Ternary logic: Difference between revisions

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@@ Line 1,677: / Line 1,677: @@
 =={{header|Pascal}}==
-{{incorrect|Pascal|The EQUAL table if it should be the '''equivalent''' table of the task description, is wrong.}}
 <lang pascal>Program TernaryLogic (output);
 type
   trit = (terTrue, terMayBe, terFalse);
 function terNot (a: trit): trit;
   begin
-	case a of
+    case a of
-	  terTrue:  terNot := terFalse;
+      terTrue:  terNot := terFalse;
-	  terMayBe: terNot := terMayBe;
+      terMayBe: terNot := terMayBe;
-	  terFalse: terNot := terTrue;
+      terFalse: terNot := terTrue;
-	end;
+    end;
   end;
 function terAnd (a, b: trit): trit;
   begin
-	terAnd := terMayBe;
+    terAnd := terMayBe;
-  	if (a = terFalse) or (b = terFalse) then
+    if (a = terFalse) or (b = terFalse) then
       terAnd := terFalse
-	else
+    else
-	  if (a = terTrue) and (b = terTrue) then
+      if (a = terTrue) and (b = terTrue) then
-	    terAnd := terTrue;
+        terAnd := terTrue;
   end;
 function terOr (a, b: trit): trit;
   begin
-	terOr := terMayBe;
+    terOr := terMayBe;
-  	if (a = terTrue) or (b = terTrue) then
+    if (a = terTrue) or (b = terTrue) then
       terOr := terTrue
-	else
+    else
-  	  if (a = terFalse) and (b = terFalse) then
+      if (a = terFalse) and (b = terFalse) then
-	    terOr := terFalse;
+        terOr := terFalse;
   end;
 function terEquals (a, b: trit): trit;
   begin
+    if a = b then
-	terEquals := terMayBe;
-  	if a = b then
       terEquals := terTrue
-	else
+    else
-  	  if a <> b then
+      if a <> b then
-	    terEquals := terFalse;
+        terEquals := terFalse;
+    if (a = terMayBe) or (b = terMayBe) then
+      terEquals := terMayBe;
   end;
 function terIfThen (a, b: trit): trit;
   begin
-	terIfThen := terMayBe;
+    terIfThen := terMayBe;
-  	if (a = terTrue) or (b = terFalse)  then
+    if (a = terTrue) or (b = terFalse)  then
       terIfThen := terTrue
-	else
+    else
-  	  if (a = terFalse) and (b = terTrue) then
+      if (a = terFalse) and (b = terTrue) then
-	    terIfThen := terFalse;
+        terIfThen := terFalse;
   end;
@@ Line 1,735: / Line 1,735: @@
   begin
     case a of
-	  terTrue:  terToStr := 'True ';
+      terTrue:  terToStr := 'True ';
-	  terMayBe: terToStr := 'Maybe';
+      terMayBe: terToStr := 'Maybe';
-	  terFalse: terToStr := 'False';
+      terFalse: terToStr := 'False';
-	end;
+    end;
   end;
 begin
@@ Line 1,794: / Line 1,792: @@
 EQUAL  True  Maybe False
-True   True  False False
+True   True  Maybe False
-Maybe  False True  False
+Maybe  Maybe Maybe Maybe
-False  False False True
+False  False Maybe True
 </pre>