bug.ipynb

{
 "metadata": {
  "language": "haskell",
  "name": "",
  "signature": "sha256:b767382b75fdfbfda5140fb6033c141304b5b103f2384f7169e9daa68c21acce"
 },
 "nbformat": 3,
 "nbformat_minor": 0,
 "worksheets": [
  {
   "cells": [
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      ":set -XTypeFamilies\n",
      ":set -XDataKinds"
     ],
     "language": "python",
     "metadata": {
      "hidden": false
     },
     "outputs": [],
     "prompt_number": 1
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "import Data.Metrology\n",
      "import Data.Metrology.SI\n",
      "import Data.Metrology.Show"
     ],
     "language": "python",
     "metadata": {
      "hidden": false
     },
     "outputs": [],
     "prompt_number": 2
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "data AngleDim = AngleDim\n",
      "data Radian = Radian\n",
      "\n",
      "instance Dimension AngleDim where\n",
      "  type DimFactorsOf AngleDim = '[]\n",
      "\n",
      "type instance DefaultUnitOfDim AngleDim = Radian\n",
      "\n",
      "instance Unit Radian where\n",
      "  type BaseUnit Radian = Canonical\n",
      "  type DimOfUnit Radian = AngleDim\n",
      "  type UnitFactorsOf Radian = '[]"
     ],
     "language": "python",
     "metadata": {
      "hidden": false
     },
     "outputs": [],
     "prompt_number": 3
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "0.3 % Radian"
     ],
     "language": "python",
     "metadata": {},
     "outputs": [
      {
       "metadata": {},
       "output_type": "display_data",
       "text": [
        "0.3"
       ]
      }
     ],
     "prompt_number": 4
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "instance Show Radian where\n",
      "  show _ = \"rad\""
     ],
     "language": "python",
     "metadata": {},
     "outputs": [],
     "prompt_number": 5
    },
    {
     "cell_type": "code",
     "collapsed": false,
     "input": [
      "0.3 % Radian"
     ],
     "language": "python",
     "metadata": {
      "hidden": false
     },
     "outputs": [
      {
       "html": [
        "<span class='err-msg'>Could not deduce (Unit Radian) arising from a use of \u2018%\u2019<br/>from the context (Fractional n) bound by the inferred type of it :: Fractional n => Qu '[] 'DefaultLCSU n at <interactive>:1:1-12<br/>In the expression: 0.3 % Radian<br/>In an equation for \u2018it\u2019: it = 0.3 % Radian</span>"
       ],
       "metadata": {},
       "output_type": "display_data",
       "text": [
        "Could not deduce (Unit Radian) arising from a use of \u2018%\u2019\n",
        "from the context (Fractional n) bound by the inferred type of it :: Fractional n => Qu '[] 'DefaultLCSU n at <interactive>:1:1-12\n",
        "In the expression: 0.3 % Radian\n",
        "In an equation for \u2018it\u2019: it = 0.3 % Radian"
       ]
      }
     ],
     "prompt_number": 6
    }
   ],
   "metadata": {}
  }
 ]
}

See gibiansky/IHaskell#367 and goldfirere/units#46