bhyde / cl-docopt-hack

Unfinished work in progress - a docopt.org like thing

Warning

I’m committing this because I sense I’m not going to spend any more calories on this, but I don’t want to lose it.

It is currently a mess. A slightly interesting mess, but still a mess.

The parser for the docopt input is usable. But then, if you look at the testcases you discover that the python vesion has accumulated all kinds of cool additional feature.

The code generating phases are now out of synch with the parse.

The only code generator I worked on was one for bash, which is a terrible target language! So that’s not done either.

Intro

Docopt is a fun approach to the problem of specifying and parsing shell command line arguments. See docopt.org. The idea is that you write your command’s usage message in a standard format and then some tool converts that message into a parser for your command line.

The original version was written in Python and many more exist now.

I was amused and wanted a solution for Bash scripts. The existing solution wasn’t what I wanted, since it calls out to a python program to do the work.

So cl-docopt is a a step toward what I wanted. It includes a parser for the usage message, and then some code that walks the resulting parse tree and generates the bash code to handle that. It’s woefully incomplete.

So, for example say we had this usage.

go-for-it <script-url> go-for-it fetch <document-url> go-for-it run <script-url> go-for-it add-key <key-url> go-for-it list-keys [ -v | –verbose ] go-for-it remove-key <key-designation

We get this bash code

function parse_arguments { ARGS = “$@” cmd = ‘<unknown>’ case $#ARGS in *) echo “Error” ; usage() ; exit 1 ;;

COMMMAND=’<unknown>’ if [ -z $#ARGS ] ; then parse_error=’insufficent arguments’ exit 1 fi ARG=$( shift $ARGS ) case $ARG in fetch): COMMAND=fetch ;; run): COMMAND=fetch ;; add-key): COMMAND=add-key ;; list-keys): COMMAND=list-keys ;; remove-keys): COMMAND=remove-keys ;; *)