regular expressions

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4 total messages Started by Maarten Litmaath Fri, 25 Aug 1989 16:12

#510

Author: Maarten Litmaath
Date: Fri, 25 Aug 1989 16:12

24 lines
932 bytes

I've always wanted to be able to do something like the following:

	case $domain in
	\(.*\)\.\(.*\)\.edu)
		department=\1
		university=\2
	*)
		# ...
	esac

instead of

	case $domain in
	*.*.edu)
		department=`echo "$domain" | sed 's/\([^.]*\).*/\1/'`
		university=`echo "$domain" | sed 's/.*\([^.]*\).edu/\1/'`
	*)
		# ...
	esac

You get the idea.  Is this possible with bash?
-- 
"rot H - dD/dt = J, div D = rho, div B = 0, |Maarten Litmaath @ VU Amsterdam:
rot E + dB/dt = 0" and there was 7-UP Light.|maart@cs.vu.nl, mcvax!botter!maart

regular expressions

#518

Author: Brian Fox
Date: Tue, 29 Aug 1989 21:00

34 lines
1288 bytes

   Date: 25 Aug 89 16:12:23 GMT
   From: maart@star.cs.vu.nl  (Maarten Litmaath)
   Organization: V.U. Informatica, Amsterdam, the Netherlands
   Sender: bug-bash-request@prep.ai.mit.edu

   I've always wanted to be able to do something like the following:

	   case $domain in
	   \(.*\)\.\(.*\)\.edu)
		   department=\1
		   university=\2
	   *)
		   # ...
	   esac

   instead of

	   case $domain in
	   *.*.edu)
		   department=`echo "$domain" | sed 's/\([^.]*\).*/\1/'`
		   university=`echo "$domain" | sed 's/.*\([^.]*\).edu/\1/'`
	   *)
		   # ...
	   esac

   You get the idea.  Is this possible with bash?

Well, not without changing the semantics of the "case" command, and
writing a regular expression parser into the shell.

The pattern matcher is a globber, not a RE parser.  Sorry.

Brian

Re: regular expressions

#520

Author: Maarten Litmaath
Date: Wed, 30 Aug 1989 15:35

24 lines
1114 bytes

bfox@AUREL.CALTECH.EDU (Brian Fox) writes:
\...	   case $domain in
\	   \(.*\)\.\(.*\)\.edu)
\		   department=\1
\		   university=\2
\	   *)
\		   # ...
\	   esac
\...
\Well, not without changing the semantics of the "case" command, and
\writing a regular expression parser into the shell.
\
\The pattern matcher is a globber, not a RE parser.  Sorry.

Of course; it was never my intention to use the (normal) `case' command for
my idea.  But perhaps a syntax extension would be worthwhile?

	ecase ... in
	...
	esace
[sic]
-- 
C, the programming language that's the same |Maarten Litmaath @ VU Amsterdam:
         in all reference frames.           |maart@cs.vu.nl, mcvax!botter!maart

Re: regular expressions

#522

Author: Rayan Zachariassen
Date: Wed, 30 Aug 1989 16:49

31 lines
1083 bytes

>   Date: 25 Aug 89 16:12:23 GMT
>   From: maart@star.cs.vu.nl  (Maarten Litmaath)
>   Organization: V.U. Informatica, Amsterdam, the Netherlands

>   I've always wanted to be able to do something like the following:

>	   case $domain in
>	   \(.*\)\.\(.*\)\.edu)
>		   department=\1
>		   university=\2
>	   *)
>		   # ...
>	   esac

>   instead of ...

You will obviously like the ZMailer configuration language: a modern shell
with exactly this extension (originally in the case statement but it will
be a 'sift' statement in the next version).  Oh, and the way to write it
is

sift $domain in
(.)\.(.)\.edu)
	department=\1
	university=\2
	;;
tfis

because I use token-based REs.

rayan

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