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diff --git a/runtime/macros/matchit.txt b/runtime/macros/matchit.txt new file mode 100644 index 000000000..8ea4de5f2 --- /dev/null +++ b/runtime/macros/matchit.txt @@ -0,0 +1,402 @@ +*matchit.txt* Extended "%" matching + +For instructions on installing this file, type + :help matchit-install +inside Vim. + +For Vim version 6.3. Last change: 2004 May 12 + + + VIM REFERENCE MANUAL by Benji Fisher + +*matchit* *matchit.vim* + +1. Extended matching with "%" |matchit-intro| +2. Activation |matchit-activate| +3. Configuration |matchit-configure| +4. Supporting a New Language |matchit-newlang| +5. Known Bugs and Limitations |matchit-bugs| + +The functionality mentioned here is a plugin, see |add-plugin|. +This plugin is only available if 'compatible' is not set. +You can avoid loading this plugin by setting the "loaded_matchit" variable +in your |vimrc| file: > + :let loaded_matchit = 1 + +{Vi does not have any of this} + +============================================================================== +1. Extended matching with "%" *matchit-intro* + + *matchit-%* +% Cycle forward through matching groups, such as "if", "else", "endif", + as specified by |b:match_words|. + + *g%* *v_g%* *o_g%* +g% Cycle backwards through matching groups, as specified by + |b:match_words|. For example, go from "endif" to "else" to "if". + + *[%* *v_[%* *o_[%* +[% Go to [count] previous unmatched group, as specified by + |b:match_words|. Similar to |[{|. + + *]%* *v_]%* *o_]%* +]% Go to [count] next unmatched group, as specified by + |b:match_words|. Similar to |]}|. + + *v_a%* +a% In Visual mode, select the matching group, as specified by + |b:match_words|, containing the cursor. Similar to |v_a[|. + A [count] is ignored, and only the first character of the closing + pattern is selected. + +In Vim, as in plain vi, the percent key, |%|, jumps the cursor from a brace, +bracket, or paren to its match. This can be configured with the 'matchpairs' +option. The matchit plugin extends this in several ways: + + You can match whole words, such as "if" and "endif", not just + single characters. You can also specify a |regular-expression|. + You can define groups with more than two words, such as "if", + "else", "endif". Banging on the "%" key will cycle from the "if" to + the first "else", the next "else", ..., the closing "endif", and back + to the opening "if". Nested structures are skipped. Using |g%| goes + in the reverse direction. + By default, words inside comments and strings are ignored, unless + the cursor is inside a comment or string when you type "%". If the + only thing you want to do is modify the behavior of "%" so that it + behaves this way, you can > + :let b:match_words = &matchpairs +< +See |matchit-details| for details on what the script does, and |b:match_words| +for how to specify matching patterns. + +MODES: *matchit-modes* *matchit-v_%* *matchit-o_%* + +Mostly, % and related motions (|g%| and |[%| and |]%|) work just like built-in +|motion| commands in |Operator-pending| and |Visual| modes. However, you +cannot make these motions |linewise| or |characterwise|, since the |:omap|s +that define them start with "v" in order to make the default behavior +inclusive. (See |o_v|.) In other words, "dV%" will not work. The +work-around is to go through Visual mode: "V%d" will work. + +LANGUAGES: *matchit-languages* + +Currently, the following languages are supported: Ada, ASP with VBS, Csh, +DTD, Entity, Essbase, Fortran, HTML, JSP (same as HTML), LaTeX, Lua, Pascal, +SGML, Shell, Tcsh, Vim, XML. Other languages may already have support via +|filetype-plugin|s. + +To support a new language, see |matchit-newlang| below. + +DETAILS: *matchit-details* *matchit-parse* + +Here is an outline of what matchit.vim does each time you hit the "%" key. If +there are |backref|s in |b:match_words| then the first step is to produce a +version in which these back references have been eliminated; if there are no +|backref|s then this step is skipped. This step is called parsing. For +example, "\(foo\|bar\):end\1" is parsed to yield +"\(foo\|bar\):end\(foo\|bar\)". This can get tricky, especially if there are +nested groups. If debugging is turned on, the parsed version is saved as +|b:match_pat|. + + *matchit-choose* +Next, the script looks for a word on the current line that matches the pattern +just constructed. It includes the patterns from the 'matchpairs' option. +The goal is to do what you expect, which turns out to be a little complicated. +The script follows these rules: + + Insist on a match that ends on or after the cursor. + Prefer a match that includes the cursor position (that is, one that + starts on or before the cursor). + Prefer a match that starts as close to the cursor as possible. + Prefer a match in |b:match_words| to a match in 'matchpairs'. + If more than one pattern in |b:match_words| matches, choose the one + that is listed first. + +Examples: + + Suppose you > + :let b:match_words = '<:>,<tag>:</tag>' +< and hit "%" with the cursor on or before the "<" in "a <tag> is born". + The pattern '<' comes first, so it is preferred over '<tag>', which + also matches. If the cursor is on the "t", however, then '<tag>' is + preferred, because this matches a bit of text containing the cursor. + If the two groups of patterns were reversed then '<' would never be + preferred. + + Suppose you > + :let b:match_words = 'if:end if' +< (Note the space!) and hit "%" with the cursor at the end of "end if". + Then "if" matches, which is probably not what you want, but if the + cursor starts on the "end " then "end if" is chosen. (You can avoid + this problem by using a more complicated pattern.) + +If there is no match, the script falls back on the usual behavior of |%|. If +debugging is turned on, the matched bit of text is saved as |b:match_match| +and the cursor column of the start of the match is saved as |b:match_col|. + +Next, the script looks through |b:match_words| (original and parsed versions) +for the group and pattern that match. If debugging is turned on, the group is +saved as |b:match_ini| (the first pattern) and |b:match_tail| (the rest). If +there are |backref|s then, in addition, the matching pattern is saved as +|b:match_word| and a table of translations is saved as |b:match_table|. If +there are |backref|s, these are determined from the matching pattern and +|b:match_match| and substituted into each pattern in the matching group. + +The script decides whether to search forwards or backwards and chooses +arguments for the |searchpair()| function. Then, the cursor is moved to the +start of the match, and |searchpair()| is called. By default, matching +structures inside strings and comments are ignored. This can be changed by +setting |b:match_skip|. + +============================================================================== +2. Activation *matchit-activate* + +You can use this script as a plugin, by copying it to your plugin directory. +See |add-global-plugin| for instructions. You can also add a line to your +|vimrc| file, such as > + :source $VIMRUNTIME/macros/matchit.vim +or > + :runtime macros/matchit.vim +Either way, the script should start working the next time you start up Vim. + +The script does nothing unless it finds a |buffer-variable| named +|b:match_words|. The script contains autocommands that set this variable for +various file types: see |matchit-languages| above. For a new language, you +can add autocommands to the script or to your vimrc file, but the recommended +method is to add a line such as > + let b:match_words = '\<foo\>:\<bar\>' +to the |filetype-plugin| for your language. See |b:match_words| below for how +this variable is interpreted. + +TROUBLESHOOTING *matchit-troubleshoot* + +The script should work in most installations of Vim. It may not work if Vim +was compiled with a minimal feature set, for example if the |+syntax| option +was not enabled. If your Vim has support for syntax compiled in, but you do +not have |syntax| highlighting turned on, matchit.vim should work, but it may +fail to skip matching groups in comments and strings. If the |filetype| +mechanism is turned off, the |b:match_words| variable will probably not be +defined automatically. + +============================================================================== +3. Configuration *matchit-configure* + +There are several variables that govern the behavior of matchit.vim. Note +that these are variables local to the buffer, not options, so use |:let| to +define them, not |:set|. Some of these variables have values that matter; for +others, it only matters whether the variable has been defined. All of these +can be defined in the |filetype-plugin| or autocommand that defines +|b:match_words| or "on the fly." + +The main variable is |b:match_words|. It is described in the section below on +supporting a new language. + + *MatchError* *matchit-hl* *matchit-highlight* +MatchError is the highlight group for error messages from the script. By +default, it is linked to WarningMsg. If you do not want to be bothered by +error messages, you can define this to be something invisible. For example, +if you use the GUI version of Vim and your command line is normally white, you +can do > + :hi MatchError guifg=white guibg=white +< + *b:match_ignorecase* +If you > + :let b:match_ignorecase = 1 +then matchit.vim acts as if 'ignorecase' is set: for example, "end" and "END" +are equivalent. If you > + :let b:match_ignorecase = 0 +then matchit.vim treats "end" and "END" differently. (There will be no +b:match_infercase option unless someone requests it.) + + *b:match_debug* +Define b:match_debug if you want debugging information to be saved. See +|matchit-debug|, below. + + *b:match_skip* +If b:match_skip is defined, it is passed as the skip argument to +|searchpair()|. This controls when matching structures are skipped, or +ignored. By default, they are ignored inside comments and strings, as +determined by the |syntax| mechanism. (If syntax highlighting is turned off, +nothing is skipped.) You can set b:match_skip to a string, which evaluates to +a non-zero, numerical value if the match is to be skipped or zero if the match +should not be skipped. In addition, the following special values are +supported by matchit.vim: + s:foo becomes (current syntax item) =~ foo + S:foo becomes (current syntax item) !~ foo + r:foo becomes (line before cursor) =~ foo + R:foo becomes (line before cursor) !~ foo +(The "s" is meant to suggest "syntax", and the "r" is meant to suggest +"regular expression".) + +Examples: + + You can get the default behavior with > + :let b:match_skip = 's:comment\|string' +< + If you want to skip matching structures unless they are at the start + of the line (ignoring whitespace) then you can > + :let b:match_skip = 'R:^\s*' +< Do not do this if strings or comments can span several lines, since + the normal syntax checking will not be done if you set b:match_skip. + + In LaTeX, since "%" is used as the comment character, you can > + :let b:match_skip = 'r:%' +< Unfortunately, this will skip anything after "\%", an escaped "%". To + allow for this, and also "\\%" (an excaped backslash followed by the + comment character) you can > + :let b:match_skip = 'r:\(^\|[^\\]\)\(\\\\\)*%' +< + See the $VIMRUNTIME/syntax/vim.vim for an example that uses both + syntax and a regular expression. + +============================================================================== +4. Supporting a New Language *matchit-newlang* + *b:match_words* +In order for matchit.vim to support a new language, you must define a suitable +pattern for |b:match_words|. You may also want to set some of the +|matchit-configure| variables, as described above. If your language has a +complicated syntax, or many keywords, you will need to know something about +Vim's |regular-expression|s. + +The format for |b:match_words| is similar to that of the 'matchpairs' option: +it is a comma (,)-separated list of groups; each group is a colon(:)-separated +list of patterns (regular expressions). It is OK to have only one group; the +effect is undefined if a group has only one pattern. A simple example is > + :let b:match_words = '\<if\>:\<endif\>,' + \ . '\<while\>:\<continue\>:\<break\>:\<endwhile\>' +(In Vim regular expressions, |\<| and |\>| denote word boundaries. Thus "if" +matches the end of "endif" but "\<if\>" does not.) Then banging on the "%" +key will bounce the cursor between "if" and the matching "endif"; and from +"while" to any matching "continue" or "break", then to the matching "endwhile" +and back to the "while". It is almost always easier to use |literal-string|s +(single quotes) as above: '\<if\>' rather than "\\<if\\>" and so on. + +Exception: If the ":" character does not appear in b:match_words, then it is +treated as an expression to be evaluated. For example, > + :let b:match_words = 'GetMatchWords()' +allows you to define a function. This can return a different string depending +on the current syntax, for example. + +Once you have defined the appropriate value of |b:match_words|, you will +probably want to have this set automatically each time you edit the +appropriate file type. The recommended way to do this is by adding the +definition to a |filetype-plugin| file. + +Tips: Be careful that your initial pattern does not match your final pattern. +See the example above for the use of word-boundary expressions. It is usually +better to use ".\{-}" (as many as necessary) instead of ".*" (as many as +possible). See |\{-|. For example, in the string "<tag>label</tag>", "<.*>" +matches the whole string whereas "<.\{-}>" and "<[^>]*>" match "<tag>" and +"</tag>". + + *matchit-spaces* *matchit-s:notend* +If "if" is to be paired with "end if" (Note the space!) then word boundaries +are not enough. Instead, define a regular expression s:notend that will match +anything but "end" and use it as follows: > + :let s:notend = '\%(\<end\s\+\)\@<!' + :let b:match_words = s:notend . '\<if\>:\<end\s\+if\>' +< *matchit-s:sol* +This is a simplified version of what is done for Ada. The s:notend is a +|script-variable|. Similarly, you may want to define a start-of-line regular +expression > + :let s:sol = '\%(^\|;\)\s*' +if keywords are only recognized after the start of a line or after a +semicolon (;), with optional white space. + + *matchit-backref* *matchit-\1* +In any group, the expressions |\1|, |\2|, ..., |\9| refer to parts of the +INITIAL pattern enclosed in |\(|escaped parentheses|\)|. These are referred +to as back references, or backrefs. For example, > + :let b:match_words = '\<b\(o\+\)\>:\(h\)\1\>' +means that "bo" pairs with "ho" and "boo" pairs with "hoo" and so on. Note +that "\1" does not refer to the "\(h\)" in this example. If you have +"\(nested \(parentheses\)\) then "\d" refers to the d-th "\(" and everything +up to and including the matching "\)": in "\(nested\(parentheses\)\)", "\1" +refers to everything and "\2" refers to "\(parentheses\)". If you use a +variable such as |s:notend| or |s:sol| in the previous paragraph then remember +to count any "\(" patterns in this variable. You do not have to count groups +defined by |\%(\)|. + +It should be possible to resolve back references from any pattern in the +group. For example, > + :let b:match_words = '\(foo\)\(bar\):more\1:and\2:end\1\2' +would not work because "\2" cannot be determined from "morefoo" and "\1" +cannot be determined from "andbar". On the other hand, > + :let b:match_words = '\(\(foo\)\(bar\)\):\3\2:end\1' +should work (and have the same effect as "foobar:barfoo:endfoobar"), although +this has not been thoroughly tested. + +You can use |zero-width| patterns such as |\@<=| and |\zs|. (The latter has +not been thouroughly tested in matchit.vim.) For example, if the keyword "if" +must occur at the start of the line, with optional white space, you might use +the pattern "\(^\s*\)\@<=if" so that the cursor will end on the "i" instead of +at the start of the line. For another example, if HTML had only one tag then +one could > + :let b:match_words = '<:>,<\@<=tag>:<\@<=/tag>' +so that "%" can bounce between matching "<" and ">" pairs or (starting on +"tag" or "/tag") between matching tags. Without the |\@<=|, the script would +bounce from "tag" to the "<" in "</tag>", and another "%" would not take you +back to where you started. + +DEBUGGING *matchit-debug* *:MatchDebug* + +If you are having trouble figuring out the appropriate definition of +|b:match_words| then you can take advantage of the same information I use when +debugging the script. This is especially true if you are not sure whether +your patterns or my script are at fault! To make this more convenient, I have +made the command :MatchDebug, which defines the variable |b:match_debug| and +creates a Matchit menu. This menu makes it convenient to check the values of +the variables described below. You will probably also want to read +|matchit-details| above. + +Defining the variable |b:match_debug| causes the script to set the following +variables, each time you hit the "%" key. Several of these are only defined +if |b:match_words| includes |backref|s. + + *b:match_pat* +The b:match_pat variable is set to |b:match_words| with |backref|s parsed. + *b:match_match* +The b:match_match variable is set to the bit of text that is recognized as a +match. + *b:match_col* +The b:match_col variable is set to the cursor column of the start of the +matching text. + *b:match_wholeBR* +The b:match_wholeBR variable is set to the comma-separated group of patterns +that matches, with |backref|s unparsed. + *b:match_iniBR* +The b:match_iniBR variable is set to the first pattern in |b:match_wholeBR|. + *b:match_ini* +The b:match_ini variable is set to the first pattern in |b:match_wholeBR|, +with |backref|s resolved from |b:match_match|. + *b:match_tail* +The b:match_tail variable is set to the remaining patterns in +|b:match_wholeBR|, with |backref|s resolved from |b:match_match|. + *b:match_word* +The b:match_word variable is set to the pattern from |b:match_wholeBR| that +matches |b:match_match|. + *b:match_table* +The back reference '\'.d refers to the same thing as '\'.b:match_table[d] in +|b:match_word|. + +============================================================================== +5. Known Bugs and Limitations *matchit-bugs* + +Just because I know about a bug does not mean that it is on my todo list. I +try to respond to reports of bugs that cause real problems. If it does not +cause serious problems, or if there is a work-around, a bug may sit there for +a while. Moral: if a bug (known or not) bothers you, let me know. + +The various |:vmap|s defined in the script (%, |g%|, |[%|, |]%|, |a%|) may +have undesired effects in Select mode |Select-mode-mapping|. At least, if you +want to replace the selection with any character in "ag%[]" there will be a +pause of |'updatetime'| first. + +It would be nice if "\0" were recognized as the entire pattern. That is, it +would be nice if "foo:\end\0" had the same effect as "\(foo\):\end\1". I may +try to implement this in a future version. (This is not so easy to arrange as +you might think!) + +============================================================================== +vim:tw=78:fo=tcq2: |