Module
Debug.Trace
- Package
- purescript-debug
- Repository
- garyb/purescript-debug
#DebugWarning Source
class DebugWarning
Nullary class used to raise a custom warning for the debug functions.
Instances
(Warn (Text "Debug.Trace usage")) => DebugWarning
#trace Source
trace :: forall b a. DebugWarning => a -> (Unit -> b) -> b
Log any PureScript value to the console for debugging purposes and then
return a value. This will log the value's underlying representation for
low-level debugging, so it may be desireable to show
the value first.
The return value is thunked so it is not evaluated until after the message has been printed, to preserve a predictable console output.
For example:
doSomething = trace "Hello" \_ -> ... some value or computation ...
#traceM Source
traceM :: forall a m. DebugWarning => Monad m => a -> m Unit
Log any PureScript value to the console and return the unit value of the
Monad m
.
#spy Source
spy :: forall a. DebugWarning => String -> a -> a
Logs any value and returns it, using a "tag" or key value to annotate the traced value. Useful when debugging something in the middle of a expression, as you can insert this into the expression without having to break it up.
- Modules
- Debug.
Trace