Macro Stepper

The macro stepper is a new DrScheme tool for debugging macros. It shows macro expansion as a sequence of rewriting steps, where a step is either a single macro transformation or an operation performed by a primitive syntactic form. The graphical display lets the programmer investigate binding and source properties of the syntax involved in expansion.

Installation/Availability

The macro stepper is part of the DrScheme distribution, starting with DrScheme 360. You do not need to take any additional steps to install the macro stepper.

Currently, the macro stepper only works on the following language levels:

Textual (MzScheme, includes R5RS)
Graphical (MrEd, includes MzScheme)
Pretty Big (includes MrEd and Advanced Student)
(module ...)

If you don't see the macro stepper button, check to make sure you have selected one of the language levels listed above.

Using the macro stepper

The macro stepper is a tool that operates on the contents of the Definitions window, like the Check Syntax tool.

Open your program in DrScheme.
Make sure you have a suitable language level selected.
Click the Macro Stepper button:
The macro stepper opens a frame displaying your program's macro expansion.
Navigate through the expansion using the navigation buttons at the top of the frame.

Read the tutorial for an illustrated introduction to the macro stepper's basic operation.

Then read the manual for information on the macro stepper's advanced features.

Bugs, feature requests, and feedback

Report bugs using the Help Desk: Under the Help menu, click "Submit Bug Report."

Or contact me directly at ryanc at ccs dot neu dot edu

Watch this space for descriptions of known bugs and workarounds.