import { fn } from "https://deno.land/x/ddc_vim@v2.5.1/deps.ts";
const { searchpair } = fn;
Search for the match of a nested start-end pair. This can be
used to find the "endif" that matches an "if", while other
if/endif pairs in between are ignored.
The search starts at the cursor. The default is to search
forward, include 'b' in {flags} to search backward.
If a match is found, the cursor is positioned at it and the
line number is returned. If no match is found 0 or -1 is
returned and the cursor doesn't move. No error message is
given.
{start}, {middle} and {end} are patterns, see |pattern|. They
must not contain ( ) pairs. Use of %( ) is allowed. When
{middle} is not empty, it is found when searching from either
direction, but only when not in a nested start-end pair. A
typical use is:
searchpair('<if>', '<else>', '<endif>')
By leaving {middle} empty the "else" is skipped.
{flags} 'b', 'c', 'n', 's', 'w' and 'W' are used like with
|search()|. Additionally:
'r' Repeat until no more matches found; will find the
outer pair. Implies the 'W' flag.
'm' Return number of matches instead of line number with
the match; will be > 1 when 'r' is used.
Note: it's nearly always a good idea to use the 'W' flag, to
avoid wrapping around the end of the file.
When a match for {start}, {middle} or {end} is found, the
{skip} expression is evaluated with the cursor positioned on
the start of the match. It should return non-zero if this
match is to be skipped. E.g., because it is inside a comment
or a string.
When {skip} is omitted or empty, every match is accepted.
When evaluating {skip} causes an error the search is aborted
and -1 returned.
{skip} can be a string, a lambda, a funcref or a partial.
Anything else makes the function fail.
In a :def
function when the {skip} argument is a string
constant it is compiled into instructions.
For {stopline} and {timeout} see |search()|.
The value of 'ignorecase' is used. 'magic' is ignored, the
patterns are used like it's on.
The search starts exactly at the cursor. A match with
{start}, {middle} or {end} at the next character, in the
direction of searching, is the first one found. Example:
if 1
if 2
endif 2
endif 1
When starting at the "if 2", with the cursor on the "i", and
searching forwards, the "endif 2" is found. When starting on
the character just before the "if 2", the "endif 1" will be
found. That's because the "if 2" will be found first, and
then this is considered to be a nested if/endif from "if 2" to
"endif 2".
When searching backwards and {end} is more than one character,
it may be useful to put "\zs" at the end of the pattern, so
that when the cursor is inside a match with the end it finds
the matching start.
Example, to find the "endif" command in a Vim script:
:echo searchpair('<if>', '<el%[seif]>', '<en%[dif]>', 'W',
\ 'getline(".") =~ "^\s*""')
The cursor must be at or after the "if" for which a match is
to be found. Note that single-quote strings are used to avoid
having to double the backslashes. The skip expression only
catches comments at the start of a line, not after a command.
Also, a word "en" or "if" halfway a line is considered a
match.
Another example, to search for the matching "{" of a "}":
:echo searchpair('{', '', '}', 'bW')
This works when the cursor is at or before the "}" for which a
match is to be found. To reject matches that syntax
highlighting recognized as strings:
:echo searchpair('{', '', '}', 'bW',
\ 'synIDattr(synID(line("."), col("."), 0), "name") =~? "string"')