33 lines
598 B
Go
33 lines
598 B
Go
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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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return &term{
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tk: *tk,
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class: classVar,
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kind: kindUnknown,
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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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}
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// -------- eval func
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func evalVar(ctx exprContext, self *term) (v any, err error) {
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var exists bool
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if v, exists = ctx.GetValue(self.tk.source); !exists {
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err = fmt.Errorf("undefined variable %q", self.tk.source)
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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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