41 lines
789 B
Go
41 lines
789 B
Go
// Copyright (c) 2024 Celestino Amoroso (celestino.amoroso@gmail.com).
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// All rights reserved.
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// operand-var.go
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package expr
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import "fmt"
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// -------- variable term
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func newVarTerm(tk *Token) *term {
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t := &term{
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tk: *tk,
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parent: nil,
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children: nil,
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position: posLeaf,
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priority: priValue,
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evalFunc: evalVar,
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}
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t.tk.Sym = SymVariable
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return t
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}
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// -------- eval func
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func evalVar(ctx ExprContext, opTerm *term) (v any, err error) {
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var exists bool
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name := opTerm.source()
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if v, exists = GetVar(ctx, name); !exists {
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if info, exists := GetFuncInfo(ctx, name); exists {
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v = info.Functor()
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} else {
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err = fmt.Errorf("undefined variable or function %q", name)
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}
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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(SymIdentifier, newVarTerm)
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}
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