Inconsistency with add operator

[jhsx]

Taking in example

    RunJetTest(t, data, nil, "actionNode_AddIntString", `{{ 2+"1" }}`, "3")
    RunJetTest(t, data, nil, "actionNode_AddStringInt", `{{ "1"+2 }}`, "12")

The first test the left operand is a number and the right is a string then the right operand is converted to a number and the expression is evaluated as add expression.

The second test the left operand is a string and the right is a number the expression is evaluated as a string concatenation.

I propose a breaking change in the template language, adding a operator for string concatenation and let numeric operators to work only with numbers. Like php $val.$val2.

@annismckenzie

[annismckenzie]

Yes, I concur with this. That means bumping the version to 3.0.

[annismckenzie]

#93 fixes this another way by treating both as arithmetic expressions:

RunJetTest(t, data, nil, "actionNode_AddIntString", `{{ 2+"1" }}`, "3")
RunJetTest(t, data, nil, "actionNode_AddStringInt", `{{ "1"+2 }}`, "3")

I'm not sure if that's a good idea though (I'll raise the issue over there too) because isn't the use case of a template engine to allow string concatenation without caring about the individual pieces' type?

As an example:

{{ someVariable := 10 }}
{{ prefix := "The answer is " }}
{{ suffix := ". Some more text." }}
{{ prefix + someVariable + suffix }}

I'd really expect this to print The answer is 10. Some more text.. /cc @maxime1907

This is also related to #83.

[mvrhov]

FYI: the twig/jinja etc use ~ as a concat operator. I don't know if this is reserved here, but It's more readable than the dot as dot can easily be lost in the visual clutter.

So if there will be a different concat oeprator, then the examples above should succedd, however RunJetTest(t, data, nil, "actionNode_AddIntString", {{ 2+"1z" }}, "3") should fail!

[maxime1907]

@mvrhov I agree with adding a special operator for specific use case like "2" ~ "2" output: "22", but ~ operator is mostly used for regex and binary operations, so it may be confusing ^^ Regarding the changes on the additive function, i made it works that way (same as perl template engine):

• {{ "2" + "2" }} will output: 4
• {{ "2" + "2hey" }} will output: 22hey
• {{ "2" + 2 }} will output: 4
• {{ someVariable := 10 }} {{ prefix := "The answer is " }} {{ suffix := ". Some more text." }} {{ prefix + someVariable + suffix }} will output: The answer is 10. Some more text.

[annismckenzie]

I'll add my examples from above as test cases and then I think I'm coming around to favor this approach. It'll still bump the version to v3 because of the potential breakages.