16 files changed, 93 insertions, 0 deletions

diff --git a/Help/command/list.rst b/Help/command/list.rst
index e6a7069..3c092bd 100644
--- a/Help/command/list.rst
+++ b/Help/command/list.rst
@@ -54,6 +54,17 @@ GET
 
 Returns the list of elements specified by indices from the list.
 
+JOIN
+""""
+
+::
+
+  list(JOIN <list> <glue> <output variable>)
+
+Returns a string joining all list's elements using the glue string.
+To join multiple strings, which are not part of a list, use ``JOIN`` operator
+from :command:`string` command.
+
 Search
 ^^^^^^
 
diff --git a/Help/command/string.rst b/Help/command/string.rst
index cd94bb4..bb07d29 100644
--- a/Help/command/string.rst
+++ b/Help/command/string.rst
@@ -161,6 +161,10 @@ JOIN
 Join all the input arguments together using the glue
 string and store the result in the named output variable.
 
+To join list's elements, use preferably the ``JOIN`` operator
+from :command:`list` command. This allows for the elements to have
+special characters like ``;`` in them.
+
 TOLOWER
 """""""
 
diff --git a/Help/release/dev/list-join.rst b/Help/release/dev/list-join.rst
new file mode 100644
index 0000000..0756b60
--- /dev/null
+++ b/Help/release/dev/list-join.rst
@@ -0,0 +1,5 @@
+list-join
+---------
+
+* The :command:`list` command learned a ``JOIN`` sub-command
+  to concatenate list's elements separated by a glue string.
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);
diff --git a/Tests/RunCMake/list/JOIN-NoArguments-result.txt b/Tests/RunCMake/list/JOIN-NoArguments-result.txt
new file mode 100644
index 0000000..d00491f
--- /dev/null
+++ b/Tests/RunCMake/list/JOIN-NoArguments-result.txt
@@ -0,0 +1 @@
+1
diff --git a/Tests/RunCMake/list/JOIN-NoArguments-stderr.txt b/Tests/RunCMake/list/JOIN-NoArguments-stderr.txt
new file mode 100644
index 0000000..5e1b98f
--- /dev/null
+++ b/Tests/RunCMake/list/JOIN-NoArguments-stderr.txt
@@ -0,0 +1,4 @@
+^CMake Error at JOIN-NoArguments.cmake:1 \(list\):
+  list sub-command JOIN requires three arguments \(1 found\).
+Call Stack \(most recent call first\):
+  CMakeLists.txt:3 \(include\)$
diff --git a/Tests/RunCMake/list/JOIN-NoArguments.cmake b/Tests/RunCMake/list/JOIN-NoArguments.cmake
new file mode 100644
index 0000000..2ab449a
--- /dev/null
+++ b/Tests/RunCMake/list/JOIN-NoArguments.cmake
@@ -0,0 +1 @@
+list(JOIN mylist)
diff --git a/Tests/RunCMake/list/JOIN-NoVariable-result.txt b/Tests/RunCMake/list/JOIN-NoVariable-result.txt
new file mode 100644
index 0000000..d00491f
--- /dev/null
+++ b/Tests/RunCMake/list/JOIN-NoVariable-result.txt
@@ -0,0 +1 @@
+1
diff --git a/Tests/RunCMake/list/JOIN-NoVariable-stderr.txt b/Tests/RunCMake/list/JOIN-NoVariable-stderr.txt
new file mode 100644
index 0000000..db1d773
--- /dev/null
+++ b/Tests/RunCMake/list/JOIN-NoVariable-stderr.txt
@@ -0,0 +1,4 @@
+^CMake Error at JOIN-NoVariable.cmake:1 \(list\):
+  list sub-command JOIN requires three arguments \(2 found\).
+Call Stack \(most recent call first\):
+  CMakeLists.txt:3 \(include\)$
diff --git a/Tests/RunCMake/list/JOIN-NoVariable.cmake b/Tests/RunCMake/list/JOIN-NoVariable.cmake
new file mode 100644
index 0000000..b60d8f1
--- /dev/null
+++ b/Tests/RunCMake/list/JOIN-NoVariable.cmake
@@ -0,0 +1 @@
+list(JOIN mylist "glue")
diff --git a/Tests/RunCMake/list/JOIN-TooManyArguments-result.txt b/Tests/RunCMake/list/JOIN-TooManyArguments-result.txt
new file mode 100644
index 0000000..d00491f
--- /dev/null
+++ b/Tests/RunCMake/list/JOIN-TooManyArguments-result.txt
@@ -0,0 +1 @@
+1
diff --git a/Tests/RunCMake/list/JOIN-TooManyArguments-stderr.txt b/Tests/RunCMake/list/JOIN-TooManyArguments-stderr.txt
new file mode 100644
index 0000000..2b09e22
--- /dev/null
+++ b/Tests/RunCMake/list/JOIN-TooManyArguments-stderr.txt
@@ -0,0 +1,4 @@
+^CMake Error at JOIN-TooManyArguments.cmake:1 \(list\):
+  list sub-command JOIN requires three arguments \(4 found\).
+Call Stack \(most recent call first\):
+  CMakeLists.txt:3 \(include\)$
diff --git a/Tests/RunCMake/list/JOIN-TooManyArguments.cmake b/Tests/RunCMake/list/JOIN-TooManyArguments.cmake
new file mode 100644
index 0000000..dc651f6
--- /dev/null
+++ b/Tests/RunCMake/list/JOIN-TooManyArguments.cmake
@@ -0,0 +1 @@
+list(JOIN mylist "glue" out one_too_many)
diff --git a/Tests/RunCMake/list/JOIN.cmake b/Tests/RunCMake/list/JOIN.cmake
new file mode 100644
index 0000000..24a623e
--- /dev/null
+++ b/Tests/RunCMake/list/JOIN.cmake
@@ -0,0 +1,18 @@
+list(JOIN undefList % out)
+if(NOT out STREQUAL "")
+  message(FATAL_ERROR "\"list(JOIN undefList % out)\" set out to \"${out}\"")
+endif()
+set(myList a)
+list(JOIN myList % out)
+if(NOT out STREQUAL "a")
+  message(FATAL_ERROR "\"list(JOIN \"a\" % out)\" set out to \"${out}\"")
+endif()
+set(myList a b)
+list(JOIN myList % out)
+if(NOT out STREQUAL "a%b")
+  message(FATAL_ERROR "\"list(JOIN \"a;b\" % out)\" set out to \"${out}\"")
+endif()
+list(JOIN myList "" out)
+if(NOT out STREQUAL "ab")
+  message(FATAL_ERROR "\"list(JOIN \"a;b\" \"\" out a)\" set out to \"${out}\"")
+endif()
diff --git a/Tests/RunCMake/list/RunCMakeTest.cmake b/Tests/RunCMake/list/RunCMakeTest.cmake
index b002ab3..1be4f85 100644
--- a/Tests/RunCMake/list/RunCMakeTest.cmake
+++ b/Tests/RunCMake/list/RunCMakeTest.cmake
@@ -15,6 +15,7 @@ run_cmake(INSERT-InvalidIndex)
 run_cmake(REMOVE_AT-InvalidIndex)
 
 run_cmake(FILTER-REGEX-TooManyArguments)
+run_cmake(JOIN-TooManyArguments)
 run_cmake(LENGTH-TooManyArguments)
 run_cmake(REMOVE_DUPLICATES-TooManyArguments)
 run_cmake(REVERSE-TooManyArguments)
@@ -31,3 +32,7 @@ run_cmake(FILTER-REGEX-InvalidMode)
 run_cmake(FILTER-REGEX-InvalidOperator)
 run_cmake(FILTER-REGEX-Valid0)
 run_cmake(FILTER-REGEX-Valid1)
+
+run_cmake(JOIN-NoArguments)
+run_cmake(JOIN-NoVariable)
+run_cmake(JOIN)