Astarisk

Astarisk is a tool to visualize RubyVM::AbstractSyntaxTree nodes on console.

That is named as "AST a risk".

NOTE: RubyVM::AbstractSyntaxTree is defined as RubyVM::AST in Ruby 2.6.0 preview3, but it'll be renamed to RubyVM::AbstractSyntaxTree in later versions.

NOTE: Use Ruby 2.6.0 preview3 or later

1. Get an AST using methods blow:

• RubyVM::AbstractSyntaxTree#parse (from ruby code)
• RubyVM::AbstractSyntaxTree#parse_file (from file path)
• RubyVM::AbstractSyntaxTree#of (from an object of Method or Proc)

2. Get a graph string

• Astarisk.draw_graph(ast)

3. Or draw graph on STDERR (in default)

• Astarisk.draw(ast)

Output example from a blank Proc object:

[NODE_SCOPE]
 |
 +--[]
 |
 +--[NODE_ARGS]
 |   |
 |   +--Integer(0)
 |   |
 |   +--NilClass(nil)
 |   |
 |   +--NilClass(nil)
 |   |
 |   +--NilClass(nil)
 |   |
 |   +--Integer(0)
 |   |
 |   +--NilClass(nil)
 |   |
 |   +--NilClass(nil)
 |   |
 |   +--NilClass(nil)
 |   |
 |   +--NilClass(nil)
 |   |
 |   +--NilClass(nil)
 |
 +--[NODE_BEGIN]
     |
     +--NilClass(nil)

Output example in compact format:

[NODE_SCOPE]
 +--[]
 +--[NODE_ARGS]
 |   +--Integer(0)
 |   +--NilClass(nil)
 |   +--NilClass(nil)
 |   +--NilClass(nil)
 |   +--Integer(0)
 |   +--NilClass(nil)
 |   +--NilClass(nil)
 |   +--NilClass(nil)
 |   +--NilClass(nil)
 |   +--NilClass(nil)
 +--[NODE_BEGIN]
     +--NilClass(nil)

Draw a graph on specified I/O destination (default: STDERR)

Arguments:

• AST node (an instance of RubyVM::AbstractSyntaxTree::Node)

Keyword arguments:

• out: output I/O to draw graph (default: STDERR)
• mode: symbol to specify :compact mode (default: :normal)

Return value: nil

Draw a graph and return it as a String

Argument:

• AST node (an instance of RubyVM::AbstractSyntaxTree::Node)

Keyword arguments:

• mode: symbol to specify :compact mode (default: :normal)

Return value: a String of graph

Bug reports and pull requests are welcome on GitHub at https://github.com/tagomoris/astarisk.

The gem is available as open source under the terms of the MIT License.