2 files changed, 32 insertions, 0 deletions
diff --git a/Source/cmListCommand.cxx b/Source/cmListCommand.cxx
index ae4f0a8..62d4ea7 100644
--- a/Source/cmListCommand.cxx
+++ b/Source/cmListCommand.cxx
@@ -42,6 +42,9 @@ bool cmListCommand::InitialPass(std::vector<std::string> const& args,
   if (subCommand == "INSERT") {
     return this->HandleInsertCommand(args);
   }
+  if (subCommand == "JOIN") {
+    return this->HandleJoinCommand(args);
+  }
   if (subCommand == "REMOVE_AT") {
     return this->HandleRemoveAtCommand(args);
   }
@@ -294,6 +297,34 @@ bool cmListCommand::HandleInsertCommand(std::vector<std::string> const& args)
   return true;
 }
 
+bool cmListCommand::HandleJoinCommand(std::vector<std::string> const& args)
+{
+  if (args.size() != 4) {
+    std::ostringstream error;
+    error << "sub-command JOIN requires three arguments (" << args.size() - 1
+          << " found).";
+    this->SetError(error.str());
+    return false;
+  }
+
+  const std::string& listName = args[1];
+  const std::string& glue = args[2];
+  const std::string& variableName = args[3];
+
+  // expand the variable
+  std::vector<std::string> varArgsExpanded;
+  if (!this->GetList(varArgsExpanded, listName)) {
+    this->Makefile->AddDefinition(variableName, "");
+    return true;
+  }
+
+  std::string value =
+    cmJoin(cmMakeRange(varArgsExpanded.begin(), varArgsExpanded.end()), glue);
+
+  this->Makefile->AddDefinition(variableName, value.c_str());
+  return true;
+}
+
 bool cmListCommand::HandleRemoveItemCommand(
   std::vector<std::string> const& args)
 {
diff --git a/Source/cmListCommand.h b/Source/cmListCommand.h
index 2965399..d6870e6 100644
--- a/Source/cmListCommand.h
+++ b/Source/cmListCommand.h
@@ -37,6 +37,7 @@ protected:
   bool HandleAppendCommand(std::vector<std::string> const& args);
   bool HandleFindCommand(std::vector<std::string> const& args);
   bool HandleInsertCommand(std::vector<std::string> const& args);
+  bool HandleJoinCommand(std::vector<std::string> const& args);
   bool HandleRemoveAtCommand(std::vector<std::string> const& args);
   bool HandleRemoveItemCommand(std::vector<std::string> const& args);
   bool HandleRemoveDuplicatesCommand(std::vector<std::string> const& args);