6.1.7 External Diff Tools

Differences between files can be shown in a number of ways, varying according to user preference and file type. These hooks allow customization of the way file differences are shown in diff and log commands.

get_encloser_pattern (file_path)

Called by mtn diff, mtn automate content_diff, mtn log, mtn automate log, for each file in the diff output, if --no-show-encloser is not given.

file_path is the pathname of the file that is being diffed.

The hook should return a string constant containing a regular expression; this regular expression will be used to find lines in the file that name the “top-level” constructs enclosing each “hunk” of changes.

If a null string is returned, no enclosers are shown.

See Regexps, for the regular expression syntax used by monotone.

The default hook treats looks at the file extension, as follows:

.texi

Returns a regular expression matching nodes, subsections, headings.

.tex

.ltx

.latex

Returns a regular expression matching part, chapter, [sub]sections, paragraphs.

.txt

Empty string.

Otherwise returns ^[[:alnum:]$_], which is correct for many programming languages.

external_diff (file_path, old_data, new_data, is_binary, diff_args, old_rev, new_rev)

Called by mtn diff, mtn automate content_diff, mtn log, mtn automate log, for each file in the diff output, if --external is given.

The hook should run a program that displays the differences between two versions of a file. The return value of the hook is not used.

file_path is the pathname of the file that is being diffed.

old_data and new_data are the contents of the old and the new file (old_data is nil if the file is new). If the content is binary, is_binary will be true, otherwise false. old_rev and new_rev are the revision IDs of the old and new data.

If an extra arguments are given via --diff-args, the string will be passed in as diff_args. Otherwise diff_args will be nil.

The default implementation of this hook calls the program diff, and if --diff-args were not passed, takes default arguments from the Lua variable external_diff_default_args. You can override this variable in your configuration file, without overriding the whole hook.