70 lines
1.5 KiB
Go
70 lines
1.5 KiB
Go
// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
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// All rights reserved.
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// operator-pre-inc-dec.go
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package expr
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// -------- pre increment term
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func newPreIncTerm(tk *Token) *term {
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return &term{
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tk: *tk,
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parent: nil,
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children: make([]*term, 0, 1),
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position: posPrefix,
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priority: priIncDec,
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evalFunc: evalPreInc,
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}
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}
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func evalPreInc(ctx ExprContext, opTerm *term) (v any, err error) {
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var childValue any
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if childValue, err = opTerm.evalPrefix(ctx); err != nil {
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return
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}
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if IsInteger(childValue) && opTerm.children[0].symbol() == SymVariable {
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i := childValue.(int64) + 1
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ctx.SetVar(opTerm.children[0].source(), i)
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v = i
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} else {
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err = opTerm.errIncompatibleType(childValue)
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}
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return
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}
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// -------- pre decrement term
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func newPreDecTerm(tk *Token) *term {
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return &term{
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tk: *tk,
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parent: nil,
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children: make([]*term, 0, 1),
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position: posPrefix,
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priority: priIncDec,
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evalFunc: evalPreDec,
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}
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}
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func evalPreDec(ctx ExprContext, opTerm *term) (v any, err error) {
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var childValue any
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if childValue, err = opTerm.evalPrefix(ctx); err != nil {
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return
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}
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if IsInteger(childValue) && opTerm.children[0].symbol() == SymVariable {
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i := childValue.(int64) - 1
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ctx.SetVar(opTerm.children[0].source(), i)
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v = i
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} else {
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err = opTerm.errIncompatibleType(childValue)
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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(SymPreInc, newPreIncTerm)
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registerTermConstructor(SymPreDec, newPreDecTerm)
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}
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