Add keywords to parser

Parsers/PascalABCParserNewSaushkin/ABCPascal.cs

@@ -2,7 +2,7 @@
 //  This CSharp output file generated by Gardens Point LEX
 //  Version:  1.1.3.301
 //  Machine:  ALEXANDER-PC
-//  DateTime: 11.05.2018 18:06:46
+//  DateTime: 12.05.2018 15:47:47
 //  UserName: Alexander
 //  GPLEX input file <ABCPascal.lex>
 //  GPLEX frame file <embedded resource>

Parsers/PascalABCParserNewSaushkin/ABCPascal.y

@@ -3716,6 +3716,10 @@ keyword
 		{ $$ = $1; }
 	| tkYield	
 		{ $$ = $1; }
+    | tkMatch
+        { $$ = $1; }
+    | tkWhen
+        { $$ = $1; }
     ;
 
 reserved_keyword

Patterns/Desugaring-v3.pas

@@ -0,0 +1,37 @@
+// Source
+
+match x with
+    My(string(s), integer(t)) when s = 'asd':
+end
+
+// Desugared code (match, 1st stage)
+
+var <>matchDone := false;
+var <>genVarExpr := x;
+if not matchDone and <>genVarExpr is My(string(s), integer(t)) then
+begin
+    if s = 'asd' then
+    begin
+        <>match1Done := true;
+        <ACTION>
+    end;
+end;
+
+// Desugared code (is, 2nd stage)
+
+var <>matchDone := false;
+var <>genVarExpr := x;
+var <>genVar1: My;
+
+if IsTest(<>genVarExpr, <>genVar1) then
+var s: string;
+var t: integer;
+
+if <>genVarExpr is My(string(s), integer(t)) then
+begin
+    if s = 'asd' then
+    begin
+        <>match1Done := true;
+        <ACTION>
+    end;
+end;