An aggressively optimizing compiler for the VL language
Overview
The name VL derives from VLAD, which is a higher-order functional programming language that supports automatic differentiation (AD); see [1] for more details. VL stands for VLAD without AD.
The compiler uses polyvariant union-free flow analysis to compile VL to an efficient, FORTRAN-like C code. This program is meant to be expository and not necessarily efficient. I've written it in order to understand polyvariant union-free flow analysis described in [1].
The name VL was coined by Alexey Radul, who wrote a VL to Scheme compiler in Scheme and suggested that I repeat this exercise in Haskell for comparison. I'm releasing the code, so that I can reference it, and hoping that somebody may find it useful, although I'm not planning to develop it any further. Still, if you spot bugs or have improvement suggestions, I'd be glad to hear from you.
Compiling
To compile the VL to C compiler, run
stack build
Testing
To build and run the test suites, run:
stack test
The package.yaml file defines two test suites: test-evaluator,
which tests both the concrete and abstract evaluator, and
test-compiler, which tests the compiler. To add more tests to the
evaluator test suite, edit the source file test/test-evaluator.hs.
To add a test to the compiler test suite, drop a file with the
extension .vl containing the VL source code of the program into the
directory test/vl and put the expected value in a comment in the
last line of that file.
Bibliography
[1] Jeffrey Siskind and Barak Pearlmutter, Using Polyvariant Union-Free Flow Analysis to Compile a Higher-Order Functional Programming Language with a First-Class Derivative Operator to Efficient FORTRAN-like Code, Purdue University ECE Technical Report, 2008, http://docs.lib.purdue.edu/ecetr/367.