Re: Bug#255788: $'' does not work after <<<

[Bart Schaefer <schaefer@brasslantern.com>]

On Sun, 27 Jun 2004, Peter Stephenson wrote:

> ... and I was talking about the end marker: it seemed to be the
> conclusion of what you were saying that in:
> 
> cat <<$foo
> ...
> cat <<$'a\tb'
> ...
> cat <<"$(echo hello)"
> 
> the \t in the middle case was exanded, but the $ in the other two
> weren't.

The conclusion seems to be that $'...' is treated as a form of quoting, 
not a form of expansion, whereas `...` is treated as a form of expansion 
rather than a form of quoting; quoting applies, but expansion does not.  
Viz:

[schaefer]$ cat <<`echo foo`
> bar
> foo
> echo foo
> `echo foo`
bar
foo
echo foo
[schaefer]$ 

> I haven't even thought about changing anything to do with the
> contents.

Had my wires crossed again, it seems.

> I don't think that's our problem.  We consistently use singsub() for
> cases like this and I can't see why we shouldn't here.

I'm not sure whether you mean "that's [not] our problem" in the sense of
"that's not what we're doing wrong" or in the sense of "it's not incumbent
upon us to deal with that."

However, if indeed $'...' is meant as a form of quoting, then singsub() 
may be the wrong place for it to be handled -- other forms of quoting are
applied earlier in the parse.