Loops

This post is focused on basic loop syntax. There is some features that I would like to add in the future that are not considered here.

For (each) loop

array : []int = {1, 2, 3, 4, 5}

for i : in array {
    // i ...
}

or more idiomatic:

for each : in array {
    // each ...
}

: )

For loop with ranges

Note how each is not a keyword, but an identifier. Also, there is a parallelism between the in keyword and the assignment operator (=).

// Full verbosity.
for each : i32 in 0 <= .. < 256 {
    // each ...
}

// With type inference.
for each : in 0 <= .. < 256 {
    // each ...
}

// Playing with the inclusion of the ends.
for each : in -1 < .. <= 255 {
    // each ...
}

// Reversed range.
for each : in 256 > .. => 0 {
    // each ...
}

For loop with implicit iterator

array : []int = {1, 2, 3, 4, 5}

for in array {
    // ...
}

(I hate this form, I may remove it later).

While loop

a = 0
while a < 256 {
    a += 1
}

Repeat-while loop

a = 0
repeat while a < 256 {
    a += 1
}

Pros:

• This loop can be quickly turned into a while loop and vice versa.
• The condition works consistently with if, for and while (like in C).
• The braces could be removed in the future easier than in other versions.
• Only one additional keyword (like in C).
• It can be less confusing and prevent errors related with copy-and-paste and dangling empty whiles (like Pascal achieves).

Cons:

• It also can be more confusing, because the condition is before the block (‘Repeat? Oh, yes, now I remember…’).
• Slightly more verbose (I considered repeat if, but semantically it would be more trouble than it is worth).