Re: regexp and valid-sre?

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To: Michael Montague <mikemon@xxxxxxxxx>

Subject: Re: regexp and valid-sre?

From: Alex Shinn <alexshinn@xxxxxxxxx>

Date: Tue, 26 Nov 2013 21:44:27 +0900

Cc: SRFI-115 discussion list <srfi-115@xxxxxxxxxxxxxxxxx>

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On Tue, Nov 26, 2013 at 12:34 PM, Michael Montague <mikemon@xxxxxxxxx> wrote:

Why can the procedure 'regexp' be called with an already compiled <re> which is just returned?

Why is the procedure 'valid-sre?' necessary? You could just call 'regexp' and use 'guard' to check for any errors.

Indeed, in fact `valid-sre?' could be defined as:

(define (valid-sre? x)

(guard (else (exn #f)) (regexp x)))

Whether you want to test in advance or catch errors

after the fact is a matter of personal style.

Alex

Follow-Ups:

Re: regexp and valid-sre?
- From: Peter Bex

References:

regexp and valid-sre?
- From: Michael Montague