*js templating

[fasterthanlime]

Basic idea:

• We need Mozilla Parser API to generate via escodegen
• ClojureScript uses js-code templates internally to generate JS — examples
• No problemo! Let's convert templates like that:

(~{} ^ ~{})

to

(_2969cddbc9cf017722f8dc6b2ffc472a ^ _5789cf9faa7b1bc2bb8928b78fe524e7)

• Parse it via esprima, then get JST like so:

{
    "type": "Program",
    "body": [{
        "type": "ExpressionStatement",
        "expression": {
            "type": "BinaryExpression",
            "operator": "^",
            "left": {
                "type": "Identifier",
                "name": "_2969cddbc9cf017722f8dc6b2ffc472a"
            },
            "right": {
                "type": "Identifier",
                "name": "_5789cf9faa7b1bc2bb8928b78fe524e7"
            }
        }
    }]
}

• Find where our unique MD5 identifiers went, remember the path to these nodes, so we know how to apply it, so that the template looks something like:

// as Shin::JST classes
{
    "type": "BinaryExpression",
    "operator": "^",
    "left": null,
    "right": null
}

arg_paths = [[:left], [:right]]

• And keep those around in a cache so we don't need to bother esprima again with it. Using those arg_paths, we can translate the arguments individually and insert them in a deep clone of the template.

And when it works well enough, we can remove some special form handling in translator (along with *js-bop *js-uop and *js-call), and support Reagent's interop.clj js-call macro.