dmildew 0.0.7

DMildew

A scripting language for the D programming language inspired by Lua and JavaScript.

This is still very much a work in progress.

Usage

The examples/ folder contains example scripts. It should look familiar to anyone who knows JavaScript. However, Mildew is not a full feature JavaScript implementation.

This project is in its early stages so you should probably use the ~main version to get the latest bug fixes. The release tags are only so that it is usable in dub.

Running the Examples

In a terminal in the main project directory run dub run :repl -- examples/nameOfExample.mds. If you want to try out the interactive shell simply type dub run :repl. In the interactive shell it is only possible to enter multiple lines by writing '' at the end of a line you want to continue. Note that functions and classes declared in one REPL command will not be accessible in the next unless stored in a var. To store a class such as class Foo {} one must write var Foo = Foo; immediately after.

Binding

See mildew/stdlib files for how to bind functions. Classes can be bound by wrapping the object inside a ScriptObject. Methods can be written as free functions or delegates stored inside the bound constructor's prototype object. In the future, there might be a more trivial way to bind using D metaprogramming.

Binding structs can only be done by wrapping the struct inside a class and storing the class object in a ScriptObject.

The function or delegate signature that can be wrapped inside a ScriptAny (and thus ScriptFunction) is ScriptAny function(Context, ScriptAny* thisObj, ScriptAny[] args, ref NativeFunctionError); And such a function is wrapped by ScriptAny(new ScriptFunction("name of function", &nativeFunction)). This is analogous to how Lua bindings work.

bindingexample.zip in the examples folder contains a simple program that binds a class and its public methods and properties. D classes that are bound can be extended by the script as long as the native function constructor checks that the thisObj parameter is an object and assigns the native object to it.

Caveats

This language is stricter than JavaScript. Global variables cannot be redeclared unless they are undefined by setting them to undefined. Local variables cannot be redeclared in the same scope likewise. Semicolons are always required.

Current Goals

• Implement postfix and prefix increment and decrement operators.
• Refactor code to easily implement all math assignment operators (such as *=).
• Allow selected bound functions to be used as properties similar to D's UFCS.
• Possibly support importing other scripts from a script. However, most host applications would probably prefer to do this with XML and their own solution.
• Bind classes with one line of code with mixins and template metaprogramming.
• Write a more complete and robust standard library for the scripting language.