From a command line:
cd <path-to>/lambda-pi/srcocamllex lexer.mllocamlyacc parser.mlymake dependmake
You should now have an executable file 'lpi' in the top level directory! If you don't, maybe you don't have the necessary Ocaml toolchain or something?
cd <path-to>/lambda-pi/./lpi
This should enter the interactive read-eval-print-loop, where you can line-by-line enter lpi commands and see all of the syntax errors you will inevitably make :).
Alternatively, the following sequence of commands:
cd <path-to>/lambda-pi/./lpi file.lpi,
will run the interpreter on the source file file.lpi and print the result of the final line in the file. Eventually I'll get around to writing a std lib to issue ```print`` calls so that you're not restricted to printing the result of the final sequentially executed instruction.
Using the language is pretty clunky. The syntax is still horrendous and I've provided a fairly restricted set of capabilities. That being said, lpi is modelled after the dependently-typed lambda calculus, and as such has some pretty cool features. Current implementation only supports a repl, but the goal is to write a compiler for ARM, which will expose the true benefits of static type-checking in a dependent type system that are lost in an interpreter. The project is intended to be a model for simple implementation of a complex system, in an approachable context. Most study on and implementation of depend type systems is done in languages such as Haskell (which have their own merits, approachable-ness not one of them), and feature techniques such as higher-order abstract syntax and quoting.