Added --bash-completion option.

This generates a bash completion script.

To use:

     eval "$(pandoc --bash-completion)"

README

@@ -250,6 +250,13 @@ General options
     `epub.css`, `templates`, `slidy`, `slideous`, or `s5` directory
     placed in this directory will override pandoc's normal defaults.
 
+`--bash-completiion`
+
+:   Generate a bash completion script.  to enable bash completion
+    with pandoc, add this to your `.bashrc`:
+
+         eval "$(pandoc --bash-completion)"
+
 `--verbose`
 
 :   Give verbose debugging output.  Currently this only has an effect

data/bash_completion.tpl

@@ -0,0 +1,62 @@
+#!/bin/bash
+
+# This script enables bash autocompletion for pandoc.  To enable
+# bash completion, add this to your .bashrc:
+# eval "$(pandoc --bash-completion)"
+
+_pandoc()
+{
+    local cur prev opts lastc informats outformats datadir
+    COMPREPLY=()
+    cur="${COMP_WORDS[COMP_CWORD]}"
+    prev="${COMP_WORDS[COMP_CWORD-1]}"
+
+    # These should be filled in by pandoc:
+    opts="%s"
+    informats="%s"
+    outformats="%s"
+    datadir="%s"
+
+    case "${prev}" in
+         --from|-f|--read|-r)
+             COMPREPLY=( $(compgen -W "${informats}" -- ${cur}) )
+             return 0
+             ;;
+         --to|-t|--write|-w|-D|--print-default-template)
+             COMPREPLY=( $(compgen -W "${outformats}" -- ${cur}) )
+             return 0
+             ;;
+         --email-obfuscation)
+             COMPREPLY=( $(compgen -W "references javascript none" -- ${cur}) )
+             return 0
+             ;;
+         --latex-engine)
+             COMPREPLY=( $(compgen -W "pdflatex lualatex xelatex" -- ${cur}) )
+             return 0
+             ;;
+         --print-default-data-file)
+             COMPREPLY=( $(compgen -W "reference.odt reference.docx $(find ${datadir} | sed -e 's/.*\/data\///')" -- ${cur}) )
+             return 0
+             ;;
+         --highlight-style)
+             COMPREPLY=( $(compgen -W "pygments tango espresso zenburn kate monochrome haddock" -- ${cur}) )
+             return 0
+             ;;
+         *)
+             ;;
+    esac
+
+    case "${cur}" in
+         -*)
+             COMPREPLY=( $(compgen -W "${opts}" -- ${cur}) )
+             return 0
+             ;;
+         *)
+             COMPREPLY=( $(compgen -f ${cur}) )
+             return 0
+             ;;
+    esac
+
+}
+
+complete -F _pandoc pandoc

pandoc.cabal

@@ -105,6 +105,8 @@ Data-Files:
                  data/dzslides/template.html
                  -- sample lua custom writer
                  data/sample.lua
+                 -- bash completion template
+                 data/bash_completion.tpl
                  -- documentation
                  README, COPYRIGHT
 Extra-Source-Files:

pandoc.hs

@@ -71,7 +71,8 @@ import qualified Data.Text as T
 import Control.Applicative ((<$>), (<|>))
 import Text.Pandoc.Readers.Txt2Tags (getT2TMeta)
 import Data.Monoid
-
+import Paths_pandoc (getDataDir)
+import Text.Printf (printf)
 import Text.Pandoc.Error
 
 type Transform = Pandoc -> Pandoc
@@ -880,6 +881,22 @@ options =
                   (\opt -> return opt { optVerbose = True }))
                  "" -- "Verbose diagnostic output."
 
+    , Option "" ["bash-completion"]
+                 (NoArg
+                  (\_ -> do
+                     ddir <- getDataDir
+                     tpl <- readDataFileUTF8 Nothing "bash_completion.tpl"
+                     let optnames (Option shorts longs _ _) =
+                           map (\c -> ['-',c]) shorts ++
+                           map ("--" ++) longs
+                     let allopts = unwords (concatMap optnames options)
+                     UTF8.hPutStrLn stdout $ printf tpl allopts
+                         (unwords (map fst readers))
+                         (unwords ("pdf": map fst writers))
+                         ddir
+                     exitWith ExitSuccess ))
+                 "" -- "Print bash completion script"
+
     , Option "v" ["version"]
                  (NoArg
                   (\_ -> do