map reduce with redo: apenwarr #1

default.stamp.do

[ -n "$OK_TO_STAMP" ] || exit 99
redo-ifchange $1.data
date  # make sure the file is nonempty so redo-targets remembers it

do-reduce

echo $ARGV

reduce.do

filelist()
{
   # FIXME: maybe delete .stamp files where the corresponding .data
   # has been deleted, before running redo-ood
   redo-ood | grep '.stamp$' || true

   for d in *.data; do
       echo "${d%.data}.stamp"
   done | sort >all-targets
   redo-targets | sort >known-targets
   comm -2 -3 all-targets known-targets
}
targets=$(filelist | sort | uniq)
sh do-reduce $targets
# only stamp them *after* reduce-files succeeds!
OK_TO_STAMP=1 redo-ifchange $targets