Indentation.h

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#ifndef fhiclcpp_detail_Indentation_h
#define fhiclcpp_detail_Indentation_h

// =========================================================
//
// Indentation
//
// Used for providing appropriate indentation for
// ParameterSet::to_indented_string.
//
// The 'pop' and 'push' commands must be used symmetrically.
//
// =========================================================

#include <cassert>
#include <stack>
#include <string>

namespace fhicl::detail {

  class Indentation {
  public:
    explicit Indentation(unsigned const iil = 0u)
      : indents_{{std::string(iil * indent_increment, ' ')}}
    {}

    explicit Indentation(std::string const& prefix) : indents_{{prefix}} {}

    std::string const&
    operator()() const
    {
      return indents_.top();
    }

    void
    modify_top(std::string const& s)
    {
      assert(!indents_.empty());
      if (indents_.size() == 1ul) {
        indents_.top() = s;
      } else {
        indents_.pop();
        indents_.emplace(indents_.top() + s);
      }
    }

    auto
    size()
    {
      return indents_.size();
    }

    void
    pop()
    {
      indents_.pop();
    }
    void
    push()
    {
      indents_.emplace(indents_.top() + std::string(indent_increment, ' '));
    }

  private:
    static constexpr std::size_t indent_increment = 3u;
    std::stack<std::string> indents_;
  };
}

#endif /* fhiclcpp_detail_Indentation_h */

// Local variables:
// mode: c++
// End: