Function ParseCodeBlock

src/parse/codeblocks.cpp:37–107

Extacts the next code block from stream f. Returns true if found.

// Extacts the next code block from stream f.
// Returns true if found.
auto ParseCodeBlock(std::istream& fin) {
  struct Res {
    bool found;
    CodeBlock block;
    std::string error;
  };
  const auto flags = fin.flags();
  fin >> std::noskipws;
  CodeBlock block;
  enum class S { begin, name, content, exit };
  S s = S::begin; // state
  char c = ' ';
  int braces = 0;
  std::string error;
  while (fin && s != S::exit && error.empty()) {
    auto next = [&fin, &c]() { fin >> c; };
    switch (s) {
      case S::begin: {
        if (std::isspace(c)) {
          next();
        } else {
          s = S::name;
        }
        break;
      }
      case S::name: {
        if (c == '{') {
          s = S::content;
          next();
        } else if (c == '}') {
          error = "name cannot contain '}', unmatched brace?";
        } else {
          block.name += c;
          next();
        }
        break;
      }
      case S::content: {
        if (c == '}' && braces == 0) {
          s = S::exit;
          next();
        } else {
          block.content += c;
          if (c == '{') {
            ++braces;
          } else if (c == '}') {
            --braces;
          }
          next();
        }
        break;
      }
      case S::exit: {
        break;
      }
    }
  }
  if (error.empty() && s != S::exit &&