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| author | Kaz Kylheku <kaz@kylheku.com> | 2014-10-16 07:05:13 -0700 |
|---|---|---|
| committer | Kaz Kylheku <kaz@kylheku.com> | 2014-10-16 07:05:13 -0700 |
| commit | a039c378390c2311e85174e3179692a453572dc6 (patch) | |
| tree | f2a3fbcd4ee7f2a1d2b9468ae9c70ba7dfcc3582 /txr.1 | |
| parent | 8eb4688b095bbdadfa05d0b853df662ac653e3d5 (diff) | |
| download | txr-a039c378390c2311e85174e3179692a453572dc6.tar.gz txr-a039c378390c2311e85174e3179692a453572dc6.tar.bz2 txr-a039c378390c2311e85174e3179692a453572dc6.zip | |
New @(line) and @(chr) directives.
* match.c (line_s): New variable.
(h_chr, v_line): New static functions.
(syms_init): line_s initialized.
(dir_tables_init): Register v_line and h_chr.
* match.h (line_s): Declared.
* txr.1: Document @(line) and @(chr) directives.
* txr.vim: Regenerated.
Diffstat (limited to 'txr.1')
| -rw-r--r-- | txr.1 | 67 |
1 files changed, 67 insertions, 0 deletions
@@ -91,6 +91,7 @@ .. .\" Multiple directive heading .de dirs +. ds s " . while (\\n[.$]>2) \{\ . as s \f[4]\\$1\f[], . shift @@ -2646,6 +2647,10 @@ explicitly in that string. The fuzz directive, inspired by the patch utility, specifies a partial match for some lines. +.ccIP @ @(line) and @ @(chr) +These directives match a variable or expression against the current line +number or character position. + .coIP @(some) Multiple clauses are each applied to the same input. Succeeds if at least one of the clauses matches the input. The bindings established by earlier @@ -3611,6 +3616,68 @@ the directive, then m of them must succeed nevertheless. (If there are fewer than m, then this is impossible.) +.dirs line chr + +The +.code line +and +.code chr +directives perform binding between the current input line number or character +position within a line, against an expression or variable: + +.cblk + @(line 42) + @(line x) + abc@(chr 3)def@(chr y) +.cble + +The directive +.code @(line 42) +means "match the current input line number against the integer 42". If +the current line is 42, then the directive matches, otherwise it fails. +.code line +is a vertical directive which doesn't consume a line of input. Thus, +the following matches at the beginning of an input stream, and +.code x +ends up bound to the first line of input: + +.cblk + @(line 1) + @(line 1) + @(line 1) + @x +.cble + +The directive +.code @(line x) +binds variable +.code x +to the current input line number, if +.code x +is an unbound variable. If +.code x +is already bound, then the value of +.code x +must match the current line number, otherwise the directive fails. + +The +.code chr +directive is similar to +.code line +except that it's a horizontal directive, and matches the character position +rather than the line position. Character positions are measured from zero, +rather than one. +.code chr +does not consume a character. Hence the two occurrences of +.code chr +in the following example both match, and +.code x +takes the entire line of input: + +.cblk + @(chr 0)@(chr 0)@x +.cble + .dirs some all none maybe cases choose These directives, called the parallel directives, combine multiple subqueries, |