fromJSON

builtins.fromJSON

Primop

Docs pulled from | This Revision | about 10 hours ago

Nix manual

Takes 1 arguments

Convert a JSON string to a Nix value. For example,

builtins.fromJSON ''{"x": [1, 2, 3], "y": null}''

returns the value { x = [ 1 2 3 ]; y = null; }.

Noogle detected

Aliases

lib.fromJSON
lib.strings.fromJSON

Detected Type

fromJSON :: String -> a

Implementation

This function is implemented in c++ and is part of the native nix runtime.

src/libexpr/primops.cc:2648

static void prim_fromJSON(EvalState & state, const PosIdx pos, Value ** args, Value & v)
{
    auto s = state.forceStringNoCtx(*args[0], pos, "while evaluating the first argument passed to builtins.fromJSON");
    try {
        parseJSON(state, s, v);
    } catch (JSONParseError & e) {
        e.addTrace(state.positions[pos], "while decoding a JSON string");
        throw;
    }
}