feat: add caller pattern from jinja

[pollend]

ref: #282 (comment)

I adjusted this quite heavily given the discussion in issue 282. This both adds the caller macro pattern and changes the syntax to align closer to jinja.

{% call super() %} is now {{ super() }}

https://jinja.palletsprojects.com/en/stable/templates/#call
https://jinja.palletsprojects.com/en/stable/templates/#child-template

{% macro render_dialog(title, class='dialog') -%}
    <div class="{{ class }}">
        <h2>{{ title }}</h2>
        <div class="contents">
            {{ caller() }}
        </div>
    </div>
{%- endmacro %}

{% call render_dialog('Hello World') %}
    This is a simple dialog rendered by using a macro and
    a call block.
{% endcall %}

[GuillaumeGomez]

Seems like a very good and solid start! I think the syntax should allow to have default values etc, but can be done in a follow-up. For now though, please support more than just identifiers as arguments when calling it.

[GuillaumeGomez]

Maybe replace "test" with 1 for this one? Like that we cover integer literals as well. :)

[pollend]

probably need a lot more test where to start?

[GuillaumeGomez]

Hard to say. ^^'

I have a few ideas:

• What happens if you call caller() inside the call block?
• What happens if you use named arguments in caller like caller(blue="a")?
• Can you call a macro caller? (That should emit an error as it should not be allowed!)
• What happens if you call caller outside of a macro?

And of course, all the same with super (which should support named arguments though).

[pollend]

the space handling was wrong didn't understand it on the first pass. I made some more adjustments hopefully the handling is correct now.

[pollend]

this does not look quite correct it should be the call. umm, not sure how to address this.

[GuillaumeGomez]

Strange indeed, seems like the span is created from the start of the arguments and not of caller.

[pollend]

having to wrap every macro in {% call .. %} and {% endcall %} seems kind of annoying. would be nice to support this syntax as well: https://jinja.palletsprojects.com/en/stable/templates/#import we can do that later

[pollend]

I added more test cases. and addressed some problems.

[GuillaumeGomez]

having to wrap every macro in {% call .. %} and {% endcall %} seems kind of annoying. would be nice to support this syntax as well: https://jinja.palletsprojects.com/en/stable/templates/#import we can do that later

It's somewhat supported. Can be revisited though.

[GuillaumeGomez]

Can you add the following test to ensure backlines are not removed around "nested" please?

{%- macro test() -%}
{{- caller() -}}
{%- endmacro -%}
{%- call() test() %}
nested
{% endcall -%}

[pollend]

is this expected??

\nnested\n\n

[GuillaumeGomez]

No it's not.

[pollend]

umm i made a mistake somewhere, any clue what I might of done wrong.

[GuillaumeGomez]

Likely. Good Luck with whitespace handling. 😉

If you can't figure it out, I can take a look later on.

[pollend]

yea ... can't quite figure it out

[GuillaumeGomez]

Still need to add tests I mentioned here.

[pollend]

Still need to add tests I mentioned here.

any clue what this test looks like i'm not quite following

• Can you call a macro caller? (That should emit an error as it should not be allowed!)

[GuillaumeGomez]

Ah sorry, I meant a macro named caller (forgot a word).

[pollend]

• if you have fewer arguments in the caller then the number passed it should it produce an error?
• should we make caller/super reserved words that can't be used?
• I don't think i deal with named arguments i could just have it immediately throw an error or should i just add it.

[GuillaumeGomez]

if you have fewer arguments in the caller then the number passed it should it produce an error?

Yes, number of arguments should match.

should we make caller/super reserved words that can't be used?

Yep!

I don't think i deal with named arguments i could just have it immediately throw an error or should i just add it.

Can be added in a follow-up, but then please add an issue and a test which fails on it (with a code comment in the test linking to the issue).

[pollend]

if you have fewer arguments in the caller then the number passed it should it produce an error?

Yes, number of arguments should match.

should we make caller/super reserved words that can't be used?

Yep!

I don't think i deal with named arguments i could just have it immediately throw an error or should i just add it.

Can be added in a follow-up, but then please add an issue and a test which fails on it (with a code comment in the test linking to the issue).

umm does Expr even supported named arguments?