Cmake loops

break

FOREACH( i IN list )
    BREAK( n )
ENDFOREACH( i )

ForEach

# Iterate over arguments
FOREACH( i 1 2 3)          
    # ...
ENDFOREACH( i )
 
 
# Iterate over list
SET( x "a" "b" "c" )
FOREACH( i IN x )
    # ...
ENDFOREACH( i )
 
# Iterate over range
FOREACH( i IN RANGE 20 )
ENDFOREACH( i )

See https://cmake.org/cmake/help/v3.0/command/foreach.html#command:foreach

while

WHILE( <expr> )
ENDWHILE( <expr> )