Loops

Loops enable repeated execution of statements until certain conditions are met. There are currently two forms of loop statements: for loops, and while loops.

For Loops

For loops take an array of elements as the input; looping through each statement in the block with each element in the array. If the input is a string, however, that string will automatically coerce into a newline-delimited array.

for element in @array
    echo $element
end

Splitting Arguments

When working with strings that you would like to splice into multiple elements for iteration, see the splicing method, @split:

let value = "one two three four"
for element in @split(value)
    echo $element
end

By default, this will split a string by whitespace. Custom patterns may also be provided:

let value = "one,two,three,four"
for element in @split(value ',')
    echo $element
end

A convenience method is also provided for @split(value '\n'): @lines

let file = $(cat file)
for line in @lines(file)
    echo = $line =
end

Breaking From Loops

Sometimes you may need to exit from the loop before the looping is finished. This is achievable using the break keyword.

for element in {1..=10}
    echo $element
    if test $element -eq 5
        break
    end
end

Continuing Loops

In other times, if you need to abort further execution of the current loop and skip to the next loop, the continue keyword serves that purpose.

for elem in {1..=10}
    if test $((elem % 2)) -eq 1
        continue
    end
    echo $elem
end

While Loops

While loops are useful when you need to repeat a block of statements endlessly until certain conditions are met. It works similarly to if statements, as it also executes a command and compares the exit status before executing each loop.

let value = 0
while test $value -lt 6
    echo $value
    let value += 1
end

Chunked Iterations

Chunked iterations allow fetching multiple values at a time.

for foo bar bazz in {1..=10}
    echo $foo $bar $bazz
end

Ion Documentation