mathvm

Introduction

This folder contains partial source code for a simple VM, with few intentionally missing pieces. This VM implements simple language (MVM language) with basic computational functionality and flow control.

MVM language

Language has simple C-style syntax and is intentionally rather basic. Language has 3 types:

• 64-bit integer type, called int
• ANSI C compatible double type, called double
• immutable strings, called string (C equivalent: char*)

Every variable is scoped, scope is marked with curly braces ({ and }). Variable has to be declared before first use, otherwise translation error will happen.

Values in variable could be modified with traditional C-style expressions, like x = 2 + y * 3; with traditional C-style operators precedence, i.e. aforementioned expression is evaluated as x = (2 + (y * 3));

Variables in topmost scope could be bound to Var class instances, to allow interoperability between MVM programs and C++.

Literals can be:

• integer, such as 42 or 123456789012345
• double, such as 42.0 or 1e-18
• string, such as '42' or 'Hello \'World\'\n'

Flow control is as following:

• for loop, with semantics:

    for (i in -10..x) {
        print('i=', i, '\n');
    }

• if conditions, such as

    if (x == 8 && y <= 2) {
        print('c1\n');
    } else {
        print('c2\n');
    }

Implementation

We provide generic source -> AST (abstract syntax tree) translator, so that implementors can focus on VM-specific issues. It means we give scanner and top-down parser, generating tree of AST nodes, representing program structure. It is up to implementors to provide remaining pieces for fully functional VM.

Tests

Directory tests contains set of tests on basic language features, along with test scripts taskN.py. Generally, for every MVM program we have an .expect file, which contains expected result of execution for given MVM program.

Source tree layout

Folder 'include' contains generic declarations of language constructs (as AST nodes), set of bytecodes with description, and certain basic interfaces.

Folder tests contains MVM tests. Feel free to implement your own tests.

Folder vm contain source code for the VM.

Building

Build shall be pretty straightforward, just type make in command line (known to work with MacOS and Linux). Use make OPT=1 for an optimized build. NO_JIT variables controls if JIT dependencies shall be compiled in. Create your own implementation in students/<year>/<your last name> folder, using students/<year>/_example template.