/fedit

Text Editor for FOUL

Primary LanguageHaskell

Foul EDITor

CS410 Final Assignment

Darren Mowat

200911909

Things added to the FOUL Language

  • Rewrote the parser using Parsec. It now output useful error messages & positions to help find errors
  • Rewrote the interpreter to handle errors more gracefully
  • Check the program before interpreting for duplicate method declarations and functions declarations that take different numbers of parameters
  • Added single line comments to the language (-- Comment Goes Here)
  • Added a module import system to the parser. Users can define their own functions in separate files and import them in.
  • Implemented some standard library modules. These modules are not part of the interpreter, they're foul files stored in the std directory of this repository. Cabals Path_fedit module is used to access them on the host system at runtime.
    • import std/math: Add, Subtract, Multiply, Divide, Equals, More Than, More Than Equals, Less Than, Less Than Equals, Square, Fibonacci & Infinity (Negative numbers aren't supported and causes a crash)
    • import std/bool: Conditional Application (cond), and, or & not
    • import std/test: Module used for testing. Its used to implement tests for std/bool & std/math (tests are in tests/FOUL)
  • Add basic integer support to the parser. Instead of writing S(S(S(Z))) you can just write 3 (both in patterns and expressions)
  • Pretty Print Values (VC "T" [] -> T, VC "S" [VC "Z" []] -> 1)

Things added to the editor

  • Fixed handleKey bug which loops forever and uses 100% CPU
  • Evaluate the main function of the file on exit
  • Save the file on exit
  • Line Numbers
  • Added a way to evaluate expressions within the files. This is available using the following syntax
    • -- eval EXPR
    • -- eval add(7, 8)
    • The answer will then be inserted into the comment -- eval add(7, 8) -> 15
    • Evaluation is triggered by typing Ctrl+e
  • Display parser errors at the bottom of the editor window
  • In line evaluation errors as comments

Installation

FOUL & Fedit are packed using Cabal as they have some external dependencies that would be hard to manage with MakeFiles. Cabal will build 2 seperate binarys when run

* foul - FOUL parser and evaluator
* fedit - Foul EDITor

Get a copy of this repository either by

git clone https://github.com/DarrenMowat/fedit.git

Or by downloading it as a zip file from https://github.com/DarrenMowat/fedit/archive/master.zip

cd fedit
cabal configure
cabal install

The fedit & foul binaries should now be available on your PATH somewhere

Sample FOUL Files

There is a modified implementation of the sorting function in sample/mysort.foul. It utilises the standard library modules, comments and the use of integers as expressions.

There are also some test files designed to test the standard library functions in tests/FOUL/*.

The standard library modules are defined in std/*. These show an example of using integers as pattern variables

Screenshots

  • Parse Error

ParseError

  • Evaluating fib(20)

Blackbox

  • Maths standard library

Blackbox