Dep.ReaderAdvice.Basic

This module contains basic examples advices.

BEWARE! These are provided for illustrative purposes only, they strive for simplicity and not robustness or efficiency.

Basic advices

returnMempty :: forall ca env m r. (Monad m, Monoid r) => Advice ca env m r

Makes functions discard their result and always return mempty.

printArgs :: forall env m r. MonadIO m => Handle -> String -> Advice Show env m r

Given a Handle and a prefix string, makes functions print their arguments to the Handle.

Synthetic call stacks

type MethodName = String

type StackFrame = NonEmpty (TypeRep, MethodName)

The typeable representation of the record which contains the invoked function, along with the field name of the invoked function.

type SyntheticCallStack = [StackFrame]

class HasSyntheticCallStack e where

Class of environments that carry a SyntheticCallStack value that can be modified.

Methods

callStack :: forall f. Functor f => (SyntheticCallStack -> f SyntheticCallStack) -> e -> f e

A lens from the environment to the call stack.

Instances

HasSyntheticCallStack SyntheticCallStack

The trivial case, useful when SyntheticCallStack is the environment type of a ReaderT.

Defined in Dep.SimpleAdvice.Basic

Methods

callStack :: Functor f => (SyntheticCallStack -> f SyntheticCallStack) -> SyntheticCallStack -> f SyntheticCallStack

HasSyntheticCallStack s => HasSyntheticCallStack (Const s x)

Defined in Dep.SimpleAdvice.Basic

Methods

callStack :: Functor f => (SyntheticCallStack -> f SyntheticCallStack) -> Const s x -> f (Const s x)

HasSyntheticCallStack s => HasSyntheticCallStack (Constant s x)

Defined in Dep.SimpleAdvice.Basic

Methods

callStack :: Functor f => (SyntheticCallStack -> f SyntheticCallStack) -> Constant s x -> f (Constant s x)

type SyntheticStackTrace = NonEmpty StackFrame

data SyntheticStackTraceException

Wraps an exception along with a SyntheticCallStack.

Constructors

SyntheticStackTraceException SomeException SyntheticStackTrace

Instances

Exception SyntheticStackTraceException

Defined in Dep.SimpleAdvice.Basic

Methods

toException :: SyntheticStackTraceException -> SomeException

fromException :: SomeException -> Maybe SyntheticStackTraceException

displayException :: SyntheticStackTraceException -> String

Show SyntheticStackTraceException

Defined in Dep.SimpleAdvice.Basic

Methods

showsPrec :: Int -> SyntheticStackTraceException -> ShowS

show :: SyntheticStackTraceException -> String

showList :: [SyntheticStackTraceException] -> ShowS

keepCallStack

Arguments

:: (MonadUnliftIO m, HasSyntheticCallStack env, Exception e)

=> (SomeException -> Maybe e)

A selector for the kinds of exceptions we want to catch. For example fromException @IOError.

-> NonEmpty (TypeRep, MethodName)

The path to the current component/method in the environment. It will be usually obtained through adviseRecord.

-> Advice ca env m r

If the environment carries a SyntheticCallStack, make advised functions add themselves to the SyntheticCallStack before they start executing.

Caught exceptions are rethrown wrapped in SyntheticStackTraceExceptions, with the current SyntheticCallStack added.