Spartan

Spartan is a small Lisp dialect that serves me as a test bed for programming language features.

Currently implemented features are:

• executable language grammar defined as a (PEG parser generator)-generated parser,
• recursion by way of letrec conversion with strongly conected components reordering & assignment conversions,
• a first-class module system with a shorthand accessor syntax (module, structure and foo.bar).
• continuations - both delimited (shift & reset) as well as undelimited (letcc),
• exception handling with restarts (raise & handle) relying on the continuations,
• actor model (spawn, send, recv),
• a built-in, Rete-based Rule Based System (signal!, assert!, retract!, select and notify-whenever),
• two compilation targets (ES6, r7rs),
• extensive compilation error handling with precise error locations and colored terminal output,
• a CLI tool sprtn with support for compile, run and repl commands,
• an interactive REPL with a twist.

See here for some usage examples. You can run these examples with:

There are also numerous test files available showcasing the compilation error handling features:

Compiler

Run ./build.sh to build the compiler CLI.

The compiler is far from being useful, it performs only rudimentary low-hanging fruit optimizations & validations. It loosely follows the nanopass framework, with currently implemented passes being:

• parsing,
• built-in macro expansion,
• syntax tree elaboration,
• implicit body handling,
• quasiquote expansion,
• constant value annotation,
• free-variable annotation,
• binding form analysis,
• syntax tree validation,
• alpha conversion,
• built-in function inlining,
• user function inlining,
• constant propagation,
• constant folding,
• common subexpression elimination,
• copy propagation,
• dead code elimination,
• letrec binding reordering,
• letrec conversion,
• continuation passing style transformation,
• flat closure conversion,
• global value hoisting,
• target-safe name mangling,
• target code generation.

REPL

The REPL supports a traditional flow of read-eval-print - each line entered is executed automatically and the results are printed immediately:

There's also a basic twist - the REPL accepts a full listing and allows editing it line by line: