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Re: Unquoted special characters in regexps
From: |
martin rudalics |
Subject: |
Re: Unquoted special characters in regexps |
Date: |
Sun, 26 Feb 2006 18:10:10 +0100 |
User-agent: |
Mozilla Thunderbird 1.0 (Windows/20041206) |
>>That of closing a character alternative. When you write
>>
>>(defvar foo "]")
>>(defvar bar "\\]")
>>
>>you can't interchangeably use `foo' and `bar' in an arbitrary regular
>>expression. Some people call this "referential transparency".
>
>
> Of course you can't, since the meaning of '\' is context dependent.
When you say that outside a character alternative `]' and `\\]' have the
same meaning you abandon the principle of referential transparency.
>>Anyway, the first `]' has a special meaning but it's not "inside" the
>>character alternative.
>
>
> It is part of it, just like the leading '['.
As a consequence, in your model "[" is a valid regexp too.
>>It does have a special meaning because `]' is special _outside_
>>character alternatives.
>
>
> This is wrong. Outside of a character set ']' has no special meaning
> whatsoever, independent of the context.
On a similar footing you can say that `*' has no special meaning unless
it's preceded by a character. Hence "*foo" is valid too in your model.
>>According to the Elisp manual all these exhibit "poor practice" since
>>you didn't quote the second `]'s.
>
>
> It's a bug in the manual.
Please fix it.
- Re: Unquoted special characters in regexps, (continued)
- Re: Unquoted special characters in regexps, martin rudalics, 2006/02/25
- Re: Unquoted special characters in regexps, Andreas Schwab, 2006/02/25
- Re: Unquoted special characters in regexps, martin rudalics, 2006/02/25
- Re: Unquoted special characters in regexps, Andreas Schwab, 2006/02/25
- Re: Unquoted special characters in regexps, martin rudalics, 2006/02/26
- Re: Unquoted special characters in regexps, Andreas Schwab, 2006/02/27
- Re: Unquoted special characters in regexps, martin rudalics, 2006/02/26
- Message not available
- Re: Unquoted special characters in regexps, Andreas Schwab, 2006/02/25
- Message not available
- Re: Unquoted special characters in regexps, martin rudalics, 2006/02/26
- Re: Unquoted special characters in regexps, Andreas Schwab, 2006/02/26
- Re: Unquoted special characters in regexps,
martin rudalics <=
- Re: Unquoted special characters in regexps, Andreas Schwab, 2006/02/26
- Re: Unquoted special characters in regexps, martin rudalics, 2006/02/26
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- Message not available
- Message not available
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- Re: Unquoted special characters in regexps, martin rudalics, 2006/02/28
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- Re: Unquoted special characters in regexps, martin rudalics, 2006/02/26
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- Re: Unquoted special characters in regexps, martin rudalics, 2006/02/26
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- Re: Unquoted special characters in regexps, martin rudalics, 2006/02/26
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- Re: Unquoted special characters in regexps, martin rudalics, 2006/02/26
- Message not available
- Re: Unquoted special characters in regexps, martin rudalics, 2006/02/26
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- Re: Unquoted special characters in regexps, martin rudalics, 2006/02/26