5 Module N_PRETTY
gullradriel edited this page 2026-10-09 00:55:18 +02:00

PRETTY: reformat JSON, XML/HTML and JavaScript text for display

Dependency-free lexical formatters aimed at viewers: they re-indent a document so a human can read it, without validating it. More...

Functions

Name
N_STR * n_pretty_xml(const char * text)
Re-indent an XML or HTML document (one tag or text run per line).
N_STR * n_pretty_json_lenient(const char * text)
Re-indent a JSON document by punctuation alone, without parsing it.
N_STR * n_pretty_json(const char * text)
Reformat a JSON document with cJSON (parse + print).
N_STR * n_pretty_js(const char * text)
Conservatively re-indent JavaScript (newlines at top-level braces and semicolons, two-space indent by brace depth).

Detailed Description

Dependency-free lexical formatters aimed at viewers: they re-indent a document so a human can read it, without validating it.

Malformed input is reformatted on a best-effort basis; the formatters never crash on it.

Limits by design (these are viewers, not compilers):

  • n_pretty_xml() treats HTML like XML with void-element and raw-text (script/style) awareness; whitespace inside text nodes is trimmed at both ends, so whitespace-significant content (pre) is not preserved exactly.
  • n_pretty_js() is a conservative re-indenter (newlines at braces and semicolons), not a beautifier. Strings, template literals, comments and regex literals are copied verbatim. A '/' is lexed as a regex when it follows an operator, an opener, a separator, or an expression keyword (return, typeof, case, ...); the remaining ambiguity (a regex right after a closing parenthesis, as in if (x) /re/.test(y)) is lexed as division, which can only mis-break lines, never corrupt the text.
  • n_pretty_json() needs the vendored cJSON (HAVE_CJSON); without it the function logs an error and returns NULL. It parses, so it reformats valid documents only: use n_pretty_json_lenient() for the rest.
  • n_pretty_json_lenient() re-indents by punctuation without parsing, so it also breaks up a document cJSON rejects (a truncated body, a trailing comma, NDJSON). It cannot report that the input was invalid and it does not normalise anything, so prefer n_pretty_json() first and label what the fallback produces as approximate.

All functions return a freshly allocated N_STR the caller must release with free_nstr(), or NULL when the input is NULL, empty, or does not look like the expected format.

Functions Documentation

function n_pretty_xml

N_STR * n_pretty_xml(
    const char * text
)

Re-indent an XML or HTML document (one tag or text run per line).

Parameters:

  • text The markup text. NULL, empty, or input whose first non-whitespace character is not '<' returns NULL.

Return: A new indented N_STR (free with free_nstr), or NULL.

function n_pretty_json_lenient

N_STR * n_pretty_json_lenient(
    const char * text
)

Re-indent a JSON document by punctuation alone, without parsing it.

Parameters:

  • text The JSON text. NULL or empty input returns NULL.

Return: A new indented N_STR (free with free_nstr), or NULL.

String literals are copied verbatim, containers open and close a level, and each comma ends a line, so a document cJSON rejects (truncated, trailing comma, concatenated values) still becomes readable.

function n_pretty_json

N_STR * n_pretty_json(
    const char * text
)

Reformat a JSON document with cJSON (parse + print).

Parameters:

  • text The JSON text. NULL, empty, or non-JSON input returns NULL.

Return: A new indented N_STR (free with free_nstr), or NULL.

function n_pretty_js

N_STR * n_pretty_js(
    const char * text
)

Conservatively re-indent JavaScript (newlines at top-level braces and semicolons, two-space indent by brace depth).

Parameters:

  • text The script text. NULL or empty input returns NULL.

Return: A new indented N_STR (free with free_nstr), or NULL.