M.V. Hutz
7318c0dac4
- Change Abstraction, Application, and Variable to use private fields with getter methods - Return value types instead of pointers from constructors - Update all type switches to match value types instead of pointer types - Remove pointer equality optimizations (not applicable with immutable values) - Return empty set instead of nil from GetFreeVariables default case
33 lines
671 B
Go
33 lines
671 B
Go
package lambda
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func ReduceOnce(e Expression) (Expression, bool) {
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switch e := e.(type) {
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case Abstraction:
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body, reduced := ReduceOnce(e.Body())
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if reduced {
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return NewAbstraction(e.Parameter(), body), true
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}
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return e, false
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case Application:
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if fn, fnOk := e.Abstraction().(Abstraction); fnOk {
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return Substitute(fn.Body(), fn.Parameter(), e.Argument()), true
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}
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abs, reduced := ReduceOnce(e.Abstraction())
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if reduced {
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return NewApplication(abs, e.Argument()), true
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}
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arg, reduced := ReduceOnce(e.Argument())
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if reduced {
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return NewApplication(e.Abstraction(), arg), true
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}
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return e, false
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default:
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return e, false
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}
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}
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