Rules of Variable Substitution

A User-defined variable name must conform to the following rules. It must

• begin with "%%" (percent sign, percent sign)
• be composed of letters, digits, and the following characters: "@" (at sign), "#" (number sign), "$" (dollar sign), and "_" (underscore)
• have a maximum of 163 characters
• not begin with
  • %%$ (percent sign, percent sign, dollar sign)
  • %%@ (percent sign, percent sign, at sign)
  • %%# (percent sign, percent sign, number sign)

  Variables that begin with these strings are either system variables or reserved user-defined variables.

Lowercase characters are not translated to uppercase characters upon resolution.

Variables are substituted sequentially from right to left, until the symbol is assigned a value. For example

%%SMF_TAPE_%%$DAY,

resolves on the third of the month to

%%SMF_TAPE_03,

Control-O then tries to resolve the symbol %%SMF_TAPE_03. Assuming the value of the symbol in the Global environment is EE1022, the result is

EE1022

To concatenate two symbols, separate them with a period. Before AutoEdit variables are concatenated, trailing blanks are eliminated. For example

%%$DAY.%%$MONTH

resolves on the 3rd of December to

0312

Note: %%$DAY%%$MONTH (written without a period) partially resolves to User-defined variable %%$DAY12, which must be fully resolved.

To put a period between two symbols, use two consecutive periods. For example

%%$DAY..%%$MONTH

resolves on the 3rd of December to

03.12

To concatenate a symbol and a constant, use %%. (concatenation symbol). For example

A91%%$DAY%%.UP

resolves on the 3rd of December to

A9103UP

Note: Resolution of A91%%DAYUP would require a search for the %%DAYUP symbol.

When Control-O assigns a value to a variable, Control-O ignores leading and trailing spaces. For example, the statement

DO SET=%%X = FRIDAY RUN

assigns the value "FRIDAY RUN" to the %%X variable, regardless of how many spaces you type before or after "FRIDAY RUN."

To assign a value with leading or trailing spaces, use the %%$BLANK system variable. For example, the statement

DO SET=%%X=%%$BLANK.FRIDAY RUN

assigns the value "FRIDAY RUN" (with a leading space) to the %%X variable. Be sure to include the "." concatenation operator between "%%$BLANK" and "FRIDAY RUN." Without the "." Control-O would look for a variable called "%%$BLANKFRIDAY."