1 files changed, 34 insertions, 0 deletions
diff --git a/vendor/pest_meta/src/optimizer/concatenator.rs b/vendor/pest_meta/src/optimizer/concatenator.rs
new file mode 100644
index 000000000..e0aab7bc1
--- /dev/null
+++ b/vendor/pest_meta/src/optimizer/concatenator.rs
@@ -0,0 +1,34 @@
+// pest. The Elegant Parser
+// Copyright (c) 2018 Dragoș Tiselice
+//
+// Licensed under the Apache License, Version 2.0
+// <LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0> or the MIT
+// license <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. All files in the project carrying such notice may not be copied,
+// modified, or distributed except according to those terms.
+
+use ast::*;
+
+pub fn concatenate(rule: Rule) -> Rule {
+    match rule {
+        Rule { name, ty, expr } => Rule {
+            name,
+            ty,
+            expr: expr.map_bottom_up(|expr| {
+                if ty == RuleType::Atomic {
+                    // TODO: Use box syntax when it gets stabilized.
+                    match expr {
+                        Expr::Seq(lhs, rhs) => match (*lhs, *rhs) {
+                            (Expr::Str(lhs), Expr::Str(rhs)) => Expr::Str(lhs + &rhs),
+                            (Expr::Insens(lhs), Expr::Insens(rhs)) => Expr::Insens(lhs + &rhs),
+                            (lhs, rhs) => Expr::Seq(Box::new(lhs), Box::new(rhs)),
+                        },
+                        expr => expr,
+                    }
+                } else {
+                    expr
+                }
+            }),
+        },
+    }
+}