Query.toAST invalid param reference

[H-Plus-Time]

So I've been testing out serialising a query to the AST representation, it looks like there's a slight bug when referencing params (serializing them is fine). So this works:
query().params({param1: 3}).filter((d, $) => d.colA}).toAST()
but including the param in any expression fails:
query().params({param1: 3}).filter((d, $) => d.colA / $.param1 }).toAST()

Presumably all verbs that boil down to an ExprObject exhibit the same problem.

Calling aq.internal.parse directly with a fake table in opt works:

const fakeTable = {
  params: () => ({param1: 3}),
  column: () => true
}
const compiledAst = aq.internal.parse({expr: `(d, $) => d.colA < $.param1`, {table: fakeTable, ast: true})

I suspect we just need to pass down the query context in query.js, as a fourth parameter to toAST in verb.js, and tweak getParams to pull in params from opt.table or opt.query.

[jheer]

Thanks for the issue, and for PR #224! I will take a closer look at this when I have time, hopefully in the coming month. I agree that improved parameter passing would be helpful.

p.s. AST generation should still be considered somewhat "experimental" at this point and is subject to change. Some significant modifications may be made to query serialization in Arquero v5.