Method ReplayZipLists

Source/cmForEachCommand.cxx:152–254

}

bool cmForEachFunctionBlocker::ReplayZipLists(
  std::vector<cmListFileFunction> const& functions,
  cmExecutionStatus& inStatus)
{
  assert("Unexpected number of iteration variables" &&
         this->IterationVarsCount >= 1);

  auto& mf = inStatus.GetMakefile();

  // Expand the list of list-variables into a list of lists of strings
  std::vector<cmList> values;
  values.reserve(this->Args.size() - this->IterationVarsCount);
  // Also track the longest list size
  std::size_t maxItems = 0u;
  for (auto const& var :
       cmMakeRange(this->Args).advance(this->IterationVarsCount)) {
    cmList items;
    auto const& value = mf.GetSafeDefinition(var);
    if (!value.empty()) {
      items.assign(value, cmList::EmptyElements::Yes);
    }
    maxItems = std::max(maxItems, items.size());
    values.emplace_back(std::move(items));
  }

  // Form the list of iteration variables
  std::vector<std::string> iterationVars;
  if (this->IterationVarsCount > 1) {
    // If multiple iteration variables has given,
    // just copy them to the `iterationVars` list.
    iterationVars.reserve(values.size());
    std::copy(this->Args.begin(),
              this->Args.begin() + this->IterationVarsCount,
              std::back_inserter(iterationVars));
  } else {
    // In case of the only iteration variable,
    // generate names as `var_name_N`,
    // where `N` is the count of lists to zip
    iterationVars.resize(values.size());
    auto const iter_var_prefix = cmStrCat(this->Args.front(), '_');
    auto i = 0u;
    std::generate(
      iterationVars.begin(), iterationVars.end(),
      [&]() -> std::string { return cmStrCat(iter_var_prefix, i++); });
  }
  assert("Sanity check" && iterationVars.size() == values.size());

  // Store old values for iteration variables
  std::map<std::string, cm::optional<std::string>> oldDefs;
  for (auto i = 0u; i < values.size(); ++i) {
    auto const& varName = iterationVars[i];
    if (mf.GetPolicyStatus(cmPolicies::CMP0124) != cmPolicies::NEW) {
      oldDefs.emplace(varName, mf.GetSafeDefinition(varName));
    } else if (mf.IsNormalDefinitionSet(varName)) {
      oldDefs.emplace(varName, *mf.GetDefinition(varName));
    } else {
      oldDefs.emplace(varName, cm::nullopt);
    }