Data commit

Task/Extend-your-language/00-META.yaml

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+---
+from: http://rosettacode.org/wiki/Extend_your_language

Task/Extend-your-language/00-TASK.txt

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+{{Control Structures}}
+Some programming languages allow you to [[wp:Extensible_programming|extend]] the language. While this can be done to a certain degree in most languages (e.g. by using macros), other languages go much further. Most notably in the Forth and Lisp families, programming per se is done by extending the language without any formal distinction between built-in and user-defined elements.
+
+If your language supports it, show how to introduce a new flow control mechanism. A practical and useful example is a four-way branch:
+
+Occasionally, code must be written that depends on ''two'' conditions, resulting in up to four branches (depending on whether both, only the first, only the second, or none of the conditions are "true"). In a C-like language this could look like the following:
+
+   if (condition1isTrue) {
+      if (condition2isTrue)
+         bothConditionsAreTrue();
+      else
+         firstConditionIsTrue();
+   }
+   else if (condition2isTrue)
+      secondConditionIsTrue();
+   else
+      noConditionIsTrue();
+
+Besides being rather cluttered, the statement(s) for 'condition2isTrue' must be written down twice. If 'condition2isTrue' were a lengthy and involved expression, it would be quite unreadable, and the code generated by the compiler might be unnecessarily large.
+
+This can be improved by introducing a new keyword '''if2'''. It is similar to '''if''', but takes two conditional statements instead of one, and up to three 'else' statements. One proposal (in pseudo-C syntax) might be:
+
+   if2 (condition1isTrue) (condition2isTrue)
+      bothConditionsAreTrue();
+   else1
+      firstConditionIsTrue();
+   else2
+      secondConditionIsTrue();
+   else
+      noConditionIsTrue();
+
+Pick the syntax which suits your language. The keywords 'else1' and 'else2' are just examples. The new conditional expression should look, nest and behave analogously to the language's built-in 'if' statement.

Task/Extend-your-language/6502-Assembly/extend-your-language.6502

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+CMP_Double .macro    ;NESASM3 syntax
+; input:
+; \1 = first condition. Valid addressing modes: immediate, zero page, or absolute.
+; \2 = second condition. Valid addressing modes: immediate, zero page, or absolute.
+; \3 = branch here if both are true
+; \4 = branch here if only first condition is true
+; \5 = branch here if only second condition is true
+; \6 = branch here if both are false
+CMP \1
+BNE .check2\@ ;\1 is not true
+     CMP \2
+     BEQ .doubletrue\@
+
+          JMP \4      ;only condition 1 is true
+.doubletrue\@:
+     JMP \3           ;both are true
+.check2\@:
+CMP \2
+BNE .doublefalse\@
+
+    JMP \5            ;only condition 2 is true
+.doublefalse:
+JMP \6                ;both are false
+.endm

Task/Extend-your-language/68000-Assembly/extend-your-language.68000

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+macro if2_EQ_DOT_L 1,2,3,4
+;input: 1 = first param (can be any addressing mode compatible with CMP)
+;       2 = second param (used for condition 1)
+;       3 = third param (used for condition 2)
+;       4 = output for comparison results (must be a data register, and can't be 1, 2, or 3. The macro will not enforce this!)
+
+; <backslash>@ represents a macro-local label that is scoped for each instance of that macro in your program
+; and doesn't cause "label already defined" conflicts if the macro is used multiple times
+
+MOVEQ #0,\4
+CMP.L \2,\1
+BEQ \@eqCond1
+;condition 1 failed.
+CMP.L \3,\1
+BEQ \@TwoButNotOne
+;both failed
+clr.b d0
+bra \@done
+\@eqCond1:
+CMP.L \3,\1
+BEQ \@Both
+move.b #2,d0
+bra \@done
+\@Both:
+move.b #3,d0
+bra \@done
+\@TwoButNotOne:
+move.b #1,d0
+\@done:
+endm

Task/Extend-your-language/ABAP/extend-your-language.abap

@@ -0,0 +1,4 @@
+DATA(result) = COND #( WHEN condition1istrue = abap_true AND condition2istrue = abap_true THEN bothconditionsaretrue
+                          WHEN condition1istrue = abap_true THEN firstconditionistrue
+                          WHEN condition2istrue = abap_true THEN secondconditionistrue
+                          ELSE noconditionistrue ).

Task/Extend-your-language/ALGOL-68/extend-your-language.alg

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+# operator to turn two boolean values into an integer - name inspired by the COBOL sample #
+PRIO ALSO = 1;
+OP   ALSO = ( BOOL a, b )INT: IF a AND b THEN 1 ELIF a THEN 2 ELIF b THEN 3 ELSE 4 FI;
+
+# using the above operator, we can use the standard CASE construct to provide the #
+# required construct, e.g.:                                                       #
+BOOL a := TRUE, b := FALSE;
+CASE a ALSO b
+  IN print( ( "both:    a and b are TRUE",  newline ) )
+   , print( ( "first:   only a is TRUE",    newline ) )
+   , print( ( "second:  only b is TRUE",    newline ) )
+   , print( ( "neither: a and b are FALSE", newline ) )
+ESAC

Task/Extend-your-language/ALGOL-W/extend-your-language.alg

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+begin
+    % executes pBoth, p1, p2 or pNeither                                      %
+    %     depending on whether c1 and c2 are true, c1 is true, c2 is true     %
+    %                          neither c1 nor c2 are true                     %
+    procedure if2 ( logical value c1, c2
+                  ; procedure     pBoth, p1, p2, pNeither
+                  );
+        if      c1 and c2 then pBoth
+        else if c1        then p1
+        else if        c2 then p2
+        else                   pNeither
+        ;
+    begin
+        logical a, b;
+        a := true;
+        b := false;
+        if2( a, b
+           , write( "both:    a and b are TRUE"  )
+           , write( "first:   only a is TRUE"    )
+           , write( "second:  only b is TRUE"    )
+           , write( "neither: a and b are FALSE" )
+           )
+    end
+end.

Task/Extend-your-language/ATS/extend-your-language.ats

@@ -0,0 +1,18 @@
+(* Languages with pattern matching ALREADY HAVE THIS! *)
+
+fn
+func (pred1 : bool, pred2 : bool) : void =
+  case+ (pred1, pred2) of
+  | (true, true) => println! ("(true, true)")
+  | (true, false) => println! ("(true, false)")
+  | (false, true) => println! ("(false, true)")
+  | (false, false) => println! ("(false, false)")
+
+implement
+main0 () =
+  begin
+    func (true, true);
+    func (true, false);
+    func (false, true);
+    func (false, false)
+  end

Task/Extend-your-language/Ada/extend-your-language.ada

@@ -0,0 +1,20 @@
+with Ada.Text_IO; use Ada.Text_IO;
+
+procedure Test_If_2 is
+
+   type Two_Bool is range 0 .. 3;
+
+   function If_2(Cond_1, Cond_2: Boolean) return Two_Bool is
+      (Two_Bool(2*Boolean'Pos(Cond_1)) + Two_Bool(Boolean'Pos(Cond_2)));
+
+begin
+   for N in 10 .. 20 loop
+      Put(Integer'Image(N) & " is ");
+      case If_2(N mod 2 = 0, N mod 3 = 0) is
+	 when 2#11# => Put_Line("divisible by both two and three.");
+	 when 2#10# => Put_Line("divisible by two, but not by three.");
+	 when 2#01# => Put_Line("divisible by three, but not by two.");
+	 when 2#00# => Put_Line("neither divisible by two, nor by three.");
+      end case;
+   end loop;
+end Test_If_2;

Task/Extend-your-language/Agda/extend-your-language.agda

@@ -0,0 +1,16 @@
+data Bool : Set where
+  true : Bool
+  false : Bool
+
+if_then_else : ∀ {l} {A : Set l} -> Bool -> A -> A -> A
+if true then t else e = t
+if false then t else e = e
+
+if2_,_then_else1_else2_else_ : ∀ {l} {A : Set l} -> (b1 b2 : Bool) -> (t e1 e2 e : A) -> A
+if2 true , true then t else1 e1 else2 e2 else e = t
+if2 true , false then t else1 e1 else2 e2 else e = e1
+if2 false , true then t else1 e1 else2 e2 else e = e2
+if2 false , false then t else1 e1 else2 e2 else e = e
+
+example : Bool
+example = if2 true , false then true else1 false else2 true else false

Task/Extend-your-language/Amazing-Hopper/extend-your-language-1.hopper

@@ -0,0 +1,26 @@
+#include <jambo.h>
+
+#defn Siambassonverdaderas(_X_,_Y_)   ##CODEIF,__firstop__=0;#ATOM#CMPLX;cpy(__firstop__),\
+                                               __secondop__=0;#ATOM#CMPLX;cpy(__secondop__);\
+                                               and;jnt(#ENDIF),
+#defn Essólolaprimeraopción           jmp(%%CODEIF), %ENDIF:, {__firstop__}, jnt(#ENDIF),
+#defn Essólolasegundaopción           jmp(%%CODEIF), %ENDIF:, {__secondop__}, jnt(#ENDIF),
+#synon Else                           Noesningunaopción?
+#synon EndIf                          FindelSi
+
+Main
+   False(v), True(w)
+   Si ambas son verdaderas ( v, w )
+       Printnl ("Son ambas opciones verdaderas")
+
+   Es sólo la primera opción
+       Printnl ("La primera opción es verdadera")
+
+   Es sólo la segunda opción
+       Printnl ("La segunda opción es verdadera")
+
+   No es ninguna opción?
+       Printnl ("Nada se cumple")
+   Fin del Si
+
+End

Task/Extend-your-language/Amazing-Hopper/extend-your-language-2.hopper

@@ -0,0 +1,49 @@
+#include <jambo.h>
+
+#defn Sitodassonverdaderas(*)      ##CODEIF,{1},#GENCODE $$$*$$$ opción#ITV=0;#ATCMLIST;\
+                                   cpy(opción#ITV);and;#ENDGEN;,jnt(#ENDIF)
+#synon Sitodassonverdaderas        Sitodaslasopciones,Sitodasestas,Sitodas
+#defn Sonverdaderas(*)             jmp(%%CODEIF), %ENDIF:, {1}, #GENCODE $$$*$$$ #ATCMLIST;\
+                                   and;#ENDGEN;jnt(#ENDIF),
+#defn Esla(_X_)                    jmp(%%CODEIF), %ENDIF:, {_X_}, jnt(#ENDIF),
+#defn Esverdaderalaopción(_X_)     jmp(%%CODEIF), %ENDIF:, {opción_X_}, jnt(#ENDIF),
+#defn Sonverdaderaslasopciones(*)  jmp(%%CODEIF), %ENDIF:,{1};#GENCODE $$$*$$$ {opción#LIST};\
+                                   and;#ENDGEN;jnt(#ENDIF),
+#synon Sonverdaderaslasopciones    Sonlasopciones
+#synon Else                        Noesningunaopción?
+#synon EndIf                       FindelSi
+#define verdadera?                 ;
+#synon  verdadera?                 verdaderas?,verdadera,verdaderas,sonverdaderas,esverdadera
+
+Main
+   True(v), True(x), True(y)
+
+   Si todas estas 'v, {0.025} Is equal to (10), x, y' son verdaderas
+       Set ("Todas las opciones son verdaderas")
+
+   Son verdaderas 'opción 2, opción 3, opción 4'
+       Set ("Sólo son verdaderas la igualdad, X e Y")
+
+   Son verdaderas las opciones '1,3,4'
+       Set ("Son verdaderas V, X e Y")
+
+   Son las opciones '1,3,4' verdaderas?
+       Set ("Son verdaderas V, X e Y")
+
+   Son verdaderas 'opción 1, opción 3'
+       Set ("Son verdaderas V y X")
+
+  /* podríamos seguir preguntando... */
+
+   Es verdadera la opción '2'
+       Set ("Al menos, la igualdad es verdadera")
+
+   Es la 'opción 4' verdadera?
+       Set ("Al menos, Y es verdadera")
+
+   No es ninguna opción?
+       Set ("Nada se cumple")
+
+   Fin del Si
+   Prnl
+End

Task/Extend-your-language/Amazing-Hopper/extend-your-language-3.hopper

@@ -0,0 +1,17 @@
+#include <jambo.h>
+
+Main
+   True(v), False(w), first option=0, second option=0
+
+   If ( var 'v' » 'first option', And ( w » 'second option' ) )
+       Printnl ("Son ambas opciones verdaderas")
+
+   Else If ( first option )
+       Printnl ("La primera opción es verdadera")
+
+   Else If ( second option )
+       Printnl ("La segunda opción es verdadera")
+   Else
+       Printnl ("Ninguna es verdadera")
+   End If
+End

Task/Extend-your-language/Arturo/extend-your-language.arturo

@@ -0,0 +1,12 @@
+if2: function [cond1 cond2 both one two none][
+	case []
+		when? [and? cond1 cond2] -> do both
+		when? [cond1] -> do one
+		when? [cond2] -> do two
+		else  -> do none
+]
+
+if2 false true [print "both"]
+			   [print "only first"]
+			   [print "only second"]
+			   [print "none"]

Task/Extend-your-language/C-sharp/extend-your-language.cs

@@ -0,0 +1,126 @@
+using System;
+using System.Reflection;
+
+namespace Extend_your_language
+{
+	
+
+	class Program
+	{
+		
+		public static void Main(string[] args)
+		{
+			Console.WriteLine();
+			Console.WriteLine("Hello World!");
+			Console.WriteLine();
+			
+			int x = 0;
+			int y = 0;
+			
+			for(x=0;x<2;x++)
+			{
+				for(y=0;y<2;y++)
+				{
+					
+					CONDITIONS( (x==0) , (y==0) ).
+						IF2  ("METHOD1").
+						ELSE1("METHOD2").
+						ELSE2("METHOD3").
+						ELSE ("METHOD4");
+					
+				}
+			}
+			
+			Console.WriteLine();
+			Console.Write("Press any key to continue . . . ");
+			Console.ReadKey(true);
+		}
+		
+		
+		
+		
+		public static void METHOD1()
+		{
+			Console.WriteLine("METHOD 1 executed - both are true");
+		}
+		
+		public static void METHOD2()
+		{
+			Console.WriteLine("METHOD 2 executed - first is true");
+		}
+		
+		public static void METHOD3()
+		{
+			Console.WriteLine("METHOD 3 executed - second is true");
+		}
+		
+		public static void METHOD4()
+		{
+			Console.WriteLine("METHOD 4 executed - both are false");
+		}
+		
+		
+		static int CONDITIONS(bool condition1, bool condition2)
+		{
+			int c = 0;
+			if(condition1 && condition2)
+				c = 0;
+			else if(condition1)
+				c = 1;
+			else if(condition2)
+				c = 2;
+			else
+				c = 3;
+			
+			return c;
+		}
+	}
+	
+	
+	public static class ExtensionMethods
+	{
+
+		public static int IF2(this int value, string method)
+		{
+			if(value == 0)
+			{
+				MethodInfo m = typeof(Program).GetMethod(method);
+				m.Invoke(null,null);
+			}
+			
+			return value;
+		}
+		
+		public static int ELSE1(this int value, string method)
+		{
+			if(value == 1)
+			{
+				MethodInfo m = typeof(Program).GetMethod(method);
+				m.Invoke(null,null);
+			}
+			
+			return value;
+		}
+		
+		public static int ELSE2(this int value, string method)
+		{
+			if(value == 2)
+			{
+				MethodInfo m = typeof(Program).GetMethod(method);
+				m.Invoke(null,null);
+			}
+			
+			return value;
+		}
+		
+		public static void ELSE(this int value, string method)
+		{
+			if(value == 3)
+			{
+				MethodInfo m = typeof(Program).GetMethod(method);
+				m.Invoke(null,null);
+			}
+		}
+		
+	}
+}

Task/Extend-your-language/C/extend-your-language-1.c

@@ -0,0 +1,16 @@
+/* Four-way branch.
+ *
+ * if2 (firsttest, secondtest
+ *			, bothtrue
+ *			, firstrue
+ *			, secondtrue
+ *			, bothfalse
+ *	)
+ */
+#define if2(firsttest,secondtest,bothtrue,firsttrue,secondtrue,bothfalse)\
+	switch(((firsttest)?0:2)+((secondtest)?0:1)) {\
+		case 0: bothtrue; break;\
+		case 1: firsttrue; break;\
+		case 2: secondtrue; break;\
+		case 3: bothfalse; break;\
+	}

Task/Extend-your-language/C/extend-your-language-2.c

@@ -0,0 +1,24 @@
+#include <limits.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include "if2.h"
+
+int main(int argc, char *argv[]) {
+	int i;
+	for (i = 1; i < argc; i++) {
+		char *arg= argv[i], *ep;
+		long lval = strtol(arg, &ep, 10); /* convert arg to long */
+		if2 (arg[0] == '\0', *ep == '\0'
+			, puts("empty string")
+			, puts("empty string")
+			, if2 (lval > 10, lval > 100
+				, printf("%s: a very big number\n", arg)
+				, printf("%s: a big number\n", arg)
+				, printf("%s: a very big number\n", arg)
+				, printf("%s: a number\n", arg)
+			)
+			, printf("%s: not a number\n", arg)
+		)
+	}
+	return 0;
+}

Task/Extend-your-language/C/extend-your-language-3.c

@@ -0,0 +1,9 @@
+$ make exten && ./exten 3 33 333 3a b " " -2
+cc     exten.c   -o exten
+3: a number
+33: a big number
+333: a very big number
+3a: not a number
+b: not a number
+ : not a number
+-2: a number

Task/Extend-your-language/C/extend-your-language-4.c

@@ -0,0 +1,34 @@
+#include <stdio.h>
+
+#define if2(a, b) switch(((a)) + ((b)) * 2) { case 3:
+#define else00	break; case 0:	/* both false */
+#define else10	break; case 1:	/* true, false */
+#define else01	break; case 2:	/* false, true */
+#define else2	break; default: /* anything not metioned */
+#define fi2	}		/* stupid end bracket */
+
+int main()
+{
+	int i, j;
+	for (i = 0; i < 3; i++) for (j = 0; j < 3; j++) {
+		printf("%d %d: ", i, j);
+		if2 (i == 1, j == 1)
+			printf("both\n");
+		else10
+			printf("left\n");
+		else01
+			printf("right\n");
+		else00 { /* <-- bracket is optional, flaw */,
+			printf("neither\n");
+			if2 (i == 2, j == 2)
+				printf("\tis 22");
+				printf("\n"); /* flaw: this is part of if2! */
+			else2
+				printf("\tnot 22\n");
+			fi2				
+		}
+		fi2
+	}
+
+	return 0;
+}

Task/Extend-your-language/COBOL/extend-your-language.cobol

@@ -0,0 +1,10 @@
+EVALUATE EXPRESSION-1 ALSO EXPRESSION-2
+   WHEN TRUE ALSO TRUE
+      DISPLAY 'Both are true.'
+   WHEN TRUE ALSO FALSE
+      DISPLAY 'Expression 1 is true.'
+   WHEN FALSE ALSO TRUE
+      DISPLAY 'Expression 2 is true.'
+   WHEN OTHER
+      DISPLAY 'Neither is true.'
+END-EVALUATE

Task/Extend-your-language/Clay/extend-your-language.clay

@@ -0,0 +1,15 @@
+alias if2(cond1:Bool,
+          cond2:Bool,
+          both,
+          first,
+          second,
+          neither)
+{
+  var res1 = cond1;
+  var res2 = cond2;
+
+  if (res1 and res2) return both;
+  if (res1) return first;
+  if (res2) return second;
+  return neither;
+}

Task/Extend-your-language/Clojure/extend-your-language-1.clj

@@ -0,0 +1,5 @@
+(defmacro if2 [[cond1 cond2] bothTrue firstTrue secondTrue else]
+  `(let [cond1# ~cond1
+         cond2# ~cond2]
+     (if cond1# (if cond2# ~bothTrue   ~firstTrue)
+                (if cond2# ~secondTrue ~else))))

Task/Extend-your-language/Clojure/extend-your-language-2.clj

@@ -0,0 +1,7 @@
+(defmacro if2
+  [cond1 cond2 both-true first-true second-true both-false]
+  `(case [~cond1 ~cond2]
+     [true true]   ~both-true,
+     [true false]  ~first-true,
+     [false true]  ~second-true
+     [false false] ~both-false))

Task/Extend-your-language/Common-Lisp/extend-your-language.lisp

@@ -0,0 +1,9 @@
+(defmacro if2 (cond1 cond2 both first second &rest neither)
+  (let ((res1 (gensym))
+        (res2 (gensym)))
+    `(let ((,res1 ,cond1)
+           (,res2 ,cond2))
+       (cond ((and ,res1 ,res2) ,both)
+             (,res1             ,first)
+             (,res2             ,second)
+             (t                 ,@neither)))))

Task/Extend-your-language/Coq/extend-your-language.coq

@@ -0,0 +1 @@
+Notation "A /\ B" := (and A B)

Task/Extend-your-language/D/extend-your-language.d

@@ -0,0 +1,32 @@
+void if2(T1, T2, T3, T4)(in bool c1, in bool c2,
+                         lazy T1 first,
+                         lazy T2 both,
+                         lazy T3 second,
+                         lazy T4 none) {
+    if (c1) {
+        if (c2)
+            both;
+        else
+            first;
+    } else {
+        if (c2)
+            second;
+        else
+            none;
+    }
+}
+
+void test(in bool a, in bool b) {
+    import std.stdio;
+    if2(a, b, writeln("first"),
+              writeln("both"),
+              writeln("second"),
+              writeln("none"));
+}
+
+void main() {
+    test(1 < 2, 3 > 4);
+    test(1 < 2, 1 < 2);
+    test(3 > 4, 3 > 4);
+    test(3 > 4, 1 < 2);
+}

Task/Extend-your-language/DUP/extend-your-language-1.dup

@@ -0,0 +1,4 @@
+{two-conditional if operator implementation}
+{    [    top cond. = true         ][      top cond. = false      ]}
+{     [ 2nd = true ][2nd = false ]   [ 2nd = true ][ 2nd = false]  }
+[(((([[)))!)))%%%%%][)))))!)%%%%%]?][[))))!))%%%%%][))))))!%%%%%]?]?]⇒¿

Task/Extend-your-language/DUP/extend-your-language-2.dup

@@ -0,0 +1 @@
+0 1_['t,'t,]['t,'f,]['f,'t,]['f,'f,]¿

Task/Extend-your-language/Delphi/extend-your-language-1.delphi

@@ -0,0 +1,15 @@
+procedure Check(Condition1: Boolean; Condition2: Boolean)
+begin
+  if Condition1 = True then
+  begin
+    if Condition2 = True then
+      BothConditionsAreTrue
+    else
+      FirstConditionIsTrue;
+  end
+  else
+    if Condition2 = True then
+      SecondConditionIsTrue
+    else
+      NoConditionIsTrue;
+end;

Task/Extend-your-language/Delphi/extend-your-language-2.delphi

@@ -0,0 +1,10 @@
+procedure Check(Condition1: Boolean; Condition2: Boolean)
+begin
+  if (Condition1 = True) and (Condition2 = True) then
+    BothConditionsAreTrue
+  else if Condition1 = True then
+    FirstConditionIsTrue
+  else if Condition2 = True then
+    SecondConditionIsTrue
+  else NoConditionIsTrue;
+end;

Task/Extend-your-language/E/extend-your-language-1.e

@@ -0,0 +1,44 @@
+pragma.enable("lambda-args") # The feature is still experimental syntax
+
+def makeIf2Control(evalFn, tf, ft, ff) {
+  return def if2Control {
+    to only1__control_0(tf) { return makeIf2Control(evalFn, tf, ft, ff) }
+    to only2__control_0(ft) { return makeIf2Control(evalFn, tf, ft, ff) }
+    to else__control_0 (ff) { return makeIf2Control(evalFn, tf, ft, ff) }
+    to run__control() {
+      def [[a :boolean, b :boolean], # Main parameters evaluated
+           tt                        # First block ("then" case)
+          ] := evalFn()
+      return (
+        if (a) { if (b) {tt} else {tf} } \
+          else { if (b) {ft} else {ff} }
+      )()
+    }
+  }
+}
+
+def if2 {
+    # The verb here is composed from the keyword before the brace, the number of
+    # parameters in the parentheses, and the number of parameters after the
+    # keyword.
+    to then__control_2_0(evalFn) {
+        # evalFn, when called, evaluates the expressions in parentheses, then
+        # returns a pair of those expressions and the first { block } as a
+        # closure.
+        return makeIf2Control(evalFn, fn {}, fn {}, fn {})
+    }
+}
+
+for a in [false,true] {
+    for b in [false,true] {
+        if2 (a, b) then {
+            println("both")
+        } only1 {
+            println("a true")
+        } only2 {
+            println("b true")
+        } else {
+            println("neither")
+        }
+    }
+}

Task/Extend-your-language/E/extend-your-language-2.e

@@ -0,0 +1,11 @@
+if2.then__control_2_0(fn {
+    [[a, b], fn {
+        println("both")
+    }]
+}).only1__control_0(fn {
+    println("a true")
+}).only2__control_0(fn {
+    println("b true")
+}).else__control_0(fn {
+    println("neither")
+}).run__control()

Task/Extend-your-language/EchoLisp/extend-your-language.l

@@ -0,0 +1,23 @@
+(define-syntax-rule
+	(if2 cond1 cond2 both cond1-only cond2-only none) ;; new syntax
+;; will expand to :
+	(if cond1
+		(if cond2 both cond1-only)
+		(if cond2 cond2-only none)))
+   → #syntax:if2
+
+(define (num-test n)
+    (if2 (positive? n) (exact? n)
+	  "positive and exact"
+	  "positive and inexact"
+	  "negative and exact"
+	  "negative and inexact"))
+	
+(num-test 3/4)
+   → "positive and exact"
+(num-test -666)
+   → "negative and exact"
+(num-test -666.42)
+   → "negative and inexact"
+(num-test PI)
+   → "positive and inexact"

Task/Extend-your-language/Emacs-Lisp/extend-your-language.l

@@ -0,0 +1,9 @@
+(defmacro if2 (cond1 cond2 both first second &rest neither)
+  (let ((res1 (gensym))
+        (res2 (gensym)))
+    `(let ((,res1 ,cond1)
+           (,res2 ,cond2))
+       (cond ((and ,res1 ,res2) ,both)
+             (,res1             ,first)
+             (,res2             ,second)
+             (t                 ,@neither)))))

Task/Extend-your-language/Es/extend-your-language-1.es

@@ -0,0 +1,9 @@
+fn if2 cond1 cond2 body11 body10 body01 body00 {
+	# Must evaluate both conditions, and should do so in order.
+	# Negation ensures a boolean result: a true condition becomes
+        # 1 for false; a false condition becomes 0 for true.
+	let (c1 = <={! $cond1}; c2 = <={! $cond2}) {
+		# Use those values to pick the body to evaluate.
+		$(body$c1$c2)
+	}
+}

Task/Extend-your-language/Es/extend-your-language-2.es

@@ -0,0 +1,9 @@
+if2 {test 1 -gt 0} {~ grill foo bar boo} {
+	echo 1 and 2
+} {
+	echo 1 but not 2
+} {
+	echo 2 but not 1
+} {
+	echo neither 1 nor 2
+}

Task/Extend-your-language/F-Sharp/extend-your-language-1.fs

@@ -0,0 +1,22 @@
+// Extend your language. Nigel Galloway: September 14th., 2021
+type elsetf=TF
+type elseft=FT
+type elseff=FF
+let elsetf,elseft,elseff=TF,FT,FF
+let if2 n g tt (TF:elsetf)tf (FT:elseft)ft (FF:elseff)ff=match(n,g) with (true,true)->tt() |(true,false)->tf() |(false,true)->ft() |_->ff()
+if2 (13<23) (23<42) (fun()->printfn "tt")
+  elsetf (fun()->printfn "tf")
+  elseft (fun()->printfn "ft")
+  elseff (fun()->printfn "ff")
+if2 (13<23) (42<23) (fun()->printfn "tt")
+  elsetf (fun()->printfn "tf")
+  elseft (fun()->printfn "ft")
+  elseff (fun()->printfn "ff")
+if2 (23<23) (23<42) (fun()->printfn "tt")
+  elsetf (fun()->printfn "tf")
+  elseft (fun()->printfn "ft")
+  elseff (fun()->printfn "ff")
+if2 (23<13) (42<23) (fun()->printfn "tt")
+  elsetf (fun()->printfn "tf")
+  elseft (fun()->printfn "ft")
+  elseff (fun()->printfn "ff")

Task/Extend-your-language/F-Sharp/extend-your-language-2.fs

@@ -0,0 +1,4 @@
+if2 (13<23) (23<42) (fun()->printfn "tt")
+  elseff (fun()->printfn "tf")
+  elseft (fun()->printfn "ft")
+  elseff (fun()->printfn "ff")

Task/Extend-your-language/F-Sharp/extend-your-language-3.fs

@@ -0,0 +1,4 @@
+if2 (13<23) (42<23) (fun()->printfn "tt")
+  elsetx (fun()->printfn "tf")
+  elseft (fun()->printfn "ft")
+  elseff (fun()->printfn "ff")

Task/Extend-your-language/Factor/extend-your-language.factor

@@ -0,0 +1,4 @@
+( scratchpad ) : 2ifte ( ..a ?0 ?1 quot0: ( ..a -- ..b ) quot1: ( ..a -- ..b ) quot2: ( ..a -- ..b ) quot3: ( ..a -- ..b ) -- ..b )
+[ [ if ] curry curry ] 2bi@ if ; inline
+( scratchpad ) 3 [ 0 > ] [ even? ] bi [ 0 ] [ 1 ] [ 2 ] [ 3 ] 2ifte .
+2

Task/Extend-your-language/Fennel/extend-your-language.fennel

@@ -0,0 +1,18 @@
+;; Fennel, being a Lisp, provides a way to define macros for new syntax.
+;; The "`" and "," characters are used to construct a template for the macro.
+(macro if2 [cond1 cond2 both first second none]
+  `(if ,cond1
+     (if ,cond2 ,both ,first)
+     (if ,cond2 ,second ,none)))
+
+(fn test-if2 [x y]
+  (if2 x y
+    (print "both")
+    (print "first")
+    (print "second")
+    (print "none")))
+
+(test-if2 true true)   ;"both"
+(test-if2 true false)  ;"first"
+(test-if2 false true)  ;"second"
+(test-if2 false false) ;"none"

Task/Extend-your-language/Forth/extend-your-language.fth

@@ -0,0 +1,14 @@
+\ in this construct, either of the ELSE clauses may be omitted, just like IF-THEN.
+
+: BOTH    postpone IF   postpone IF ; immediate
+: ORELSE  postpone THEN postpone ELSE postpone IF ; immediate
+: NEITHER postpone THEN postpone THEN ; immediate
+
+: fb ( n -- )
+  dup 5 mod 0=  over 3 mod 0=
+  BOTH   ." FizzBuzz "
+  ELSE   ." Fizz "
+  ORELSE ." Buzz "
+  ELSE   dup .
+  NEITHER drop ;
+: fizzbuzz ( n -- ) 0 do i 1+ fb loop ;

Task/Extend-your-language/Fortran/extend-your-language-1.f

@@ -0,0 +1,51 @@
+      LOGICAL A,B		!These are allocated the same storage
+      INTEGER IA,IB		!As the default integer size.
+      EQUIVALENCE (IA,A),(IB,B)	!So, this will cause no overlaps.
+
+      WRITE (6,*) "Boolean tests via integers..."
+      DO 199 IA = 0,1	!Two states for A.
+        DO 199 IB = 0,1		!Two states for B.
+          IF (IA) 666,99,109		!Not four ways, just three.
+   99     IF (IB) 666,100,101		!Negative values are surely wrong.
+  100     WRITE (6,*) "FF",IA,IB
+          GO TO 199
+  101     WRITE (6,*) "FT",IA,IB
+          GO TO 199
+  109     IF (IB) 666,110,111		!A second test.
+  110     WRITE (6,*) "TF",IA,IB
+          GO TO 199
+  111     WRITE (6,*) "TT",IA,IB
+  199 CONTINUE		!Both loops finish here.
+
+      WRITE (6,*) "Boolean tests via integers and computed GO TO..."
+      DO 299 IA = 0,1	!Two states for A.
+        DO 299 IB = 0,1		!Two states for B.
+          GO TO (200,201,210,211) 1 + IA*2 + IB	!Counting starts with one.
+  200     WRITE (6,*) "FF",IA,IB
+          GO TO 299
+  201     WRITE (6,*) "FT",IA,IB
+          GO TO 299
+  210     WRITE (6,*) "TF",IA,IB
+          GO TO 299
+  211     WRITE (6,*) "TT",IA,IB
+  299 CONTINUE		!Both loops finish here.
+
+  300 WRITE (6,301)
+  301 FORMAT (/,"Boolean tests via LOGICAL variables...",/
+     1 " AB    IA    IB (IA*2 + IB)")
+      A = .TRUE.	!Syncopation.
+      B = .TRUE.	!Via the .NOT., the first pair will be FF.
+      DO I = 0,1	!Step through two states.
+        A = .NOT.A		!Thus generate F then T.
+        DO J = 0,1		!Step through the second two states.
+          B = .NOT.B			!Thus generate FF, FT, TF, TT.
+          WRITE (6,302) A,B,IA,IB,IA*2 + IB	!But with strange values.
+  302     FORMAT (1X,2L1,2I6,I8)		!Show both types.
+        END DO			!Next value for B.
+      END DO		!Next value for A.
+      GO TO 999
+
+  666 WRITE (6,*) "Huh?"
+
+  999 CONTINUE
+      END

Task/Extend-your-language/Fortran/extend-your-language-2.f

@@ -0,0 +1,6 @@
+      INTEGER FUNCTION IF2(A,B)	!Combine two LOGICAL variables.
+       LOGICAL A,B		!These.
+        IF2 = 0			!Wasted effort if A is true.
+        IF (A) IF2 = 2		!But it avoids IF ... THEN ... ELSE ... END IF blather.
+        IF (B) IF2 = IF2 + 1	!This relies on IF2 being a variable. (Standard in F90+)
+      END FUNCTION IF2		!Thus produce a four-way result.

Task/Extend-your-language/Fortran/extend-your-language-3.f

@@ -0,0 +1,6 @@
+      SELECT CASE(IF2(A,B))
+       CASE(B"00"); WRITE (6,*) "Both false."
+       CASE(B"01"); WRITE (6,*) "B only."
+       CASE(B"10"); WRITE (6,*) "A only."
+       CASE(B"11"); WRITE (6,*) "Both true."
+      END SELECT

Task/Extend-your-language/Free-Pascal/extend-your-language.pas

@@ -0,0 +1,24 @@
+program fourWay(input, output, stdErr);
+var
+	tuple: record
+			A: boolean;
+			B: char;
+		end;
+begin
+	tuple.A := true;
+	tuple.B := 'Z';
+	case tuple of
+		(A: false; B: 'R'):
+		begin
+			writeLn('R is not good');
+		end;
+		(A: true; B: 'Z'):
+		begin
+			writeLn('Z is great');
+		end;
+		else
+		begin
+			writeLn('No');
+		end;
+	end;
+end.

Task/Extend-your-language/FreeBASIC/extend-your-language.basic

@@ -0,0 +1,32 @@
+' FB 1.05.0 Win64
+
+#Macro If2(condition1, condition2)
+#Define Else1 ElseIf CBool(condition1) Then
+#Define Else2 ElseIf CBool(condition2) Then
+If CBool(condition1) AndAlso CBool(condition2) Then
+#Endmacro
+
+Sub test(a As Integer, b As Integer)
+  If2(a > 0, b > 0)
+    print "both positive"
+  Else1
+    print "first positive"
+  Else2
+    print "second positive"
+  Else
+    print "neither positive"
+  End If
+End Sub
+
+Dim As Integer a, b
+Print "a = 1, b = 1 => ";
+test(1, 1)
+Print "a = 1, b = 0 => ";
+test(1, 0)
+Print "a = 0, b = 1 => ";
+test(0, 1)
+Print "a = 0, b = 0 => ";
+test(0, 0)
+Print
+Print "Press any key to quit"
+Sleep

Task/Extend-your-language/Go/extend-your-language.go

@@ -0,0 +1,58 @@
+package main
+
+import "fmt"
+
+type F func()
+
+type If2 struct {cond1, cond2 bool}
+
+func (i If2) else1(f F) If2 {
+    if i.cond1 && !i.cond2 {
+        f()
+    }
+    return i
+}
+
+func (i If2) else2(f F) If2 {
+    if i.cond2 && !i.cond1 {
+        f()
+    }
+    return i
+}
+
+func (i If2) else0(f F) If2 {
+    if !i.cond1 && !i.cond2 {
+        f()
+    }
+    return i
+}
+
+func if2(cond1, cond2 bool, f F) If2 {
+    if cond1 && cond2 {
+        f()
+    }
+    return If2{cond1, cond2}
+}
+
+func main() {
+    a, b := 0, 1
+    if2 (a == 1, b == 3, func() {
+        fmt.Println("a = 1 and b = 3")
+    }).else1 (func() {
+        fmt.Println("a = 1 and b <> 3")
+    }).else2 (func() {
+        fmt.Println("a <> 1 and b = 3")
+    }).else0 (func() {
+        fmt.Println("a <> 1 and b <> 3")
+    })
+
+    // It's also possible to omit any (or all) of the 'else' clauses or to call them out of order
+    a, b = 1, 0
+    if2 (a == 1, b == 3, func() {
+        fmt.Println("a = 1 and b = 3")
+    }).else0 (func() {
+        fmt.Println("a <> 1 and b <> 3")
+    }).else1 (func() {
+        fmt.Println("a = 1 and b <> 3")
+    })
+}

Task/Extend-your-language/Haskell/extend-your-language.hs

@@ -0,0 +1,7 @@
+if2 :: Bool -> Bool -> a -> a -> a -> a -> a
+if2 p1 p2 e12 e1 e2 e =
+  if p1 then
+    if p2 then e12 else e1
+    else if p2 then e2 else e
+
+main = print $ if2 True False (error "TT") "TF" (error "FT") (error "FF")

Task/Extend-your-language/Icon/extend-your-language.icon

@@ -0,0 +1,20 @@
+procedure main(A)
+    if2 { (A[1] = A[2]), (A[3] = A[4]),   # Use PDCO with all three else clauses
+          write("1: both true"),
+          write("1: only first true"),
+          write("1: only second true"),
+          write("1: neither true")
+        }
+    if2 { (A[1] = A[2]), (A[3] = A[4]),    # Use same PDCO with only one else clause
+          write("2: both true"),
+          write("2: only first true"),
+        }
+end
+
+procedure if2(A)		# The double-conditional PDCO
+    suspend if @A[1] then
+        if @A[2] then |@A[3]    # Run-err if missing 'then' clause
+        else @\A[4]	        # (all else clauses are optional)
+    else if @A[2] then |@\A[5]
+    else |@\A[6]
+end

Task/Extend-your-language/Idris/extend-your-language.idris

@@ -0,0 +1,5 @@
+if2 : Bool -> Bool -> Lazy a -> Lazy a -> Lazy a -> Lazy a -> a
+if2 True True  v _ _ _ = v
+if2 True False _ v _ _ = v
+if2 False True _ _ v _ = v
+if2 _     _    _ _ _ v = v

Task/Extend-your-language/Inform-7/extend-your-language-1.inf

@@ -0,0 +1,4 @@
+To if2 (c1 - condition) and-or (c2 - condition) begin -- end: (- switch (({c1})*2 + ({c2})) { 3: do -).
+To else1 -- in if2: (- } until (1); 2: do { -).
+To else2 -- in if2: (- } until (1); 1: do { -).
+To else0 -- in if2: (- } until (1); 0: -).

Task/Extend-your-language/Inform-7/extend-your-language-2.inf

@@ -0,0 +1,12 @@
+Home is a room.
+
+When play begins:
+    if2 (the player is in Home) and-or (the player is a person) begin;
+        say "both";
+    else1;
+        say "only 1";
+    else2;
+        say "only 2";
+    else0;
+        say "neither";
+    end if2.

Task/Extend-your-language/Inform-7/extend-your-language-3.inf

@@ -0,0 +1,6 @@
+To say if2 (c1 - condition) and-or (c2 - condition) -- beginning if2:
+    (- switch (({c1})*2 + ({c2})) { 3: -).
+To say else1 -- continuing if2: (- 2: -).
+To say else2 -- continuing if2: (- 1: -).
+To say else0 -- continuing if2: (- 0: -).
+To say end if2 -- ending if2: (- } -).

Task/Extend-your-language/Inform-7/extend-your-language-4.inf

@@ -0,0 +1,4 @@
+Home is a room.
+
+When play begins:
+    say "[if2 the player is not in Home and-or the player is not a person]both[else1]only 1[else2]only 2[else0]neither[end if2]".

Task/Extend-your-language/J/extend-your-language-1.j

@@ -0,0 +1,4 @@
+if2=: 2 :0
+  '`b1 b2'=. n
+  m@.(b1 + 2 * b2) f.
+)

Task/Extend-your-language/J/extend-your-language-2.j

@@ -0,0 +1,14 @@
+f0=: [: smoutput 'neither option: ' , ":
+f1=: [: smoutput 'first option: ' , ":
+f2=: [: smoutput 'second option: ' , ":
+f3=: [: smoutput 'both options: ' , ":
+
+isprime=: 1&p:
+iseven=: 0 = 2&|
+
+   f0`f1`f2`f3 if2 (isprime`iseven)"0 i.5
+second option: 0
+neither option: 1
+both options: 2
+first option: 3
+second option: 4

Task/Extend-your-language/Java/extend-your-language-1.java

@@ -0,0 +1,13 @@
+public class If2 {
+
+    public static void if2(boolean firstCondition, boolean secondCondition,
+                           Runnable bothTrue, Runnable firstTrue, Runnable secondTrue, Runnable noneTrue) {
+        if (firstCondition)
+            if (secondCondition)
+                bothTrue.run();
+            else firstTrue.run();
+        else if (secondCondition)
+            secondTrue.run();
+        else noneTrue.run();
+    }
+}

Task/Extend-your-language/Java/extend-your-language-2.java

@@ -0,0 +1,15 @@
+import static If2.if2;
+class Main {
+    private static void print(String s) {
+        System.out.println(s);
+    }
+
+    public static void main(String[] args) {
+        // prints "both true"
+        if2(true, true,
+                () -> print("both true"),
+                () -> print("first true"),
+                () -> print("second true"),
+                () -> print("none true"));
+    }
+}

Task/Extend-your-language/Java/extend-your-language-3.java

@@ -0,0 +1,41 @@
+public class If2 {
+    private final boolean firstCondition;
+    private final boolean secondCondition;
+
+    public If2(boolean firstCondition, boolean secondCondition) {
+        this.firstCondition = firstCondition;
+        this.secondCondition = secondCondition;
+    }
+
+    public static If2 if2(boolean firstCondition, boolean secondCondition) {
+        return new If2(firstCondition, secondCondition);
+    }
+
+    public If2 then(Runnable runnable) {
+        if (firstCondition && secondCondition) {
+            runnable.run();
+        }
+        return this;
+    }
+
+    public If2 elseNone(Runnable runnable) {
+        if (!firstCondition && !secondCondition) {
+            runnable.run();
+        }
+        return this;
+    }
+
+    public If2 elseIfFirst(Runnable runnable) {
+        if (firstCondition && !secondCondition) {
+            runnable.run();
+        }
+        return this;
+    }
+
+    public If2 elseIfSecond(Runnable runnable) {
+        if (!firstCondition && secondCondition) {
+            runnable.run();
+        }
+        return this;
+    }
+}

Task/Extend-your-language/Java/extend-your-language-4.java

@@ -0,0 +1,14 @@
+// prints "both true"
+if2(true, true)
+    .then(() -> print("both true"))
+    .elseIfFirst(() -> print("first true"))
+    .elseIfSecond(() -> print("second true"))
+    .elseNone(() -> print("none true"));
+
+// if we only care about both true and none true...
+// prints "none true"
+if2(false, false)
+    .then(() -> print("both true"))
+    .elseNone(() -> { // a lambda can have a block body
+        print("none true");
+    });

Task/Extend-your-language/Jq/extend-your-language-1.jq

@@ -0,0 +1,6 @@
+def if2($c1; $c2; both; first; second; neither):
+  if $c1 and $c2 then both
+  elif $c1 then first
+  elif $c2 then second
+  else neither
+  end;

Task/Extend-your-language/Jq/extend-your-language-2.jq

@@ -0,0 +1,8 @@
+def if2(c1; c2; both; first; second; neither):
+  c1 as $c1
+  | c2 as $c2
+  | if $c1 and $c2 then both
+    elif $c1 then first
+    elif $c2 then second
+    else neither
+    end;

Task/Extend-your-language/Julia/extend-your-language.julia

@@ -0,0 +1,91 @@
+const CSTACK1 = Array{Bool,1}()
+const CSTACK2 = Array{Bool,1}()
+const CSTACK3 = Array{Bool,1}()
+
+macro if2(condition1, condition2, alltrue)
+    if !(length(CSTACK1) == length(CSTACK2) == length(CSTACK3))
+        throw("prior if2 statement error: must have if2, elseif1, elseif2, and elseifneither")
+    end
+    ifcond1 = eval(condition1)
+    ifcond2 = eval(condition2)
+    if ifcond1 && ifcond2
+        eval(alltrue)
+        push!(CSTACK1, false)
+        push!(CSTACK2, false)
+        push!(CSTACK3, false)
+    elseif ifcond1
+        push!(CSTACK1, true)
+        push!(CSTACK2, false)
+        push!(CSTACK3, false)
+    elseif ifcond2
+        push!(CSTACK1, false)
+        push!(CSTACK2, true)
+        push!(CSTACK3, false)
+    else
+        push!(CSTACK1, false)
+        push!(CSTACK2, false)
+        push!(CSTACK3, true)
+    end
+end
+
+macro elseif1(block)
+    quote
+        if pop!(CSTACK1)
+            $block
+        end
+    end
+end
+
+macro elseif2(block)
+    quote
+        if pop!(CSTACK2)
+            $block
+        end
+    end
+end
+
+macro elseifneither(block)
+    quote
+        if pop!(CSTACK3)
+            $block
+        end
+    end
+end
+
+
+# Testing of code starts here
+
+@if2(2 != 4, 3 != 7, begin x = "all"; println(x) end)
+
+@elseif1(begin println("one") end)
+
+@elseif2(begin println("two") end)
+
+@elseifneither(begin println("neither") end)
+
+
+@if2(2 != 4, 3 == 7, println("all"))
+
+@elseif1(begin println("one") end)
+
+@elseif2(begin println("two") end)
+
+@elseifneither(begin println("neither") end)
+
+
+@if2(2 == 4, 3 != 7, begin x = "all"; println(x) end)
+
+@elseif1(begin println("one") end)
+
+@elseif2(begin println("two") end)
+
+@elseifneither(begin println("neither") end)
+
+
+@if2(2 == 4, 3 == 7, println("last all") end)
+
+@elseif1(begin println("one") end)
+
+@elseif2(begin println("two") end)
+
+@elseifneither(begin println("neither") end)

Task/Extend-your-language/Kotlin/extend-your-language.kotlin

@@ -0,0 +1,53 @@
+// version 1.0.6
+
+data class IfBoth(val cond1: Boolean, val cond2: Boolean) {
+    fun elseFirst(func: () -> Unit): IfBoth {
+        if (cond1 && !cond2) func()
+        return this
+    }
+
+    fun elseSecond(func: () -> Unit): IfBoth {
+        if (cond2 && !cond1) func()
+        return this
+    }
+
+    fun elseNeither(func: () -> Unit): IfBoth {
+        if (!cond1 && !cond2) func()
+        return this  // in case it's called out of order
+    }
+}
+
+fun ifBoth(cond1: Boolean, cond2: Boolean, func: () -> Unit): IfBoth {
+    if (cond1 && cond2) func()
+    return IfBoth(cond1, cond2)
+}
+
+fun main(args: Array<String>) {
+    var a = 0
+    var b = 1
+    ifBoth (a == 1, b == 3) {
+        println("a = 1 and b = 3")
+    }
+    .elseFirst {
+        println("a = 1 and b <> 3")
+    }
+    .elseSecond {
+        println("a <> 1 and b = 3")
+    }
+    .elseNeither {
+        println("a <> 1 and b <> 3")
+    }
+
+    // It's also possible to omit any (or all) of the 'else' clauses or to call them out of order
+    a = 1
+    b = 0
+    ifBoth (a == 1, b == 3) {
+        println("a = 1 and b = 3")
+    }
+    .elseNeither {
+        println("a <> 1 and b <> 3")
+    }
+    .elseFirst {
+        println("a = 1 and b <> 3")
+    }
+}

Task/Extend-your-language/Lambdatalk/extend-your-language.lambdatalk

@@ -0,0 +1,18 @@
+{macro \{if2 (true|false|\{[^{}]*\}) (true|false|\{[^{}]*\})\}
+    to {if {and $1 $2}
+       then both are true
+       else {if {and $1 {not $2}}
+       then the first is true
+       else {if {and {not $1} $2}
+       then the second is true
+       else neither are true}}}}
+
+{if2 true true} -> both are true
+{if2 true false} -> the first is true
+{if2 false true} -> the second is true
+{if2 false false} -> neither are true
+
+{if2 {< 1 2} {< 3 4}} -> both are true
+{if2 {< 1 2} {> 3 4}} -> the first is true
+{if2 {> 1 2} {< 3 4}} -> the second is true
+{if2 {> 1 2} {> 3 4}} -> neither are true

Task/Extend-your-language/Langur/extend-your-language-1.langur

@@ -0,0 +1,6 @@
+given .x nxor, .y nxor {
+    case true: ...          # both true
+    case true, false: ...   # first true, second false
+    case false, true: ...   # first false, second true
+    default: ...            # both false
+}

Task/Extend-your-language/Langur/extend-your-language-2.langur

@@ -0,0 +1,7 @@
+given .x, .y {
+    case true: ...          # both true
+    case true, false: ...   # first true, second false
+    case false, true: ...   # first false, second true
+    case null, _: ...       # first null, second irrelevant
+    default: ...            # other
+}

Task/Extend-your-language/Lasso/extend-your-language-1.lasso

@@ -0,0 +1,23 @@
+// Create a type to handle the captures
+
+define if2 => type {
+    data private a, private b
+    public oncreate(a,b) => {
+        .a = #a
+        .b = #b
+        thread_var_push(.type,self)
+        handle => { thread_var_pop(.type)}
+        return givenblock()
+    }
+    public ifboth => .a && .b ? givenblock()
+    public else1  => .a && !.b ? givenblock()
+    public else2  => !.a && .b ? givenblock()
+    public else => !.a && !.b ? givenblock()
+}
+
+// Define methods to consider givenblocks
+
+define ifboth => thread_var_get(::if2)->ifboth => givenblock
+define else1 => thread_var_get(::if2)->else1 => givenblock
+define else2 => thread_var_get(::if2)->else2 => givenblock
+define else => thread_var_get(::if2)->else => givenblock

Task/Extend-your-language/Lasso/extend-your-language-2.lasso

@@ -0,0 +1,14 @@
+if2(true,true) => {
+    ifboth => {
+        bothConditionsAreTrue
+    }
+    else1 => {
+        firstConditionIsTrue
+    }
+    else2 => {
+        secondConditionIsTrue
+    }
+    else => {
+        noConditionIsTrue
+    }
+}

Task/Extend-your-language/Lua/extend-your-language.lua

@@ -0,0 +1,41 @@
+-- Extend your language, in Lua, 6/17/2020 db
+-- not to be taken seriously, ridiculous, impractical, esoteric, obscure, arcane ... but it works
+
+-------------------
+-- IMPLEMENTATION:
+-------------------
+
+function if2(cond1, cond2)
+  return function(code)
+    code = code:gsub("then2", "[3]=load[[")
+    code = code:gsub("else1", "]],[2]=load[[")
+    code = code:gsub("else2", "]],[1]=load[[")
+    code = code:gsub("neither", "]],[0]=load[[")
+    code = "return {" .. code .. "]]}"
+    local block, err = load(code)
+    if (err) then error("syntax error in if2 statement: "..err) end
+    local tab = block()
+    tab[(cond1 and 2 or 0) + (cond2 and 1 or 0)]()
+  end
+end
+
+----------
+-- TESTS:
+----------
+
+for i = 1, 2 do
+  for j = 1, 2 do
+    print("i="..i.." j="..j)
+
+    if2 ( i==1, j==1 )[[ then2
+      print("both conditions are true")
+    else1
+      print("first is true, second is false")
+    else2
+      print("first is false, second is true")
+    neither
+      print("both conditions are false")
+    ]]
+
+  end
+end

Task/Extend-your-language/M2000-Interpreter/extend-your-language.m2000

@@ -0,0 +1,39 @@
+module if2 {
+             over 3 : read &c
+             c=not (stackitem() and stackitem(2))
+}
+module ifelse1 {
+             over 3 : read &c
+             c=not (stackitem() and not stackitem(2))
+}
+module ifelse2 {
+             over 3 : read &c
+             c=not (stackitem(2) and not stackitem())
+}
+module ifelse {
+             over 3 : read &c
+             c=stackitem() or stackitem(2)
+}
+module endif2 {
+             if not empty then drop 3
+}
+ctrl=true
+for a=1 to 2
+      for b=1 to 2
+            Print "a=";a, "b=";b
+            if2 a=1, b=2, &ctrl : Part {
+                  print "both", a, b
+            } as ctrl
+            ifelse1 : Part {
+                  print "first", a
+            } as ctrl
+            ifelse2  : Part {
+                  print "second", b
+            } as ctrl
+            ifelse  : part {
+                  print "no one"
+            } as ctrl
+            endif2
+      next b
+next a
+Print "ok"

Task/Extend-your-language/M4/extend-your-language.m4

@@ -0,0 +1,21 @@
+divert(-1)
+
+#
+# m4 is a macro language, so this is just a matter of defining a
+# macro, using the built-in branching macro "ifelse".
+#
+# ifelse2(x1,x2,y1,y2,exprxy,exprx,expry,expr)
+#
+# Checks if x1 and x2 are equal strings and if y1 and y2 are equal
+# strings.
+#
+define(`ifelse2',
+  `ifelse(`$1',`$2',`ifelse(`$3',`$4',`$5',`$6')',
+          `ifelse(`$3',`$4',`$7',`$8')')')
+
+divert`'dnl
+dnl
+ifelse2(1,1,2,2,`exprxy',`exprx',`expry',`expr')
+ifelse2(1,1,2,-2,`exprxy',`exprx',`expry',`expr')
+ifelse2(1,-1,2,2,`exprxy',`exprx',`expry',`expr')
+ifelse2(1,-1,2,-2,`exprxy',`exprx',`expry',`expr')

Task/Extend-your-language/Mathematica/extend-your-language-1.math

@@ -0,0 +1,9 @@
+If2[test1_, test2_, condBoth_, cond1_, cond2_, condNone_] := With[
+   {result1 = test1,
+    result2 = test2},
+   Which[
+    result1 && result2, condBoth,
+    result1, cond1,
+    result2, cond2,
+    True, condNone]];
+SetAttributes[If2, HoldAll];

Task/Extend-your-language/Mathematica/extend-your-language-2.math

@@ -0,0 +1,5 @@
+x = 0;
+If2[Mod[(++x), 2] == 0, Mod[x, 3] == 1, Print["Both: ", x], Print["First: ", x], Print["Second: ", x], Print["Neither: ", x]];
+If2[Mod[(++x), 2] == 0, Mod[x, 3] == 1, Print["Both: ", x], Print["First: ", x], Print["Second: ", x], Print["Neither: ", x]];
+If2[Mod[(++x), 2] == 0, Mod[x, 3] == 1, Print["Both: ", x], Print["First: ", x], Print["Second: ", x], Print["Neither: ", x]];
+If2[Mod[(++x), 2] == 0, Mod[x, 3] == 1, Print["Both: ", x], Print["First: ", x], Print["Second: ", x], Print["Neither: ", x]];

Task/Extend-your-language/Min/extend-your-language.min

@@ -0,0 +1,22 @@
+(
+  :none :two :one :both -> :r2 -> :r1
+  (
+    ((r1 r2 and)(both))
+    ((r1)(one))
+    ((r2)(two))
+    ((true)(none))
+  ) case
+) :if2
+
+(3 4 >) (0 0 ==)
+("both are true")
+("the first is true")
+("the second is true")
+("both are false")
+if2 puts!   ;the second is true
+
+;compare to regular if
+(4 even?)
+("true")
+("false")
+if puts!   ;true

Task/Extend-your-language/Morfa/extend-your-language.morfa

@@ -0,0 +1,77 @@
+import morfa.base;
+
+// introduce 4 new operators to handle the if2 syntax
+operator then   { kind = infix,   precedence = mul,   associativity = right}
+operator else1  { kind = infix,   precedence = not,   associativity = left }
+operator else2  { kind = infix,   precedence = not,   associativity = left }
+operator none   { kind = infix,   precedence = not,   associativity = left }
+
+// function which bounds the condition expression to the if2 "actions"
+public func then(condition: IF2.Condition, actionHolder: IF2): void
+{
+    actionHolder.actions[condition]();
+}
+
+// functions (bound to operators) used to "build" the if2 "statement"
+public func else1(bothAction: func(): void, else1Action: func(): void): IF2
+{
+    return IF2([IF2.Condition.both -> bothAction,
+                IF2.Condition.else1 -> else1Action]);
+
+}
+public func else2(actionHolder: IF2, action: func(): void): IF2
+{
+    return checkAndAdd(actionHolder, action, IF2.Condition.else2);
+}
+public func none(actionHolder: IF2, action: func(): void): IF2
+{
+    return checkAndAdd(actionHolder, action, IF2.Condition.none);
+}
+
+// finally, function which combines two conditions into a "trigger" for the if2 "statement"
+public func if2(condition1: bool, condition2: bool): IF2.Condition
+{
+    if (condition1 and condition2)
+        return IF2.Condition.both;
+    else if (condition1)
+        return IF2.Condition.else1;
+    else if (condition2)
+        return IF2.Condition.else2;
+    else
+        return IF2.Condition.none;
+}
+
+// private helper function to build the IF2 structure
+func checkAndAdd(actionHolder: IF2, action: func(): void, actionName: IF2.Condition): IF2
+{
+    if (actionHolder.actions.contains(actionName))
+        throw new Exception("action defined twice for one condition in if2");
+    else
+        actionHolder.actions[actionName] = action;
+    return actionHolder;
+}
+
+// helper structure to process the if2 "statement"
+struct IF2
+{
+    public enum Condition { both, else1, else2, none };
+    public var actions: Dict<Condition, func(): void>;
+}
+
+// usage
+if2 (true, false) then func()
+{
+    println("both true");
+}
+else1 func()
+{
+    println("first true");
+}
+else2 func()
+{
+    println("second true");
+}
+none func()
+{
+    println("none true");
+};

Task/Extend-your-language/Nemerle/extend-your-language-1.nemerle

@@ -0,0 +1,12 @@
+// point of interest: the when keyword and && operator inside the macro definition are macros themselves
+
+macro if2 (cond1, cond2, bodyTT, bodyTF, bodyFT, bodyFF)
+syntax ("if2", "(", cond1, ")", "(", cond2, ")", bodyTT, "elseTF", bodyTF, "elseFT", bodyFT, "else", bodyFF)
+{
+    <[
+        when($cond1 && $cond2) {$bodyTT};
+        when($cond1 && !($cond2)) {$bodyTF};
+        when(!($cond1) && $cond2) {$bodyFT};
+        when(!($cond1) && !($cond2)) {$bodyFF};
+    ]>
+}

Task/Extend-your-language/Nemerle/extend-your-language-2.nemerle

@@ -0,0 +1,20 @@
+using System;
+using System.Console;
+
+module UseIf2
+{
+    Main() : void
+    {
+        def happy = true;
+        def knowit = false;
+
+        if2 (happy) (knowit)
+            Write("Clap hands")
+        elseTF
+            Write("You're happy")
+        elseFT
+            Write("Cheer up")
+        else
+            Write("You're unhappy, cheer up");
+    }
+}

Task/Extend-your-language/NewLISP/extend-your-language.l

@@ -0,0 +1,23 @@
+(context 'if2)
+
+(define-macro (if2:if2 cond1 cond2 both-true first-true second-true neither)
+  (cond
+    ((eval cond1)
+      (if (eval cond2)
+            (eval both-true)
+            (eval first-true)))
+    ((eval cond2)
+      (eval second-true))
+    (true
+      (eval neither))))
+
+(context MAIN)
+
+> (if2 true true 'bothTrue 'firstTrue 'secondTrue 'else)
+bothTrue
+> (if2 true false 'bothTrue 'firstTrue 'secondTrue 'else)
+firstTrue
+> (if2 false true 'bothTrue 'firstTrue 'secondTrue 'else)
+secondTrue
+> (if2 false false 'bothTrue 'firstTrue 'secondTrue 'else)
+else

Task/Extend-your-language/Nim/extend-your-language.nim

@@ -0,0 +1,62 @@
+import macros
+
+proc newIfElse(c, t, e: NimNode): NimNode {.compiletime.} =
+  result = newIfStmt((c, t))
+  result.add(newNimNode(nnkElse).add(e))
+
+macro if2(x, y: bool; z: untyped): untyped =
+  var parts: array[4, NimNode]
+  for i in parts.low .. parts.high:
+    parts[i] = newNimNode(nnkDiscardStmt).add(NimNode(nil))
+
+  assert z.kind == nnkStmtList
+  assert z.len <= 4
+
+  for i in 0 ..< z.len:
+    assert z[i].kind == nnkCall
+    assert z[i].len == 2
+
+    var j = 0
+
+    case $z[i][0]
+    of "then":  j = 0
+    of "else1": j = 1
+    of "else2": j = 2
+    of "else3": j = 3
+    else: assert false
+
+    parts[j] = z[i][1].last
+
+  result = newIfElse(x,
+    newIfElse(y, parts[0], parts[1]),
+    newIfElse(y, parts[2], parts[3]))
+
+if2 2 > 1, 3 < 2:
+  then:
+    echo "1"
+  else1:
+    echo "2"
+  else2:
+    echo "3"
+  else3:
+    echo "4"
+
+# Missing cases are supported:
+if2 2 > 1, 3 < 2:
+  then:
+    echo "1"
+  else2:
+    echo "3"
+  else3:
+    echo "4"
+
+# Order can be swapped:
+if2 2 > 1, 3 < 2:
+  then:
+    echo "1"
+  else2:
+    echo "3"
+  else1:
+    echo "2"
+  else3:
+    echo "4"

Task/Extend-your-language/OCaml/extend-your-language.ocaml

@@ -0,0 +1,13 @@
+(* Languages with pattern matching ALREADY HAVE THIS! *)
+
+let myfunc pred1 pred2 =
+  match (pred1, pred2) with
+  | (true, true) -> print_endline ("(true, true)");
+  | (true, false) -> print_endline ("(true, false)");
+  | (false, true) -> print_endline ("(false, true)");
+  | (false, false) -> print_endline ("(false, false)");;
+
+myfunc true true;;
+myfunc true false;;
+myfunc false true;;
+myfunc false false;;

Task/Extend-your-language/PARI-GP/extend-your-language-1.parigp

@@ -0,0 +1,7 @@
+if2(c1,c2,tt,tf,ft,ff)={
+  if(c1,
+    if(c2,tt,tf)
+  ,
+    if(c2,ft,ff)
+  )
+};

Task/Extend-your-language/PARI-GP/extend-your-language-2.parigp

@@ -0,0 +1,14 @@
+GEN
+if2(GEN c1, GEN c2, GEN tt, GEN tf, GEN ft, GEN ff)
+{
+  if (gequal0(c1))
+    if (gequal0(c2))
+      return ff ? closure_evalgen(ff) : gnil;
+    else
+      return ft ? closure_evalgen(ft) : gnil;
+  else
+    if (gequal0(c2))
+      return tf ? closure_evalgen(tf) : gnil;
+    else
+      return tt ? closure_evalgen(tt) : gnil;
+}

Task/Extend-your-language/PARI-GP/extend-your-language-3.parigp

@@ -0,0 +1,2 @@
+install("if2","GGDEDEDEDE","if2","./if2.gp.so");
+addhelp(if2, "if2(a,b,{seq1},{seq2},{seq3},{seq4}): if a is nonzero and b is nonzero, seq1 is evaluated; if a is nonzero and b is zero, seq2 is evaluated; if a is zero and b is nonzero, seq3 is evaluated; otherwise seq4. seq1 through seq4 are optional.");

Task/Extend-your-language/PARI-GP/extend-your-language-4.parigp

@@ -0,0 +1,4 @@
+/*
+GP;install("if2","GGDEDEDEDE","if2","./if2.gp.so");
+GP;addhelp(if2, "if2(a,b,{seq1},{seq2},{seq3},{seq4}): if a is nonzero and b is nonzero, seq1 is evaluated; if a is nonzero and b is zero, seq2 is evaluated; if a is zero and b is nonzero, seq3 is evaluated; otherwise seq4. seq1 through seq4 are optional.");
+*/

Task/Extend-your-language/PHL/extend-your-language.phl

@@ -0,0 +1,53 @@
+module stmts;
+
+import phl::lang::io;
+
+/* LinkedList --> Each element contains a condition */
+struct @ConditionalChain {
+	field @Boolean cond;
+	field @ConditionalChain next;
+	
+	@ConditionalChain init(@Boolean cond, @ConditionalChain next) [
+		this::cond = cond;
+		this::next = next;
+		
+		return this;
+	]
+	
+	/*
+	 *	If the condition is true executes the closure and returns a false element, otherwise returns the next condition
+	 *	
+	 *	Execution starts from the first element, and iterates until the right element is found.
+	 */
+	@ConditionalChain then(@Closure<@Void> closure) [
+		if (isNull(next())) return new @ConditionalChain.init(false, null);
+		if (cond()) {
+			closure();
+			return new @ConditionalChain.init(false, null);
+		}
+		else return next();
+	]
+
+	/* Operators create a cool look */	
+	@ConditionalChain operator then(@Closure<@Void> closure) alias @ConditionalChain.then;
+	@ConditionalChain operator else1(@Closure<@Void> closure) alias @ConditionalChain.then;
+	@ConditionalChain operator else2(@Closure<@Void> closure) alias @ConditionalChain.then;
+	@ConditionalChain operator orElse(@Closure<@Void> closure) alias @ConditionalChain.then;
+};
+
+/* Returns linked list [a && b, a, b, true] */
+@ConditionalChain if2(@Boolean a, @Boolean b) [
+	return new @ConditionalChain.init(a && b, new @ConditionalChain.init(a, new @ConditionalChain.init(b, new @ConditionalChain.init(true, null))));
+]
+
+@Void main [
+	if2(false, true) then [
+		println("Not this!");
+	] else1 [
+		println("Not this!");
+	] else2 [
+		println("This!");
+	] orElse [
+		println("Not this!");
+	];
+]

Task/Extend-your-language/Perl/extend-your-language-1.pl

@@ -0,0 +1,134 @@
+#!/usr/bin/perl
+use warnings;
+use strict;
+use v5.10;
+
+=for starters
+
+Syntax:
+
+    if2 condition1, condition2, then2 {
+        # both conditions are true
+    }
+    else1 {
+        # only condition1 is true
+    }
+    else2 {
+        # only condition2 is true
+    }
+    orelse {
+        # neither condition is true
+    };
+
+Any (but not all) of the `then' and `else' clauses can be omitted, and else1
+and else2 can be specified in either order.
+
+This extension is imperfect in several ways:
+* A normal if-statement uses round brackets, but this syntax forbids them.
+* Perl doesn't have a `then' keyword; if it did, it probably wouldn't be
+  preceded by a comma.
+* Unless it's the last thing in a block, the whole structure must be followed
+  by a semicolon.
+* Error messages appear at runtime, not compile time, and they don't show the
+  line where the user's syntax error occurred.
+
+We could solve most of these problems with a source filter, but those are
+dangerous.  Can anyone else do better?  Feel free to improve or replace.
+
+=cut
+
+# All the new `keywords' are in fact functions.  Most of them return lists
+# of four closures, one of which is then executed by if2.  Here are indexes into
+# these lists:
+
+use constant {
+    IdxThen     => 0,
+    IdxElse1    => 1,
+    IdxElse2    => 2,
+    IdxOrElse   => 3
+};
+
+# Most of the magic is in the (&) prototype, which lets a function accept a
+# closure marked by nothing except braces.
+
+sub orelse(&) {
+    my $clause = shift;
+    return undef, undef, undef, $clause;
+}
+
+sub else2(&@) {
+    my $clause = shift;
+    die "Can't have two `else2' clauses"
+        if defined $_[IdxElse2];
+
+    return (undef, $_[IdxElse1], $clause, $_[IdxOrElse]);
+}
+
+sub else1(&@) {
+    my $clause = shift;
+    die "Can't have two `else1' clauses"
+        if defined $_[IdxElse1];
+
+    return (undef, $clause, $_[IdxElse2], $_[IdxOrElse]);
+}
+
+sub then2(&@) {
+    die "Can't have two `then2' clauses"
+        if defined $_[1+IdxThen];
+
+    splice @_, 1+IdxThen, 1;
+    return @_;
+}
+
+# Here, we collect the two conditions and four closures (some of which will be
+# undefined if some clauses are missing).  We work out which of the four
+# clauses (closures) to call, and call it if it exists.
+
+use constant {
+    # Defining True and False is almost always bad practice, but here we
+    # have a valid reason.
+    True  => (0 == 0),
+    False => (0 == 1)
+};
+
+sub if2($$@) {
+    my $cond1 = !!shift;    # Convert to Boolean to guarantee matching
+    my $cond2 = !!shift;    # against either True or False
+
+    die "if2 must be followed by then2, else1, else2, &/or orelse"
+        if @_ != 4
+        or grep {defined and ref $_ ne 'CODE'} @_;
+
+    my $index;
+    if (!$cond1 && !$cond2) {$index = IdxOrElse}
+    if (!$cond1 &&  $cond2) {$index = IdxElse2 }
+    if ( $cond1 && !$cond2) {$index = IdxElse1 }
+    if ( $cond1 &&  $cond2) {$index = IdxThen  }
+
+    my $closure = $_[$index];
+    &$closure   if defined $closure;
+}
+
+# This is test code.  You can play with it by deleting up to three of the
+# four clauses.
+
+sub test_bits($) {
+    (my $n) = @_;
+
+    print "Testing $n: ";
+
+    if2 $n & 1, $n & 2, then2 {
+        say "Both bits 0 and 1 are set";
+    }
+    else1 {
+        say "Only bit 0 is set";
+    }
+    else2 {
+        say "Only bit 1 is set";
+    }
+    orelse {
+        say "Neither bit is set";
+    }
+}
+
+test_bits $_   for 0 .. 7;

Task/Extend-your-language/Perl/extend-your-language-2.pl

@@ -0,0 +1,10 @@
+msl@64Lucid:~/perl$ ./if2
+Testing 0: Neither bit is set
+Testing 1: Only bit 0 is set
+Testing 2: Only bit 1 is set
+Testing 3: Both bits 0 and 1 are set
+Testing 4: Neither bit is set
+Testing 5: Only bit 0 is set
+Testing 6: Only bit 1 is set
+Testing 7: Both bits 0 and 1 are set
+msl@64Lucid:~/perl$

Task/Extend-your-language/Phix/extend-your-language-1.phix

@@ -0,0 +1,8 @@
+(phixonline)-->
+ <span style="color: #008080;">switch</span> <span style="color: #0000FF;">{</span><span style="color: #000000;">condition1</span><span style="color: #0000FF;">,</span><span style="color: #000000;">condition2</span><span style="color: #0000FF;">}</span> <span style="color: #008080;">do</span>
+     <span style="color: #008080;">case</span> <span style="color: #0000FF;">{</span><span style="color: #004600;">true</span><span style="color: #0000FF;">,</span><span style="color: #004600;">true</span><span style="color: #0000FF;">}:</span>
+     <span style="color: #008080;">case</span> <span style="color: #0000FF;">{</span><span style="color: #004600;">true</span><span style="color: #0000FF;">,</span><span style="color: #004600;">false</span><span style="color: #0000FF;">}:</span>
+     <span style="color: #008080;">case</span> <span style="color: #0000FF;">{</span><span style="color: #004600;">false</span><span style="color: #0000FF;">,</span><span style="color: #004600;">true</span><span style="color: #0000FF;">}:</span>
+     <span style="color: #008080;">case</span> <span style="color: #0000FF;">{</span><span style="color: #004600;">false</span><span style="color: #0000FF;">,</span><span style="color: #004600;">false</span><span style="color: #0000FF;">}:</span>
+ <span style="color: #008080;">end</span> <span style="color: #008080;">switch</span>
+<!--

Task/Extend-your-language/Phix/extend-your-language-2.phix

@@ -0,0 +1,12 @@
+(phixonline)-->
+ <span style="color: #008080;">function</span> <span style="color: #000000;">if2</span><span style="color: #0000FF;">(</span><span style="color: #004080;">bool</span> <span style="color: #000000;">c1</span><span style="color: #0000FF;">,</span> <span style="color: #004080;">bool</span> <span style="color: #000000;">c2</span><span style="color: #0000FF;">)</span>
+     <span style="color: #008080;">return</span> <span style="color: #000000;">c1</span><span style="color: #0000FF;">*</span><span style="color: #000000;">10</span><span style="color: #0000FF;">+</span><span style="color: #000000;">c2</span>
+ <span style="color: #008080;">end</span> <span style="color: #008080;">function</span>
+
+ <span style="color: #008080;">switch</span> <span style="color: #000000;">if2</span><span style="color: #0000FF;">(</span><span style="color: #000000;">condition1</span><span style="color: #0000FF;">,</span><span style="color: #000000;">condition2</span><span style="color: #0000FF;">)</span> <span style="color: #008080;">do</span>
+     <span style="color: #008080;">case</span> <span style="color: #000000;">11</span><span style="color: #0000FF;">:</span>
+     <span style="color: #008080;">case</span> <span style="color: #000000;">10</span><span style="color: #0000FF;">:</span>
+     <span style="color: #008080;">case</span> <span style="color: #000000;">01</span><span style="color: #0000FF;">:</span>
+     <span style="color: #008080;">case</span> <span style="color: #000000;">00</span><span style="color: #0000FF;">:</span>
+ <span style="color: #008080;">end</span> <span style="color: #008080;">switch</span>
+<!--

Task/Extend-your-language/Phix/extend-your-language-3.phix

@@ -0,0 +1,14 @@
+(phixonline)-->
+ <span style="color: #008080;">enum</span> <span style="color: #000000;">BOTH</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">0b11</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">FIRST</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">0b10</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">SECOND</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">0b01</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">NEITHER</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">0b00</span>
+
+ <span style="color: #008080;">function</span> <span style="color: #000000;">if2</span><span style="color: #0000FF;">(</span><span style="color: #004080;">bool</span> <span style="color: #000000;">c1</span><span style="color: #0000FF;">,</span> <span style="color: #004080;">bool</span> <span style="color: #000000;">c2</span><span style="color: #0000FF;">)</span>
+     <span style="color: #008080;">return</span> <span style="color: #000000;">c1</span><span style="color: #0000FF;">*</span><span style="color: #000000;">2</span><span style="color: #0000FF;">+</span><span style="color: #000000;">c2</span>
+ <span style="color: #008080;">end</span> <span style="color: #008080;">function</span>
+
+ <span style="color: #004080;">integer</span> <span style="color: #000000;">r</span> <span style="color: #0000FF;">=</span> <span style="color: #000000;">if2</span><span style="color: #0000FF;">(</span><span style="color: #000000;">condition1</span><span style="color: #0000FF;">,</span><span style="color: #000000;">condition2</span><span style="color: #0000FF;">)</span>
+ <span style="color: #008080;">if</span>    <span style="color: #000000;">r</span><span style="color: #0000FF;">=</span><span style="color: #000000;">BOTH</span> <span style="color: #008080;">then</span>
+ <span style="color: #008080;">elsif</span> <span style="color: #000000;">r</span><span style="color: #0000FF;">=</span><span style="color: #000000;">FIRST</span> <span style="color: #008080;">then</span>
+ <span style="color: #008080;">elsif</span> <span style="color: #000000;">r</span><span style="color: #0000FF;">=</span><span style="color: #000000;">SECOND</span> <span style="color: #008080;">then</span>
+ <span style="color: #008080;">elsif</span> <span style="color: #000000;">r</span><span style="color: #0000FF;">=</span><span style="color: #000000;">NEITHER</span> <span style="color: #008080;">then</span>
+ <span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
+<!--

Task/Extend-your-language/Phix/extend-your-language-4.phix

@@ -0,0 +1,5 @@
+(phixonline)-->
+ <span style="color: #008080;">global</span> <span style="color: #008080;">constant</span> <span style="color: #000000;">T_if2</span>       <span style="color: #0000FF;">=</span> <span style="color: #000000;">5200</span>  <span style="color: #000000;">tt_stringF</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"if2"</span><span style="color: #0000FF;">,</span><span style="color: #000000;">T_if2</span><span style="color: #0000FF;">)</span>
+ <span style="color: #008080;">global</span> <span style="color: #008080;">constant</span> <span style="color: #000000;">T_else1</span>     <span style="color: #0000FF;">=</span> <span style="color: #000000;">5200</span>  <span style="color: #000000;">tt_stringF</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"else1"</span><span style="color: #0000FF;">,</span><span style="color: #000000;">T_else1</span><span style="color: #0000FF;">)</span>
+ <span style="color: #008080;">global</span> <span style="color: #008080;">constant</span> <span style="color: #000000;">T_else2</span>     <span style="color: #0000FF;">=</span> <span style="color: #000000;">5200</span>  <span style="color: #000000;">tt_stringF</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"else2"</span><span style="color: #0000FF;">,</span><span style="color: #000000;">T_else2</span><span style="color: #0000FF;">)</span>
+<!--

Task/Extend-your-language/Phix/extend-your-language-5.phix

@@ -0,0 +1,4 @@
+(phixonline)-->
+ <span style="color: #000080;font-style:italic;">--constant T_endelseelsif = {T_end,T_else,T_elsif,T_case,T_default,T_fallthru,T_fallthrough}</span>
+ <span style="color: #008080;">constant</span> <span style="color: #000000;">T_endelseelsif</span> <span style="color: #0000FF;">=</span> <span style="color: #0000FF;">{</span><span style="color: #000000;">T_end</span><span style="color: #0000FF;">,</span><span style="color: #000000;">T_else</span><span style="color: #0000FF;">,</span><span style="color: #000000;">T_else1</span><span style="color: #0000FF;">,</span><span style="color: #000000;">T_else2</span><span style="color: #0000FF;">,</span><span style="color: #000000;">T_elsif</span><span style="color: #0000FF;">,</span><span style="color: #000000;">T_case</span><span style="color: #0000FF;">,</span><span style="color: #000000;">T_default</span><span style="color: #0000FF;">,</span><span style="color: #000000;">T_fallthru</span><span style="color: #0000FF;">,</span><span style="color: #000000;">T_fallthrough</span><span style="color: #0000FF;">}</span>
+<!--

Task/Extend-your-language/Phix/extend-your-language-6.phix

@@ -0,0 +1,3 @@
+(phixonline)-->
+  <span style="color: #008080;">elsif</span> <span style="color: #000000;">ttidx</span><span style="color: #0000FF;">=</span><span style="color: #000000;">T_if2</span> <span style="color: #008080;">then</span>      <span style="color: #000000;">DoIf2</span><span style="color: #0000FF;">()</span>
+<!--

Task/Extend-your-language/Phix/extend-your-language-7.phix

@@ -0,0 +1,14 @@
+(phixonline)-->
+ <span style="color: #008080;">for</span> <span style="color: #000000;">N</span><span style="color: #0000FF;">=</span><span style="color: #000000;">10</span> <span style="color: #008080;">to</span> <span style="color: #000000;">20</span> <span style="color: #008080;">do</span>
+   <span style="color: #7060A8;">printf</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"%d is "</span><span style="color: #0000FF;">,</span><span style="color: #000000;">N</span><span style="color: #0000FF;">)</span>
+   <span style="color: #000000;">if2</span> <span style="color: #7060A8;">mod</span><span style="color: #0000FF;">(</span><span style="color: #000000;">N</span><span style="color: #0000FF;">,</span><span style="color: #000000;">2</span><span style="color: #0000FF;">)=</span><span style="color: #000000;">0</span><span style="color: #0000FF;">,</span> <span style="color: #7060A8;">mod</span><span style="color: #0000FF;">(</span><span style="color: #000000;">N</span><span style="color: #0000FF;">,</span><span style="color: #000000;">3</span><span style="color: #0000FF;">)=</span><span style="color: #000000;">0</span> <span style="color: #008080;">then</span>
+      <span style="color: #7060A8;">puts</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"divisible by both two and three.\n"</span><span style="color: #0000FF;">)</span>
+   <span style="color: #000000;">else1</span>
+      <span style="color: #7060A8;">puts</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"divisible by two, but not by three.\n"</span><span style="color: #0000FF;">)</span>
+   <span style="color: #000000;">else2</span>
+      <span style="color: #7060A8;">puts</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"divisible by three, but not by two.\n"</span><span style="color: #0000FF;">)</span>
+   <span style="color: #008080;">else</span>
+      <span style="color: #7060A8;">puts</span><span style="color: #0000FF;">(</span><span style="color: #000000;">1</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"neither divisible by two, nor by three.\n"</span><span style="color: #0000FF;">)</span>
+   <span style="color: #008080;">end</span> <span style="color: #000000;">if2</span>
+ <span style="color: #008080;">end</span> <span style="color: #008080;">for</span>
+<!--

Task/Extend-your-language/PicoLisp/extend-your-language.l

@@ -0,0 +1,8 @@
+(undef 'if2)  # Undefine the built-in 'if2'
+
+(de if2 "P"
+   (if (eval (pop '"P"))
+      (eval ((if (eval (car "P")) cadr caddr) "P"))
+      (if (eval (car "P"))
+         (eval (cadddr "P"))
+         (run (cddddr "P")) ) ) )

Task/Extend-your-language/PlainTeX/extend-your-language.tex

@@ -0,0 +1,13 @@
+\def\iftwo#1#2#3#4#5\elsefirst#6\elsesecond#7\elseneither#8\owtfi
+{\if#1#2\if#3#4#5\else#6\fi\else\if#3#4#7\else#8\fi\fi}
+
+\def\both{***both***}
+\def\first{***first***}
+\def\second{***second***}
+\def\neither{***neither***}
+\message{\iftwo{1}{1}{2}{2}\both\elsefirst\first\elsesecond\second\elseneither\neither\owtfi}
+\message{\iftwo{1}{1}{2}{-2}\both\elsefirst\first\elsesecond\second\elseneither\neither\owtfi}
+\message{\iftwo{1}{-1}{2}{2}\both\elsefirst\first\elsesecond\second\elseneither\neither\owtfi}
+\message{\iftwo{1}{-1}{2}{-2}\both\elsefirst\first\elsesecond\second\elseneither\neither\owtfi}
+
+\bye

Task/Extend-your-language/PowerShell/extend-your-language-1.psh

@@ -0,0 +1,47 @@
+function When-Condition
+{
+    [CmdletBinding()]
+    Param
+    (
+        [Parameter(Mandatory=$true, Position=0)]
+        [bool]
+        $Test1,
+
+        [Parameter(Mandatory=$true, Position=1)]
+        [bool]
+        $Test2,
+
+        [Parameter(Mandatory=$true, Position=2)]
+        [scriptblock]
+        $Both,
+
+        [Parameter(Mandatory=$true, Position=3)]
+        [scriptblock]
+        $First,
+
+        [Parameter(Mandatory=$true, Position=4)]
+        [scriptblock]
+        $Second,
+
+        [Parameter(Mandatory=$true, Position=5)]
+        [scriptblock]
+        $Neither
+    )
+
+    if ($Test1 -and $Test2)
+    {
+        return (&$Both)
+    }
+    elseif ($Test1 -and -not $Test2)
+    {
+        return (&$First)
+    }
+    elseif (-not $Test1 -and $Test2)
+    {
+        return (&$Second)
+    }
+    else
+    {
+        return (&$Neither)
+    }
+}

Task/Extend-your-language/PowerShell/extend-your-language-2.psh

@@ -0,0 +1,6 @@
+When-Condition -Test1 (Test-Path .\temp.txt) -Test2 (Test-Path .\tmp.txt) `
+    -Both { "both true"
+}   -First { "first true"
+}   -Second { "second true"
+}   -Neither { "neither true"
+}