Coming from C# or Python

FutureBlitz has much of what C# and Python have, written in words rather than braces or indentation, and compiled to a native executable with no runtime to install.

At a glance

Blocks end with words

A block ends with End and what it was, so there are no braces, and indentation is style, which fb fmt keeps.

Import std.core

Function Grade(score: Int): String
    If score >= 90
        Return "A"
    ElseIf score >= 75
        Return "B"
    End If
    Return "C"
End Function

For score In [95, 80, 60]
    Print("{score}: {Grade(score)}")
End For

95: A
80: B
60: C

Types are checked before it runs

Like C#, and unlike Python, every value has a type the compiler knows, though most are inferred. A value that can be missing has a type that says so, and the compiler won’t let code use it before checking.

Import std.core
Import std.collections

Local stock = {"apples": 12, "plums": 7}
Local pears: Int? = stock.Get("pears")
Print(pears ?? 0)
If pears != Null Then Print(pears + 1)
Print(stock.Get("plums") ?? 0)

0
7

Errors say what can throw

A Function that can throw says so with Throws, and a call to it is marked with Try, so a reader sees each place an error can come from. A panic, like an index out of range, is a bug, not an error to catch, and it stops the program with a stack trace.

Import std.core

Class EmptyCart Extends Error
End Class

Function Total(prices: Int[]): Int Throws EmptyCart
    If prices.Count == 0 Then Throw EmptyCart("nothing to pay for")
    Local sum = 0
    For price In prices
        sum += price
    End For
    Return sum
End Function

Try
    Print(Try Total([250, 125]))
    Print(Try Total([]))
Catch e As EmptyCart
    Print("can't total: {e.Message}")
End Try

375
can't total: nothing to pay for

Memory without a collector

Objects are reference-counted: one is freed the moment the last reference to it goes, so a program never pauses for a collector, and a Class’s Destroy Method runs at a known time, like C#‘s Dispose or Python’s with, with nothing to call. Two objects that refer to each other need one reference to be Weak, so the pair can go; in a debug build, fb reports what leaks.

Threads are checked

Spawn runs work on a pool of worker threads, and the compiler checks what it takes: only values that are safe to share between threads, so there are no data races to find later. Async and Await let a Function wait for I/O or for another task without blocking its thread, as in C#.

Packages and tools

One command does what dotnet or pip with a formatter, a test runner, and a build tool do: fb new, fb run, fb test, fb fmt, fb add, and fb publish. Tools has each one.