| 102 |
works internally just with numbers, using an external table to translate |
works internally just with numbers, using an external table to translate |
| 103 |
between numbers and names. The following are some specific differences: |
between numbers and names. The following are some specific differences: |
| 104 |
.sp |
.sp |
| 105 |
(a) After matching a pattern such as (?|(?<a>A)|(?<b)B) where the two capturing |
(a) A pattern such as (?|(?<a>A)|(?<b)B), where the two capturing |
| 106 |
parentheses have the same number but different names, it is not possible to |
parentheses have the same number but different names, is not supported, and |
| 107 |
distinguish which parentheses matched, because both names map to capturing |
causes an error at compile time. If it were allowed, it would not be possible |
| 108 |
subpattern number 1. |
to distinguish which parentheses matched, because both names map to capturing |
| 109 |
|
subpattern number 1. To avoid this confusing situation, an error is given at |
| 110 |
|
compile time. |
| 111 |
.sp |
.sp |
| 112 |
(b) A condition test for a subpattern with a name that is duplicated gives |
(b) A condition test for a subpattern with a name that is duplicated gives |
| 113 |
unpredictable results. For example, when the pattern |
unpredictable results. For example, when the pattern |
| 172 |
.rs |
.rs |
| 173 |
.sp |
.sp |
| 174 |
.nf |
.nf |
| 175 |
Last updated: 29 September 2009 |
Last updated: 03 October 2009 |
| 176 |
Copyright (c) 1997-2009 University of Cambridge. |
Copyright (c) 1997-2009 University of Cambridge. |
| 177 |
.fi |
.fi |
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