Flow-control structures: Difference between revisions

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=={{header|Wren}}==

Wren has ~~just two~~ control flow statements, '''break''' and '''return'''.

Wren has three control flow statements, '''break''', '''continue''' and '''return'''.

'''Break''' exits from the nearest enclosing for or while loop and transfers control to the next statement after that.

'''Continue''' (from v0.4.0) jumps to the next iteration of the nearest enclosing for or while loop.

⚫

'''Return''' exits from a method or function and can be optionally followed by a value. Controls returns to the caller. ~~Although undocumented, it~~ can also be used to exit the ~~script~~ ~~entirely~~ from 'top level' code.

⚫

'''Return''' exits from a method or function and can be optionally followed by a value. Controls returns to the caller. It can also be used to exit the current module from 'top level' code.

Whilst part of the standard library rather than the language itself, the '''Fiber.abort''' method can be used to exit the script when an error occurs. However, it is possible to catch the error using '''Fiber.try'''.

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var i = 1

while (true) {

if (i == 1) {

i = i + 1

continue // jumps to next iteration

}

System.print(i)

if (i == n) break // exits while loop

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for (n in a) {

func.call(n)

if (n > 2) return // end script

if (n > 2) return // end module and hence the script as its a single module script

var error = fiber.try() // catch any error

System.print("Caught error: " + error)

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<pre>

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Caught error: Demo error

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