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Re: regexp and valid-sre?

This page is part of the web mail archives of SRFI 115 from before July 7th, 2015. The new archives for SRFI 115 contain all messages, not just those from before July 7th, 2015.

I just briefly looked through the documentation for GNU Emacs and could not find the equivalent of  'valid-sre?'.

And it looks like the regular expressions are not compiled before they are used: string-match takes a regular _expression_ to search for as a string: http://www.gnu.org/software/emacs/manual/html_node/elisp/Regexp-Search.html#Regexp-Search Finally, the bottom of this page talking about using Icicles to interactively learn
about using regular expressions: http://www.emacswiki.org/emacs/RegularExpression
On 11/26/2013 12:18 PM, Arthur A. Gleckler wrote:

Implementing Emacs in Scheme is a use case for this.

On Nov 26, 2013 11:17 AM, "Michael Montague" <mikemon@xxxxxxxxx> wrote:
On 11/26/2013 10:24 AM, John Cowan wrote:
Michael Montague scripsit:

I don't think that these are strong arguments for having
'valid-sre?'. An implementation for which compiling is expensive,
could easily internally do the "is it valid"-type check before
compiling. Having it in the interface adds no functionality that is
not already easily available.
It tells the compiler only to syntax-check and not go on to actually
compile.  This is a very common feature in compilers: for example,
in gcc the -fsyntax-only option activates this mode.  Sometimes
all you want to know at present is whether something is syntactically valid.

The only use case for 'valid-sre?' mentioned so far is Peter's interactive regular _expression_ IDE. The C standard does not require the -fsyntax-only option. These do not seem like compelling arguments for including