ERPLAG: a minimalist compiler

ERPLAG is a strongly typed, compiled language. It is minimalist because it currently does not encompass the full capabilities of most modern programming languages like character and string handling or defining structs/classes.

Prerequisites

• gcc >= 7.0
• nasm >= 2.14.02

How to build

The code has been tested in Ubuntu >= 16.04, and the README has been prepared accordingly. Users of other OSes will need to figure out the equivalent commands or supporting software wherever applicable.

1. Clone the repository
   $ git clone https://github.com/MayankJasoria/Compiler-Project.git

2. Build

   $ cd Compiler-Project  
   $ make
   

   This should create a binary file named 'compiler' in the same directory.

3. Execute
   Run the ERPLAG compiler in the following manner:

   $ ./compiler <source-code> <assembly-file>.asm
   $ nasm -f elf64 <assembly-file>.asm
   $ gcc -no-pie <assembly-file>.o -o <output>.out
   $ ./<output>.out
   

Language Features

ERPLAG supports the following features:

• Primitive datatypes - integers, floating points
• Non-primitive - arrays, boolean
• Basic arithmetic operations - add, subtract, multiply, divide
• Statements:

  • Comments
    Examples:

     ** single line comment **
    
     **
     Multiline comment
     **
    

  • Declarative
    Examples:
    Declaring variables:

     declare index:integer;
     declare t:boolean;
     declare s:real;
    

    Declaring a module:

     declare module readArr;
    

  • Assignment
    Examples:

     sum := sum + 4; ** Integer assignment **
     pi := 3.14; ** Floating point assignment **
     bool2 := a < b ** Boolean assignment **
     arr2 := arr1; ** Assigning one array into another variable **
    

  • Input/output
    Examples:
    Input:

     get_value(var);
    

    Output

     print(var);
    

  • Conditional
    Examples:

     switch(c) ** switch case on boolean **
     start
     	case true:
     		** statements **;
     		break;
     	case false: 
     		** statements **;
     		break;
     end
    
     switch(int1) ** switch case on integer **
     start
     	case 1:
     		** statements **
     		break;
     	case 2:
     		** statements **
     	case 3:
     		** statements **
     		break;
     	default:
     		** statements **
     end
    

  • Iterative
    Examples: While loop

     while(a >= b)
     start
     	** statements **
     end
    

    For loop

     for(idx1 in 1..10)
     start
     	** statements **
     end
    

  • Module declaration and call
    Examples:

    Driver (main) module
    Note: Driver module is the entry-point of an ERPLAG program.

     <<<driver program>>>
     start
     	** statements **
     end
    

    Module declaration

     declare module m1; ** allows module definition to be given after 'driver' **
    
     <<module arraySum>> ** Declaration and definition may be combined this way, if it appears in the code before driver module **
     takes input[list:array[1..15] of real, n:integer];
     returns  [sum:real]; 
     start
     	** statements **
     end
     
     <<module printReal>>
     takes input[n:real];
     start
     	print(n);
     end
    

    Module call

     [sum]:= use module arraySum with parameters A,k;
     use module printReal with parameters pi;
    

A detailed language specification can be found here.

Contributing

This project is no longer under active development. Any issues opened on this repository are likely to be ignored. However, well worked out pull requests are entertained.