Coming from Blitz3D

FutureBlitz keeps Blitz3D’s plain words and programs that read from the top, and adds types, null safety, errors, generics, and threads. It isn’t source-compatible: a .bb file is translated, and this guide is that translation, part by part.

The language, mapped

Keywords are PascalCase, as Blitz3D’s usual style wrote them, and case-sensitive: if is an ordinary name. When one written in another case breaks a line, the error says how it’s spelled.

Types become Classes

A Blitz3D Type is a record and a global list in one. In FutureBlitz the record is a Class, and the list is an array the program keeps, so there can be several, and nothing is in one by accident.

Type Order
    Field item$, count%
End Type

o.Order = New Order
o\item = "pears" : o\count = 0

For o.Order = Each Order
    If o\count = 0 Then Delete o
Next

Import std.core
Import std.collections

Class Order
    Field item: String
    Field count: Int

    New(item: String, count: Int)
        Self.item = item
        Self.count = count
    End New
End Class

Local orders: Order[] = [Order("apples", 3), Order("pears", 0), Order("plums", 5)]
orders.RemoveAll(Function(o: Order) => o.count == 0)
For o In orders
    Print("{o.count} {o.item}")
End For

3 apples
5 plums

An object is freed the moment the last reference to it goes, so a removed order is gone without a Delete.

Globals and Functions

Top-level code is the program, as in Blitz3D. Its Locals are its own, and a Function sees the file’s Globals and Consts.

Import std.core

Const MAX_TRIES = 3
Global tries = 0

Function TryAgain(): Bool
    tries += 1
    Return tries < MAX_TRIES
End Function

While TryAgain()
    Print("try {tries}")
End While
Print("gave up after {tries}")

try 1
try 2
gave up after 3

Strings

Strings take values in braces, with format specs after a colon. + joins Strings only, so a number goes in braces rather than being added.

Import std.core

Local total = 1500
Local share = 0.875
Print("Total: {total:,}   Share: {share:.1%}")

Total: 1,500   Share: 87.5%

Arrays

Dim becomes an array type. An array knows its length, grows with Add, and is checked on every index, so an index out of range is a panic that names the line, not a crash.

Import std.core
Import std.collections

Local scores: Int[] = [40, 75]
scores.Add(90)
scores.Sort()
Print("{scores.Count} scores, best {scores[scores.Count - 1]}")

3 scores, best 90

Graphics and sound

FutureBlitz is a general-purpose language. Its standard library draws on images, with std.image’s canvas and fonts, but has no windows, 3D rendering, or sound. A program that opens a window or plays sound uses a package for it, installed with fb add, or calls a C library directly, as Using a C library shows. The language, its tools, and the standard library are the same whichever one a program uses.