Parsing arguments in custom functions

[CeleritasCelery]

I saw this on reddit and am super excited to try out this package! I did have one quick question though. I noticed that when writing your own shx functions it will take all the command line arguments present and put them in a big string. It is then the responsibility of the function to parse out the arguments. Why does it not pass the arguments as a list as one might expect? Is this a technical limitation?

[riscy]

Thank you! :)

You're correct, it'll just be one big string, and currently it's the responsibility of the function to figure out what to do.

But I think passing the arguments through as a list is the right thing to do -- it's probably time to make the change you suggest. I've got some free time this week, so keep an eye out for version 0.1.0!

[CeleritasCelery]

Also does the shell preform parameter expansion before the arguments are passed to the function?

[riscy]

Hmm, can you give me an example?

[CeleritasCelery]

If I have a shell variable $var which is set to file.txt could I use :edit $var to edit that file?

[riscy]

Oh, right. This one I'll file under technical limitation until I can figure out an easy way to extract environment variables (live) from a running shell. :\

Ideally it would be as easy as running env and parsing that output, but shx should run just as well on top of bash as on top of a python or ruby interpreter.

[riscy]

As a workaround, you could do something like this:

file=test.txt
echo \<edit `echo $file`\>

i.e. create some markup that looks like <edit test.txt> and echo it.

[CeleritasCelery]

Is it possible in comint buffers to query the underlying REPL without showing the user? You could always Send a shell echo "<original arguments>" and it would do variable expansion for you. Though I suppose you are right that this wouldn't work in interpreters that don't have echo or equivalent.

[riscy]

Yeah, it's definitely possible but there's some bookkeeping involved. For example typically the REPL will emit another prompt, which you have to hide from the user or things will start to get confusing.

[riscy]

After review I noticed many commands won't want the input string tokenized into a list. For now, I decided to leave it up to the function to parse out the arguments.

But, I'd love it if you could let me knowwhat you think of this: https://github.com/riscy/shx-for-emacs/tree/develop#example-invoking-ediff-from-the-shell -- that new example shows how I've made it much clearer how to take that raw string and parse it into a list.

[CeleritasCelery]

That shx-tokenize function is perfect. A simple way to grab arguments. Thanks! I tried out shx and it works great!