String interpolation

[dijs]

Could this ever be a thing in Kal?

test = "#{2 + 2}"
# where test would equal "4"

Obviously, it would be great to use variables also...

[dijs]

This is from Douglas Crawford's "Remedial Javascript". I thought I might help.

String.prototype.supplant = function (o) {
    return this.replace(/{([^{}]*)}/g,
        function (a, b) {
            var r = o[b];
            return typeof r === 'string' || typeof r === 'number' ? r : a;
        }
    );
};
// Usage:
alert("I'm {age} years old!".supplant({ age: 29 }));
alert("The {a} says {n}, {n}, {n}!".supplant({ a: 'cow', n: 'moo' }));

I thought this was a clean way to approach the problem.

[rzimmerman]

If I'm understanding you correctly, you're looking for string syntax like:

s = "I am #{50+1} years old"

Which is already supported. The supplant thing is not supported right now (kind of like Python's old % operator?), although you could do:

a = cow
n = moo
print "The #{a} says #{n}, #{n}, #{n}!"

[rzimmerman]

Also, it only works with double quoted strings, not single quoted strings (on purpose like CoffeeScript).

[dijs]

Facepalm I had no idea this was already supported...

Is it in your documentation?

[rzimmerman]

Technically yes, but it's just one little line in the readme (I agree it's not obvious at all). I'll add something more substantive.