Admin with slim is broken

[ujifgc]

This commit breaks slim Admin pages: forms content is duplicated: 02e643e

Steps to reproduce:

padrino g project test -e slim -d datamapper
padrino g admin
rake db:migrate
padrino s

[namusyaka]

Thanks for report, I confirmed.

[namusyaka]

If we use = form_tag... instead of - form_tag.., it works well.
However, I think this behavior is not correct. What do you think?

[dariocravero]

It happens on haml too. Erb doesn't have the issue. Using = form_tag... "solves" it on slim and haml. Erb fails if =... is used.

[ujifgc]

There should be some convention how to capture blocks in slim, haml, erb templates.

[dariocravero]

Looking back at slim and haml docs, I have a feeling that the right approach should be to use = instead of -.
- should be used for control code and = for output. See this and this. Thoughts?

[ujifgc]

So, according to official docs slim and haml should capture on =. Vanilla erb captures on -, Rails-flavored erb captures on =.

After merge 02e643e our rendering does official slim, haml, erb, right?

Then we should fix our admin generators and break a lot of user apps. A good change for 0.12 I think.

[dariocravero]

I agree with that. @padrino/core-members?

[namusyaka]

I agree. In any case, we also should fix this.

[ujifgc]

Thanks @namusyaka for the fast fix!