True if numbers n1, n2 are roughly equal; that is to say, equal to within tolerance (defaults to one part in a million).

If object is not of kind-type expected, throws an IllegalArgumentException with an appropriate message; otherwise, returns object. If checkfn is supplied, it should be a function which tests whether the object is of the expected kind-type.

Macro, so that the exception is thrown from the calling function.

If some item on sequence s is not of the expected kind-type, throws an IllegalArgumentException with an appropriate message; otherwise, returns object. If checkfn is supplied, it should be a function which tests whether the object is of the expected kind-type.

Macro, so that the exception is thrown from the calling function.

Recursively merges maps. If vals are not maps, the last value wins.

Identify the type of an object, e.g. for logging. If it has a :kind key, it’s one of ours, and that’s what we want. Otherwise, we want its type; but the type of nil is nil, which doesn’t get printed when assembling error ,essages, so return “nil”.

If string s is more than n characters long, return the first n characters; otherwise, return s.