Re: [bug-gawk] feature request: expanding escape sequences

[Aharon Robbins]

> Date: Sun, 06 Jul 2014 13:25:31 -0500
> From: Ed Morton <address@hidden>
> To: Manuel Collado <address@hidden>, address@hidden
> Subject: Re: [bug-gawk] feature request: expanding escape sequences
>
> On 7/6/2014 1:05 PM, Manuel Collado wrote:
> > El 06/07/2014 16:26, Ed Morton escribi?:
> >> Arnold - I don't believe it can be done fairly easily in any way. For
> >> example, wrt your suggestion of splitting on an RE, let's say I define my
> >> escape-sequence matching RE as '\[[:alpha:]]`. Well, that's wrong:
> >
> > Please try this RE:
> >
> >   /\\(x[0-9a-fA-F]*|[0-7]{1,3}|.)/
> >
> > It should match every valid escape sequence. And every unnecessarily 
> > escaped 
> > normal character.
> >
> > Hope this helps. Regards.
>
> That does identify the escape sequences in my small set of test cases, so 
> assuming it works for every case (and it looks like it should) then all 
> that'd 
> be left to do is mapping them to their equivalent literal characters. Any 
> suggestions on a concise way of doing that?
>
> Thanks,
>
>       Ed.

Manuel, thanks for the regexp.

Ed, if there is exactly one character after the \, you can use

        i = index("abfnrtv", c)

if i > 0 then use

        c = substr("\a\b\f\n\r\t\v", i, 1)

to get the corresponding real character.  For a hex value after
the \, use

        c = sprintf("%c", strtonum("0x" rest_of_str))

and for an octal value use

        c = sprintf("%c", strtonum("0" rest_of_str))

You should be able to figure out how to put it all together.

If you want me to write the function for you from scratch,
I will charge a high consulting fee. :-)

Good luck,

Arnold