9 Project Syntax Implementation Code Walk🔗

Due by March 12: Email me a link to your project’s repository. Make it public or give me access to view it. I am @michaelballantyne on GitHub.

Code Walk Dates: March 13, 17, 19, and 20.

For this assignment, you will implement a first version of the syntax layer for your project and present the code to the class.

We will spend 20 minutes in class on each pair’s project. You will present using your own computer, so please install the Mersive Solstice app for the projecter and test your computer in the classroom prior to the scheduled date.

See Piazza for the schedule of presentations.

Structure your presentation following the design recipe for DSL syntax:

• Focused purpose statement. Very briefly remind us of the purpose of your DSL, the concepts in the domain, and the advantages your DSL aims to provide as compared to general-purpose code.

• Example input: an example program in the DSL syntax. Show us a DSL program that illustrates the syntax you have implemented and how the concepts of the domain are used in DSL code.

• Example output: the example program compiled to Racket and your runtime. The input to your syntax layer is a DSL program; the output is a Racket program using the runtime support functions you have implemented. So, to help us understand the syntax layer, show us the Racket program that results from expansion or compilation of the example program. (This may not apply if your DSL is implemented using only functions and no macros.)

• Grammar. The grammar for your DSL is the analog of a signature in the design recipe for functions.

• Realization of the grammar by syntax-parse, syntax-spec, or function signatures. The syntax-parse patterns, syntax-spec declarations, or collection of functions in an embedding serve to realize your DSL’s syntax. Discuss your rationale for which of the three implementation approaches that you chose, and note any difficulties in realizing the intended grammar of your language.

• Template for the compiler. Now that you’ve explained how the syntax of your DSL is parsed, explain how the compilation to Racket is structured. Is it a collection of mutually recursive macros? A series of static checks and compiler passes implemented as compile-time functions? For a DSL that only uses runtime functions, explain the structure of composition in the runtime and associated signature—for example, in the animation DSL, composition is in terms of the animation signature (-> Time Image). Discuss your rationale for the compiler architecture choice in relationship to the advantages your DSL aims to provide as compared to general-purpose code: how does it enable the syntax, static semantics, optimizations, user-extensibility, or other benefits you intend?

• Tests. Show us how you have tested the compilation and error behavior of the syntax layer of your DSL.

Your presentation should be in the form of showing us the code of your project and associated design documentation, not as slides. I will choose which partner presents which of the parts above, so both partners should be prepared to present any portion. I or Matthias might ask you to redirect your presentation to look at a specific part of your code. 20 minutes isn’t a long time when including audience questions and discussion, so be prepared to address each point concisely.