arithmetic, e.g. $(word $(num)-1,$(list))

[Markus Mauhart]

Hi, given ....

    list = a b c
    num = $(words $(list))

... how to compute the string for the arithmetic result of 'num - 1' ?


I tried the following but it didnt work as you can see:

//-----makefile-----
list := eins zwei drei
num := $(words $(list))
num_minus_1 := $(shell echo $$(($(num) - 1)))

all:
 @echo num = $(num)
 echo $$(($(num) - 1))
 @echo num_minus_1 = $(num_minus_1)

//----inside cygwin's bash----
//1st test the shell's arithmetic directly:
$ echo $((3 - 1))
2
//now run make:
$ make
num = 3
echo $((3 - 1))
+ 3 - 1+
num_minus_1 = + 3 - 1+

$
//-----

Q1: is there another way for computing an arithmetic expression
    except $(shell echo $$((expression))) ?

Q2: Does $(shell echo $$((expression))) work in some better
    environment than mine ? (cygwin 1.3.20-1, bash 2.05b-9,
    make-3.79.1-7 and make-3.80)


Thanks,
Markus.