[procedure] type-of object

Returns a symbol name for the type of object.

[procedure] coerce object result-type [default-proc]

Converts and returns object to result-type.

• result-type is a symbol.
• default-proc is (-> object-type-symbol object result-type-symbol object) and is invoked when coercion fails.
• Builtin types are char, number, string, symbol, list, and vector.

[procedure] coerce-all list-of-object list-of-result-type [default-proc]

Returns a list of every element of list-of-object coerced to the corresponding element of list-of-result-type.

• default-proc and result-type are as for coerce.

[procedure] extend-coerce identifier predicate convertor

Extends the domain of coerce with the type definition {identifier predicate convertor}.

• identifier is a symbol.
• predicate is a procedure, (-> object boolean), testing whether the argument is a type.
• convertor is a procedure, (-> object symbol on-error object), converting from the type to a result type.
• The convertor must invoke (on-error) when conversion not possible. Usually case-coerce would be used to create the convertor, which automatically handles calling of the on-error parameter.

[procedure] composite-coerce-extension identifier predicate convertor

Extends the domain of an existing coerce extension.

• identifier, predicate, and convertor are as for extend-coerce.
• The new convertor is try'ed before the existing procedure, then the existing procedure is try'ed "on-error".
• Should the new predicate and existing predicate be eq? the predicates are not "composited" using or.

[procedure] remove-coerce-extension identifier

Delete any existing coerce extension for identifier.

[procedure] make-case-coerce convertor [alist]

Returns a coercion procedure for use with extend-coerce

• convertor is a coercion procedure, (-> object symbol on-error object).
• alist is a list of (symbol . (-> object object)).

[macro] case-coerce case ...

Returns a coercion procedure for use with extend-coerce.

• case is of the form ((symbol ...) expression ...), or (else expression ...)
• The variable object is bound to the object to coerce within the case-body, case ....
• The variable on-error is bound to a thunk within the case-body, case ..., to invoke on error.