87 lines
2.1 KiB
Go
87 lines
2.1 KiB
Go
// Copyright (c) 2024-2026 Celestino Amoroso (celestino.amoroso@gmail.com).
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// All rights reserved.
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// operator-selector.go
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package expr
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import (
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"git.portale-stac.it/go-pkg/expr/kern"
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"git.portale-stac.it/go-pkg/expr/scan"
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)
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//-------- selector term
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func newSelectorTerm(tk *scan.Token) (inst *scan.Term) {
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return &scan.Term{
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Tk: *tk,
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Children: make([]*scan.Term, 0, 3),
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Position: scan.PosInfix,
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Priority: scan.PriSelector,
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EvalFunc: evalSelector,
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}
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}
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func trySelectorCase(ctx kern.ExprContext, exprValue, caseSel any, caseIndex int) (match bool, selectedValue any, err error) {
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caseData, _ := caseSel.(*selectorCase)
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if caseData.filterList == nil {
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selectedValue, err = caseData.caseExpr.Eval(ctx)
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match = true
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} else if filterList, ok := caseData.filterList.Value().([]*scan.Term); ok {
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if len(filterList) == 0 {
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var valueAsInt = int64(0)
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if b, ok := exprValue.(bool); ok {
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if !b {
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valueAsInt = 1
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}
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} else if valueAsInt, ok = exprValue.(int64); !ok {
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return
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}
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if valueAsInt == int64(caseIndex) {
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selectedValue, err = caseData.caseExpr.Eval(ctx)
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match = true
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}
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} else {
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var caseValue any
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for _, caseTerm := range filterList {
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if caseValue, err = caseTerm.Compute(ctx); err != nil || caseValue == exprValue {
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selectedValue, err = caseData.caseExpr.Eval(ctx)
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match = true
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break
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}
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}
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}
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}
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return
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}
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func evalSelector(ctx kern.ExprContext, opTerm *scan.Term) (v any, err error) {
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var exprValue any
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var match bool
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if err = opTerm.CheckOperands(); err != nil {
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return
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}
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exprTerm := opTerm.Children[0]
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if exprValue, err = exprTerm.Compute(ctx); err != nil {
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return
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}
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caseListTerm := opTerm.Children[1]
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caseList, _ := caseListTerm.Value().([]*scan.Term)
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for i, caseTerm := range caseList {
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caseSel := caseTerm.Value()
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if match, v, err = trySelectorCase(ctx, exprValue, caseSel, i); err != nil || match {
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break
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}
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}
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if err == nil && !match {
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err = exprTerm.Tk.Errorf("no case catches the value (%v) of the selection expression", exprValue)
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}
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return
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}
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// init
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func init() {
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scan.RegisterTermConstructor(scan.SymSelector, newSelectorTerm)
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}
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