Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.lang.forth > #26481

Re: EuroForth 2013 proceedings available

Show all headers | View raw

On 07/10/2013 16:41, Anton Ertl wrote:
> The EuroForth 2013 proceedings and the individual papers and/or
> presentation slides are now available on
>
> <http://www.complang.tuwien.ac.at/anton/euroforth/ef13/papers/>
>

>

I read the "Standardize Strings Now!" paper with interest and broadly 
agree with the contents.  The bit on regular expressions (RE) is a bit 
weak and as I've developed a RE package which I've used quite a lot I 
offer the following comments:

I found it best to always compile a RE before using it with one of the 3 
words (all self-explanatory I hope):

regex ( "ccc..." -- rgx ) where rgx is a RE identifier
regex$ ( caddr u -- rgx )
parse-regex ( char "ccc<char>" -- rgx ) char is a terminating delimiter

For matching, the word SEARCH-REGEXP suffers from the problem mentioned 
about too many stack parameters. I have:

match ( caddr1 u1 rgx -- caddr2 u2 -1 | caddr1 u1 0 ) where (caddr2 u2) 
is the rest of the input string (caddr1 u1) *after* the match. If no 
match is found return the input string and 0

The reason I don't return the match is that I implemented so-called 
"capturing parentheses" which record matching sub-expressions. These are 
held in an array and it is convenient to hold the (caddr u) of the 
matching string in the 0th element of that array.

One thing, that would have to be decided, and was not discussed at all 
is how to specify a RE. There seem to be 2 choices:
- use a Perl or similar format which is common across most programming 
languages (I did this as does the FFL and iForth's regexp.frt) or
- use a reverse polish type notation as used in GForth's regexp.fs

Which is preferred? I suppose the first alternative could be built on 
top of the second but it would still be worth standardising the first 
for portability.

To use the results from a RE match I found it tiresome to use existing 
string primitives, S+ etc and developed a higher level, complementary 
package to build strings from a pattern string, much like a greatly 
extended sprintf(). This concatenates characters with results from the 
RE match as well as allowing other Forth words to be executed, RE 
searches to be nested etc. IF it proves difficult or impossible to agree 
on a set of strings word for concatenation and other string operations 
perhaps a similar higher level specification is a possibility?


-- 
Gerry

Back to comp.lang.forth | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

EuroForth 2013 proceedings available anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-10-07 15:41 +0000
  Re: EuroForth 2013 proceedings available mentifex@myuw.net - 2013-10-07 10:18 -0700
  Re: EuroForth 2013 proceedings available Mark Wills <markrobertwills@yahoo.co.uk> - 2013-10-08 00:35 -0700
  Re: EuroForth 2013 proceedings available Paul Rubin <no.email@nospam.invalid> - 2013-10-08 01:36 -0700
    Re: EuroForth 2013 proceedings available anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-10-09 13:53 +0000
      Re: EuroForth 2013 proceedings available Paul Rubin <no.email@nospam.invalid> - 2013-10-19 10:59 -0700
        Re: EuroForth 2013 proceedings available anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-10-28 16:09 +0000
  Re: EuroForth 2013 proceedings available Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2013-10-13 20:24 +0100
    Re: EuroForth 2013 proceedings available anton@mips.complang.tuwien.ac.at (Anton Ertl) - 2013-10-15 15:32 +0000
      Re: EuroForth 2013 proceedings available Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2013-10-17 11:22 +0100
        Re: EuroForth 2013 proceedings available Gerry Jackson <gerry@jackson9000.fsnet.co.uk> - 2013-10-26 20:55 +0100

csiph-web