Re: Add and document AS_VAR_COPY, speed up configure

[Eric Blake]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

According to Ralf Wildenhues on 10/17/2008 1:05 PM:
> Overall very nice, only nits.  Thanks!

Applied, with these changes:

> 
>> Subject: [PATCH] Add AS_VAR_COPY.
>>
>> +# AS_VAR_SET(VARIABLE, VALUE)
>> +# ---------------------------
>> +# Set the VALUE of the shell VARIABLE.
>> +# If the variable contains indirections (e.g. `ac_cv_func_$ac_func')
>> +# perform whenever possible at m4 level, otherwise sh level.
> 
> This sentence is hard to understand; I'd guess:
> 
> +# If VARIABLE contains indirections (e.g. `ac_cv_func_$ac_func'),
> +# perform indirection at the m4 level whenever possible, otherwise
> +# at the sh level.

That was pre-existing text, moved down in the file.  I've floated all the
macro moves into a separate patch (turning the series of 3 into 4), then
reworded this to state:

# Set the contents of the polymorphic shell VARIABLE to the shell
# expansion of VALUE.

>> Subject: [PATCH] Test AS_VAR interfaces.
> 
>> +AT_SETUP([AS@&address@hidden)
>> +AT_KEYWORDS([m4sh AS@&address@hidden AS@&address@hidden AS@&address@hidden
>> +AS@&address@hidden AS@&address@hidden AS@&address@hidden AS@&address@hidden
>> +AS@&address@hidden)
> 
> FWIW, you can use multiple AT_KEYWORDS instead of wrapping, too.

Sure, and that reads a little better.  Changed.

> 
>> --- a/NEWS
>> +++ b/NEWS
> 
> s/\n/  /g | fmt   ?
> (but you can do that in an independent patch if you prefer)

Sure; it matches prior release notes.

>> +Often times, it is convenient to write a macro that will emit shell code
> 
> s/ times//  ?

Done.

>> +M4sh supports the notion of polymorphic shell variables, making it easy
>> +to write a macro that can deal with either literal or indirect variable
>> +names and output shell code appropriate to both use cases.  Behavior is
> 
> appropriate for?

Yes, that sounds better.

>> address@hidden), then @var{if-not} is expanded.  The implementation is
>> +somewhat conservative (for example, @samp{'[$]'} is a single-quoted
>> +shell literal, but causes @var{if-not} to be expanded), in order to
>> +offer speed to the common case of deciding whether a variable name is
> 
> speed for?

I went with:

In order to reduce the
time spent deciding whether an expression is literal, the implementation
is somewhat conservative (for example, @samp{'[$]'} is a single-quoted
shell literal, but causes @var{if-not} to be expanded).  While this
macro is often used for recognizing shell variable names, it can also be
used in other contexts.

> 
>> address@hidden AS_VAR_IF (@var{var}, @ovar{value}, @ovar{if-match}, 
>> @ovar{if-diff})
> 
> if-equal and if-not-equal?

That does sound nicer.

>> +into a valid shell name by @code{AS_TR_SH}.  In order to access the
>> +composed variable name based on @var{value}, it easier to declare a
> 
> s/it /&is /

Thanks for catching all my grammar slip-ups.

- --
Don't work too hard, make some time for fun as well!

Eric Blake             address@hidden
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.9 (Cygwin)
Comment: Public key at home.comcast.net/~ericblake/eblake.gpg
Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org

iEYEARECAAYFAkj5BuUACgkQ84KuGfSFAYCA2ACfTtuAYQH+K0y4UFcqUaTJ0C20
7f8AoIGaw9vSz5iYt75tUeZ1Lk+N57Z6
=8Yq6
-----END PGP SIGNATURE-----