feat: extract code for compiling equal operator

[zhuliquan]

Whether OpEqualInt and OpEqualInt need to be applied to the operator != when convert ast to bytecode, and if so, whether to consider extracting the code that handles equal into a function named equalBinnaryNode

[antonmedv]

Why this code is needed?

[zhuliquan]

Why this code is needed?

I'm not sure. I notice that you have applied three OpCode in equal operator case as below.

expr/compiler/compiler.go

Lines 412 to 418 in d523107

	if l == r && l == reflect.Int && leftAndRightAreSimple {
	c.emit(OpEqualInt)
	} else if l == r && l == reflect.String && leftAndRightAreSimple {
	c.emit(OpEqualString)
	} else {
	c.emit(OpEqual)
	}

I'm guessing you want to make the most of the right and left type information in BinaryNode, so that the Bytecode generated later runs faster. Because. I notice that assert interface{} to int / string directly in case OpEqualInt/OpEqualString as below.

expr/vm/vm.go

Lines 165 to 173 in d523107

	case OpEqualInt:
	b := vm.pop()
	a := vm.pop()
	vm.push(a.(int) == b.(int))
	case OpEqualString:
	b := vm.pop()
	a := vm.pop()
	vm.push(a.(string) == b.(string))

Since this trick is already used in case of ==, why not use it in case of !=? Further, I think that if this trick can be used in case of !=, why not extract code of == case and apply it to both the case of == and the case of !=.

[antonmedv]

Since this trick is already used in case of ==, why not use it in case of !=?

Got it. This makes sense.