Text.PrettyPrint.PrettyTable

This module features methods that can be used to print values contained inside a list / a map / or a vector in a tabular format.

Example of output

ticker     price          marketCap
"YHOO"     42.2910101         4.0e10
"GOOG"     774.210101      5.3209e11
"AMZN"     799.161717      3.7886e11

Basic Steps

• Declare the new data type that will be the element of a list, map or a vector.
• The type could be a basic data constructor or a record type
• Derive Generic and Data for the type
• Make the type an instance of Tabilize
• Create values of the type and add them to a list, map or vector
• Use one of the printList, printMap and printVector methods to print the values in a tabular format

Usage Example

-- Printing a list of records
:set -XDeriveGeneric
:set -XDeriveDataTypeable

import qualified GHC.Generics as G
import Data.Data

-- A record structure that will in a list
data Stock = Stock {ticker::String, price::Double, marketCap::Double} deriving (Data, G.Generic)

-- Create an instance of Tabilize
instance Tabilize Stock

let yahoo =  Stock {ticker="YHOO", price=42.29101010, marketCap=40e9}
let google = Stock {ticker="GOOG", price=774.210101, marketCap=532.09e9}
let amazon = Stock {ticker="AMZN", price=799.161717, marketCap=378.86e9}

-- List of records
let tickers = [yahoo, google, amazon]

printList tickers

ticker     price          marketCap
"YHOO"     42.2910101         4.0e10
"GOOG"     774.210101      5.3209e11
"AMZN"     799.161717      3.7886e11

Tabilize methods

class Data a => Tabilize a where

Specialized class that provides default methods methods to print List, Map or Vector values as a pretty table

Methods

listToBox :: [a] -> [[Box]]

Return a list of values wrapped in a Box. Each entry in input is assumed to be a list of records keyed by any data type. The first entry in the list of values will be used to infer the names of fields

mapToBox :: Show b => Map b a -> [[Box]]

Return a list of values wrapped in Box. Each entry in input is assumed to be a list of records keyed by any data type. The first entry in the list of values will be used to infer the names of fields

vectorToBox :: Vector a -> [[Box]]

Return a list of values wrapped in Box. Each entry in input is assumed to be a list of records keyed by any data type. The first entry in the list of values will be used to infer the names of fields

listToBox :: (Generic a, GTabilize (Rep a)) => [a] -> [[Box]]

Return a list of values wrapped in a Box. Each entry in input is assumed to be a list of records keyed by any data type. The first entry in the list of values will be used to infer the names of fields

mapToBox :: (Generic a, GTabilize (Rep a), Show b) => Map b a -> [[Box]]

Return a list of values wrapped in Box. Each entry in input is assumed to be a list of records keyed by any data type. The first entry in the list of values will be used to infer the names of fields

vectorToBox :: (Generic a, GTabilize (Rep a)) => Vector a -> [[Box]]

Return a list of values wrapped in Box. Each entry in input is assumed to be a list of records keyed by any data type. The first entry in the list of values will be used to infer the names of fields

printMap :: Show b => Map b a -> IO ()

import qualified Data.Map as M
-- declare a Map
data Portfolio = M.Map String Stock
Add the Stock values we create
let p = M.fromList [("YHOO", yahoo), ("GOOG", google), ("AMZN" amazon)]

printMap p

Key        ticker     price          marketCap
"amzn"     "AMZN"     799.161717      3.7886e11
"goog"     "GOOG"     774.210101      5.3209e11
"yhoo"     "YHOO"     42.2910101         4.0e10

printList :: [a] -> IO ()

-- List of records
let tickers = [yahoo, google, amazon]

printList tickers

ticker     price          marketCap
"YHOO"     42.2910101         4.0e10
"GOOG"     774.210101      5.3209e11
"AMZN"     799.161717      3.7886e11

printVector :: Vector a -> IO ()

import qualified Data.Vector as V
-- Vector of records
let tickers = V.fromList [yahoo, google, amazon]

printVector tickers

ticker     price          marketCap
"YHOO"     42.2910101         4.0e10
"GOOG"     774.210101      5.3209e11
"AMZN"     799.161717      3.7886e11

Custom Rendering

In cases, where the printList, printMap or printVector statements are not adequate, the listToBox, vectorToBox and mapToBox methods return the B.Box value. The user can then use some of the methods provided by Text.PrettyPrint.Box module.