expr/operator-shift.go
Celestino Amoroso d91e7eb979 The list operator '<<' (append) and '>>' (prepend) have been replaced
with the new operators '<+' and '+>' respectively.
'<<' and '>>' are now used only for left and right binary shit
respectively. Further, their priority has been increased moving them to
a higher priority than that of the assignment operator.
2024-12-28 09:17:27 +01:00

86 lines
1.9 KiB
Go

// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
// All rights reserved.
// operator-shift.go
package expr
//-------- shift term
func newRightShiftTerm(tk *Token) (inst *term) {
return &term{
tk: *tk,
children: make([]*term, 0, 2),
position: posInfix,
priority: priBinShift,
evalFunc: evalRightShift,
}
}
func evalRightShift(ctx ExprContext, opTerm *term) (v any, err error) {
var leftValue, rightValue any
if leftValue, rightValue, err = opTerm.evalInfix(ctx); err != nil {
return
}
if IsInteger(leftValue) && IsInteger(rightValue) {
leftInt := leftValue.(int64)
rightInt := rightValue.(int64)
v = leftInt >> rightInt
} else {
err = opTerm.errIncompatibleTypes(leftValue, rightValue)
}
return
}
func newLeftShiftTerm(tk *Token) (inst *term) {
return &term{
tk: *tk,
children: make([]*term, 0, 2),
position: posInfix,
priority: priBinShift,
evalFunc: evalLeftShift,
}
}
func evalLeftShift(ctx ExprContext, opTerm *term) (v any, err error) {
var leftValue, rightValue any
if leftValue, rightValue, err = opTerm.evalInfix(ctx); err != nil {
return
}
if IsInteger(leftValue) && IsInteger(rightValue) {
leftInt := leftValue.(int64)
rightInt := rightValue.(int64)
v = leftInt << rightInt
} else {
err = opTerm.errIncompatibleTypes(leftValue, rightValue)
}
return
}
// func evalAssignAppend(ctx ExprContext, self *term) (v any, err error) {
// var leftValue, rightValue any
// if leftValue, rightValue, err = self.evalInfix(ctx); err != nil {
// return
// }
// if IsList(leftValue) {
// list, _ := leftValue.(*ListType)
// newList := append(*list, rightValue)
// v = &newList
// if
// } else {
// err = self.errIncompatibleTypes(leftValue, rightValue)
// }
// return
// }
// init
func init() {
registerTermConstructor(SymDoubleGreater, newRightShiftTerm)
registerTermConstructor(SymDoubleLess, newLeftShiftTerm)
}