1.1.1.6 Reserved Words
A reserved word is a character-string with a predefined meaning in a COBOL
source program. IBM COBOL reserved words are listed in Appendix D,
"Reserved Words" in topic APPENDIX1.4.
X Information on selecting an alternate reserved word table can be found in
X the IBM COBOL Programming Guide for your platform.
There are six types of reserved words:
- Keywords
- Optional words
- Figurative constants
- Special character words
- X Special object identifiers
- Special registers
-
Keywords
-
Keywords are reserved words that are required within a given clause,
entry, or statement. Within each format, such words appear in
uppercase on the main path.
-
Optional Words
-
Optional words are reserved words that can be included in the format
of a clause, entry, or statement in order to improve readability.
They have no effect on the execution of the program.
-
Figurative Constants
-
See "Figurative Constants" in topic 1.1.2.
-
Special Character Words
-
There are two types of special characters, which are only recognized
as special characters when represented in single-byte.
-
X Special Object Identifiers
-
X COBOL provides two special object identifiers, SELF and SUPER, used in
X a method Procedure Division:
-
X SELF
-
X A special object identifier you can use in the Procedure Division
X of a method. SELF refers to the object instance used to invoke
X the currently-executing method. You can specify SELF only in
X source program positions that are explicitly listed in the syntax
X diagrams.
-
X SUPER
-
X A special object identifier you can use in the Procedure Division
X of a method only as the object identifier in an INVOKE statement.
X When used in this way, SUPER refers to the object instance used to
X invoke the currently-executing method. The resolution of the
X method to be invoked ignores any methods declared in the class
X definition of the currently-executing method and methods defined
X in any class derived from that class. Thus, the method invoked is
X inherited from an ancestor class.
-
Special Registers
-
See "Special Registers" in topic 1.1.3.
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