Data commit

Task/Boolean-values/Elm/boolean-values.elm

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+--True and False directly represent Boolean values in Elm
+--For eg to show yes for true and no for false
+if True then "yes" else "no"
+
+--Same expression differently
+if False then "no" else "yes"
+
+--This you can run as a program
+--Elm allows you to take anything you want for representation
+--In the program we take T for true F for false
+import Html exposing(text,div,Html)
+import Html.Attributes exposing(style)
+
+type Expr = T | F | And Expr Expr | Or Expr Expr | Not Expr
+
+evaluate : Expr->Bool
+evaluate expression =
+ case expression of
+ T ->
+  True
+
+ F ->
+  False
+
+ And expr1 expr2 ->
+  evaluate expr1 && evaluate expr2
+
+ Or expr1 expr2 ->
+  evaluate expr1 || evaluate expr2
+
+ Not expr ->
+  not (evaluate expr)
+
+--CHECKING RANDOM LOGICAL EXPRESSIONS
+ex1= Not F
+ex2= And T F
+ex3= And (Not(Or T F)) T
+
+main =
+    div [] (List.map display  [ex1, ex2, ex3])
+
+display expr=
+   div [] [ text ( toString expr ++ "-->" ++ toString(evaluate expr) ) ]
+--END