Lowerdash is an object-oriented extension to SmileBasic. It lets you write code very similar to C++, Java, or Javascript. In this tutorial, I present a quick-overview of the high-level features and how they compare to other object-oriented languages.

Pointer

Lowerdash overloads the $ variable type to mean "pointer" rather than just "string". You store objects to variables post-fixed with $. $ variables are passed by reference.

VAR myO$ = new myMod(42)

Objects

Objects in Lowerdash are like most objects: they can contain properties and functions. A "singleton" object is equivalent to a MODULE. Modules implicitly end at the end of a file, or can be closed with the END keyword. VARs inside a module will always be attached to the object. DEFs are only attached to a module if they are declared STATIC. You can create a module by defining it in code:

MODULE myMod
  VAR inner
  STATIC DEF myFunc
     PRINT _.inner
     'doing stuff 
  END
END

Classes

In Lowerdash, Classes are just Modules with a function named "new". This makes it simpler to think about operations: All modules are objects, all instances are objects. As mentioned, a Module that is used as a class must provide a constructor. The constructor must be declared with EXPORT. EXPORT will add a DEF to a special table that belongs to the current Module. This table contains the properties of a module that are only usable by instances. You can also add instance members (vars) to this table by using the MEM keyword.

MODULE myMod
  MEM member
  EXPORT DEF new(arg)
    me.member = arg
    return me
  END
END

Instances

Instances are constructed with the new keyword, just like most languages. Instances behave just like modules. Under the hood, they have some Lowerdash managed state. An instance behaves the same as the MODULE that constructed it, but will also have access to anything that has been EXPORTed from that module as well.

MODULE myMod
  ...
  EXPORT DEF act
    print "This is an action"
  END
  ...
END

VAR o$ = new myMod(42)
o$.act

Scoping

Scopes are not truly recursive in SmileBasic like other languages. There only exists the global scope and the function scope. In Lowerdash, STATIC and EXPORT DEFs have special properties added to their scopes: STATIC: - _ - a placeholder for the current module. EXPORT: - _ - a placeholder for the current module. - me - the calling object. equivalent to this in most other languages (just shorter to type)

Examples

Java to Lowerdash

Suggest code for me to translate...

Javascript to Lowerdash

Suggest code for me to translate...

C++ to Lowerdash

Suggest code for me to translate...