Fix issue #31

The syntax is still fairly constrained - but on purpose in order to keep
the `--` the definitive EOA marker. The reason `[--] ARGS` is allowed,
despite not being "correct" is for compatibilites sake.

examples/git/add.js

@@ -1,9 +1,8 @@
 require('shelljs/global');
 
-// XXX: -- should be [--]. See #31
 module.exports = (argv) => {
 const args = require('../..').run(`
-usage: git add [options] -- <pathspec>...
+usage: git add [options] [--] <pathspec>...
 
 Options:
   -n, --dry-run         dry run

examples/git/bisect.js

@@ -3,15 +3,14 @@ const _ = require('lodash');
 
 // The git-bisect help text is a bit unconventional and requires some special
 // treatment for prepartion
-// XXX: -- should be [--]. See #31
 module.exports = (argv) => {
 
 const help = `
 usage: git bisect [help|start|bad|good|skip|next|reset|visualize|replay|log|run] [<args>...]
 
 git bisect help
     print this long help message.
-git bisect start [--no-checkout] [<bad> [<good>...]] -- [<pathspec>...]
+git bisect start [--no-checkout] [<bad> [<good>...]] [--] [<pathspec>...]
     reset bisect state and start bisection.
 git bisect bad [<rev>]
     mark <rev> a known-bad revision.

examples/git/checkout.js

@@ -1,6 +1,5 @@
 require('shelljs/global');
 
-// XXX: -- should be [--]. See #31
 module.exports = (argv) => {
 const args = require('../..').run(`
 

examples/git/clone.js

@@ -1,10 +1,9 @@
 require('shelljs/global');
 
-// XXX: -- should be [--]. See #31
 module.exports = (argv) => {
 const args = require('../..').run(`
 
-usage: git clone [options] -- <repo> [<dir>]
+usage: git clone [options] [--] <repo> [<dir>]
 
 options:
   -v, --verbose         be more verbose

examples/git/commit.js

@@ -1,10 +1,9 @@
 require('shelljs/global');
 
-// XXX: -- should be [--]. See #31
 module.exports = (argv) => {
 const args = require('../..').run(`
 
-usage: git commit [options] -- <pathspec>...
+usage: git commit [options] [--] <pathspec>...
 
 options:
     -q, --quiet           suppress summary after successful commit

examples/git/diff.js

@@ -1,9 +1,8 @@
 require('shelljs/global');
 
-// XXX: -- should be [--]. See #31
 module.exports = (argv) => {
 const args = require('../..').run(`
-usage: git diff [<options>] [<commit> [<commit>]] -- [<path>...]
+usage: git diff [<options>] [<commit> [<commit>]] [--] [<path>...]
 `, { argv: argv, smartOptions: true });
 
 echo(args);

examples/git/fetch.js

@@ -1,6 +1,5 @@
 require('shelljs/global');
 
-// XXX: -- should be [--]. See #31
 // Note: `[<options>]` has been edited to `[options]`.
 module.exports = (argv) => {
 const args = require('../..').run(`

examples/git/grep.js

@@ -1,11 +1,9 @@
 require('shelljs/global');
 
-// XXX: -- should be [--]. See #31
-// original: usage: git grep [options] [-e] <pattern> [<rev>...] [[--] <path>...]
 module.exports = (argv) => {
 const args = require('../..').run(`
 
-usage: git grep [options] <pattern> [<rev>...] -- [<path>...]
+usage: git grep [options] <pattern> [<rev>...] [[--] <path>...]
 
 options:
     --cached              search in index instead of in the work tree

src/Language/Docopt/Parser/Usage.purs

@@ -6,6 +6,7 @@ module Language.Docopt.Parser.Usage (
   ) where
 
 import Prelude
+import Debug.Trace
 import Language.Docopt.Parser.Lexer as L
 import Language.Docopt.Parser.Usage.Option as O
 import Language.Docopt.Parser.Usage.Usage as U
@@ -25,7 +26,7 @@ import Language.Docopt.Parser.Usage.Argument (Argument(..))
 import Language.Docopt.Parser.Usage.Usage (Usage(..))
 import Text.Parsing.Parser (ParseError) as P
 import Text.Parsing.Parser.Combinators (try, optional, choice, sepBy1, between,
-                                       lookAhead) as P
+                                       optionMaybe, lookAhead) as P
 import Text.Parsing.Parser.Combinators ((<?>), (<??>))
 import Text.Parsing.Parser.Pos (Position(Position)) as P
 
@@ -72,9 +73,12 @@ usageParser smartOpts = do
                   (many $ P.try $ moreIndented *> elem) `P.sepBy1` L.vbar
       eoa <- P.choice [
         P.try $ do
-          moreIndented *> L.doubleDash
-          P.optional do
+          maybeInParens do
+            maybeInParens do
+              L.doubleDash
+              many elem
             many elem
+          many elem
           return $ Just EOA
       , (do
           L.eof <|> (P.lookAhead $ lessIndented <|> sameIndent)
@@ -92,6 +96,15 @@ usageParser smartOpts = do
           (\as -> as ++ (singleton e))
           xs
 
+    maybeInParens p = do
+      Tuple close v <- moreIndented *> do
+        Tuple
+          <$> (P.optionMaybe $ P.choice [ L.lparen  *> return L.rparen
+                                        , L.lsquare *> return L.rsquare ])
+          <*> p
+      fromMaybe (pure unit) close
+      return v
+
     elem :: L.TokenParser Argument
     elem = defer \_ -> do
       P.choice $ P.try <$>

testcases.docopt

@@ -2721,3 +2721,22 @@ $ prog/s -b 2000
 
 $ prog/s -a 1000 -b 2000
 {"-a": [1000], "-b": [2000]}
+
+# Fix issue #31
+# The syntax is still fairly constrained - but on purpose in order to keep
+# the `--` the definitive EOA marker. The reason `[--] ARGS` is allowed, despite
+# not being "correct" is for compatibilites sake.
+
+r"""
+Usage: foo [--] <pathspec>...
+"""
+
+$ prog
+{"--": []}
+
+r"""
+Usage: foo [[--] ARGS]
+"""
+
+$ prog
+{"--": []}