not-ocamlfind

Front-end to ocamlfind to add a few new commands

Features

The command not-ocamlfind is a pass-thru to ocamlfind, but adds three new commands: preprocess, reinstall-if-diff and package-graph.

reinstall-if-diff

1. reinstall-if-diff does what it says on the label: only reinstalls (remove then install) if the file-content of the package has changed.

A regular ocamlfind install command like

ocamlfind install pa_ppx_base -destdir $(DESTDIR)/lib META $(TARGET) pa_ppx_base.cmx pa_ppx_base.cmi

installs a package pa_ppx_base, failing if the package is already installed. Rewrite that to

ocamlfind reinstall-if-diff pa_ppx_base -destdir $(DESTDIR)/lib META $(TARGET) pa_ppx_base.cmx pa_ppx_base.cmi

and it checks (a) that the package is already-installed, (b) that the files-to-be-installed are identical in names and checksums to the files already-installed, (c) if not does

ocamlfind remove pa_ppx_base
ocamlfind install pa_ppx_base -destdir $(DESTDIR)/lib META $(TARGET) pa_ppx_base.cmx pa_ppx_base.cmi

and (d) if they are identical in names and checksums, does nothing.

In projects will multiple directories, if each directory locally installs a findlib package, then other directories can use those packages; they can also put those packages into their make depend dependencies, viz.

EXTERNAL := $(shell $(OCAMLFIND) query -predicates byte $(PACKAGES))
$(CMO) $(CMI) $(CMX): $(EXTERNAL)

hence causing rebuilds to occur when other directories have changed.

preprocess

A compile command using PPX rewriters

ocamlfind ocamlc -package ounit2,ppx_deriving.show -c test_deriving_show.ml

can be coaxed to produce its preprocessed output by adding "-dsource". But this is messy and ugly, esp. when we might want to use that source for further compilation. It also isn't very helpful when dealing with a multi-stage PPX rewriter sequence. preprocess produces the source and does not attempt to compile it; as an added benefit, it prints (to stderr) the commands it executed to produce that source. So you can use this for debugging multi-stage PPX rewriter sequences:

ocamlfind preprocess -package ounit2,ppx_deriving.show test_deriving_show.ml

Note well that all the options destined only for the compiler, linker, etc, are removed (and henced rejected) for preprocess. Only options required for preprocessing are accepted (-package, -syntax, -predicates, -ppopt, -ppxopt, -intf, -impl).

This can work for camlp5 also, but that little bit of documentation is TBD.

package-graph

This command outputs a graph in the format accepted by the dot command of graphviz. By default you get the package-dependency graph, with sizes of the archives for each packages as part of the node-label. If you add -dominator-from <node>, it will compute the dominator-tree from that node. and if you add -xdot, it will automatically invoke xdot on the graph. Example:

not-ocamlfind package-graph -xdot -package camlp5,ounit2,pa_ppx.here.link -dominator-from pa_ppx.here.link -xdot

Installation

To install not-ocamlfind you need a slightly-patched version of ocamlfind (branch export-more-cmis). Until (and unless) this patch gets integrated into the ocamlfind distribution, we build a local copy with that patch. So you merely need to:

./configure <customary args for ocamlfind's configure>
make
make install