55 lines
1.1 KiB
Go
55 lines
1.1 KiB
Go
// Copyright (c) 2024-2026 Celestino Amoroso (celestino.amoroso@gmail.com).
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// All rights reserved.
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// operator-map.go
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package expr
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import (
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"fmt"
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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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//-------- map term
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func newMapTerm(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, 2),
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Position: scan.PosInfix,
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Priority: scan.PriIterOp,
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EvalFunc: evalMap,
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}
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}
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func evalMap(ctx kern.ExprContext, opTerm *scan.Term) (v any, err error) {
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// var leftValue, rightValue any
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var leftValue any
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var it kern.Iterator
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// var item any
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var ok bool
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if err = opTerm.CheckOperands(); err != nil {
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return
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}
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if leftValue, err = opTerm.Children[0].Compute(ctx); err != nil {
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return
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}
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if it, ok = leftValue.(kern.Iterator); !ok {
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if it, err = NewIterator(ctx, leftValue, nil); err != nil {
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return nil, fmt.Errorf("left operand of MAP must be an iterable data-source; got %s", kern.TypeName(leftValue))
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}
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}
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v, err = NewIterIter(it, ctx, opTerm.Children[1:])
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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.SymKwMap, newMapTerm)
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}
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