efci - Effective Curry Interpreter

This repository accompanies the Haskell'24 paper Making a Curry Interpreter using Effects and Handlers.

The most recent code might differ from the version shown in the paper. You can check out

• 4db98c2 for the original interpreter
• 1421632 for an extended version featuring unification
• 90dfb99 for 'fusion all the way'

Installation (tested with stack 3.7.1 and cabal 3.12.1.0)

git clone https://github.com/nbun/efci
cd efci
git submodules pull --init
stack install

Usage

Run

efci [filename]

from the directory where filename.curry is located. If efci is called without an argument, only the Prelude module is loaded. If you have rlwrap installed, use rlwrap efci [filename] to get an input history for the interpreter.

Options

• Without an option, the input is interpreted as a Curry expression within the loaded file.
• :q exits interpreter.
• :o rotates between the available interpretation modes
• :time toggles printing time elapsed during interpretation
• :fcy toggles printing of the main expression generated from the input.

Run tests

stack test effective-curry-interpreter

Run benchmarks

stack bench effective-curry-interpreter

Known issues

• Ambiguous types are not defaulted. For example, 1 + 2 needs to be annotated as 1 + 2 :: Int.
• Not all external functions are implemented.