structural-typing.assist.defaults

User-visible default behaviors.

Much of this is gathered into the catchall structural-typing.types namespace.

default-error-handler

This error handler takes the output of type checking (a sequence of oopsies) and prints each one’s explanation to standard output. It returns nil, allowing constructs like this:

 (some-> (type/built-like :Patient p)
         (assoc :handled true)
         ...)
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default-predicate-explainer

(default-predicate-explainer {:keys [predicate-string leaf-value], :as expred})

Converts an oopsie into a string of the form “%s should be %s; it is %s”.

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default-success-handler

The default success handler just returns the original candidate structure passed to built-like.

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throwing-error-handler

(throwing-error-handler oopsies)

In contrast to the default error handler, this one throws a java.lang.Exception whose message is the concatenation of the explanations of the oopsies.

To make all type mismatches throw failures, do this:

   (global-type/on-error! type/throwing-error-handler) ; for the global type repo
   (type/replace-error-handler type-repo type/throwing-error-handler) ; local repo
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