0004572: ocamlbuild does not give correct switches to ocamldep when running menhir

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0004572

OCaml

OCaml general

public

2008-06-30 17:16

2008-07-25 16:50

Reporter

inalan

Assigned To

ertai

Priority

normal

Severity

block

Reproducibility

always

Status

closed

Resolution

fixed

Platform

OS Version

Product Version

3.10.1

Target Version

Fixed in Version

3.11+dev

Summary

0004572: ocamlbuild does not give correct switches to ocamldep when running menhir

Description

Generally, ocamlbuild finds dependencies for menhir .mly files by invoking menhir with the switch: --ocamldep '<ocamldep_options>'. The ocamldep options are however taken from the same list of options as are given to menhir itself during the dependency check. Thus, if menhir requires options that ocamldep does not support, an error is thrown.

Suppose, for example, I have written a parser using menhir and it uses an external token file. Thus, my files are:
main.ml
parser.mly
tokens.mly
lexer.mll

To make this compile, I define a tags file:
"tokens.mly": only-tokens

Then, I define a myocamlbuild.ml file with:
let parserFlags =
        (atomize
           ["--external-tokens";
            "Tokens";
            "--base";
            "Parser";
            "tokens.mly";
           ]
        )

let _ = dispatch begin function
  | After_rules ->
    flag ["ocaml"; "menhir_ocamldep"; "only-tokens"] (A "--only-tokens");
    flag ["ocaml"; "parser"; "menhir"; "only-tokens"] (A "--only-tokens");

    flag ["ocaml"; "menhir_ocamldep"; "parser.mly"] parserFlags
    flag ["ocaml"; "parser"; "menhir"; "parser.mly"] parserFlags

(* plus some dep lines, not shown *)

When running a Make with this myocamlbuild.ml file, ocamlbuild ends up giving both menhir and ocamldep the --base and --external-tokens arguments, like so:

menhir --base Parser --external-tokens Tokens --raw-depends --ocamldep '--base Parser --external-tokens Tokens' etc.

Then ocamldep throws an error and we can't proceed any further. Actually, the switches are given three times in the same command; once to menhir, once to ocamldep, and then once to pp. The real issue here is that when figuring out the dependencies, menhir requires a different set of arguments than does ocamldep. There is no easy way to hack around this using tags.

Additional Information

The only quick workaround I've found is to copy the menhir dependencies rule into myocamlbuild.ml along with its supporting functions, and then throw out the tags when passed to ocamldep. A full, working example (of just the myocamlbuild.ml file) is attached. Here is the short version:

let notags=Ocamlbuild_pack.Tags.of_list []

(* copied and modified from ocamlbuild sources: *)
let ocamldep_command' tags spec =
  let tags' = tags++"ocaml"++"ocamldep" in
    S [!Options.ocamldep; T tags'; Ocamlbuild_pack.Ocaml_utils.ocaml_ppflags (tags++"pp:dep");
       spec; A "-modules"]

let menhir_ocamldep_command' tags ~menhir_spec ~ocamldep_spec out =
  let menhir = if !Options.ocamlyacc = N then V"MENHIR" else !Options.ocamlyacc
  in Cmd(S[menhir; T tags; A"--raw-depend";
    (*A"--ocamldep"; Quote (ocamldep_command' tags ocamldep_spec);*)
    A"--ocamldep"; Quote (ocamldep_command' notags ocamldep_spec);
    menhir_spec ; Sh ">"; Px out])

let menhir_ocamldep_command arg out env _build =
  let arg = env arg and out = env out in
  let tags = tags_of_pathname arg++"ocaml"++"menhir_ocamldep" in
  let ocamldep_spec = ignore (Ocamlbuild_pack.Tools.flags_of_pathname arg) in
  menhir_ocamldep_command' tags ~menhir_spec:(P arg) ~ocamldep_spec out

   | After_rules ->
       rule "ocaml: menhir dependencies0"
        ~prod: "%.mly.depends"
        ~dep: "%.mly"
        ~insert: (`before "ocaml: menhir dependencies")
        (menhir_ocamldep_command "%.mly" "%.mly.depends");

Notes
(0004543) ertai (developer) 2008-07-25 16:49	Fixed in CVS trunk, thanks for the report.

Issue History
Date Modified	Username	Field	Change
2008-06-30 17:16	inalan	New Issue
2008-06-30 17:16	inalan	File Added: myocamlbuild.ml
2008-07-25 16:49	ertai	Note Added: 0004543
2008-07-25 16:50	ertai	Assigned To	=> ertai
2008-07-25 16:50	ertai	Status	new => closed
2008-07-25 16:50	ertai	Resolution	open => fixed
2008-07-25 16:50	ertai	Fixed in Version	=> 3.11+dev
2008-07-25 16:50	ertai	Description Updated
2008-07-25 16:50	ertai	Additional Information Updated

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