Reproduction
In tests/helper_macro.rs, within the function test_macro_helper, you can add the following assertion.
assert_eq!(
hbs.render_template("{{tag 'html'}}", &()).unwrap(),
"<html>"
);thread 'test_macro_helper' panicked at 'called `Result::unwrap()` on an `Err` value: RenderError { desc: "`tag` helper: Couldn't convert parameter t to type `str`. It's Null as JSON. Got these params: [PathAndJson { relative_path: Some(\"'html'\"), value: Missing }]", template_name: None, line_no: Some(1), column_no: Some(1), cause: None, unimplemented: false }', tests/helper_macro.rs:77:52
Cause
I believe the origin of this behavior is
|
if let Ok(json) = Json::from_str(s) { |
|
Parameter::Literal(json) |
|
} else { |
|
Parameter::Name(s.to_owned()) |
|
} |
The single-quoted literal matches the Rule::literal parser rule, but it is not valid JSON, so it becomes a Name object.
As evidence of this, here is the data structure I get by parsing the template {{tag 'html'}}:
Template {
name: None,
elements: [
Expression(HelperTemplate {
name: Name("tag"),
params: [Name("'html'")],
hash: {},
block_param: None,
template: None,
inverse: None,
block: false
})
],
mapping: [TemplateMapping(1, 1)]
}
Proposal
I think the way forward is to somehow extract more information from the pest parse results.
Here is a rough sketch of how I think that logic might look. As you can see, I'm out of my depth here, but this passes all the tests!
Rule::literal => {
let param = param.into_inner().next().unwrap();
match param.as_rule() {
Rule::string_literal => {
let string_inner = param.into_inner().next().unwrap();
// don't double-escape characters - see test_string_no_escape_422
let double_quoted = format!("\"{}\"", string_inner.as_str());
Parameter::Literal(Json::from_str(&double_quoted).unwrap())
}
_ => {
Parameter::Literal(Json::from_str(param_span.as_str()).unwrap())
}
}
}(In the suggestion above I removed the Name code path, since I don't think any other JSON data type would make sense as a Name.)
Thank you very much, for reading this report and for all your work on this project.
Reproduction
In
tests/helper_macro.rs, within the functiontest_macro_helper, you can add the following assertion.Cause
I believe the origin of this behavior is
handlebars-rust/src/template.rs
Lines 292 to 296 in 27a9a9a
The single-quoted literal matches the
Rule::literalparser rule, but it is not valid JSON, so it becomes a Name object.As evidence of this, here is the data structure I get by parsing the template
{{tag 'html'}}:Proposal
I think the way forward is to somehow extract more information from the pest parse results.
Here is a rough sketch of how I think that logic might look. As you can see, I'm out of my depth here, but this passes all the tests!
(In the suggestion above I removed the Name code path, since I don't think any other JSON data type would make sense as a Name.)
Thank you very much, for reading this report and for all your work on this project.