Clearer error for mixed spaces / tabs nesting in cassius

[rehno-lindeque]

Is it possible to add a clearer error message when mixing tabs with spaces by accident in cassius?
It currently says:

Internal Server Error 
Only LineSingle may have nested content 

Perhaps you could simply add "Did you accidentally mix tabs and spaces?" as a quick fix if that is possible...?

(This is using cassiusFileDebug)

[snoyberg]

I'm not sure how to figure out that it's the tabs/spaces mix which is causing the problem. One possible idea (probably a good one) is to simply ban tabs from denoting indentation; I doubt anyone will really complain.

However, the bigger issue here is... well, how do I say this politely... I did a god-awful job with the cassius error messages. What the hell does the "Only LineSingle" mean? Fixing that up should definitely rank high on my todo list.

[rehno-lindeque]

Hahaha :) Hopefully this issue will serve as a reminder!

[snoyberg]

Hey Rehno,

I've pushed some commits that bump Hamlet to 0.6 and hopefully make error messages from Cassius much clearer. Mind having a look? I will require modifying Persistent and Yesod to have a higher version bounds on Hamlet.

Michael

[rehno-lindeque]

Thanks Michael. I quickly started upgrading to yesod 0.6 today, but it looks like I have to upgrade some stuff first! It might take me a little while to catch up with yesod development :)

[Shimuuar]

I'd vote to ban tabs. They may change meaning of program silently. If your editor and hamlet/cassius have different tab width it may lead either to error or it could be parsed not as you expected. Second case is real. I encountered it.

IMHO mixing tabs and significant indentation is generally bad idea™

[snoyberg]

OK, just pushed this commit, tabs for indentation give an error.