Ttyjfyk

The Makefile is:

%.pdf: %.tex
 rubber -d $<

If there is a doc.tex in the directory, then make doc.pdf builds doc.pdf. The problem is that when I type make, the autocompletion gives nothing: it doesn't even allow to autocomplete to make doc.tex. What can be done about it?

The bash-completion package doesn't do this, it does some acrobatics to handle both command line options and extract a list of Makefile targets, but it does not try to generate matches by applying wildcards or otherwise handling any pattern rules.

It can be done however, here's a simple version with a few caveats.

function _mkcache() 
 gawk '/^# *Make data base/,/^# *Finished Make data base/
 if (/^# Not a target/) getline; next 
 ## handle "target: ..."
 if (match($0,/^([^.#% ][^:%=]+) *:($' > ".$_file:-Makefile.targets"


function _bc_make() 
 local ctok=$COMP_WORDS[COMP_CWORD] # curr token
 local ptok=$COMP_WORDS[COMP_CWORD-1] # prev token
 local -a mkrule maybe
 local try rr lhs rhs rdir pat makefile=Makefile

 ## check we're not doing any make options 
 [[ $ctok:0:1 != "-" && ! $ptok =~ ^-[fCIjloW] ]] && try="$rdir$rhs/%/$ctok*"

 maybe=( $(compgen -G "$try") ) # try must be quoted

 ## maybe[] is an array of filenames from expanded prereq globs
 (( $#maybe[*] )) && 

 [[ "$rhs" =~ % ]] && 
 ## promote rhs glob to a regex: % -> (.*)
 rhs="$rhs/./\."
 pat="$rdir$rhs/%/(.*)"

 ## use regex to extract stem from RHS, sub "%" on LHS
 for nn in "$maybe[@]"; do 
 [[ $nn =~ $pat ]] && 
 COMPREPLY+=( "$lhs/%/$BASH_REMATCH[1]" )
 
 done
 
 done
 return
 
 COMPREPLY=() #default

complete -F _bc_make $MAKE:-make

There are two parts, a function _mkcache extracts all the rules and targets from a Makefile and caches these. It also does a bit of processing so the rules are simplified to a single "target : pre-req" form in that cache.

Then, a completion function _bc_make takes the token you attempt completion on and tries to match against targets, and uses the pattern rules to expand a glob based on the pre-requisites and the word for completion. If one or more matches are found, it builds a list of targets based on the pattern rules.

GNU make is assumed. It should correctly handle:

• targets and pattern rules (though not all of them, see below)


• new and old form .c.o → %.o : %.c
  


• paths in prereqs (e.g RCS/)


• with or without all default rules (add -r to make if preferred)

Caveats, and not supported:

• intermediate or chained dependencies, it's not as smart as make
  


• 
  VPATH or vpath
  


• .SUFFIXES


• make -C dir


• "archive(member)" targets, explicit or implicit


• 
  make options expansion


• pathological junk in the environment that can cause Makefile parsing problems (TERMCAP for example)


• Makefiles named other than Makefile
  

Somme of the above can be added relatively simply, others like the archive handling are not so simple.