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| author | Kaz Kylheku <kaz@kylheku.com> | 2017-10-29 19:58:52 -0700 |
|---|---|---|
| committer | Kaz Kylheku <kaz@kylheku.com> | 2017-10-29 19:58:52 -0700 |
| commit | 78a77b00d40befdacd4f5044f504ed132755609e (patch) | |
| tree | 1f8b89a8f005d299ddd6d850d9b43f0a0ba16e6f /txr.1 | |
| parent | d7a93957e27bbfe6eaebc25b9d539f82dd9e4df3 (diff) | |
| download | txr-78a77b00d40befdacd4f5044f504ed132755609e.tar.gz txr-78a77b00d40befdacd4f5044f504ed132755609e.tar.bz2 txr-78a77b00d40befdacd4f5044f504ed132755609e.zip | |
awk: implement ranges right using functions.
* share/txr/stdlib/awk.tl (sys:awk%--rng, sys:awk%--rng-,
sys:awk%rng+, sys:awk%-rng+, sys:awk%--rng+): New functions.
(sys:awk-mac-let): Rewritten range expander. The four basic
ranges rng, rng-, -rng and -rng- are handled with in-line
expansion, because by doing that we avoid unnecessarily
evaluating the from-expression. The remaining cases expand
to function calls to the new functions, which receive the
flag vector, the index position in that vector and the values
of the from and to expressions. The behavior change is that
that the -- forms now do the right thing: they hide all
leading records that satisfy the from-expression, right to the
last record of the range if necessary.
* tests/015/awk-rng.expected: Updated.
* txr.1: Revise semantic description the -- range types, plus
minor fixes.
Diffstat (limited to 'txr.1')
| -rw-r--r-- | txr.1 | 17 |
1 files changed, 9 insertions, 8 deletions
@@ -47280,17 +47280,20 @@ However, the range expression yields .code nil for the entire leading sequence of consecutive records for which .meta from -is true. Regardless of this, it yields true for the last record -for which +is true. If +.meta from +is true of the .meta to -is true. +record which terminates the range, +.code nil +is returned for that record also. .meIP (--rng- < from << to ) This type of range is active under the same conditions as However, the range expression yields .code nil for the entire leading sequence of consecutive records for which .meta from -is true, and also yields nil for the last record which trigger the +is true, and also yields nil for the last record which triggers the .meta to condition. .meIP (rng+ < from << to ) @@ -47326,11 +47329,9 @@ However, the range expression yields .code nil for the entire leading sequence of consecutive records for which .meta from -is true, and for which -.meta to -is false. For the terminating records for which +is true. This is the case even for those for which the .meta to -is true, it yields true. +expression is true. .RE .coNP Macro @ ff |