diff options
| -rw-r--r-- | lib/std/jsonutils.nim | 32 | ||||
| -rw-r--r-- | tests/stdlib/tjsonutils.nim | 26 |
2 files changed, 50 insertions, 8 deletions
diff --git a/lib/std/jsonutils.nim b/lib/std/jsonutils.nim index bfa600fa9..be3d7e7c8 100644 --- a/lib/std/jsonutils.nim +++ b/lib/std/jsonutils.nim @@ -2,9 +2,17 @@ This module implements a hookable (de)serialization for arbitrary types. Design goal: avoid importing modules where a custom serialization is needed; see strtabs.fromJsonHook,toJsonHook for an example. - ]## +runnableExamples: + import std/[strtabs,json] + type Foo = ref object + t: bool + z1: int8 + let a = (1.5'f32, (b: "b2", a: "a2"), 'x', @[Foo(t: true, z1: -3), nil], [{"name": "John"}.newStringTable]) + let j = a.toJson + doAssert j.jsonTo(type(a)).toJson == j + import std/[json,tables,strutils] #[ @@ -12,10 +20,14 @@ xxx use toJsonHook,fromJsonHook for Table|OrderedTable add Options support also using toJsonHook,fromJsonHook and remove `json=>options` dependency -future direction: -add a way to customize serialization, for eg allowing missing -or extra fields in JsonNode, field renaming, and a way to handle cyclic references -using a cache of already visited addresses. +Future directions: +add a way to customize serialization, for eg: +* allowing missing or extra fields in JsonNode +* field renaming +* allow serializing `enum` and `char` as `string` instead of `int` + (enum is more compact/efficient, and robust to enum renamings, but string + is more human readable) +* handle cyclic references, using a cache of already visited addresses ]# proc isNamedTuple(T: typedesc): bool {.magic: "TypeTrait".} @@ -65,8 +77,10 @@ proc fromJson*[T](a: var T, b: JsonNode) = fromJson(a[], b) elif T is array: checkJson a.len == b.len, $(a.len, b.len, $T) - for i, val in b.getElems: - fromJson(a[i], val) + var i = 0 + for ai in mitems(a): + fromJson(ai, b[i]) + i.inc elif T is seq: a.setLen b.len for i, val in b.getElems: @@ -114,12 +128,14 @@ proc toJson*[T](a: T): JsonNode = result = newJArray() for v in a.fields: result.add toJson(v) elif T is ref | ptr: - if a == nil: result = newJNull() + if system.`==`(a, nil): result = newJNull() else: result = toJson(a[]) elif T is array | seq: result = newJArray() for ai in a: result.add toJson(ai) elif T is pointer: result = toJson(cast[int](a)) + # edge case: `a == nil` could've also led to `newJNull()`, but this results + # in simpler code for `toJson` and `fromJson`. elif T is distinct: result = toJson(a.distinctBase) elif T is bool: result = %(a) elif T is Ordinal: result = %(a.ord) diff --git a/tests/stdlib/tjsonutils.nim b/tests/stdlib/tjsonutils.nim index 01c6aa05a..fca980dc9 100644 --- a/tests/stdlib/tjsonutils.nim +++ b/tests/stdlib/tjsonutils.nim @@ -13,12 +13,26 @@ proc testRoundtrip[T](t: T, expected: string) = import tables import strtabs +type Foo = ref object + id: int + +proc `==`(a, b: Foo): bool = + a.id == b.id + template fn() = block: # toJson, jsonTo type Foo = distinct float testRoundtrip('x', """120""") when not defined(js): testRoundtrip(cast[pointer](12345)): """12345""" + when nimvm: + discard + # bugs: + # Error: unhandled exception: 'intVal' is not accessible using discriminant 'kind' of type 'TNode' [ + # Error: VM does not support 'cast' from tyNil to tyPointer + else: + testRoundtrip(pointer(nil)): """0""" + testRoundtrip(cast[pointer](nil)): """0""" # causes workaround in `fromJson` potentially related to # https://github.com/nim-lang/Nim/issues/12282 @@ -40,5 +54,17 @@ template fn() = testRoundtrip(a): """[1.1,"fo",120,[10,11],[true,false],[{"mode":"modeCaseSensitive","table":{"y":"Y","z":"Z"}},{"mode":"modeCaseSensitive","table":{}}],[0,3],-4,{"foo":0.5,"bar":{"a1":"abc"},"bar2":null}]""" + block: + # edge case when user defined `==` doesn't handle `nil` well, eg: + # https://github.com/nim-lang/nimble/blob/63695f490728e3935692c29f3d71944d83bb1e83/src/nimblepkg/version.nim#L105 + testRoundtrip(@[Foo(id: 10), nil]): """[{"id":10},null]""" + + block: + type Foo = enum f1, f2, f3, f4, f5 + type Bar = enum b1, b2, b3, b4 + let a = [f2: b2, f3: b3, f4: b4] + doAssert b2.ord == 1 # explains the `1` + testRoundtrip(a): """[1,2,3]""" + static: fn() fn() |