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1. class Show a

   quaalude	Essentials

   Conversion of values to readable Strings. Derived instances of Show have the following properties, which are compatible with derived instances of Read:

   • The result of show is a syntactically correct Haskell expression containing only constants, given the fixity declarations in force at the point where the type is declared. It contains only the constructor names defined in the data type, parentheses, and spaces. When labelled constructor fields are used, braces, commas, field names, and equal signs are also used.
   • If the constructor is defined to be an infix operator, then showsPrec will produce infix applications of the constructor.
   • the representation will be enclosed in parentheses if the precedence of the top-level constructor in x is less than d (associativity is ignored). Thus, if d is 0 then the result is never surrounded in parentheses; if d is 11 it is always surrounded in parentheses, unless it is an atomic expression.
   • If the constructor is defined using record syntax, then show will produce the record-syntax form, with the fields given in the same order as the original declaration.
   For example, given the declarations

   infixr 5 :^:
   data Tree a =  Leaf a  |  Tree a :^: Tree a
   

   the derived instance of Show is equivalent to

   instance (Show a) => Show (Tree a) where
   
   showsPrec d (Leaf m) = showParen (d > app_prec) $
   showString "Leaf " . showsPrec (app_prec+1) m
   where app_prec = 10
   
   showsPrec d (u :^: v) = showParen (d > up_prec) $
   showsPrec (up_prec+1) u .
   showString " :^: "      .
   showsPrec (up_prec+1) v
   where up_prec = 5
   

   Note that right-associativity of :^: is ignored. For example,
   • show (Leaf 1 :^: Leaf 2 :^: Leaf 3) produces the string "Leaf 1 :^: (Leaf 2 :^: Leaf 3)".

2. class Show a

   verset	Verset

   Conversion of values to readable Strings. Derived instances of Show have the following properties, which are compatible with derived instances of Read:

   • The result of show is a syntactically correct Haskell expression containing only constants, given the fixity declarations in force at the point where the type is declared. It contains only the constructor names defined in the data type, parentheses, and spaces. When labelled constructor fields are used, braces, commas, field names, and equal signs are also used.
   • If the constructor is defined to be an infix operator, then showsPrec will produce infix applications of the constructor.
   • the representation will be enclosed in parentheses if the precedence of the top-level constructor in x is less than d (associativity is ignored). Thus, if d is 0 then the result is never surrounded in parentheses; if d is 11 it is always surrounded in parentheses, unless it is an atomic expression.
   • If the constructor is defined using record syntax, then show will produce the record-syntax form, with the fields given in the same order as the original declaration.
   For example, given the declarations

   infixr 5 :^:
   data Tree a =  Leaf a  |  Tree a :^: Tree a
   

   the derived instance of Show is equivalent to

   instance (Show a) => Show (Tree a) where
   
   showsPrec d (Leaf m) = showParen (d > app_prec) $
   showString "Leaf " . showsPrec (app_prec+1) m
   where app_prec = 10
   
   showsPrec d (u :^: v) = showParen (d > up_prec) $
   showsPrec (up_prec+1) u .
   showString " :^: "      .
   showsPrec (up_prec+1) v
   where up_prec = 5
   

   Note that right-associativity of :^: is ignored. For example,
   • show (Leaf 1 :^: Leaf 2 :^: Leaf 3) produces the string "Leaf 1 :^: (Leaf 2 :^: Leaf 3)".

3. class Show a

   xmonad-contrib	XMonad.Config.Prime

   Conversion of values to readable Strings. Derived instances of Show have the following properties, which are compatible with derived instances of Read:

   • The result of show is a syntactically correct Haskell expression containing only constants, given the fixity declarations in force at the point where the type is declared. It contains only the constructor names defined in the data type, parentheses, and spaces. When labelled constructor fields are used, braces, commas, field names, and equal signs are also used.
   • If the constructor is defined to be an infix operator, then showsPrec will produce infix applications of the constructor.
   • the representation will be enclosed in parentheses if the precedence of the top-level constructor in x is less than d (associativity is ignored). Thus, if d is 0 then the result is never surrounded in parentheses; if d is 11 it is always surrounded in parentheses, unless it is an atomic expression.
   • If the constructor is defined using record syntax, then show will produce the record-syntax form, with the fields given in the same order as the original declaration.
   For example, given the declarations

   infixr 5 :^:
   data Tree a =  Leaf a  |  Tree a :^: Tree a
   

   the derived instance of Show is equivalent to

   instance (Show a) => Show (Tree a) where
   
   showsPrec d (Leaf m) = showParen (d > app_prec) $
   showString "Leaf " . showsPrec (app_prec+1) m
   where app_prec = 10
   
   showsPrec d (u :^: v) = showParen (d > up_prec) $
   showsPrec (up_prec+1) u .
   showString " :^: "      .
   showsPrec (up_prec+1) v
   where up_prec = 5
   

   Note that right-associativity of :^: is ignored. For example,
   • show (Leaf 1 :^: Leaf 2 :^: Leaf 3) produces the string "Leaf 1 :^: (Leaf 2 :^: Leaf 3)".

4. showChar :: Char -> ShowS

   base	Prelude

   utility function converting a Char to a show function that simply prepends the character unchanged.

5. showList :: Show a => [a] -> ShowS

   base	Prelude

   The method showList is provided to allow the programmer to give a specialised way of showing lists of values. For example, this is used by the predefined Show instance of the Char type, where values of type String should be shown in double quotes, rather than between square brackets.

6. showParen :: Bool -> ShowS -> ShowS

   base	Prelude

   utility function that surrounds the inner show function with parentheses when the Bool parameter is True.

7. showString :: String -> ShowS

   base	Prelude

   utility function converting a String to a show function that simply prepends the string unchanged.

8. shows :: Show a => a -> ShowS

   base	Prelude

   equivalent to showsPrec with a precedence of 0.

9. showsPrec :: Show a => Int -> a -> ShowS

   base	Prelude

   Convert a value to a readable String. showsPrec should satisfy the law

   showsPrec d x r ++ s  ==  showsPrec d x (r ++ s)
   

   Derived instances of Read and Show satisfy the following:
   • (x,"") is an element of (readsPrec d (showsPrec d x "")).
   That is, readsPrec parses the string produced by showsPrec, and delivers the value that showsPrec started with.

10. showLitChar :: Char -> ShowS

    base	Data.Char

    Convert a character to a string using only printable characters, using Haskell source-language escape conventions. For example:

    showLitChar '\n' s  =  "\\n" ++ s
    

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