# Erlang Syntax Tools

Copyright © 1997-2004 Richard Carlsson

Version: 1.4.1

Authors: Richard Carlsson (`richardc@csd.uu.se`).

This package contains modules for handling abstract Erlang syntax trees, in a way that is compatible with the "parse trees" of the standard library module `erl_parse`, together with utilities for reading source files in unusual ways and pretty-printing syntax trees. Also included is an amazing module merger and renamer called Igor, as well as an automatic code-cleaner.

The abstract layer (defined in `erl_syntax`) is nicely structured and the node types are context-independent. The layer makes it possible to transparently attach source-code comments and user annotations to nodes of the tree. Using the abstract layer makes applications less sensitive to changes in the `//stdlib/erl_parse` data structures, only requiring the `erl_syntax` module to be up-to-date.

The pretty printer `erl_prettypr` is implemented on top of the library module `prettypr`: this is a powerful and flexible generic pretty printing library, which is also distributed separately.

For a short demonstration of parsing and pretty-printing, simply compile the included module `demo.erl`, and execute `demo:run()` from the Erlang shell. It will compile the remaining modules and give you further instructions.

Also try the `erl_tidy` module, as follows:

        erl_tidy:dir("any-erlang-source-dir", [test, old_guard_tests]).

("`test`" assures that no files are modified).

News in 1.4:

- Added support for cond-expressions, try-expressions and class-qualifier patterns.
- Added support for parameterized modules.
- Igor is officially included.
- Quick-parse functionality added to `epp_dodger`.

News in 1.3:

- Added support for qualified names (as used by "packages").
- Various internal changes.

News in 1.2:

- HTML Documentation (generated with EDoc).
- A few bug fixes and some minor interface changes (sorry for any inconvenience).

News in 1.1:

- Module `erl_tidy`: check or tidy either a single module, or a whole directory tree recursively. Rewrites and reformats the code without losing comments or expanding macros. Safe mode allows generating reports without modifying files.
- Module `erl_syntax_lib`: contains support functions for easier analysis of the source code structure.
- Module `epp_dodger`: Bypasses the Erlang preprocessor - avoids macro expansion, file inclusion, conditional compilation, etc. Allows you to find/modify particular definitions/applications of macros, and other things previously not possible.