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font-lock-profiler - Coverage and timing tool for font-lock keywords

Author: Anders Lindgren<br> Version: 0.0.3<br> URL: https://github.com/Lindydancer/font-lock-profiler<br>

A profiler for font-lock keywords. This package measures time and counts the number of times each part of a font-lock keyword is used. For matchers, it counts the total number and the number of successful matches.

The result is presented in table that can be sorted by count or time. The table can be expanded to include each part of the font-lock keyword.

In addition, this package can generate a log of all font-lock events. This can be used to verify font-lock implementations, concretely, this is used for back-to-back tests of the real font-lock engine and Font Lock Studio, an interactive debugger for font-lock keywords.

Usage

Use the following functions:

• font-lock-profiler-buffer -- Fontify the entire buffer and present the profiling result.
• font-lock-profiler-region -- Fontify the region and present the profiling result.
• font-lock-profiler-start -- Enable "live" profiling. Do whatever you want to do measure (like editing or scrolling). When done, run font-lock-profiler-stop-and-report.

The result buffer

Once the profiling has been performed, the reporter buffer, *FontLockProfiler* is displayed. It contains a list of all font-lock keywords, the number of times they matched and the total time that was spent running them.

By pressing x, the view is expanded into displaying the corresponding information for each highlight rule, including anchored highlights.

Additional features

• The variable font-lock-profiler-remaining-matches, when set to an integer, the instrumented keywords will fake a match failure after this many matches. This is useful, for example, when working with keywords where a search would never terminate (without this, Emacs would hang).

Other Font Lock Tools

This package is part of a suite of font-lock tools. The other tools in the suite are:

Font Lock Studio

Interactive debugger for font-lock keywords (Emacs syntax highlighting rules).

Font Lock Studio lets you single-step Font Lock keywords -- matchers, highlights, and anchored rules, so that you can see what happens when a buffer is fontified. You can set breakpoints on or inside rules and run until one has been hit. When inside a rule, matches are visualized using a palette of background colors. The explainer can describe a rule in plain-text English. Tight integration with Edebug allows you to step into Lisp expressions that are part of the Font Lock keywords.

Highlight Refontification

Minor mode that visualizes how font-lock refontifies a buffer. This is useful when developing or debugging font-lock keywords, especially for keywords that span multiple lines.

The background of the buffer is painted in a rainbow of colors, where each band in the rainbow represent a region of the buffer that has been refontified. When the buffer is modified, the rainbow is updated.

Faceup

Emacs is capable of highlighting buffers based on language-specific font-lock rules. This package makes it possible to perform regression test for packages that provide font-lock rules.

The underlying idea is to convert text with highlights ("faces") into a plain text representation using the Faceup markup language. This language is semi-human readable, for example:

«k:this» is a keyword

By comparing the current highlight with a highlight performed with stable versions of a package, it's possible to automatically find problems that otherwise would have been hard to spot.

This package is designed to be used in conjunction with Ert, the standard Emacs regression test system.

The Faceup markup language is a generic markup language, regression testing is merely one way to use it.

Font Lock Regression Suite

A collection of example source files for a large number of programming languages, with ERT tests to ensure that syntax highlighting does not accidentally change.

For each source file, font-lock reference files are provided for various Emacs versions. The reference files contains a plain-text representation of source file with syntax highlighting, using the format "faceup".

Of course, the collection source file can be used for other kinds of testing, not limited to font-lock regression testing.

Converted from font-lock-profiler.el by el2markdown.