if: Implement new IN_LIST operator

Help/command/if.rst

@@ -134,6 +134,9 @@ Possible expressions are:
  Component-wise integer version number comparison (version format is
  ``major[.minor[.patch[.tweak]]]``).
 
+``if(<variable|string> IN_LIST <variable>)``
+ True if the given element is contained in the named list variable.
+
 ``if(DEFINED <variable>)``
  True if the given variable is defined.  It does not matter if the
  variable is true or false just if it has been set.  (Note macro

Help/policy/CMP0057.rst

@@ -1,4 +1,14 @@
 CMP0057
 -------
 
-This policy is reserved for future use.
+Support new :command:`if` IN_LIST operator.
+
+CMake 3.3 adds support for the new IN_LIST operator.
+
+The ``OLD`` behavior for this policy is to ignore the IN_LIST operator.
+The ``NEW`` behavior is to interpret the IN_LIST operator.
+
+This policy was introduced in CMake version 3.3.
+CMake version |release| warns when the policy is not set and uses
+``OLD`` behavior.  Use the :command:`cmake_policy` command to set
+it to ``OLD`` or ``NEW`` explicitly.

Help/release/dev/if-IN_LIST.rst

@@ -0,0 +1,5 @@
+if-IN_LIST
+----------
+
+* Add a new IN_LIST operator to if() that evaluates true
+  if a given element is contained in a named list.

Source/cmConditionEvaluator.cxx

@@ -15,7 +15,8 @@
 cmConditionEvaluator::cmConditionEvaluator(cmMakefile& makefile):
   Makefile(makefile),
   Policy12Status(makefile.GetPolicyStatus(cmPolicies::CMP0012)),
-  Policy54Status(makefile.GetPolicyStatus(cmPolicies::CMP0054))
+  Policy54Status(makefile.GetPolicyStatus(cmPolicies::CMP0054)),
+  Policy57Status(makefile.GetPolicyStatus(cmPolicies::CMP0057))
 {
 
 }
@@ -676,6 +677,41 @@ bool cmConditionEvaluator::HandleLevel2(cmArgumentList &newArgs,
           reducible, arg, newArgs, argP1, argP2);
         }
 
+      if (argP1 != newArgs.end() && argP2 != newArgs.end() &&
+          this->IsKeyword("IN_LIST", *argP1))
+        {
+        if(this->Policy57Status != cmPolicies::OLD &&
+          this->Policy57Status != cmPolicies::WARN)
+          {
+          bool result = false;
+
+          def = this->GetVariableOrString(*arg);
+          def2 = this->Makefile.GetDefinition(argP2->GetValue());
+
+          if(def2)
+            {
+            std::vector<std::string> list;
+            cmSystemTools::ExpandListArgument(def2, list, true);
+
+            result = std::find(list.begin(), list.end(), def) != list.end();
+            }
+
+          this->HandleBinaryOp(result,
+            reducible, arg, newArgs, argP1, argP2);
+          }
+          else if(this->Policy57Status == cmPolicies::WARN)
+            {
+            std::ostringstream e;
+            e << (this->Makefile.GetPolicies()->GetPolicyWarning(
+              cmPolicies::CMP0057)) << "\n";
+            e << "IN_LIST will be interpreted as an operator "
+              "when the policy is set to NEW.  "
+              "Since the policy is not set the OLD behavior will be used.";
+
+            this->Makefile.IssueMessage(cmake::AUTHOR_WARNING, e.str());
+            }
+        }
+
       ++arg;
       }
     }

Source/cmConditionEvaluator.h

@@ -93,6 +93,7 @@ private:
   cmMakefile& Makefile;
   cmPolicies::PolicyStatus Policy12Status;
   cmPolicies::PolicyStatus Policy54Status;
+  cmPolicies::PolicyStatus Policy57Status;
 };
 
 #endif

Source/cmPolicies.cxx

@@ -390,6 +390,11 @@ cmPolicies::cmPolicies()
     CMP0060, "CMP0060",
     "Link libraries by full path even in implicit directories.",
     3,3,0, cmPolicies::WARN);
+
+  this->DefinePolicy(
+    CMP0057, "CMP0057",
+    "Support new IN_LIST if() operator.",
+    3,3,0, cmPolicies::WARN);
 }
 
 cmPolicies::~cmPolicies()

Source/cmPolicies.h

@@ -117,6 +117,7 @@ public:
     CMP0059, ///< Do not treat ``DEFINITIONS`` as a built-in directory
     /// property.
     CMP0060, ///< Link libraries by full path even in implicit directories.
+    CMP0057, ///< Support new IN_LIST if() operator.
 
     /** \brief Always the last entry.
      *

Tests/RunCMake/CMP0057/CMP0057-NEW.cmake

@@ -0,0 +1,31 @@
+cmake_policy(SET CMP0057 NEW)
+
+set(MY_NON_EXISTENT_LIST)
+
+set(MY_EMPTY_LIST "")
+
+set(MY_LIST foo bar)
+
+if(NOT "foo" IN_LIST MY_LIST)
+  message(FATAL_ERROR "expected item 'foo' not found in list MY_LIST")
+endif()
+
+if("baz" IN_LIST MY_LIST)
+  message(FATAL_ERROR "unexpected item 'baz' found in list MY_LIST")
+endif()
+
+if("foo" IN_LIST MY_NON_EXISTENT_LIST)
+  message(FATAL_ERROR
+    "unexpected item 'baz' found in non existent list MY_NON_EXISTENT_LIST")
+endif()
+
+if("foo" IN_LIST MY_EMPTY_LIST)
+  message(FATAL_ERROR
+    "unexpected item 'baz' found in empty list MY_EMPTY_LIST")
+endif()
+
+set(VAR "foo")
+
+if(NOT VAR IN_LIST MY_LIST)
+  message(FATAL_ERROR "expected item VAR not found in list MY_LIST")
+endif()

Tests/RunCMake/CMP0057/CMP0057-OLD-result.txt

@@ -0,0 +1 @@
+1

Tests/RunCMake/CMP0057/CMP0057-OLD-stderr.txt

@@ -0,0 +1,8 @@
+CMake Error at CMP0057-OLD.cmake:5 \(if\):
+  if given arguments:
+
+    "foo" "IN_LIST" "MY_LIST"
+
+  Unknown arguments specified
+Call Stack \(most recent call first\):
+  CMakeLists.txt:3 \(include\)

Tests/RunCMake/CMP0057/CMP0057-OLD.cmake

@@ -0,0 +1,7 @@
+cmake_policy(SET CMP0057 OLD)
+
+set(MY_LIST foo bar)
+
+if("foo" IN_LIST MY_LIST)
+  message("foo is in MY_LIST")
+endif()

Tests/RunCMake/CMP0057/CMP0057-WARN-result.txt

@@ -0,0 +1 @@
+1

Tests/RunCMake/CMP0057/CMP0057-WARN-stderr.txt

@@ -0,0 +1,19 @@
+CMake Warning \(dev\) at CMP0057-WARN.cmake:3 \(if\):
+  Policy CMP0057 is not set: Support new IN_LIST if\(\) operator.  Run "cmake
+  --help-policy CMP0057" for policy details.  Use the cmake_policy command to
+  set the policy and suppress this warning.
+
+  IN_LIST will be interpreted as an operator when the policy is set to NEW.
+  Since the policy is not set the OLD behavior will be used.
+Call Stack \(most recent call first\):
+  CMakeLists.txt:3 \(include\)
+This warning is for project developers.  Use -Wno-dev to suppress it.
+
+CMake Error at CMP0057-WARN.cmake:3 \(if\):
+  if given arguments:
+
+    "foo" "IN_LIST" "MY_LIST"
+
+  Unknown arguments specified
+Call Stack \(most recent call first\):
+  CMakeLists.txt:3 \(include\)

Tests/RunCMake/CMP0057/CMP0057-WARN.cmake

@@ -0,0 +1,5 @@
+set(MY_LIST foo bar)
+
+if("foo" IN_LIST MY_LIST)
+  message("foo is in MY_LIST")
+endif()

Tests/RunCMake/CMP0057/CMakeLists.txt

@@ -0,0 +1,3 @@
+cmake_minimum_required(VERSION 3.2)
+project(${RunCMake_TEST} NONE)
+include(${RunCMake_TEST}.cmake)

Tests/RunCMake/CMP0057/RunCMakeTest.cmake

@@ -0,0 +1,5 @@
+include(RunCMake)
+
+run_cmake(CMP0057-OLD)
+run_cmake(CMP0057-WARN)
+run_cmake(CMP0057-NEW)

Tests/RunCMake/CMakeLists.txt

@@ -63,6 +63,7 @@ add_RunCMake_test(CMP0051)
 add_RunCMake_test(CMP0053)
 add_RunCMake_test(CMP0054)
 add_RunCMake_test(CMP0055)
+add_RunCMake_test(CMP0057)
 add_RunCMake_test(CMP0059)
 add_RunCMake_test(CMP0060)
 if(CMAKE_GENERATOR STREQUAL "Ninja")