Method Evaluate

Source/cmGeneratorExpressionNode.cxx:3088–3139

  int NumExpectedParameters() const override { return ZeroOrMoreParameters; }

  std::string Evaluate(
    std::vector<std::string> const& parameters, cm::GenEx::Evaluation* eval,
    GeneratorExpressionContent const* content,
    cmGeneratorExpressionDAGChecker* dagChecker) const override
  {
    if (!eval->HeadTarget || !dagChecker ||
        !(dagChecker->EvaluatingLinkExpression() ||
          dagChecker->EvaluatingLinkLibraries() ||
          dagChecker->EvaluatingLinkerLauncher())) {
      reportError(eval, content->GetOriginalExpression(),
                  "$<LINK_LANGUAGE:...> may only be used with binary targets "
                  "to specify link libraries, link directories, link options "
                  "and link depends.");
      return std::string();
    }
    if (dagChecker->EvaluatingLinkLibraries() && parameters.empty()) {
      reportError(
        eval, content->GetOriginalExpression(),
        "$<LINK_LANGUAGE> is not supported in link libraries expression.");
      return std::string();
    }

    cmGlobalGenerator const* gg = eval->Context.LG->GetGlobalGenerator();
    std::string genName = gg->GetName();
    if (genName.find("Makefiles") == std::string::npos &&
        genName.find("Ninja") == std::string::npos &&
        genName.find("FASTBuild") == std::string::npos &&
        genName.find("Visual Studio") == std::string::npos &&
        genName.find("Xcode") == std::string::npos &&
        genName.find("Watcom WMake") == std::string::npos &&
        genName.find("Green Hills MULTI") == std::string::npos) {
      reportError(eval, content->GetOriginalExpression(),
                  "$<LINK_LANGUAGE:...> not supported for this generator.");
      return std::string();
    }

    if (dagChecker->EvaluatingLinkLibraries()) {
      eval->HadHeadSensitiveCondition = true;
      eval->HadLinkLanguageSensitiveCondition = true;
    }

    if (parameters.empty()) {
      return eval->Context.Language;
    }

    for (auto const& param : parameters) {
      if (eval->Context.Language == param) {
        return "1";
      }
    }
    return "0";
  }
} linkLanguageNode;

namespace {