Keywords

A keyword is the first word of a statement. It determines the meaning of the entire statement. There are four different types of keywords:

These keywords define data types or declare the data objects which the program can access. Examples of declarative keywords are:

TYPES, DATA, TABLES

The system processes declarative keywords during the generation of a program, not at runtime. They are processed independently of their position in the program code. For the sake of clarity, you should specify all declarative keywords together in a "declaration section" at the beginning of the program.

For more information about declarative keywords, see Declaring Data

These keywords define processing blocks in an ABAP program. Processing blocks are groups of statements which are processed during the execution of an ABAP program as soon as they are called from another point.

Modularization keywords comprise:

Event keywords

The respective processing blocks are processed as soon as a particular event occurs. Examples of event keywords are:

AT SELECTION SCREEN, START-OF-SELECTION, AT USER-COMMAND

For more information about event keywords, see Controlling the Flow of ABAP Programs Using Events

Defining keywords

These keywords define processing blocks that are processed as soon as they are called by an explicit statement in an ABAP program or in a screen flow logic. Examples of defining keywords are:

FORM, ENDFORM, FUNCTION, ENDFUNCTION, MODULE, ENDMODULE.

For more information about defining keywords, see Modularizing ABAP Programs.

These keywords control the flow of an ABAP program according to certain conditions. Examples of control keywords are:

IF, WHILE, CASE

For more information about control keywords, see Controlling the Flow of an ABAP Program.

These keywords call processing blocks (defined by modularization keywords) in the same or other ABAP programs or branch completely to other ABAP programs. Examples of calling keywords are:

PERFORM, CALL, SUBMIT, LEAVE TO

For more information about calling keywords, see the respective sections of this guide.

These keywords process the data (defined by declarative keywords) when certain processing blocks (triggered by events or called by calling keywords) are processed and certain conditions (defined by control keywords) occur. Examples of operational keywords are:

WRITE, MOVE, ADD

For more information about operational keywords, see Processing Data