Genex: Add a COMPILE_LANGUAGE generator expression.

1 files changed, 31 insertions, 1 deletions

diff --git a/Source/cmGeneratorExpressionEvaluator.cxx b/Source/cmGeneratorExpressionEvaluator.cxx
index ba18faa..63a46f2 100644
--- a/Source/cmGeneratorExpressionEvaluator.cxx
+++ b/Source/cmGeneratorExpressionEvaluator.cxx
@@ -16,6 +16,7 @@
 #include "cmGeneratorExpressionDAGChecker.h"
 #include "cmGeneratorExpression.h"
 #include "cmLocalGenerator.h"
+#include "cmGlobalGenerator.h"
 #include "cmSourceFile.h"
 
 #include <cmsys/String.h>
@@ -89,7 +90,8 @@ std::string cmGeneratorExpressionNode::EvaluateDependentExpression(
                         context->Quiet,
                         headTarget,
                         currentTarget,
-                        dagChecker);
+                        dagChecker,
+                        context->Language);
   if (cge->GetHadContextSensitiveCondition())
     {
     context->HadContextSensitiveCondition = true;
@@ -806,6 +808,33 @@ static const struct JoinNode : public cmGeneratorExpressionNode
   }
 } joinNode;
 
+static const struct CompileLanguageNode : public cmGeneratorExpressionNode
+{
+  CompileLanguageNode() {}
+
+  virtual int NumExpectedParameters() const { return OneOrZeroParameters; }
+
+  std::string Evaluate(const std::vector<std::string> &parameters,
+                       cmGeneratorExpressionContext *context,
+                       const GeneratorExpressionContent *content,
+                       cmGeneratorExpressionDAGChecker *) const
+  {
+    if(context->Language.empty())
+      {
+      reportError(context, content->GetOriginalExpression(),
+          "$<COMPILE_LANGUAGE:...> may only be used to specify include "
+          "directories compile definitions, compile options and to evaluate "
+          "components of the file(GENERATE) command.");
+      return std::string();
+      }
+    if (parameters.empty())
+      {
+      return context->Language;
+      }
+    return context->Language == parameters.front() ? "1" : "0";
+  }
+} languageNode;
+
 #define TRANSITIVE_PROPERTY_NAME(PROPERTY) \
   , "INTERFACE_" #PROPERTY
 
@@ -1829,6 +1858,7 @@ cmGeneratorExpressionNode* GetNode(const std::string &identifier)
     nodeMap["INSTALL_PREFIX"] = &installPrefixNode;
     nodeMap["JOIN"] = &joinNode;
     nodeMap["LINK_ONLY"] = &linkOnlyNode;
+    nodeMap["COMPILE_LANGUAGE"] = &languageNode;
     }
   NodeMap::const_iterator i = nodeMap.find(identifier);
   if (i == nodeMap.end())