Urldecode

$urldecode(text) is a compatibility alias in builtins, not a registered C built-in. It returns $xform(-url text). Its defining script must be loaded; default startup normally loads it. The reverse wrapper is urlencode.

The direct xform form is:

$xform(-url hello%20there)

This returns hello there. A percent sign followed by two hexadecimal digits is decoded to the corresponding byte; other bytes are copied. Hexadecimal letters are accepted in either case. Malformed percent sequences remain literal rather than producing a separate validation error. A plus sign stays +: this is not HTML form decoding that converts plus signs to spaces. Empty input yields empty.

The decoder does one pass and does not parse a URL into components, fetch a resource, or perform character-set conversion. %2520 therefore becomes %20, not a space. The returned text can contain punctuation meaningful to later script or shell evaluation; decoding does not provide quoting for those later contexts.

Ordinary script values are C strings. %00 produces a NUL, truncating the visible final result. To process binary data safely, keep decoding and a final text-safe encoding in one xform chain, which retains intermediate lengths. See xform for supported transforms and result limitations.

Source references

• script/builtins: URL compatibility wrappers.
• source/ircaux.c: percent decoder and URL transform registration.
• source/functions.c: xform entry point and current function registry.