Cuttle VM

A virtual machine to be used with Cuttle System as a caching engine.

Reference

C++ deque is being used as a data container. Every operation ends with \n. Cuttle VM supports the next types of operations:

• b — push back to data deque, accepts type and value, e.g. b i 123;
• f — push from to data deque, accepts type and value, e.g. f i 123;
• c — call a function, accepts total number of arguments, number of arguments to deduce type from and function name, e.g. c 2 0 array;
• l — name the position in the code, e.g. l foo;
• r — name the position in data container, e.g. r bar;
• g — go to the position of the code if the last entry in data container is boolean true, accepts direction(< - backward, > - forward) and label name, e.g. g < while_start_label;
• a — call a function with arguments from data container up to the first position with the given name, accepts position name and function name, e.g. a array_start array.

The following data types are supported:

• i — integral number data type;
• s — string data type, ends with \n, to escape it use \\n;
• r — real number data type;
• b — boolean data type, true stands for true and everything else stands false.

This is an example of VM's code:

b s foo
b i 1
c 2 2 setvar
l start
b s foo
b s foo
c 1 1 getvar
b i 1
c 2 2 +
c 2 2 setvar
b s foo
c 1 1 getvar
b i 2
c 1 1 >
g < start
b s This is a test string

API

#include "interpreter.hpp"
// ...
std::stringstream input("b r 100.0\nb r 101.0\nb r 19.012383");
std::deque<value_t> arg_stack;
context_t context;
interpret(input, context, arg_stack);

For the previous code the next code works:

value_t val1 = value_t{ { type_id::real },{ context.gc.add(new real_t(100.0)) } };
value_t val2 = value_t{ { type_id::real },{ context.gc.add(new real_t(101.0)) } };
value_t val3 = value_t{ { type_id::real },{ context.gc.add(new real_t(19.012383)) } };
std::deque<value_t> expected = { val1, val2, val3 };
assert(arg_stack == expected);

Building

Prerequisites

• CMake 3.0.2
• Cygwin or MSYS Git if on Windows
• GCC 8.1.0 with C++
• GNU Make if manual process is followed

Default process

1. Enable CMake support in your IDE (Visual Studio, Visual Studio Code or CLion).
2. Open directory using your IDE.

Manual process

1. Under the project directory execute:
   • ./scripts/get-deps.sh if you don't have ssh authorization
   • ./scripts/get-deps.sh dev if you have ssh authorization
2. Create directory build under the project directory.
3. Under the project directory run
   1. cd build
   2. cmake ..
   3. make