71 lines
1.7 KiB
Go
71 lines
1.7 KiB
Go
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// Copyright (c) 2024 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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//-------- export all term
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func newSelectorTerm(tk *Token) (inst *term) {
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return &term{
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tk: *tk,
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class: classOperator,
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kind: kindUnknown,
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children: make([]*term, 0, 3),
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position: posMultifix,
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priority: priSelector,
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evalFunc: evalSelector,
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}
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}
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func isSelectorCase(ctx exprContext, exprValue, caseSel any, caseIndex int) (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, false)
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} else {
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filterList := caseData.filterList.children
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if len(filterList) == 0 && exprValue == int64(caseIndex) {
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selectedValue, err = caseData.caseExpr.Eval(ctx, false)
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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, false)
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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 exprContext, self *term) (v any, err error) {
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var exprValue any
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// var caseList []*term
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if err = self.checkOperands(); err != nil {
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return
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}
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exprTerm := self.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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caseList := self.children[1:]
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for i, caseTerm := range caseList {
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caseSel := caseTerm.value()
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if v, err = isSelectorCase(ctx, exprValue, caseSel, i); err != nil || v != nil {
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break
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}
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}
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if err == nil && v == nil {
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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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registerTermConstructor(SymSelector, newSelectorTerm)
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}
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