$x //Re: $(value) of function parameters

[Markus Mauhart]

"Paul D. Smith" <address@hidden> wrote ...
> %% Noel Yap <address@hidden> writes:
>   ny> $(warning $(call fn,$))
[...]
>   ny> GNUmakefile:5:
>
> The problem is that the arguments to $(call ...) are themselves
> evaluated before being passed to the function.  So, your '$' is being
> expanded before fn gets it.

But why is the 2nd '$' expanded allone instead of expanding '$)' together ?

(Expanding '$)' together IMHO would have to result in the error
"missing closing ')'")


And now, after doing lots of experiments with cygwin's make 3.80-1 and
reading make 3.80 docu, I've got real troubles (cause I want to add
make-compatible variables and functions to upp.sourceforge.net):

6.1 Basics of Variable References:

  A dollar sign followed by a character other than a dollar sign,
  open-parenthesis or open-brace treats that single character as
  the variable name. Thus, you could reference the variable x
  with `$x'. However, this practice is strongly discouraged, except
  in the case of the automatic variables (see section
  Automatic Variables).

Or have I missed other parts of the manual w.r.t. $x-expansion ?

If not, the trouble is that AFAICS make380 doesnt implement this
behaviour w.r.t. the 1st 3 characters in string ",)}"; AFAICS
they behave different from normal (and automatic) single-char-
-variable-names, but also different from each other:

* e.g. the upper (original) example ... according to 6.1, I would
  expect "error: missing closing ')'" or similar.

* try out this sample makefile:
#\/\/\/\/\/\/\/\
RP := )
RB := }

$(warning $(empty))
$(warning part1 ... where $(RP) and $(RB) DONT behave analogous:)
$(warning $(empty))
a := a$xz
$(warning [value of a] = [$(value a)])
a := a$$z
$(warning [value of a] = [$(value a)])
a := a$ z
$(warning [value of a] = [$(value a)])
a := a$,z
$(warning [value of a] = [$(value a)])
a := a$}z
$(warning [value of a] = [$(value a)])
a := a$)z
$(warning [value of a] = [$(value a)])
a := a$}z
${warning [value of a] = [${value a}]}
a := a$)z
${warning [value of a] = [${value a}]}

$(warning $(empty))
$(warning part2 ... where $(RP) and $(RB) DONT behave analogous:)
$(warning $(empty))
F = 1=[$1], 2=[$2], 3=[$3], 4=[$4]
$(warning value(F)= [$(value F)])

qwe := $(call F, , , , )
a = $(call F,a,bb,c)
$(warning [value of a] = [$(value a)] , [$$a] = [$a])
qwe := $(call F, , , , )
a = $(call F,a,$$,c)
$(warning [value of a] = [$(value a)] , [$$a] = [$a])
qwe := $(call F, , , , )
a = $(call F,a,$,,c)
$(warning [value of a] = [$(value a)] , [$$a] = [$a])
qwe := $(call F, , , , )
a = $(call F,a,$},c)
$(warning [value of a] = [$(value a)] , [$$a] = [$a])
qwe := $(call F, , , , )
a = $(call F,a,$),c)
$(warning [value of a] = [$(value a)] , [$$a] = [$a])
qwe := $(call F, , , , )
a = ${call F,a,$},c}
${warning [value of a] = [${value a}] , [$$a] = [$a]}
qwe := $(call F, , , , )
a = ${call F,a,$),c}
${warning [value of a] = [${value a}] , [$$a] = [$a]}

$(warning $(empty))
$(warning part3 ... where $(RP) and $(RB) DONT behave analogous:)
$(warning $(empty))
iftrue,true,false := value of var with strange name
a = $(iftrue,true,false)
$(warning [value of a] = [$(value a)] , [$$a] = [$a])
a = $(if  true,true,false)
$(warning [value of a] = [$(value a)] , [$$a] = [$a])
a = $(if$ true,true,false)
$(warning [value of a] = [$(value a)] , [$$a] = [$a])
a = $(if$,true,true,false)
$(warning [value of a] = [$(value a)] , [$$a] = [$a])
a = $(if$}true,true,false)
$(warning [value of a] = [$(value a)] , [$$a] = [$a])
a = $(if$)true,true,false)
$(warning [value of a] = [$(value a)] , [$$a] = [$a])
a = ${if$}true,true,false}
${warning [value of a] = [${value a}] , [$$a] = [$a]}
a = ${if$)true,true,false}
${warning [value of a] = [${value a}] , [$$a] = [$a]}

.PHONY: all

all:
#\/\/\/\/\/\/\/\


Assuming that patched gnumake80 or gnumake381beta still has this
inconsistencies w.r.t. ",)}" I see multiple different solutions
for the next version of gnumake+docu:

1) dont change the implementation, but add to the docu:
  The effect of using $x with x in ",)}" is deliberately not
  documented in this manual, it is deprecated and hence may
  be an error in future versions.

2) dont change the implementation, but change the docu: document
the current behaviour, and probably add something like ...
  Using $x with x in ",)}" is deprecated and hence may be an error
  in future versions.

3) change the implementation according to the following simple
additional docu:
  $x with x in "$,)}" is expanded as if x was a simply expanded
  variable, with value of x = name of x = x; e.g. after line
  "A := x" (and A never changed elsewhere), $A and $x are completely
  interchangable.

4) change the implementation according to the following simple
additional docu:
  $x with x in ",)}" is expanded as if x was a simply expanded
  variable with empty value; e.g. after line "A :=" (and A never
  changed elsewhere), $A and $x are completely interchangable.

And dont forget x in ":=" or other ASCII-non-isalnums currently
not representing automatic variables ... maybe for all of them
$x should be 'reserved/deprecated' -> 1) or 2).


Any other suggestions that might help me parsing and implementing
make-compatible variables and functions ?


Regards,
Markus.