Add zsh support to auto-complete

This required the replacement of calls to _filedir in the script.

scripts/bash-autocomplete/Readme.md

@@ -1,19 +1,37 @@
 # CBMC Autocomplete Scripts for Bash
 This directory contains an autocomplete script for bash.
-## Installation
+
+## Installation for bash
 1. Compile cbmc and
 
 2. `cd scripts/bash-autocomplete`
 
 3.  `./extract-switches.sh`
 
-4. Put the following at the end of you in your `~/.bashrc`, with the directories adapted to your directory structure:
+4. Put the following at the end of your `~/.bashrc`, with the directories adapted to your directory structure:
     ```bash
     cbmcautocomplete=~/diffblue/cbmc/scripts/bash-autocomplete/cbmc.sh
     if [ -f $cbmcautocomplete ]; then
       . $cbmcautocomplete
     fi
     ```
+
+5. `source ~/.bashrc`
+
+## Installation for zsh
+Follow 1. 2. and 3. as above.
+
+4. Put the following at the end of your `~/.zshrc`, with the directories adapted to your directory structure:
+    ```bash
+    autoload bashcompinit
+    bashcompinit
+    cbmcautocomplete=~/diffblue/cbmc/scripts/bash-autocomplete/cbmc.sh
+    if [ -f $cbmcautocomplete ]; then
+      . $cbmcautocomplete
+    fi
+    ```
+5. `source ~/.zshrc`
+
 ## Usage
 As with the usual autocomplete in bash, start typing a switch to complete it, for example:
 ```

scripts/bash-autocomplete/cbmc.sh.template

@@ -26,7 +26,7 @@ _cbmc_autocomplete()
    -I|--classpath|-cp|--outfile|--existing-coverage|--graphml-cex)
      #a switch that takes a file parameter of which we don't know an extension
      #TODO probably we can do more for -I, --classpath, -cp
-     _filedir
+     COMPREPLY=( $(compgen -f -- $cur) )
      return 0
      ;;
   esac
@@ -38,6 +38,6 @@ _cbmc_autocomplete()
   fi
 
   #if none of the above applies, offer directories and files that we can analyze
-  _filedir "@(class|jar|cpp|cc|c\+\+|ii|cxx|c|i|gb)"
+  COMPREPLY=( $(compgen -G '*.class|*.jar|*.cpp|*.cc|*.c\+\+|*.ii|*.cxx|*.c|*.i|*.gb' -- $cur) )
 }
 complete -F _cbmc_autocomplete cbmc