From 568634d64f67da9f9dae3a1523f6d030bf149471 Mon Sep 17 00:00:00 2001
From: Sean Geles <seang_173@hotmail.com>
Date: Mon, 8 Apr 2024 09:51:32 +1000
Subject: [PATCH 1/2] Add string concatenation operator to scripting

---
 .../behaviortree_cpp/scripting/operators.hpp  | 21 ++++++++++++++++++-
 1 file changed, 20 insertions(+), 1 deletion(-)

diff --git a/include/behaviortree_cpp/scripting/operators.hpp b/include/behaviortree_cpp/scripting/operators.hpp
index 176fa2df0..5faca77b3 100644
--- a/include/behaviortree_cpp/scripting/operators.hpp
+++ b/include/behaviortree_cpp/scripting/operators.hpp
@@ -150,6 +150,7 @@ struct ExprBinaryArithmetic : ExprBase
     minus,
     times,
     div,
+    concat,
 
     bit_and,
     bit_or,
@@ -171,6 +172,8 @@ struct ExprBinaryArithmetic : ExprBase
         return "*";
       case div:
         return "/";
+      case concat:
+        return "..";
       case bit_and:
         return "&";
       case bit_or:
@@ -276,6 +279,12 @@ struct ExprBinaryArithmetic : ExprBase
     {
       return Any(lhs_v.cast<std::string>() + rhs_v.cast<std::string>());
     }
+    else if (op == concat && ((rhs_v.isString() && lhs_v.isString()) ||
+                            (rhs_v.isString() && lhs_v.isNumber()) ||
+                            (rhs_v.isNumber() && lhs_v.isString())))
+    {
+      return Any(lhs_v.cast<std::string>() + rhs_v.cast<std::string>());
+    }
     else
     {
       throw RuntimeError("Operation not permitted");
@@ -722,6 +731,16 @@ struct Expression : lexy::expression_production
     using operand = math_product;
   };
 
+  // x .. y
+  struct string_concat : dsl::infix_op_left
+  {
+    static constexpr auto op = [] {
+      return dsl::op<Ast::ExprBinaryArithmetic::concat>(LEXY_LIT(".."));
+    }();
+    
+    using operand = math_sum;
+  };
+
   // ~x
   struct bit_prefix : dsl::prefix_op
   {
@@ -785,7 +804,7 @@ struct Expression : lexy::expression_production
         dsl::op<Ast::ExprBinaryArithmetic::logic_or>(LEXY_LIT("||")) /
         dsl::op<Ast::ExprBinaryArithmetic::logic_and>(LEXY_LIT("&&"));
 
-    using operand = comparison;
+    using operand = dsl::groups<string_concat, comparison>;
   };
 
   // x ? y : z

From 1093b4eec2b73f4aa5b70ac40defd4b5afa8c54a Mon Sep 17 00:00:00 2001
From: Sean Geles <58413041+seanng-1@users.noreply.github.com>
Date: Sun, 14 Apr 2024 11:27:52 +1000
Subject: [PATCH 2/2] Linting

---
 include/behaviortree_cpp/scripting/operators.hpp | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/include/behaviortree_cpp/scripting/operators.hpp b/include/behaviortree_cpp/scripting/operators.hpp
index 5faca77b3..14cf04f43 100644
--- a/include/behaviortree_cpp/scripting/operators.hpp
+++ b/include/behaviortree_cpp/scripting/operators.hpp
@@ -279,9 +279,9 @@ struct ExprBinaryArithmetic : ExprBase
     {
       return Any(lhs_v.cast<std::string>() + rhs_v.cast<std::string>());
     }
-    else if (op == concat && ((rhs_v.isString() && lhs_v.isString()) ||
-                            (rhs_v.isString() && lhs_v.isNumber()) ||
-                            (rhs_v.isNumber() && lhs_v.isString())))
+    else if(op == concat && ((rhs_v.isString() && lhs_v.isString()) ||
+                             (rhs_v.isString() && lhs_v.isNumber()) ||
+                             (rhs_v.isNumber() && lhs_v.isString())))
     {
       return Any(lhs_v.cast<std::string>() + rhs_v.cast<std::string>());
     }
@@ -737,7 +737,7 @@ struct Expression : lexy::expression_production
     static constexpr auto op = [] {
       return dsl::op<Ast::ExprBinaryArithmetic::concat>(LEXY_LIT(".."));
     }();
-    
+
     using operand = math_sum;
   };