The let builtin is used to create local variables within the shell, and apply basic arithmetic to variables. The export keyword may be used to do the same for the creation of external variables. Variables cannot be created the POSIX way, as the POSIX way is awkard to read/write and parse.

let string_variable = "hello string"
let array_variable = [ hello array ]

Ion also supports setting multiple values at the same time

let a b = one two
echo $a
echo $b

let a b = one [two three four]
echo $a
echo @b

one
two
one
two three four

It's also possible to designate the type that a variable is allowed to be initialized with. Boolean type assignments will also normalize inputs into either true or false. When an invalid value is supplied, the assignment operation will fail and an error message will be printed. All assignments after the failed assignment will be ignored.

let a:bool = 1
let b:bool = true
let c:bool = n
echo $a $b $c


let a:str b[] c:int d:float[] = one [two three] 4 [5.1 6.2 7.3]
echo $a
echo @b
echo $c
echo @d

true
true
false
one
two three
4
5.1 6.2 7.3

• []
• bool
• bool[]
• float
• float[]
• int
• int[]
• str
• str[]
• hmap[]
• bmap[]