Yotc

LLVM frontend for yot - a toy language.

Running

• Install LLVM 9.0
• Run cargo install yotc
• Usage: yotc (path to file)
• Run yotc --help for more options

Yot Syntax

• Note: every variable is a 32-bit int and functions must return an int as well. Comparison operators return 1 or 0
• Functions:
  • Regular syntax

    @sum[a, b] {
        -> a + b // -> is the return keyword
    }
    

  • Short-hand notation for just return statement

    @sum[a, b] -> a + b;
    

  • External functions

    @!print[_, _];
    

  • Calling a function

    sum(a, b);
    

• Variables:
  • Declaration with value

    @a = 5;
    

  • Declaration without value (will be assigned to trash value)

    @a;
    

  • Referencing a variable

    @b = a + 5;
    

• Operations
  • Available operations =, +, -, *, /, ==, !=, <, >, <=, >=.

    @a = (-b + 5) - 10 / -(5 - -2);
    

• Comments
  • Comments start with // and tokens are ignored until the end of the line
• Programs
  • A program consists of just top-level functions (no global variables yet)
  • main function entry point
• Example
  • equals_ten.yot

    // External functions
    @!println[_];
    @!next_int[];
    
    @plus_five[a] -> a + 5;
    
    @main[] {
        @input = next_int();
        @equals_ten = plus_five(input) == 10;
        println(equals_ten);
    
        -> 0;
    }
    

  • io.cc

    #include <iostream>
    
    extern "C" {
        int println(int a) {
            std::cout << a << std::endl;
            return 0;
        }
    
        int next_int() {
            int input;
            std::cin >> input;
            return input;
        }
    }
    

  • Run by first generating the object file of equals_ten.yot with yotc equals_ten.yot --output-format=object-file
  • Compile and link io.cpp with g++ io.cc equals_ten.o to generate an executable

Todo

• If, for, while statements
• Support printing string literals
• Better compiler errors
  • Current errors are either vague or plain wrong and dont have any information about line number
  • Most errors are caught by LLVM, meaning more ugly and vague error messages
• More data types (float, bool, char)
• Testing