json

Recursive-descent JSON parse + stringify.

1 file lib/json/json.vader 10 exports

JsonValue is the tagged union of every JSON shape. parse returns JsonValue | JsonError ; parse failures surface as the JsonError variant, propagated by an explicit if e is JsonError { return e } narrowing guard. stringify writes a value back, compact or indented.

Numbers are stored as f64 for MVP: fine for the compiler's use cases (manifests, diagnostics) but loses precision past 2^53. Cf. TODO.md std/json v2 for the post-MVP compile-time-generated parser à la kotlinx-serialization.

Types

JsonValue

type json.vader:26

JsonValue :: JsonString | JsonNumber | JsonBool | JsonNull | JsonArray | JsonObject

Tagged union covering every JSON shape (null, true/false, numbers, strings, arrays, objects). Discriminated via is JsonString etc. in match. Numbers carry an f64 ; precision past 2^53 is lost (MVP limitation).

JsonString

struct json.vader:29

JsonString :: struct

JSON string variant: UTF-8 decoded, escape-resolved.

Fields

value: string

No description.

JsonNumber

struct json.vader:33

JsonNumber :: struct

JSON number variant: f64. Integer-valued numbers round-trip through to_compact_str for cleaner output.

Fields

value: f64

No description.

JsonBool

struct json.vader:36

JsonBool :: struct

JSON true/false.

Fields

value: bool

No description.

JsonNull

struct json.vader:39

JsonNull :: struct

JSON null. No payload.

JsonArray

struct json.vader:42

JsonArray :: struct

JSON array: ordered list of JsonValues.

Fields

items: JsonValue[]

No description.

JsonObject

struct json.vader:46

JsonObject :: struct

JSON object: string-keyed map of JsonValues. Insertion order is preserved by the parser ; lookup is O(1) average via MutableMap.

Fields

entries: MutableMap<string, JsonValue>

No description.

JsonError

struct json.vader:52

JsonError :: struct

Error raised by parse when the input isn't valid JSON. pos is the byte offset of the offending character.

Fields

msg: string

No description.

pos: i64

No description.

Implements Error message :: fn(self) -> string

Functions

parse

fn json.vader:470

parse :: fn(input: string) -> JsonValue | JsonError

Parse a complete JSON document. The input must contain exactly one JSON value optionally surrounded by whitespace ; trailing non-whitespace is an error.

Policy: malformed syntax (a bad escape, an unterminated string / container, an invalid number, nesting past MAX_DEPTH) returns a JsonError. A syntactically valid but unpaired \u surrogate is handled leniently: it decodes to U+FFFD (matching Go's encoding/json), since a lone surrogate has no UTF-8 representation.

Parameters

input string the JSON text.

Returns

JsonValue | JsonError the parsed JsonValue on success.

Errors

JsonError carrying a short message and the byte offset of the offending character.

stringify

fn json.vader:601

stringify :: fn(v: JsonValue, indent: i32 = 0) -> string

Serialise v to a JSON string, one line per element when indent is positive.

Parameters

v	`JsonValue`	the value to serialise.
indent	`i32` = `0`	spaces per nesting level; 0, the default, and below write the smallest valid encoding.

Returns

string

Example

list :: JsonArray { .items = [JsonNumber { .value = 1.0 }, JsonNull {}] }
stringify(list)      // "[1,null]"
stringify(list, 2)   // "[\n  1,\n  null\n]"