Programs can be easier to read if certain constructs are vertically aligned. By default all alignments are set ON. Through the -A0 switch you may reset the default to OFF, and then use one or more of the other -An switches to activate alignment for specific constructs.
:=in initializations in declarations
:=in assignment statements
atkeywords in the component clauses in record representation clauses
The -A switches are mutually compatible; any combination is allowed.