https://github.com/ncaq/debug-trace-var

You do not have to write variable names twice in Debug.Trace
https://github.com/ncaq/debug-trace-var

haskell

Last synced: 29 days ago
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You do not have to write variable names twice in Debug.Trace

• Host: GitHub
• URL: https://github.com/ncaq/debug-trace-var
• Owner: ncaq
• License: mit
• Created: 2018-06-08T10:27:48.000Z (over 6 years ago)
• Default Branch: master
• Last Pushed: 2018-06-09T15:10:41.000Z (over 6 years ago)
• Last Synced: 2024-04-26T02:31:01.223Z (9 months ago)
• Topics: haskell
• Language: Haskell
• Size: 7.81 KB
• Stars: 3
• Watchers: 4
• Forks: 1
• Open Issues: 0
• Metadata Files:
  • Readme: README.md
  • Changelog: ChangeLog.md
  • License: LICENSE

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[![Hackage](https://img.shields.io/hackage/v/debug-trace-var.svg)](https://hackage.haskell.org/package/debug-trace-var)

[![Stackage LTS](http://stackage.org/package/debug-trace-var/badge/lts)](http://stackage.org/lts/package/debug-trace-var)

# debug-trace-var

When writing print debug, we often write.

~~~hs

import           Debug.Trace

main :: IO ()

main = do

  let a = 1

  traceIO $ "a = " ++ show a

~~~

This is troublesome to describe the name of the variable twice.

With debug-trace-var you write variables only once.

~~~hs

{-# LANGUAGE QuasiQuotes #-}

import           Debug.Trace.Var

main :: IO ()

main = do

  let a = 1

  [traceVarIO|a|]

~~~

or

~~~hs

{-# LANGUAGE TemplateHaskell #-}

import           Debug.Trace.Var

main :: IO ()

main = let a = 1 :: Int

       in $(traceMTH 'a)

~~~

You may avoid name quotes that are confusing with character literals,

Or often it may be to avoid the QuasiQuotes to destroy the syntax highlight of the text editor.

# Example

~~~hs

{-# LANGUAGE QuasiQuotes     #-}

{-# LANGUAGE TemplateHaskell #-}

import           Debug.Trace.Var

-- > a

-- n = 1

-- s = "あ"

a :: IO ()

a = let n = 1

        s = "あ"

    in [traceVar|n|] ([traceVar|s|] return ())

-- > b

-- "n = 1

-- n = 1"

b :: String

b = let n = 1

    in [traceVarId|n|]

-- > c

-- n = 344

c :: IO ()

c = let n = 344

    in [traceStackVar|n|] (return ())

-- > d

-- n = 344

-- n = 344

d :: IO ()

d = do

  let n = 344

  [traceVarIO|n|]

  [traceVarIO|n|]

-- > e

-- n = 344

e :: IO ()

e = do

  let n = 344

  [traceVarM|n|]

-- > f

-- n = 344

f :: IO ()

f = let n = 344

    in $(traceMTH 'n)

~~~

# Motivation

I wanted to use Template Haskell.

# One point advice

You can use [ndmitchell/debug: Haskell library for debugging](https://github.com/ndmitchell/debug)