Re: An m4 puzzlement.

Hi R.

On 14 Dec 2011, at 17:43, R. Clayton wrote:
> I'm not understanding why this
> 
>  $ cat t
>  m4_define(_itlvar,
>    `m4_ifelse(m4_regexp($1, ^[[:alpha:]]*$), -1, $1, itl($1))')
> 
>  m4_define(subsen, `_itlvar($1) \(\sqsubseteq\) _itlvar($2)')
> 
>  subsen(a, b)
>  subsen(a, bld(b))
>  subsen(bld(a), b)
> 
>  $ 
> 
> produces this
> 
>  $ m4 -P < t
> 
> 
> 
> 
>  itl(a) \(\sqsubseteq\) b
>  itl(a) \(\sqsubseteq\) bld(b)
>  bld(a) \(\sqsubseteq\) b


M4 1.4 does not support ERE expressions, so [[:alpha:]]* is read as
zero or more characters from the set `[:alph]'.  I didn't check
whether your quoting is correct, but you should have more luck with
`^[a-zA-Z]*$'.

Cheers,
-- 
Gary V. Vaughan (gary AT gnu DOT org)