Metasyntax used for the macros

Elements of the metasyntax

Representation	Meaning	Examples
UPPERCASE LETTERS	Uppercase letters are used for keywords or constants, which the user must enter exactly as they are shown. Keywords must begin with * in case both keywords and names of constants or variables can be specified.	DIB FORCED=*YES
Lowercase letters	Lowercase letters denote data types of the values or variables which the user can specify.	DIB = <var: pointer>
< >	Angle brackets denote variables whose range of values is described by the data types.	<var: pointer>
Underscoring	Underscoring denotes the default value of an operand. If an operand does not have a default value, another value must be specified for it.	FORCED = *NO / *YES
=	The equals sign connects an operand name with the associated operand values.	DATA = <var: pointer>
/	A slash serves to separate alternative operand values.	FORCED = *NO / *YES
[ ]	Square brackets enclose optional entries, i.e entries which may be omitted. If the comma is inside the square brackets, it is needed only if this optional entry is used and may be omitted for the first operand in a command. If, in contrast, the comma is outside the brackets, it must always be entered, even if no optional entry is specified. Note that normal (round) parentheses must always be entered.	F[REE]SIZE Enter: FREESIZE or the shortened form FSIZE
list-poss(n)	The entry “list-poss” signifies that a list of operand values can be given at this point. If (n) is present, it means that the list must not have more than n elements. A list of more than one element must be enclosed in parentheses.	FLAG=list-poss(3): *SLI / *SKIP / *DC Specification: FLAG=*SKIP FLAG=(*SLI,*DC)

An operand is assigned an operand value from a defined range of values by means of the equals sign. 

This value range is determined by a data type. The following table contains the data types of the operand values.

Data types of the operand values

Data type	Character set	Special rules
c-string	EBCDIC character	Must be enclosed within single quotes
integer	[+-] 0..2147483647	Is a decimal number
var:	Introduces a variable specification. The colon is followed by the type of the variable (see table "Data types for variables" below)	<var:var-type>
reg:	Registers 0..15	Specification: (<reg:var-type>)

Suffixes for data types

Suffix	Meaning
n..m	With data type “integer”, n..m means an interval specification; n: minimum value m: maximum value
	With data type “c-string”, n..m means a length specification in bytes; n: minimum length m: maximum length with n < m
n	With data type “c-string”, n means a length specification in bytes; n must be adhered to.

The operand values can be entered directly as a character string or integer (see data types “c-string” and “integer”), or indirectly via a variable (see data type “var:”). The following table contains the possible data types for variables.

Data types for variables

Data type	Description	Definition in program
char:n	The variable is a string of n characters. If the length specification is omitted, n=1 is assumed.	CLn
int:n	The variable is an integer occupying n bytes. If the length specification is omitted, n=1 is assumed. Condition: n <= 4	FLn
enum-of E:n	The variable is the list E, which occupies n bytes. If the length specification is omitted, n=1 is assumed. (n <= 4)	XLn
pointer	The variable is an address or an address value.	A