[CMake] doing simple math in cmake or useless foreach( RANGE )

[Hendrik Sattler]

Hi,

either I cannot find it or it's not there: doing simple mathematic things like
substract 1 from a variable.

If that's not present, I do not understand how
LIST( LENGTH MYLIST COUNT )
FOREACH ( index RANGE ${COUNT} )
list ( GET MYLIST ${index} entry )
....

will address non-present indexes in the list. I would the above statement
cover the range from 0 to COUNT-1 but it also cover COUNT itself like said in
the documentation. Does that actually make sense as the variable in the
documentation is called "total" but the loop count is "total+1"?

Currently I use a
if ( LESS )
work-around but that looks like a hack.

Any ideas?

HS

[Matthew Woehlke]

Post by Hendrik Sattler
either I cannot find it or it's not there: doing simple mathematic things like
substract 1 from a variable.
[snip]
Any ideas?

cmake --help-command math
??

[Nicolas Desprès]

On Tue, May 19, 2009 at 6:29 PM, Hendrik Sattler

Post by Hendrik Sattler
If that's not present, I do not understand how
LIST( LENGTH MYLIST COUNT )
FOREACH ( index RANGE ${COUNT} )
list ( GET MYLIST ${index} entry )
....
will address non-present indexes in the list. I would the above statement
cover the range from 0 to COUNT-1 but it also cover COUNT itself like said in
the documentation. Does that actually make sense as the variable in the
documentation is called "total" but the loop count is "total+1"?

I also experienced this problem and I don't like this behavior. I'm
more use to the traditional

for (i = 0; i < n; ++i)

instead of <=

[Mats Kindahl]

Post by Hendrik Sattler
Hi,
either I cannot find it or it's not there: doing simple mathematic things like
substract 1 from a variable.
If that's not present, I do not understand how
LIST( LENGTH MYLIST COUNT )
FOREACH ( index RANGE ${COUNT} )
list ( GET MYLIST ${index} entry )
....
will address non-present indexes in the list. I would the above statement
cover the range from 0 to COUNT-1 but it also cover COUNT itself like said in
the documentation. Does that actually make sense as the variable in the
documentation is called "total" but the loop count is "total+1"?
Currently I use a
if ( LESS )
work-around but that looks like a hack.
Any ideas?

I used:

list(LENGTH MYLIST _len)
math(EXPR COUNT "${_len}-1")
foreach(index RANGE ${COUNT})

but I also think that foreach() should assign integers in the range
0..${COUNT}-1 instead of 0..${COUNT}.

Just my few cents,
Mats Kindahl

Post by Hendrik Sattler
HS
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