diff options
Diffstat (limited to 'txr.1')
-rw-r--r-- | txr.1 | 42 |
1 files changed, 42 insertions, 0 deletions
@@ -24840,6 +24840,22 @@ The value stored in .meta right-place is also returned. +If +.meta left-place +and +.meta right-place +are ranges of the same sequence, the behavior is not specified +if the ranges overlap or are of unequal length. + +Note: the +.code rotate +macro's behavior is somewhat more specified in this regard. +Thus, although any correct +.code swap +expression can be expressed using +.code rotate , +but the reverse isn't true. + .coNP Macro @ push .synb .mets (push < item << place ) @@ -24965,6 +24981,19 @@ into the last place. Finally, the saved original value of the first place is returned. +If any of the places are ranges which index into the same sequence, +and the behavior is not otherwise unspecified due to the issue +noted in an earlier paragraph, the effect upon the multiply-stored +sequence can be inferred from the above-described storage order. +Note that even if stores take place which change the length of +the sequence and move some elements, not-yet-processed stores whose ranges +to refer to these elements are not adjusted. + +With regard to the foregoing paragraph, a recommended practice is +that if subranges of the same sequence object are shifted, they be +given to the macro in ascending order of starting index. Furthermore, the +semantics is simpler if the ranges do not overlap. + .coNP Macro @ rotate .synb .mets (rotate << place *) @@ -25002,6 +25031,19 @@ a later .meta place form. +If any of the places are ranges which index into the same sequence, +and the behavior is not otherwise unspecified due to the issue +noted in the preceding paragraph, the effect upon the multiply-stored +sequence can be inferred from the above-described storage order. +Note that even if stores take place which change the length of +the sequence and move some elements, not-yet-processed stores whose ranges +to refer to these elements are not adjusted. + +With regard to the foregoing paragraph, a recommended practice is +that if subranges of the same sequence object are shifted, they be +given to the macro in ascending order of starting index. Furthermore, the +semantics is simpler if the ranges do not overlap. + .coNP Macro @ del .synb .mets (del << place ) |