TextDisplay

The default representation of any type is the string and the show function, which returns a string for each element of an instance of the Show class. But sometimes, it is more intuitive, if a type is represented by a more three-dimensional layout. For that matter, we not only have a show function for many types to come, but also a textFrame converter, where a TextFrame is basically defined as a list of strings of equal length. Similar to the Show type class, we also define a Display type class.

Text frames

type TextFrame = [String]

A TextFrame is a list of strings. But for a correct TextFrame, there are more constraints that have to hold: 1. The strings must all be of equal length. 2. There must be no white space characters in a string, other than the space character ' '.

isNonSpaceWhite :: Char -> Bool

True if the character is any white space character, except the space character itself.

findTextFrameError :: [String] -> Maybe String

A TextFrame is correct iff all its strings are of equal length and (isNonSpaceWhite ch) is false for all characters ch.

correctTextFrame :: [String] -> TextFrame

Turns the argument string list into a correct version by adding spaces. But returns an error in case any string contains a character ch with (isNonSpaceWhite ch). IMPROVE the String instance of Display: new line characters should create new lines in the text frame and what about tabs etc? !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

width :: TextFrame -> Int

The width of a TextFrame [str1,...,strN] is the maximal length of the strings str1,...,strN. In particular,

 (width []) == 0           (width [""]) == 0

height :: TextFrame -> Int

The height of a TextFrame [str1,...,strN] is N.

printTextFrame :: TextFrame -> IO ()

prints its TextFrame argument.

textFrameBox :: TextFrame -> TextFrame

surrounds the text frame with a solid line

textFrameBracket :: TextFrame -> TextFrame

surrounds the text frame with a square bracket

defaultTextFrame :: Show a => a -> TextFrame

(defaultTextFrame x) == [show x]

The Display type class

class Display a where

Methods

textFrame :: a -> TextFrame

display :: a -> IO ()

Instances

Display Bool

Display Char

Display Double

Display Float

Display Int

Display Integer

Display String

Display ()

Display IForm

(Ord a, Display a) => Display [Valuator a]

Display a => Display (PropForm a)

Display a => Display (MultiTruthTable a)

Display a => Display (TruthTable a)

Display a => Display (Valuator a)

Display a => Display (LiteralPair a)

Display a => Display (MixForm a)

Display a => Display (XPCNF a)

Display a => Display (XPDNF a)

Display a => Display (XForm a)

textFrame converts into a TextFrame. display prints the text frame (actually, display = printTextFrame . textFrame, i.e. to define an instance of Display, Actually, when an instance of Display is defined, only textFrame needs to be specified.

Text frame tables

type TextFrameTable = [[TextFrame]]

A TextFrameTable is a list of rows, where each cell is a TextFrame. For example,

 [[["aaa","aaa"],["b","b","b"]],
  [["cccccccc","cccccccc"],["ddddddddd","ddddddddd","ddddddddd"],["eeeee","eeeee","eeeee","eeeee"]],
  [["ff","ff"],[],["ggg","ggg","ggg","ggg"]]]

or, more intuitively in table layout

   "aaa"      "b"
   "aaa"      "b"
              "b"

   "cccccccc" "ddddddddd" "eeeee"
   "cccccccc" "ddddddddd" "eeeee"
              "ddddddddd" "eeeee"
                          "eeeee"

   "ff"                   "ggg"
   "ff"                   "ggg"
                          "ggg"
                          "ggg"

columnWidthList :: TextFrameTable -> [Int]

rowHeightList :: TextFrameTable -> [Int]

Column widths and row heights for the previous example text frame table tft are given by

 (columnWidthList tft) == [8,9,5]
 (rowHeightList tft)   == [3,4,4]

correctTextFrameTable :: TextFrameTable -> TextFrameTable

A TextFrameTable is said to be correct, if (1) each row has the same amount of cells, (2) there is no column of zero width, (3) there is no row of zero height. With correctTextFrameTable we remove these flaws.

bottomAlign :: TextFrameTable -> TextFrameTable

topAlign :: TextFrameTable -> TextFrameTable

centerAlign :: TextFrameTable -> TextFrameTable

leftAlign :: TextFrameTable -> TextFrameTable

rightAlign :: TextFrameTable -> TextFrameTable

middleAlign :: TextFrameTable -> TextFrameTable

A TextFrameTable is said to be normal, if it is correct and each of its TextFrame cells has the width of its according column and the height of its row. To convert a text frame table into a normal one, we need to perform two steps (in arbitrary order):

• A row normalization, which makes all text frame cells in one row of equal height. We use three modes to achieve that: bottomAlign, topAlign and centerAlign.
• A column normalization, which makes all text frame cells in one column of equal width. Again, we have three functions to do that: leftAlign, rightAlign, and middleAlign.

For example, given the correct text frame table tft, we obtain (we use _ for space characters):

   tft =                               leftAlign tft =                      middleAlign (leftAlign tft) =

   "aaa"      "b"         ""           "aaa ____" "b________" "_____"       "aaa_____" "b________" "_____"
   "aaa"      "b"                      "aaa_____" "b________"               "aaa_____" "b________" "_____"
              "b"                                 "b________"               "________" "b________" "_____"

   "cccccccc" "ddddddddd" "eeeee"      "cccccccc" "ddddddddd" "eeeee"       "________" "ddddddddd" "eeeee"
   "cccccccc" "ddddddddd" "eeeee"      "cccccccc" "ddddddddd" "eeeee"       "cccccccc" "ddddddddd" "eeeee"
              "ddddddddd" "eeeee"                 "ddddddddd" "eeeee"       "cccccccc" "ddddddddd" "eeeee"
                          "eeeee"                             "eeeee"       "________" "_________" "eeeee"

   "ff"                   "ggg"        "ff______" "_________" "ggg__"       "________" "_________" "ggg__"
   "ff"                   "ggg"        "ff______"             "ggg__"       "ff______" "_________" "ggg__"
                          "ggg"                               "ggg__"       "ff______" "_________" "ggg__"
                          "ggg"                               "ggg__"       "________" "_________" "ggg__"

normalTextFrameTable :: TextFrameTable -> TextFrameTable

The default way to convert any text frame table into a normal one is defined by the normalTextFrameTable function, which is defined by

 normalTextFrameTable = middleAlign . centerAlign . correctTextFrameTable

plainMerge :: TextFrameTable -> TextFrame

gridMerge :: TextFrameTable -> TextFrame

There is a plainMerge and a gridMerge to turn a normal text frame table into a single text frame. For the example,

   tft =                              plainMerge tft =               gridMerge tft =

   "___aaa__" "____b____" "_____"     "___aaa______b_________"       "+----------+-----------+-------+"
   "___aaa__" "____b____" "_____"     "___aaa______b_________"       "| ___aaa__ | ____b____ | _____ |"
   "________" "____b____" "_____"     "____________b_________"       "| ___aaa__ | ____b____ | _____ |"
                                      "________dddddddddeeeee"       "| ________ | ____b____ | _____ |"
   "________" "ddddddddd" "eeeee"     "ccccccccdddddddddeeeee"       "+----------+-----------+-------+"
   "cccccccc" "ddddddddd" "eeeee"     "ccccccccdddddddddeeeee"       "| ________ | ddddddddd | eeeee |"
   "cccccccc" "ddddddddd" "eeeee"     "_________________eeeee"       "| cccccccc | ddddddddd | eeeee |"
   "________" "_________" "eeeee"     "__________________ggg_"       "| cccccccc | ddddddddd | eeeee |"
                                      "___ff_____________ggg_"       "| ________ | _________ | eeeee |"
   "________" "_________" "_ggg_"     "___ff_____________ggg_"       "+----------+-----------+-------+"
   "___ff___" "_________" "_ggg_"     "__________________ggg_"       "| ________ | _________ | _ggg_ |"
   "___ff___" "_________" "_ggg_"                                    "| ___ff___ | _________ | _ggg_ |"
   "________" "_________" "_ggg_"                                    "| ___ff___ | _________ | _ggg_ |"
                                                                     "| ________ | _________ | _ggg_ |"
                                                                     "+----------+-----------+-------+"