Module json 

v4.14 minimal JSON parser for the -> / ->> operators.

Hand-rolled, no external dep — same policy as the rest of the engine. Supports the JSON grammar from RFC 8259: objects, arrays, strings (with \" / \\ / \/ / \b / \f / \n / \r / \t / \uXXXX escapes), numbers, true / false / null. The parser returns a tree we walk by key (object) or integer index (array); accesses that miss return Value::Null per PG semantics.

path_get(doc, key, as_text) is the public entry. When as_text is true (->> operator), JSON strings unwrap to raw text and other scalars render as their canonical text; when false (->), the result is wrapped back into a Json value (the inner subtree rendered to its canonical JSON string form).

Enums

JsonValue

ParseError

Functions

build_array

json_build_array(...) — variadic; empty → “[]”. Each arg encoded via value_to_json_text.

build_object

json_build_object(k, v, k, v, …) — variadic, even-length. NULL key → error (PG: “argument cannot be null”). Values encoded via value_to_json_text. Returns Value::Json.

contains

v6.4.5 — PG json @> sub_json containment. Returns BOOL. lhs @> rhs is true when every member of rhs is structurally contained in lhs:

insert

jsonb_insert(target, path, new_value [, insert_after]) — insert at path. insert_after defaults to false.

parse

path_get

PG json -> key / json ->> key. lhs must be JSON or TEXT containing JSON. rhs is either a TEXT key (object access) or an INT index (array access). as_text=true for ->> (returns Value::Text); false for -> (returns Value::Json).

path_query

v7.17.0 Phase 3.9 — jsonb_path_query(doc, path) — returns the matched JSON values as a TextArray (each element is the JSON encoding of one match).

path_query_array

v7.17.0 Phase 3.9 — jsonb_path_query_array(doc, path) returns the matched values wrapped as a single JSON array.

path_query_first

v7.17.0 Phase 3.9 — jsonb_path_query_first(doc, path) returns the first matched JSON value as a Json, or NULL on no match.

path_walk

v6.4.5 — PG json #> path_text / json #>> path_text. The right-hand side is a PG text-array literal '{a,0,b}' whose elements are walked left-to-right; each element is either an object key or (when it parses as a non-negative integer) an array index. Missing or non-existent steps return Value::Null.

set

jsonb_set(target, path, new_value [, create_missing]) — replace at PG text-array path. create_missing defaults to true.

value_to_json_text

Encode a Value as its canonical JSON text (no surrounding quotes for non-strings). Used by every builder below.