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new operator ':=', it assigns a value to a variable by deep copy

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This commit is contained in:
Celestino Amoroso
2026-05-17 05:02:07 +02:00
parent 08617378e0
commit 0c719025cd
9 changed files with 201 additions and 198 deletions
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operator-assign.go
+29 -5
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@@ -22,6 +22,26 @@ func newAssignTerm(tk *scan.Token) (inst *scan.Term) {
}
}
func evalAssign(ctx kern.ExprContext, opTerm *scan.Term) (v any, err error) {
v, err = generalEvalAssign(ctx, opTerm, false)
return
}
func newDeepCopyAssignTerm(tk *scan.Token) (inst *scan.Term) {
return &scan.Term{
Tk: *tk,
Children: make([]*scan.Term, 0, 2),
Position: scan.PosInfix,
Priority: scan.PriAssign,
EvalFunc: evalDeepCopyAssign,
}
}
func evalDeepCopyAssign(ctx kern.ExprContext, opTerm *scan.Term) (v any, err error) {
v, err = generalEvalAssign(ctx, opTerm, true)
return
}
func assignCollectionItem(ctx kern.ExprContext, collectionTerm, keyListTerm *scan.Term, value any) (err error) {
var collectionValue, keyListValue, keyValue any
var keyList *kern.ListType
@@ -57,16 +77,19 @@ func assignCollectionItem(ctx kern.ExprContext, collectionTerm, keyListTerm *sca
return
}
func assignValue(ctx kern.ExprContext, leftTerm *scan.Term, v any) (err error) {
func assignValue(ctx kern.ExprContext, leftTerm *scan.Term, v any, deepCopy bool) (err error) {
if leftTerm.Symbol() == scan.SymIndex {
err = assignCollectionItem(ctx, leftTerm.Children[0], leftTerm.Children[1], v)
} else {
if deepCopy {
v = kern.Clone(v)
}
ctx.UnsafeSetVar(leftTerm.Source(), v)
}
return
}
func evalAssign(ctx kern.ExprContext, opTerm *scan.Term) (v any, err error) {
func generalEvalAssign(ctx kern.ExprContext, opTerm *scan.Term, deepCopy bool) (v any, err error) {
if err = opTerm.CheckOperands(); err != nil {
return
}
@@ -93,10 +116,10 @@ func evalAssign(ctx kern.ExprContext, opTerm *scan.Term) (v any, err error) {
err = opTerm.Errorf("unknown function %s()", rightChild.Source())
}
} else {
err = assignValue(ctx, leftTerm, v)
err = assignValue(ctx, leftTerm, v, deepCopy)
}
} else {
err = assignValue(ctx, leftTerm, v)
err = assignValue(ctx, leftTerm, v, deepCopy)
}
}
if err != nil {
@@ -203,7 +226,7 @@ func evalOpAssign(ctx kern.ExprContext, opTerm *scan.Term) (v any, err error) {
err = opTerm.Errorf("unsupported assign operator %q", opTerm.Source())
}
if err == nil {
err = assignValue(ctx, leftTerm, v)
err = assignValue(ctx, leftTerm, v, false)
}
}
}
@@ -213,6 +236,7 @@ func evalOpAssign(ctx kern.ExprContext, opTerm *scan.Term) (v any, err error) {
// init
func init() {
scan.RegisterTermConstructor(scan.SymEqual, newAssignTerm)
scan.RegisterTermConstructor(scan.SymColonEqual, newDeepCopyAssignTerm)
scan.RegisterTermConstructor(scan.SymPlusEqual, newOpAssignTerm)
scan.RegisterTermConstructor(scan.SymMinusEqual, newOpAssignTerm)
scan.RegisterTermConstructor(scan.SymStarEqual, newOpAssignTerm)