Ticket #122

[olwmc]

This PR solves issue #122 by

A) Disallowing negative step values for list comprehensions

B) Inferring step direction by range start and end

Because I'm using python ranges to accomplish this functionality I had to do a little bit of work to get the offset correct. Regardless, this should work as intended.

Please break this PR if you can, I'd love to improve it.

[lutzhamel]

did we want to change the syntax from step to stride in order to highlight the fact this is not your Python step but something else?

[olwmc]

Oh I'd be happy to do that in this PR. I was going to open a syntax change issue after this was merged. I'll get on that tomorrow morning.

[lutzhamel]

I think implementing stride as part of #122 makes sense given that the discussion on stride happened in issue #122.

[olwmc]

Makes sense! I’ll get on it.

[lutzhamel]

I changed target of the pull request from 'master' to 'dev-1.0.0'

[olwmc]

So the only thing I have left to fix are in User Guide.rst, User Guide.txt, Reference Guide.rst, Reference Guide.txt and Asteroid in Action.rst.

I'm not super sure how these files work since I believe they're machine generated. How should I go about fixing the instances here?

Note: I found out which files still have a step->stride fix needed by grepping the repo for 'step' and looking through each one to see if it is the 'step' we're actually talking about

[olwmc]

Figured it out! This should be good to go.

[olwmc]

Hold on. Sorry. There's some weird issue going on with the documentation generation.

[lutzhamel]

Looking good! Did you get a chance to take a peek at the asteroid/programs folder? I have no idea if there are programs in there that need a fix for the new syntax...

feel free to merge your PR and any time! Excellent Job!

[olwmc]

Yes I checked the whole tree of files. Grep has a -r directive but just to make sure I went through each folder/subfolder.