Loops.md

Loops

Testo-lang supports loop management with a for clause. The for loops have the next syntax:

for (<counter> IN <range>) {
	action1
	action2
	action3
	...
} [else {
	action1
	action2
	...
}]

Loop header

The for clause header consists of the <counter> declaration (which must be an identifier) followed by the key-word IN and counter's values definition with the range construct. The range section describes how many iterations would the loop have. The range could be specified with one the following ways:

1. RANGE <start> <finish>, where the start and finish are non-negative integers or strings. If a string is used, the value inside the string must be convertible to a non-negative integer. Inside the string param referencing is available. The finish value must be greater than the start value. During the loop run, the counter will take all the consecutive integer values, starting from the start value (included) and finishing with the finish - 1 value (included).
2. RANGE <finish>. This may be considered as a special case for the RANGE <start> <finish>, with the start is set to 0 by default.

RANGE examples:

RANGE 5 10 # The counter will take values 5, 6, 7, 8, 9
RANGE "5" "10" # The same as above
RANGE 5 # The counter will take values 0, 1, 2, 3, 4
RANGE "${max_iterations}" # The counter will take values based on the the "max_iterations" param value.

Loop body

Inside the loop body you can use all the language constructs, which are available inside a command body: actions, conditions, macro calls. Additionally there are special loop-control statements available: continue (go the the next iteration) and break (exit the loop).

It is possible to specify a non-mandatory else clause for a loop. The else clause executes after all the iterations complete normally. This means that the loop run did not encounter a break statement.

Inside the loop you can access the counter's value like any param value.

Example

test some_test {
	some_vm {
		for (i IN RANGE 5 100) {
			if ("${i}" EQUAL "10") {
				continue
			}
			print "${i}"
			if ("${i}" EQUAL "20") {
				break
			}
		} else {
			print "All the loops worked without a break"
		}
	}
}

Pay attantion that in this example control never reaches the else clause, because on the 15th iteration the break statement is reached.