Mon Nov 22

coming attractions

I've posted the description of the end of term compiler/interpreter project ... and tried to make it open ended enough that you have several options of what to do. Check out the assignment - we'll discuss your choices in class.

today

We'll continue our work on the dickinson language in class; I've posted a summary of your ideas so far. The next step is to use those ideas to write a formal grammar, and to to generate some examples together with what we think the corresponding parser tree and corresponding lisp code would be.

I've also set up a ladder of tasks to accomplish in this create-a-new-language project ... we'll see how far we can get in what time we have left.

Questions to address in the semantics (not just the syntax) of our new language:

• Is there a difference in variable assignment analogous to "define" vs "set!" in our language? * What should the corresponding lisp code be for "x is 1 + x" ?
• Can functions be defined within functions?
• Can functions call themselves (or other functions) recursively?
• Can global variables be modified from within functions?
• What operations do we want for data structures : arrays, lists, hashes, strings, ...
• Are all of these mutable?
• Is there anything analogous to lisp's "symbol" in this language?
• Are arguments to functions evaluated before being passed? Or is there a "lazy" option?
• Can functions have a variable number of arguments?

Next steps

Create (a) a grammar, and (b) examples, (c) tests for the successive parts (variables, functions, conditionals, ...)

I can continue to act as the central clearing house, combining what you folks (and I) do into successive versions ... or we can move to github or a similar setup, if we want to take the time to setup a space with access for all of us.