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6.11 Error Types ¶

There are not many cases in which FSet signals an error; most operations that can fail return a success flag as an additional value instead. But there are a few error cases.

Condition: lookup-error (error) ¶

An abstract superclass for errors signalled by lookup methods.

Condition: map-domain-error (lookup-error) map key ¶

The condition signalled when lookup is called on a map and a key that is not in the map, and the map has no default.

Condition: seq-bounds-error (lookup-error) seq index ¶

The condition signalled when lookup is called on a seq and an index that is out of bounds for the seq, and the seq has no default.

Condition: empty-seq-error (lookup-error) seq ¶

The condition signalled when first or last is called on an empty seq, and the seq has no default.

Condition: tuple-value-type-error (type-error) key datum expected-type ¶

The condition signalled when with is called on a tuple, key, and value, such that the value is not of the correct type for the key.

Condition: tuple-key-unbound-error (lookup-error) tuple key ¶

The condition signalled when lookup is called on a tuple and a key, when the key is not in the tuple.