Haskell Parser Project

This is a parser project in Haskell, demonstrating monadic parsing concepts with Parsec.

Overview

• app/Main.hs

  • Contains the main entry point.
  • Prints a greeting and demonstrates the parser with various hardcoded strings.
  • Optionally parses the first command-line argument passed in.

• src/Lib.hs

  • Defines msg :: String (our greeting).
  • Exports runMyParser :: String -> Either ParseError MyParsed, which runs a simple parser on an input string.
  • Implements helper functions (alphaString, integer, etc.) to parse alphabetic words plus optional digits, returning MyParsed objects.

• test/Spec.hs & test/LibSpec.hs

  • Uses Hspec for tests.
  • Currently includes a minimal test that checks the msg string.
  • You can add additional tests to verify parser correctness under various scenarios.

Setup

1. Check Dependencies
   Make sure you have Stack or GHC/cabal installed.
   The package.yaml (or .cabal) declares dependencies on parsec and hspec.

2. Build

   stack build
   

   This will fetch and build all required dependencies.

3. Run

   stack run
   

   You’ll see:

   • The greeting: "Hello, MPCS 51400 World!"
   • A series of hardcoded parse attempts (e.g. "Hello123", "ABC", etc.)
   • Optionally, if you do stack run "Example999", you’ll see parse results for "Example999".

4. Test Runs Hspec tests in test/. By default, we have a test confirming Lib.msg == "Hello, MPCS 51400 World!". You can add more tests as needed (see below).

5. Modify

• Tweak the parser in Lib.hs to handle more sophisticated grammars.
• Add more sample parse cases to Main.hs or more tests in test/.