Regular Expressions 101

Community Library Entry

26

Regular Expression
PCRE (PHP <7.3)

/
(?(DEFINE) # Note that everything is atomic, JSON does not need backtracking if it's valid # and this prevents catastrophic backtracking (?<json>(?>\s*(?&object)\s*|\s*(?&array)\s*)) (?<object>(?>\{\s*(?>(?&pair)(?>\s*,\s*(?&pair))*)?\s*\})) (?<pair>(?>(?&STRING)\s*:\s*(?&value))) (?<array>(?>\[\s*(?>(?&value)(?>\s*,\s*(?&value))*)?\s*\])) (?<value>(?>true|false|null|(?&STRING)|(?&NUMBER)|(?&object)|(?&array))) (?<STRING>(?>"(?>\\(?>["\\\/bfnrt]|u[a-fA-F0-9]{4})|[^"\\\0-\x1F\x7F]+)*")) (?<NUMBER>(?>-?(?>0|[1-9][0-9]*)(?>\.[0-9]+)?(?>[eE][+-]?[0-9]+)?)) ) \A(?&json)\z
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x

Description

Matches any valid JSON object, matches recursively.

Passes all JSON test cases I found.

Submitted by Mateon1 - 10 years ago