Allow block definitions in if/for/match blocks (fixes #335)

[djc]

No description provided.

[djc]

@jmafc do you want to try this out?

[jmafc]

Do I just have to reference the master branch in my Cargo.toml to do that?

[djc]

Well, the deep-blocks branch for now, but yes, that should do it.

[jmafc]

Ok, I tried it, but it still causes the message: blocks ('meta_descrip') are only allowed at the top level of a template or another block. The meta_descrip is the what meta_x stood for in previous examples, and as shown in the example, the block is nested within an {% else %}. I'm pretty I got your code because the Cargo.lock shows source = "git+https://github.com/djc/askama?branch=deep-blocks#79374b96812dc8454b28bccd05757d90e87b104f" which is your commit.
Also, in order to test I had to disable a call to a macro, because it was causing message: unable to parse template. The macro was parsing and processing OK when building with askama 0.8.0. The macro has a for loop to output HTML list items and includes an if !loop.last block.
Let me know if you need further details.

[djc]

Ah yes, I forgot to strip out the code in the code generator that panics if it encounters a nested block definition. That's fixed with the latest push.

Can you file a separate issue about the macro thing? That seems unrelated, and potentially a regression. Would like have a minimal reproduction of the template syntax for that.

[jmafc]

Ok, the blocks ('meta_descrip') are only allowed at the top level of a template or another block is no longer reported. I'll file the issue about the macro regression later today.

[djc]

And does the template with the if-nested block produce the expected output? :)

[jmafc]

Yes it did produce the expected output (eventually, because one of my templates had an unrecognized field, but I've fixed that now).

[djc]

Cool, thanks for checking.