21 lines
428 B
Go
21 lines
428 B
Go
package lambda
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import "git.maximhutz.com/max/lambda/pkg/set"
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func GetFreeVariables(e Expression) *set.Set[string] {
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switch e := e.(type) {
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case *Variable:
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return set.New(e.Value)
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case *Abstraction:
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vars := GetFreeVariables(e.Body)
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vars.Remove(e.Parameter)
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return vars
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case *Application:
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vars := GetFreeVariables(e.Abstraction)
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vars.Merge(GetFreeVariables(e.Argument))
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return vars
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default:
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return nil
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}
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}
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