add --emit-file option to emit .wat files

CHANGES.md

@@ -1,5 +1,6 @@
 ## unreleased
 
+- add `--emit-file` option to `wasm2wat` to emit .wat files
 - adds flags `--fail-on-trap-only` and `fail-on-assertion-only`
 - parameterize the `Thread` module on the symbolic memory and the `Choice_monad` module on a Thread
 - adds a `owi_char` function to create char symbolic value

example/README.md

@@ -53,7 +53,7 @@ COMMANDS
  validate [--debug] [OPTION]… [ARG]…
  Validate a module
 
- wasm2wat [OPTION]… [ARG]…
+ wasm2wat [--emit-file] [OPTION]… [ARG]…
  Generate a text format file (.wat) from a binary format file
  (.wasm)
 

example/wasm2wat/README.md

@@ -28,7 +28,11 @@ NAME
  file (.wasm)
 
 SYNOPSIS
- owi wasm2wat [OPTION]… [ARG]…
+ owi wasm2wat [--emit-file] [OPTION]… [ARG]…
+
+OPTIONS
+ --emit-file
+ emit (.wat) files from corresponding (.wasm) files
 
 COMMON OPTIONS
  --help[=FMT] (default=auto)

src/bin/owi.ml

@@ -39,6 +39,10 @@ let files =
  let f = existing_non_dir_file in
  Cmdliner.Arg.(value & pos_all f [] (info [] ~doc))
 
+let emit_files =
+ let doc = "emit (.wat) files from corresponding (.wasm) files" in
+ Cmdliner.Arg.(value & flag & info [ "emit-file" ] ~doc)
+
 let no_exhaustion =
  let doc = "no exhaustion tests" in
  Cmdliner.Arg.(value & flag & info [ "no-exhaustion" ] ~doc)
@@ -245,7 +249,7 @@ let wasm2wat_cmd =
  let man = [] @ shared_man in
  Cmd.info "wasm2wat" ~version ~doc ~sdocs ~man
  in
- Cmd.v info Term.(const Cmd_wasm2wat.cmd $ files)
+ Cmd.v info Term.(const Cmd_wasm2wat.cmd $ files $ emit_files)
 
 let wat2wasm_cmd =
  let open Cmdliner in

src/cmd/cmd_wasm2wat.ml

@@ -4,13 +4,17 @@
 
 open Syntax
 
-let cmd_one file =
+(** Utility function to handle writing to a file or printing to stdout *)
+let cmd_one emitfile file =
  let ext = Fpath.get_ext file in
+ let wat_file = Fpath.set_ext "wat" file in
+
  match ext with
  | ".wasm" ->
  let* m = Parse.Binary.Module.from_file file in
  let m = Binary_to_text.modul m in
- Ok (Fmt.pr "%a@\n" Text.pp_modul m)
+ if emitfile then Bos.OS.File.writef wat_file "%a@\n" Text.pp_modul m
+ else Ok (Fmt.pr "%a@\n" Text.pp_modul m)
  | ext -> Error (`Unsupported_file_extension ext)
 
-let cmd files = list_iter cmd_one files
+let cmd files emitfile = list_iter (cmd_one emitfile) files

src/cmd/cmd_wasm2wat.mli

@@ -2,4 +2,4 @@
 (* Copyright © 2021-2024 OCamlPro *)
 (* Written by the Owi programmers *)
 
-val cmd : Fpath.t list -> unit Result.t
+val cmd : Fpath.t list -> bool -> unit Result.t

test/help/help.t

@@ -31,7 +31,7 @@ no subcommand should print help
  validate [--debug] [OPTION]… [ARG]…
  Validate a module
 
- wasm2wat [OPTION]… [ARG]…
+ wasm2wat [--emit-file] [OPTION]… [ARG]…
  Generate a text format file (.wat) from a binary format file
  (.wasm)
 

test/wasm2wat/emit.t

@@ -0,0 +1,21 @@
+test that we can emit to a file: 
+ $ owi wasm2wat m.wasm --emit-file
+ $ cat m.wat
+ (module
+
+ (type (sub final (func (param i32) (param i32) (result i32))))
+
+ (type (sub final (func)))
+ (func (param i32) (param i32) (result i32)
+ local.get 0
+ local.get 1
+ i32.add
+ )
+ (func
+ i32.const 22
+ i32.const 20
+ call 0
+ drop
+ )
+ (start 1)
+ )

test/wasm2wat/not_exists.t

@@ -1,6 +1,6 @@
  $ owi wasm2wat idontexist.wat
  owi: no file 'idontexist.wat'
- Usage: owi wasm2wat [OPTION]… [ARG]…
+ Usage: owi wasm2wat [--emit-file] [OPTION]… [ARG]…
  Try 'owi wasm2wat --help' or 'owi --help' for more information.
  [124]
  $ owi wasm2wat bad.ext