Add pattern statement

spec/propane_spec.rb

@@ -110,4 +110,17 @@ EOF
     compile("spec/test_user_code.d")
     run
   end
+
+  it "supports a pattern statement" do
+    write_grammar <<EOF
+token abc;
+/def/ <<
+  writeln("def!");
+>>
+Start -> abc;
+EOF
+    build_parser
+    compile("spec/test_pattern.d")
+    run
+  end
 end

spec/test_pattern.d

@@ -0,0 +1,18 @@
+import testparser;
+import std.stdio;
+
+int main()
+{
+    return 0;
+}
+
+unittest
+{
+    string input = "abcdef";
+    auto parser = new Testparser.Parser(cast(const(ubyte) *)input.ptr, input.length);
+    assert(parser.parse() == true);
+
+    input = "defabcdef";
+    parser = new Testparser.Parser(cast(const(ubyte) *)input.ptr, input.length);
+    assert(parser.parse() == true);
+}