DAG Structure

Vertices

Three Types:

1. Source Files: .erl, .yrl, .xrl, .mib

   • Label: LastModified (timestamp)
   • Example: {"/path/to/file.erl", 1234567890}

2. Header/Include Files: .hrl, other included files

   • Label: LastModified (timestamp)
   • Example: {"/path/to/file.hrl", 1234567890}

3. Artifact Files: .beam, .bin, compiled outputs

   • Label: {artifact, Metadata}
   • Metadata includes: compiler options, compiler version
   • Example: {"/path/to/file.beam", {artifact, [{compiler_version, "8.0"}, ...]}}

Edges

Two Types:

1. Dependency Edges: Source/header → dependency

   • Label: [] (empty list)
   • Direction: File points TO what it depends ON
   • Example: my_module.erl → types.hrl

2. Artifact Edges: Artifact → source

   • Label: artifact (atom)
   • Direction: Artifact points TO source that created it
   • Example: my_module.beam → my_module.erl

Special Vertex

Dirty Bit: '$r3_dirty_bit'

• Presence indicates DAG has been modified
• Used to determine if save is needed
• Not a real file