expr/operator-post-inc-dec.go

98 lines
2.3 KiB
Go

// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
// All rights reserved.
// operator-post-inc-dec.go
package expr
import (
"git.portale-stac.it/go-pkg/expr/kern"
)
// -------- post increment term
func newPostIncTerm(tk *Token) *term {
return &term{
tk: *tk,
parent: nil,
children: make([]*term, 0, 1),
position: posPostfix,
priority: priIncDec,
evalFunc: evalPostInc,
}
}
func evalPostInc(ctx kern.ExprContext, opTerm *term) (v any, err error) {
var childValue any
if childValue, err = opTerm.evalPrefix(ctx); err != nil {
return
}
if it, ok := childValue.(kern.Iterator); ok {
var namePrefix string
v, err = it.Next()
if opTerm.children[0].symbol() == SymVariable {
namePrefix = opTerm.children[0].Source()
}
ctx.UnsafeSetVar(namePrefix+"_index", it.Index())
if c, err1 := it.Current(); err1 == nil {
ctx.UnsafeSetVar(namePrefix+"_current", c)
}
if it.HasOperation(kern.KeyName) {
if k, err1 := it.CallOperation(kern.KeyName, nil); err1 == nil {
ctx.UnsafeSetVar(namePrefix+"_key", k)
}
}
if it.HasOperation(kern.ValueName) {
if v1, err1 := it.CallOperation(kern.ValueName, nil); err1 == nil {
ctx.UnsafeSetVar(namePrefix+"_value", v1)
}
}
} else if kern.IsInteger(childValue) && opTerm.children[0].symbol() == SymVariable {
v = childValue
i, _ := childValue.(int64)
ctx.SetVar(opTerm.children[0].Source(), i+1)
} else {
err = opTerm.errIncompatiblePrefixPostfixType(childValue)
}
return
}
// -------- post decrement term
func newPostDecTerm(tk *Token) *term {
return &term{
tk: *tk,
parent: nil,
children: make([]*term, 0, 1),
position: posPostfix,
priority: priIncDec,
evalFunc: evalPostDec,
}
}
func evalPostDec(ctx kern.ExprContext, opTerm *term) (v any, err error) {
var childValue any
if childValue, err = opTerm.evalPrefix(ctx); err != nil {
return
}
/* if it, ok := childValue.(Iterator); ok {
v, err = it.Next()
} else */if kern.IsInteger(childValue) && opTerm.children[0].symbol() == SymVariable {
v = childValue
i, _ := childValue.(int64)
ctx.SetVar(opTerm.children[0].Source(), i-1)
} else {
err = opTerm.errIncompatiblePrefixPostfixType(childValue)
}
return
}
// init
func init() {
registerTermConstructor(SymDoublePlus, newPostIncTerm)
registerTermConstructor(SymDoubleMinus, newPostDecTerm)
}