Re: Why does the order in the Makefile matter?

[Judicael Courant <Judicael.Courant@lri.fr>]

Pierre Weis a écrit :
> > So it would be nice if the compiler itself could put the .cmo files
> > in an order compatible with the static binding rule. This would
> > remove the tedium of putting the .cmo files in an appropriate order
> > from the programmer.
> 
> We can propose an external tool that will try to find for you some
> order compatible with static binding if any, something similar to
> ocamldep for module compilation dependancy. This existed in Caml Light
> and was named ``lorder'':
> 
> lorder
> ------
>   A tool to compute the dependencies between a set of .zo files
>   and suggest a correct linking order.
> 
> > Would this be difficult to implement?
> 

It is quite easy to implement in bash, using sed and the tsort Unix
utility (in the code of xxargs, you may notice that bash supports
higher-order functions!). I have already done it (*).
Here are the functions you need:

-------------------------------------------------------------
# general-purpose function
# xxargs f reads lines on its standard input an applies f to each
# of them, in order
# ignores the last line if it does not end with a newline
xxargs ()
{
local F
local ARGS
F=$1
while read ARGS
do
 $F $ARGS
done
}


# takes a list of dependency with form
# f f1 ... fn
# meaning f depends on f1 and ... and fn
# and outputs a list within tsort format
format ()
{
read f l
while [ "$f" != "" ]
do
 set -- $l
 while [ "$1" != "" ]
 do
 echo $1 $f
 shift
 done
read f l
done
}

# tidy the input: if a line begins
# with a .cmi or .cmx, we ignore it, since we want to know the
# relations between .cmo files (in order to link).
# otherwise, delete the ":", and change .cmi into .cmo in order to
# have the "must be linked before" relation (if the corresponding .mli
file
# has no associated .ml file, this can introduce fake .cmo files)
# files, that is, files t) 
# Moreover, we delete the prefix "./" in filenames
tidy ()
{
case "$1" in
*.cmo:) echo "$@" | sed -e "s/://g" -e "s/.cmi/.cmo/g" -e "s|\./||g";;
*) ;;
esac
}

# removes .cmo that would not have a corresponding .ml
tidyout ()
{
local BASE
local DIR
BASE=`basename $1 .cmo`
DIR=`dirname $1`
if [ -f "$DIR/$BASE.ml" ]
then
echo "$1"
fi
}

# takes a list of dependencies in ocamldep format and outputs
# the topologically sorted list of .cmo
# typical usage:
# ocamldep -I foo foo/*.ml foo/*.mli *.ml .mli | order
# or: cat .depend
order ()
{
xxargs tidy | format | tsort | xxargs tidyout
}
-------------------------------------------------------------


Enjoy!

Judicaël Courant.

(*) When I wrote this, my aim was to have a script to automagically
check that the code of my students' would compile and do some automated
tests over it. For security reasons (the students would submit through
an anonymous web form), I did not want to do just a "make all". So I
wrote a script that just did the necessary job. The above functions are
part of the script. More about this if anybody is interested.

-- 
Judicael.Courant@lri.fr, http://www.lri.fr/~jcourant/
(+33) (0)1 69 15 64 85
"Montre moi des morceaux de ton monde, et je te montrerai le mien"
Tim, matricule #929, condamné à mort.
http://rozenn.picard.free.fr/tim.html