The Compiler-Front library

The Compiler-Front library is repsonsible for processing the Front End Representation of a Dylan program. It depends only on the Compiler-Base library.

Data is passed from the Compiler-Parser library to the Compiler-Front library by the Compiler-Convert library.

The Builder-Interface Module

This module defines an interface which can be used to build the front-end representation (FER) of a parsed Dylan program.

Note that this module actually defines two interfaces: <flow-builder>, an abstract interface for constructing basic blocks (see the Section called The Flow Module); and <fer-builder>, a more specific version of that interface which is used to construct the front-end representation. It's not apparent that the former, more general interface is actually used anywhere else.

This interface is implemented by the Front module.

The optimize-component generic function gets implemented by the Compiler-Optimize library. We need to figure out why it's defined here instead of there.

The Primitives Module

This module defines the primitive operations which may appear in Dylan code.

The Front Module

This module does all the heavy lifting for the front-end of the compiler. It's split across a number of source files:


The data structures used in the front-end representation. These extend the classes defined in the Flow module.


Abstract classes and generic functions for the <flow-builder> and <fer-builder> classes.


The actual implementation of the various builders. This seems to be where the actual front-end code lives.


Code for dumping the front-end representation as text.


Code to clone the data structures representing a top-level function. This seems to be used when inlining functions.

To add a new class to the FER hiearchy, you'll need to add code to the following files: front.dylan, fer-dump.dylan, clone.dylan, fer-od.dylan and base/od-format.dylan. If you miss any of these spots, things will break in various entertaining ways.

The FER-OD Module

This module contains code for dumping the front-end representation as ODF (see the Section called The OD-Format Module). Special case is taken to make sure that all dumps start with a <function-literal> object; smaller components of the front-end representation can not be dumped individually.

The Function-Definitions Module

This module implements various subclasses of <definition> representing functions (see the Section called The Definitions Module). Most of the machinery for adding methods to a generic function at compile-time lives here, as does a good chunk of code related to sealing.

The Variable-Definitions Module

This module implements <variable-definition>. It also contains some of the code for handling load-time type expressions.

The Top-Level-Forms Module

This is not a very meaty module. It doesn't make much sense in the absence of the Compiler-Convert library. It does, however, contain a few classes for describing the things found at the top level of a Dylan file and provides the generic function finalize-top-level-form, which is called by the compilation driver once everything has been parsed.

This should not be confused with the Top-Level-Expressions module, which instantiates the data structures defined in this module.