A command, in general, has the following structure:
command_name op
, op
, 
, op
;
A command_name is a string consisting of upper-case roman letters and numbers only. There must be one or more than one blanck characters after a command_name before the first operand.
`op
' is an operand having either one of the following forms:
An operand of the form (a) is a flag-type operand. In some commands, the first operand must be a positional operand of the flag-type. (For example, DO command must be either DO WHILE or DO REPEAT.) In such a case, the ``,'' after the keyword may be omitted. (There is no ambiguity because keywords do not contain blanck characters in contrast to expressions.) FLAG command is special in that all the commas may be omitted because all the operands are type(a).
The right-hand-side of type(c) can be (expr,expr,),
or can be a character string for some operands
Now, let us describe the each command in detail.
When describing the command
formats in this manual, the type-faced characters are those to be typed
in the input data as it is. (The variable names in the FORTRAN source
also appear in type-face.)
The items embraced by square brackets [ ] may be omitted in some cases
and the vertical stroke ``
'' indicates an exclusive choice of one of
the items. Thus, [AB] means to choose either one of A or
B or to omit both. Note that [ ] and [ ] are different.
The dagger 
indicates that the operands to the left of it are
positional operands .
The quantities printed in math-font in command syntax can be expressions.