# Documentation

Datastructure for representing the "head symbol" of an expression. It is the key of KExprMap. Examples:

• The head of f a is .const f
• The head of let x := 1; f x is .const f
• The head of fun x => fun is .lam

HeadIndex is a very simple index, and is used in situations where we want to find definitionally equal terms, but we want to minimize the search by checking only pairs of terms that have the same HeadIndex.

Instances For

Hash code for a HeadIndex value.

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• One or more equations did not get rendered due to their size.
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Return the number of arguments in the given expression with respect to its HeadIndex

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Convert the given expression into a HeadIndex.

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• = match with | some i => i | none =>