basic cmdliner interface

Author: gasche

bin/dune

@@ -2,4 +2,4 @@
  (name mustache_cli)
  (public_name mustache)
  (modules mustache_cli)
- (libraries mustache ezjsonm))
+ (libraries mustache ezjsonm cmdliner))

bin/mustache_cli.ml

@@ -40,11 +40,21 @@ let run json_filename template_filename =
       Mustache.pp_render_error err;
     exit 2
 
-let usage () =
-  print_endline "Usage: mustache-cli json_filename template_filename"
+let run_command =
+  let open Cmdliner in
+  let doc = "renders Mustache template from JSON data files" in
+  let json_file =
+    let doc = "data file in JSON format" in
+    Arg.(required & pos 0 (some file) None & info [] ~docv:"DATA.json" ~doc)
+  in
+  let template_file =
+    let doc = "mustache template" in
+    Arg.(required & pos 1 (some file) None & info [] ~docv:"TEMPLATE.mustache" ~doc)
+  in
+  Term.(const run $ json_file $ template_file),
+  Term.info "mustache" ~doc
+
 
 let () =
-  match Sys.argv with
-  | [| _ ; json_filename ; template_filename |]
-    -> run json_filename template_filename
-  | _ -> usage ()
+  let open Cmdliner in
+  Term.exit @@ Term.eval run_command

bin/test/errors/json-errors.t

@@ -4,10 +4,14 @@
 
 Empty json file:
   $ mustache empty.json foo.mustache
-  Fatal error: exception Ezjsonm.Parse_error(870828711, "JSON.of_buffer expected JSON text (JSON value)")
-  [2]
+  mustache: internal error, uncaught exception:
+            Ezjsonm.Parse_error(870828711, "JSON.of_buffer expected JSON text (JSON value)")
+            
+  [125]
 
 Invalid json file:
   $ mustache invalid.json foo.mustache
-  Fatal error: exception Ezjsonm.Parse_error(870828711, "JSON.of_buffer expected value separator or object end (',' or '}')")
-  [2]
+  mustache: internal error, uncaught exception:
+            Ezjsonm.Parse_error(870828711, "JSON.of_buffer expected value separator or object end (',' or '}')")
+            
+  [125]

bin/test/errors/sys-errors.t

@@ -3,10 +3,15 @@
 
 Nonexistent json file:
   $ mustache nonexistent.json foo.mustache
-  Fatal error: exception Sys_error("nonexistent.json: No such file or directory")
-  [2]
+  mustache: DATA.json argument: no `nonexistent.json' file or directory
+  Usage: mustache [OPTION]... DATA.json TEMPLATE.mustache
+  Try `mustache --help' for more information.
+  [124]
 
 Nonexistent template file:
   $ mustache foo.json nonexistent.mustache
-  Fatal error: exception Sys_error("nonexistent.mustache: No such file or directory")
-  [2]
+  mustache: TEMPLATE.mustache argument: no `nonexistent.mustache' file or
+            directory
+  Usage: mustache [OPTION]... DATA.json TEMPLATE.mustache
+  Try `mustache --help' for more information.
+  [124]

dune-project

@@ -27,4 +27,5 @@ Contains the `mustache` command line utility for driving logic-less templates.
   ezjsonm
   (ounit :with-test)
   (menhir (>= 20180703))
+  (cmdliner (>= 1.0.4))
   (ocaml (>= 4.06))))

mustache.opam

@@ -20,6 +20,7 @@ depends: [
   "ezjsonm"
   "ounit" {with-test}
   "menhir" {>= "20180703"}
+  "cmdliner" {>= "1.0.4"}
   "ocaml" {>= "4.06"}
   "odoc" {with-doc}
 ]