Control Structures

Control words are punctuation that determine the sequence of execution in an explicit definition. Matching control words and the enclosed sentences make up a control structure. The following control words and control structures are available:

assert. T

break.

continue.

for.     T do. B end.
for_xyz. T do. B end.

goto_name.
label_name.

if. T do. B end.

if. T do. B else. B1 end.

if.     T  do. B
elseif. T1 do. B1
elseif. T2 do. B2
end.

return.

select. T
 case.  T0 do. B0
 fcase. T1 do. B1
 case.  T2 do. B2
end.

try. B catch. B1 end.

while.  T do. B end.
whilst. T do. B end.

Words beginning with B or T denote blocks, comprising zero or more simple sentences and control structures. The last sentence executed in a T block is tested for a non-zero value in its leading atom, and determines the block to be executed next. (An empty T block result or an omitted T block tests true.)

These control words and control structures are further detailed in the immediately following pages.

Next • Previous • Vocabulary • Index • Main