Dropped: Do-While
The syntax construct
do <body> while <cond>
is no longer supported. Instead, it is recommended to use the equivalent while
loop below:
while ({ <body> ; <cond> }) ()
For instance, instead of
do
i += 1
while (f(i) == 0)
one writes
while
i += 1
f(i) == 0
do ()
The idea to use a block as the condition of a while also gives a solution to the "loop-and-a-half" problem. Here is another example:
while
val x: Int = iterator.next
x >= 0
do print(".")
Why Drop The Construct?
do-while
is used relatively rarely and it can be expressed faithfully using justwhile
. So there seems to be little point in having it as a separate syntax construct.- Under the new syntax rules
do
is used as a statement continuation, which would clash with its meaning as a statement introduction.
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