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

  • equalsten.yot ``` // External functions @!println[]; @!next_int[];

    @plus_five[a] -> a + 5;

    @main[] { @input = nextint(); @equalsten = plusfive(input) == 10; println(equalsten);

    -> 0;
    

    } ```

  • io.cc ```

    include

    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