Required data and optional data

All data must be given by the user in the command file in the same order as they appear in the command scheme. They are separated by blanks or comma's.


Required data (indicated in the description of each individual command) must be given explicitly as character string or numbers.


Optional data are indicated

(a)

in the text of each individual command or

(b)

for sets of data: in parenthesis around the data concerned

               ( data )

For example:

                KEY1word KEY2word 'name' ([nnn] [mmm]) [zzz]

or

(c)

some optional data are indicate in the same way as optional keywords are indicated:

                | .....data.....|
               <                 >
                | .....data.....|

Optional data of the kind (a) or (b) may be omitted by giving blanks between comma's (SWAN then substitutes reasonable default values). If after a required datum all data is optional (till the next keyword or the next end-of-line), then the comma's may be omitted too. Optional data of the kind (c) are to be treated in the same way as optional keywords.