Improve the syntax documentation

[mc-butler]

Important

This issue was migrated from Trac:

Origin	https://midnight-commander.org/ticket/3734
Reporter	mooffie (@mooffie)

There are several features not documented well, or not documented at all:

[I'll edit this text from time to time to improve and extend it. Everybody: feel free to add comments and I'll incorporate them here. When we're finished we'll convert this to nroff format.]

Star

Matches any length of characters (except newline). To be exact, it matches any character which is not the next one in the pattern. This effectively makes it "non-greedy" and lets you do ${*} to match a shell variable.

Plus

Surprisingly, it does not mean "match 1 or more characters". TODO.

Braces

\{chars\} matches one character.

Brackets

\[chars\] matches 0 or more characters. It's greedy, which means that if chars contains any of the characters appearing later in the pattern then the match will fail. (TODO: what's the purpose of "if (p[1] == d) i--;" introduced in commit df20f28 ?)

Misc

• Pressing C-s twice effectively reloads the syntax file (so you don't have to exit the editor, or MC itself, to test your syntax modifications).

[mc-butler]

Changed by andrew_b (@aborodin) on Sep 28, 2019 at 8:18 UTC (comment 1)

• Component changed from mcedit to documentation

[jip]

Plus matches 0 or more any but space or tab characters.

My results:

mcedit    PCRE2's equivalent
[a-c]     \[a-c\]    (no special meaning of [ ])
\[a-c\]   (a|-|c)*   (no special meaning of -  )
{a-c}     \{a-c\}    (no special meaning of { })
\{a-c\}   [ac-]      (no special meaning of -  )
.         \.
(         \(
)         \)
*         .*
+         [^ \t]*
?         \?
\*        \*
\+        \+
^         \^
$         \$
|         \|
\s        [ ]        (single space)
\t        \t
\n        \n

[zyv]

Feel free to submit a PR for documentation. Unfortunately, the author of this issue is unlikely to ever come back to it.

[jip]

Ok.