Re: [PATCH] test defs: add subroutine for input unindenting

[Ralf Wildenhues]

* Stefano Lattarini wrote on Tue, Feb 15, 2011 at 01:36:16PM CET:
> OK, here's my shot at it.  The implementation might be suboptimal,
> but since it wasn't completely obvious to get right, I'd rather not
> tweak it anymore, until there's a real need at least.

Lemme tweak it for you.  ;-)

> (By the way, I think that we should really start testing non-obvious
> subroutines and pieces of code defined in tests/defs.  But that's
> for another thread).

Fine with me, on all accounts.

> Subject: [PATCH] test defs: add subroutine for input unindenting
> 
> * tests/defs.in (unindent): New subroutine.

> --- a/tests/defs.in
> +++ b/tests/defs.in
> @@ -440,6 +440,31 @@ AUTOMAKE_fails ()
>    AUTOMAKE_run 1 ${1+"$@"}
>  }
>  
> +# unindent [input files...]
> +# -------------------------
> +# Remove the "proper" amount of leading whitespace from the given files,
> +# and output the result on stdout.  That amount is determined by looking
> +# at the leading whitespace of the first non-blank line in the input
> +# files.  If no input file is specified, standard input is implied.
> +unindent ()
> +{
> +  cat ${1+"$@"} > deindent.tmp
> +  indentation=`sed <deindent.tmp -n "
> +    /^[ $tab]*$/n
> +    s/[^ $tab].*$//
> +    t end
> +    b
> +: end
> +    p
> +    q
> +  "`

The space after : is not portable.  The sed script could be shortened to
  sed -n "/[^ $tab].*$/{
            s///p
            d
          }"

> +  case $indentation in
> +    '') cat deindent.tmp;;
> +     *) sed "s/^$indentation//" deindent.tmp;;
> +  esac

These four lines can be shortened to
  sed "s/^$indentation//" deindent.tmp

> +  rm -f deindent.tmp
> +}

OK with those addressed.

It's a bit of a shame this uses a temp file though.  awk should be able
to cope without (but be sure to try old Solaris awk if you go for it).

Thanks,
Ralf