pretty-simple-2.2.0.1: pretty printer for data types with a 'Show' instance.

Copyright | (c) Dennis Gosnell 2017
License | BSD-style (see LICENSE file)
Maintainer | cdep.illabout@gmail.com
Stability | experimental
Portability | POSIX
Safe Haskell | None
Language | Haskell2010

Debug.Pretty.Simple

Contents

- Trace with color on dark background
- Trace without color

Description

This module contains the same functionality with Prelude's Debug.Trace module, with pretty printing the debug strings.

Warning: This module also shares the same unsafety of Debug.Trace module.

Synopsis

- pTrace :: String -> a -> a
- pTraceId :: String -> String
- pTraceShow :: Show a => a -> b -> b
- pTraceShowId :: Show a => a -> a
- pTraceIO :: String -> IO ()
- pTraceM :: Applicative f => String -> f ()
- pTraceShowM :: (Show a, Applicative f) => a -> f ()
- pTraceStack :: String -> a -> a
- pTraceEvent :: String -> a -> a
- pTraceEventIO :: String -> IO ()
- pTraceMarker :: String -> a -> a
- pTraceMarkerIO :: String -> IO ()
- pTraceNoColor :: String -> a -> a
- pTraceIdNoColor :: String -> String
- pTraceShowNoColor :: Show a => a -> b -> b
- pTraceShowIdNoColor :: Show a => a -> a
- pTraceMNoColor :: Applicative f => String -> f ()
- pTraceShowMNoColor :: (Show a, Applicative f) => a -> f ()
- pTraceStackNoColor :: String -> a -> a
- pTraceEventNoColor :: String -> a -> a
- pTraceEventIONoColor :: String -> IO ()
- pTraceMarkerNoColor :: String -> a -> a
- pTraceMarkerIONoColor :: String -> IO ()
- pTraceIONoColor :: String -> IO ()

# Trace with color on dark background

pTrace :: String -> a -> a Source #

The `pTrace` function pretty prints the trace message given as its first argument, before returning the second argument as its result.

For example, this returns the value of `f x` but first outputs the message.

    pTrace ("calling f with x = " ++ show x) (f x)

The `pTrace` function should only be used for debugging, or for monitoring execution. The function is not referentially transparent: its type indicates that it is a pure function but it has the side effect of outputting the trace message.

Since: 2.0.1.0

pTraceId :: String -> String Source #

Like `pTrace` but returns the message instead of a third value.

Since: 2.0.1.0

pTraceShow :: Show a => a -> b -> b Source #

Like `pTrace`, but uses `show` on the argument to convert it to a `String`.

This makes it convenient for printing the values of interesting variables or expressions inside a function. For example here we print the value of the variables `x` and `z`:

    f x y =
        pTraceShow (x, z) $ result
      where
        z = ...
        ...

Since: 2.0.1.0

pTraceShowId :: Show a => a -> a Source #

Like `pTraceShow` but returns the shown value instead of a third value.

Since: 2.0.1.0

pTraceIO :: String -> IO () Source #

The `pTraceIO` function outputs the trace message from the IO monad. This sequences the output with respect to other IO actions.

Since: 2.0.1.0

pTraceM :: Applicative f => String -> f () Source #

Like `pTrace` but returning unit in an arbitrary `Applicative` context. Allows for convenient use in do-notation.

Note that the application of `pTraceM` is not an action in the `Applicative` context, as `pTraceIO` is in the `IO` type. While the fresh bindings in the following example will force the `traceM` expressions to be reduced every time the `do`-block is executed, `traceM "not crashed"` would only be reduced once, and the message would only be printed once. If your monad is in `MonadIO`, `liftIO . pTraceIO` may be a better option.

    ... = do
      x <- ...
      pTraceM $ "x: " ++ show x
      y <- ...
      pTraceM $ "y: " ++ show y

Since: 2.0.1.0

pTraceShowM :: (Show a, Applicative f) => a -> f () Source #

Like `pTraceM`, but uses `show` on the argument to convert it to a `String`.

    ... = do
      x <- ...
      pTraceShowM $ x
      y <- ...
      pTraceShowM $ x + y

Since: 2.0.1.0

pTraceStack :: String -> a -> a Source #

like `pTrace`, but additionally prints a call stack if one is available.

In the current GHC implementation, the call stack is only available if the program was compiled with `-prof`; otherwise `pTraceStack` behaves exactly like `pTrace`. Entries in the call stack correspond to `SCC` annotations, so it is a good idea to use `-fprof-auto` or `-fprof-auto-calls` to add SCC annotations automatically.

Since: 2.0.1.0

pTraceEvent :: String -> a -> a Source #

The `pTraceEvent` function behaves like `trace` with the difference that the message is emitted to the eventlog, if eventlog profiling is available and enabled at runtime.

It is suitable for use in pure code. In an IO context use `pTraceEventIO` instead.

Note that when using GHC's SMP runtime, it is possible (but rare) to get duplicate events emitted if two CPUs simultaneously evaluate the same thunk that uses `pTraceEvent`.

Since: 2.0.1.0

pTraceEventIO :: String -> IO () Source #

The `pTraceEventIO` function emits a message to the eventlog, if eventlog profiling is available and enabled at runtime.

Compared to `pTraceEvent`, `pTraceEventIO` sequences the event with respect to other IO actions.

Since: 2.0.1.0

pTraceMarker :: String -> a -> a Source #

The `pTraceMarker` function emits a marker to the eventlog, if eventlog profiling is available and enabled at runtime. The `String` is the name of the marker. The name is just used in the profiling tools to help you keep clear which marker is which.

This function is suitable for use in pure code. In an IO context use `pTraceMarkerIO` instead.

Note that when using GHC's SMP runtime, it is possible (but rare) to get duplicate events emitted if two CPUs simultaneously evaluate the same thunk that uses `pTraceMarker`.

Since: 2.0.1.0

pTraceMarkerIO :: String -> IO () Source #

The `pTraceMarkerIO` function emits a marker to the eventlog, if eventlog profiling is available and enabled at runtime.

Compared to `pTraceMarker`, `pTraceMarkerIO` sequences the event with respect to other IO actions.

Since: 2.0.1.0

# Trace without color

pTraceNoColor :: String -> a -> a Source #

Similar to `pTrace`, but without color.

    >>> pTraceNoColor "wow" ()
    wow
    ()

Since: 2.0.2.0

pTraceIdNoColor :: String -> String Source #

Similar to `pTraceId`, but without color.

    >>> pTraceIdNoColor "(1, 2, 3)" `seq` ()
    ( 1
    , 2
    , 3
    )
    ()

Since: 2.0.2.0

pTraceShowNoColor :: Show a => a -> b -> b Source #

Similar to `pTraceShow`, but without color.

    >>> import qualified Data.Map as M
    >>> pTraceShowNoColor (M.fromList [(1, True)]) ()
    fromList
        [
            ( 1
            , True
            )
        ]
    ()

Since: 2.0.2.0

pTraceShowIdNoColor :: Show a => a -> a Source #

Similar to `pTraceShowId`, but without color.

    >>> import qualified Data.Map as M
    >>> pTraceShowIdNoColor (M.fromList [(1, True)]) `seq` ()
    fromList
        [
            ( 1
            , True
            )
        ]
    ()

Since: 2.0.2.0

pTraceMNoColor :: Applicative f => String -> f () Source #

Similar to `pTraceM`, but without color.

    >>> pTraceMNoColor "wow"
    wow

Since: 2.0.2.0

pTraceShowMNoColor :: (Show a, Applicative f) => a -> f () Source #

Similar to `pTraceShowM`, but without color.

    >>> pTraceShowMNoColor [1,2,3]
    [ 1
    , 2
    , 3
    ]

Since: 2.0.2.0

pTraceStackNoColor :: String -> a -> a Source #

Similar to `pTraceStack`, but without color.

    >>> pTraceStackNoColor "wow" () `seq` ()
    wow
    ()

Since: 2.0.2.0

pTraceEventNoColor :: String -> a -> a Source #

Similar to `pTraceEvent`, but without color.

Since: 2.0.2.0

pTraceEventIONoColor :: String -> IO () Source #

Similar to `pTraceEventIO`, but without color.

Since: 2.0.2.0

pTraceMarkerNoColor :: String -> a -> a Source #

Similar to `pTraceMarker`, but without color.

Since: 2.0.2.0

pTraceMarkerIONoColor :: String -> IO () Source #

Similar to `pTraceMarkerIO`, but without color.

Since: 2.0.2.0

pTraceIONoColor :: String -> IO () Source #

Similar to `pTraceIO`, but without color.

    >>> pTraceIONoColor "(1, 2, 3)"
    ( 1
    , 2
    , 3
    )

Since: 2.0.2.0