s: var SomeSet[A], jsonNode: JsonNode) = +proc fromJsonHook*[A](s: var SomeSet[A], jsonNode: JsonNode, opt = Joptions()) = ## Enables `fromJson` for `HashSet` and `OrderedSet` types. ## ## See also: @@ -408,9 +405,9 @@ proc fromJsonHook*[A](s: var SomeSet[A], jsonNode: JsonNode) = "type is `" & $jsonNode.kind & "`." clear(s) for v in jsonNode: - incl(s, jsonTo(v, A)) + incl(s, jsonTo(v, A, opt)) -proc toJsonHook*[A](s: SomeSet[A]): JsonNode = +proc toJsonHook*[A](s: SomeSet[A], opt = initToJsonOptions()): JsonNode = ## Enables `toJson` for `HashSet` and `OrderedSet` types. ## ## See also: @@ -422,9 +419,9 @@ proc toJsonHook*[A](s: SomeSet[A]): JsonNode = result = newJArray() for k in s: - add(result, toJson(k)) + add(result, toJson(k, opt)) -proc fromJsonHook*[T](self: var Option[T], jsonNode: JsonNode) = +proc fromJsonHook*[T](self: var Option[T], jsonNode: JsonNode, opt = Joptions()) = ## Enables `fromJson` for `Option` types. ## ## See also: @@ -438,11 +435,11 @@ proc fromJsonHook*[T](self: var Option[T], jsonNode: JsonNode) = assert isNone(opt) if jsonNode.kind != JNull: - self = some(jsonTo(jsonNode, T)) + self = some(jsonTo(jsonNode, T, opt)) else: self = none[T]() -proc toJsonHook*[T](self: Option[T]): JsonNode = +proc toJsonHook*[T](self: Option[T], opt = initToJsonOptions()): JsonNode = ## Enables `toJson` for `Option` types. ## ## See also: @@ -455,7 +452,7 @@ proc toJsonHook*[T](self: Option[T]): JsonNode = assert $toJson(optNone) == "null" if isSome(self): - toJson(get(self)) + toJson(get(self), opt) else: newJNull() |