62 lines
1.2 KiB
Go
62 lines
1.2 KiB
Go
|
// operator-sign.go
|
||
|
|
package expr
|
||
|
|
|
||
|
|
//-------- plus sign term
|
||
|
|
|
||
|
|
func newPlusSignTerm(tk *Token) (inst *term) {
|
||
|
|
return &term{
|
||
|
|
tk: *tk,
|
||
|
|
class: classOperator,
|
||
|
|
kind: kindUnknown,
|
||
|
|
children: make([]*term, 0, 1),
|
||
|
|
position: posPrefix,
|
||
|
|
priority: priSign,
|
||
|
|
evalFunc: evalSign,
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
func newMinusSignTerm(tk *Token) (inst *term) {
|
||
|
|
return &term{
|
||
|
|
tk: *tk,
|
||
|
|
class: classOperator,
|
||
|
|
kind: kindUnknown,
|
||
|
|
children: make([]*term, 0, 1),
|
||
|
|
position: posPrefix,
|
||
|
|
priority: priSign,
|
||
|
|
evalFunc: evalSign,
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
func evalSign(ctx exprContext, self *term) (v any, err error) {
|
||
|
|
var rightValue any
|
||
|
|
|
||
|
|
if rightValue, err = self.evalPrefix(ctx); err != nil {
|
||
|
|
return
|
||
|
|
}
|
||
|
|
|
||
|
|
if isFloat(rightValue) {
|
||
|
|
if self.tk.Sym == SymChangeSign {
|
||
|
|
f, _ := rightValue.(float64)
|
||
|
|
v = -f
|
||
|
|
} else {
|
||
|
|
v = rightValue
|
||
|
|
}
|
||
|
|
} else if isInteger(rightValue) {
|
||
|
|
if self.tk.Sym == SymChangeSign {
|
||
|
|
i, _ := rightValue.(int64)
|
||
|
|
v = -i
|
||
|
|
} else {
|
||
|
|
v = rightValue
|
||
|
|
}
|
||
|
|
} else {
|
||
|
|
err = self.errIncompatibleType(rightValue)
|
||
|
|
}
|
||
|
|
return
|
||
|
|
}
|
||
|
|
|
||
|
|
// init
|
||
|
|
func init() {
|
||
|
|
registerTermConstructor(SymUnchangeSign, newPlusSignTerm)
|
||
|
|
registerTermConstructor(SymChangeSign, newMinusSignTerm)
|
||
|
|
}
|