Re: New make modifiers: :C///W, :tW, and :[]

At 7:58 PM +0200 7/31/03, Alan Barrett wrote:
>I propose adding a new :[] modifier to make(1) in NetBSD,
>and possibly also adding some other modifiers.
>
>":[]" will allow you to extract a single word from a
>space-separated list, like this:
>
>         CC= /usr/bin/gcc -Wall
>         .if exists(${CC:[1]})
>         ...

Of course, this assumes that the filename path does not have any
blanks in *it*...  :-)
(yes, I have written some scripts for MacOS 10, why do you ask?)

The following are just my own opinions.  I do not pretend
to be speaking for "the FreeBSD project"...

>Briefly, the proposals are
>
>         :tW     Set a flag that causes subsequent ...
>
>         :tw     Undo the effect of :tW.

I think we could skip with these two.  Given the other proposed
options, all this gives us more stuff to document.  (IMO)

>         :C///W  A "one big word" variant...
>         :S///W  A "one big word" variant...

These are also redundant, but I think they serve a useful
purpose in reminding people the significance of blanks
with the standard C/// and S///.  Also, it's more intuitive
than having to reference ':[0]' before doing the C or S.

>
>         :[N]    Select the Nth word, where N is a positive
>                 integer.  :[1] selects the first word.
>         :[-N]   Select the Nth word from the end.  :[-1]
>                 selects the last word.
>         :[0]    Select the entire string, but treat it as
>                 one big word.  (Equivalent to :tw.)

I expect that you mean ':tW' here!

>         :[*]    Select the entire string, treating it as a
>                 sequence of space-separated words.  (Undoes
>                 the effects of :[0];  equivalent to :tw.)

Some of the replies to your message also suggested various
additional options.  I liked the idea of ':[#]' to give the
number of words, and I liked the idea of having some way to
specify a range.  If a person wants to do something special
with word #1, then they might also want to do something
special with word#2->last_word.  I don't particularly care
what syntax is used for a range, though I would like it to
include a way to say "to the last word" without having to
dig up the # value.  Probably just ':[N..-M]', with M==1
would include everything up to the last word.

If other freebsd developers do not object to the *idea* of
these changes, I would be willing to look at installing
similar changes to FreeBSD, after NetBSD has worked with
them for a little while.

-- 
Garance Alistair Drosehn            =   gad-AvF0vkkS99i66gPnRoyaY/[email protected]
Senior Systems Programmer           or  [email protected]
Rensselaer Polytechnic Institute    or  [email protected]

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