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# Erlang Syntax and Metaprogramming tools

## Overview

This package contains modules for handling abstract syntax trees (ASTs) in
Erlang, in a way that is compatible with the "abstract format" parse trees of
the stdlib module `erl_parse`, together with utilities for reading source files,
[pretty-printing syntax trees](`m:erl_prettypr`), and doing
[metaprogramming](`m:merl`) in Erlang.

The abstract layer (defined in `m: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 `m:erl_parse`
data structures, only requiring the `erl_syntax` module to be up-to-date.

The pretty printer `m:erl_prettypr` is implemented on top of the library module
`m: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 [assets/demo.erl](assets/demo.erl), and execute `demo:run()` from the Erlang
shell. It will compile the remaining modules and give you further instructions.