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Module: (curry json)

v1.2.2 — 2026-06-07

Pure-C JSON parser and serialiser. No external dependencies.

Installation

No extra packages required. Enabled by default (-DBUILD_MODULE_JSON=ON).

Import

(import (curry json))

Procedures

(json-parse string) → value

Parse a JSON string and return the corresponding Scheme value.

JSON Scheme
null #f
true #t
false #f
number fixnum or flonum
string string
array list
object association list ((key . value) ...) where keys are strings

Raises an error if the input is not valid JSON.

(json-stringify value) → string

Serialise a Scheme value to a JSON string.

Scheme JSON
#f null
#t true
fixnum / flonum number
bignum / exact rational / other numeric-tower value number (converted to its nearest double — JSON's own number type is IEEE double, so this is the same lossy tradeoff as exact->inexact; a bignum too large to fit becomes +inf.0/-inf.0-range double behavior; for a complex value, only the real part is used — the imaginary part is silently dropped, matching how the rest of curry's numeric tower already treats a complex-to-real conversion elsewhere)
string string (with escaping)
list of pairs ((k . v) ...) object
list array
vector array

Examples

(import (curry json))

(define data (json-parse "{\"name\":\"Alice\",\"age\":30,\"tags\":[\"admin\",\"user\"]}"))
; => (("name" . "Alice") ("age" . 30) ("tags" . ("admin" "user")))

(cdr (assoc "name" data))   ; => "Alice"
(cdr (assoc "age"  data))   ; => 30

(json-stringify '(("x" . 1) ("y" . 2)))
; => "{\"x\":1,\"y\":2}"

(json-stringify '(1 2 3 "hello" #t))
; => "[1,2,3,\"hello\",true]"

Notes

  • null maps to #f (there is no distinct null value in Scheme). If you need to distinguish null from false, check the JSON source before parsing or use a wrapper.
  • Object keys are returned as strings, not symbols.
  • Numbers with a decimal point or exponent become flonums; integers become fixnums.