error stops execution and displays an error message.
This is thrown when the user calls error. The String is the argument given to error.
C-specific Marshalling support: Handling of C "errno" error codes.
Routines for testing return values and raising a userError exception in case of values indicating an error state.
Standard IO Errors.
* Computation type: Computations which may fail or throw exceptions.
* Binding strategy: Failure records information about the cause/location of the failure. Failure values bypass the bound function, other values are used as inputs to the bound function.
* Useful for: Building computations from sequences of functions that may fail or using exception handling to structure error handling.
* Zero and plus: Zero is represented by an empty error and the plus operation executes its second argument if the first fails.
* Example type: Either String a
The Error monad (also called the Exception monad).
This monad transformer adds the ability to fail or throw exceptions to a monad.
A sequence of actions succeeds, producing a value, only if all the actions in the sequence are successful. If one fails with an error, the rest of the sequence is skipped and the composite action fails with that error.
If the value of the error is not required, the variant in Control.Monad.Trans.Maybe may be used instead.
An exception to be thrown.
Minimal complete definition: noMsg or strMsg.
GL/GLU errors consist of a general error category and a description of what went wrong.
This philosophy behind this package is that it is often better to find out all of the errors that have occured in a computation and report them simultaneously, rather than aborting as soon as the first error is encountered. Towards this end, this module supplies a type of combinable error messages so that all of the errors from subcomputations can be gathered and presented together.
New in version 1.1: Removed Monoid instance for Doc (it should now be supplied by ansi-wl-pprint), added ErrorMessageOr type alias.
General GL/GLU error categories
Workaround so that we can have a Haskell 98 instance Error String.
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