FOPL Course Project

The Mini Language interpreter, developed with Haskell.

Building (using stack):

stack setup
stack build

Features:

1. Extended mini language syntax
2. Minimum error message
3. GC (Memory management detail will be printed to standard output)

Program1:
  Pro
    Print Num 2 End
    Decl x End
  End
ErrorMessage1:
  "program.txt" (line 3, column 3):
  unexpected "D"
  expecting "End"

Program2:
  Pro
    Print Id x End End
  End
ErrorMessage2:
  Variable x is not in scope! "program.txt" (line 1, column 14)

Program3:
  Pro
    Decl x End
    Print Id x End End
  End
ErrorMessage3:
  Unprintable object!

3. First citizen function, making the use of keyword FunName obsolete

Program:
  Pro
    Func f Para End
      Pro
        Print Num 2 End End
      End
    End
    Func g Para x End
      Pro
        Return Id x End End
      End
    End
    Decl q End
    LetBe q AppFun g List Id f End End End End
    AppFun q  List End End
  End    
Output:
  2

4. Closure

Program:
  Pro
    Func f Para n End
      Pro
        Decl x End
        LetBe x Id n End End
        Func g Para m End
          Pro
            LetBe x
              Plus Id x End Id m End End
            End
            Print Id x End End
          End
        End
        Return Id g End End
      End
    End

    Decl add End
    LetBe add
      AppFun f List Num 0 End End End
    End
    AppFun add List Num 2 End End End
    AppFun add List Num 3 End End End
  End
Output:
  2
  5