Add procedural type example

simple_examples/procedural_type.pas

@@ -0,0 +1,24 @@
+program procedural_type;
+
+{$mode objfpc}{$H+}
+
+// Interface for an event handler
+// This is a 'procedural type'
+type TOneStringParamProc = procedure(aString: string);
+
+var stringProc: TOneStringParamProc = nil;
+
+// A possible implementation
+procedure ShowStr(s: string);
+begin
+	WriteLn('The string passed to this procedure is ', s);
+end;
+
+begin
+	// Use the event handler
+	stringProc := @ShowStr;
+	stringProc('"string parameter"');
+	{$IFDEF WINDOWS}
+	ReadLn;
+	{$ENDIF}
+end.