LHS inference for type assertions (Pre proposal discussion)

[Dexter Plameras]

Greetings,

As per the requirement before putting together a proposal, a discussion on LHS inference for type assertions

Currently, type assertions take the form of:

//

// Pre assertion

//

var original string = "Hello Type Assertions"

var data interface{} = original // or "var data any"

//

// Assertions

// 

// fails compiler checks

destInt := data.(int)

// passes compiler checks

destString := data.(string)

Proposal:
Instead of a RHS type assertion, I'd like to propose a language change that would take the type assertion as an inference from the LHS, potentially using a new assignment operator.

//

// Pre assertion

//

original := "Hello Type Assertions"

var data interface{} = original  // or var data any

// LHS inference of the int type. Compiler checks fail. (notice the ".=" assignment operator, it could be variation of the assignment operator that makes it clearer)

var destInt int .= data

// LHS inference of the string type.

var destString string .= data

// or

var destString string

destString .= data

This could potentially work with multiple RHS returns too.

var data string

var err error

data, err .= function()

I'm certainly no programming language expert but does this hold any value?

[Ian Lance Taylor]

You didn't explain why the new syntax is better. It doesn't seem any
clearer to me, so I don't see what we gain. Thanks.

Ian

[Dexter Plameras]

My apologies,

So as to not waste your time or anybody else's, I'll follow the proposal headings in the (proposal/.../TEMPLATE.md), and post here.