CSCI 468: Compilers

This is the base upstream repository for CSCI 468, compilers. It holds the base code for the compiler that we will write for the class.

Note that this class is a capstone class in the CSCI department and, as such, requires capstone documentation. An outline of this can be found in the /capstone directory.

Getting Your Repo Set Up

Please set up your private repository via these instructions:

• Create a private repository in your own account by
  • Going to https://github.com/new
  • Enter the name csci-468-spring2025-private
  • Select Private
  • DO NOT ADD A README.MD or .gitignore!
  • Navigate to the Settings -> Manage Access section
  • Add 1cg as a collaborator

Once your repository is initialized, you can pull it down to your local machine.

Next, you should add the class repository as an upstream git repo:

$ git remote add upstream https://github.com/msu/csci-468-spring2025.git
$ git pull upstream main
$ git push origin main

This will synchronize your private repository with the class repository.

When you want to get an update from the public class repository you can run this command:

$ git pull upstream main

CatScript

In this course we will be creating a small programming language called CatScript

CatScript Grammar

catscript_program = { program_statement };

program_statement = statement |
                    function_declaration;

statement = for_statement |
            if_statement |
            print_statement |
            variable_statement |
            assignment_statement |
            return_statement |
            function_call_statement;

for_statement = 'for', '(', IDENTIFIER, 'in', expression ')', 
                '{', { statement }, '}';

if_statement = 'if', '(', expression, ')', '{', 
                    { statement }, 
               '}' [ 'else', ( if_statement | '{', { statement }, '}' ) ];

print_statement = 'print', '(', expression, ')'

variable_statement = 'var', IDENTIFIER, 
     [':', type_expression, ] '=', expression;

function_call_statement = function_call;

assignment_statement = IDENTIFIER, '=', expression;

function_declaration = 'function', IDENTIFIER, '(', parameter_list, ')' + 
                       [ ':' + type_expression ], '{',  { statement },  '}';

parameter_list = [ parameter, {',' parameter } ];

parameter = IDENTIFIER [ , ':', type_expression ];

return_statement = 'return' [, expression];

expression = equality_expression;

equality_expression = comparison_expression { ("!=" | "==") comparison_expression };

comparison_expression = additive_expression { (">" | ">=" | "<" | "<=" ) additive_expression };

additive_expression = factor_expression { ("+" | "-" ) factor_expression };

factor_expression = unary_expression { ("/" | "*" ) unary_expression };

unary_expression = ( "not" | "-" ) unary_expression | primary_expression;

primary_expression = IDENTIFIER | STRING | INTEGER | "true" | "false" | "null"| 
                     list_literal | function_call | "(", expression, ")"

list_literal = '[', expression,  { ',', expression } ']'; 

function_call = IDENTIFIER, '(', argument_list , ')'

argument_list = [ expression , { ',' , expression } ]

type_expression = 'int' | 'string' | 'bool' | 'object' | 'list' [, '<' , type_expression, '>']

CatScript Types

CatScript is statically typed, with a small type system as follows

• int - a 32 bit integer
• string - a java-style string
• bool - a boolean value
• list - a list of values with the type 'x'
• null - the null type
• object - any type of value