# Clang 4 documentation

## LibFormat

LibFormat is a library that implements automatic source code formatting based on Clang. This documents describes the LibFormat interface and design as well as some basic style discussions.

If you just want to use clang-format as a tool or integrated into an editor, checkout ClangFormat.

## Design

FIXME: Write up design.

## Interface

The core routine of LibFormat is `reformat()`:

    tooling::Replacements reformat(const FormatStyle &Style, Lexer &Lex,
                                   SourceManager &SourceMgr,
                                   std::vector<CharSourceRange> Ranges);

This reads a token stream out of the lexer `Lex` and reformats all the code ranges in `Ranges`. The `FormatStyle` controls basic decisions made during formatting. A list of options can be found under Style Options.

## Style Options

The style options describe specific formatting options that can be used in order to make ClangFormat comply with different style guides. Currently, two style guides are hard-coded:

    /// \brief Returns a format style complying with the LLVM coding standards:
    /// http://llvm.org/docs/CodingStandards.html.
    FormatStyle getLLVMStyle();

    /// \brief Returns a format style complying with Google's C++ style guide:
    /// http://google-styleguide.googlecode.com/svn/trunk/cppguide.xml.
    FormatStyle getGoogleStyle();

These options are also exposed in the standalone tools through the -style option.

In the future, we plan on making this configurable.