Keywords

One line: One page per ABAP keyword — what it does, the trap it comes with, and a program that demonstrates it.

ABAP's vocabulary is unusually large and unusually layered. Statements added in 1998 still work, still appear in production code, and sit three lines away from expressions added in 2013 that do the same job differently. A keyword page here answers four questions: what it does, what it quietly does not do, which release it needs, and what to write instead when the answer is "something newer".

Most pages carry a program in a snippets/ folder. Topics take the other cut through the same material: one page per idea, pulling several keywords together.

What the machine checks here, and what it cannot

Every program under snippets/ is parsed and syntax-checked by abaplint on every push, against the release named in abaplint.json. None of them has been run, because nothing in CI can run ABAP — so a snippet page shows code and never shows output. The examples/ folder is the other half of that rule: a program in there was run by a human, and carries the transcript to prove it.

Knowing exactly where the gate stops matters more than the reassurance that one exists. Measured against abaplint 2.120.19:

A mistake like this	Caught?
lv_total = lv_does_not_exist + 1.	Yes — "lv_does_not_exist" not found, findTop (check_syntax)
FOR x IN itab WHERE ( table_line MOD 2 = 1 ) — arithmetic in a WHERE	Yes, as a parser error; the construct is not ABAP
MESSAGE 'text' TYPE 'S' INTO lv_var. — an addition that form does not take	Yes, as a parser error
cl_abap_typedescr=>describe_by_data_no_such_method( x )	No — the SAP class library is not in this repo, so a wrong method or parameter on a standard class passes untouched
A class that inherits from cx_static_check	Reported as not found, which is why local exception classes appear on the page as prose rather than in a snippet

So: the syntax is checked, the SAP-side names are not, and the behaviour is not. Where a page states what a construct produces, it is stating the documented rule, not a recorded run.

Declaring things

Keyword	Page	In one line
DATA	DATA — and DATA( )	A variable, declared up front or born where it is first written
TYPES, CONSTANTS	TYPES and CONSTANTS	Naming a shape once so the rest of the program refers to it
FIELD-SYMBOLS, ASSIGN	FIELD-SYMBOLS and ASSIGN	Another name for memory you already have — and the dynamic escape hatch
REF, REF TO data, ->*	Data references	A value that points at memory, and can be kept and stored
STATICS	STATICS	A local variable that survives between calls
TYPES BEGIN OF ENUM	Enumerations	A fixed set of values the compiler can check
TYPE RANGE OF	Ranges tables	Sign, option, low, high — what a SELECT-OPTIONS hands you
TYPES BEGIN OF MESH	Meshes	Tables with declared associations between them; rare, and worth recognising

Building values

Keyword	Page	In one line
VALUE	VALUE	A structure or a whole table as one expression
FOR	FOR	The loop that lives inside an expression
REDUCE	REDUCE	Many rows folded into one value
FILTER	FILTER	A subset of a table, if the table has the right key
CORRESPONDING	CORRESPONDING and MOVE-CORRESPONDING	Copy by matching names — and the difference that costs a field
LET	LET	A local name inside an expression
NEW	NEW	An object, or a data reference, in one expression
CAST, CONV, EXACT	CAST, CONV and EXACT	Changing the type of a reference, of a value, or refusing to
\|…\|	String templates	Text with expressions in it, and formatting options that do the work
xsdbool( ), boolc( )	Booleans	There is no boolean type; here is the convention, and the trap
abs, round, nmax, DIV, MOD	Numeric functions and operators	Rounding modes, integer operators, and the MOD that is never negative

Choosing and repeating

Keyword	Page	In one line
IF, CASE	IF and CASE	The statements — and when each is the wrong one
COND, SWITCH	COND and SWITCH	The same two choices as expressions
CASE TYPE OF, IS INSTANCE OF	CASE TYPE OF	Branching on an object's class — and why that is usually a missing method
DO, WHILE	DO and WHILE	Counting loops, and sy-index
CHECK, CONTINUE, EXIT, RETURN	CHECK, CONTINUE, EXIT, RETURN	Four ways out, and only two of them mean what they look like
LEAVE, STOP	LEAVE and STOP	Leaving a screen, a list, a transaction or the program

Internal tables

Keyword	Page	In one line
LOOP AT	LOOP AT	INTO copies, ASSIGNING does not, GROUP BY replaces the control break
READ TABLE, itab[ ]	READ TABLE and table expressions	sy-subrc or an exception — you choose which by how you write the read
APPEND, INSERT, MODIFY, DELETE	Changing a table	Which statement the table kind allows, and what each costs
COLLECT	COLLECT	Summing rows into a table by key, in one statement
SORT, DELETE ADJACENT DUPLICATES	SORT and adjacent duplicates	The pair that must be used together, and usually is not
AT NEW, AT END OF, SUM	Control breaks	Totals per group the 1990s way, and the masking rule nobody expects
DESCRIBE, lines( )	DESCRIBE and lines( )	How many rows, and why the old statement lingers

Talking to the database

Keyword	Page	In one line
SELECT	SELECT	Columns, joins, aggregates, and the @ that the strict syntax insists on
INSERT, UPDATE, MODIFY, DELETE	Database writes	Four write statements, sy-dbcnt, and the commit that is a separate decision
WITH	WITH — common table expressions	A named subquery, used like a table, in one round trip (7.51)
OPEN CURSOR, FETCH, SELECT … ENDSELECT	Cursors	Reading a result set too big to hold, and the commit that closes it
EXEC SQL, ADBC	Native SQL	Bypassing Open SQL, and everything that bypasses with it
COMMIT WORK, ROLLBACK WORK	COMMIT WORK and ROLLBACK WORK	Where the database LUW ends, and what ends it without asking
AUTHORITY-CHECK	AUTHORITY-CHECK	The check the database will not do for you

Text and files

Keyword	Page	In one line
CONCATENATE, SPLIT	CONCATENATE and SPLIT	The statements, and the expressions that replaced one of them
CONDENSE, TRANSLATE, SHIFT	In-place string statements	Change the variable where it stands — and the function twins that return a value
FIND, REPLACE	FIND and REPLACE	Searching with and without regular expressions
CALL TRANSFORMATION	CALL TRANSFORMATION	ABAP to XML and JSON, with the identity transformation and your own
OPEN DATASET	OPEN DATASET	Files on the application server, and the encoding you must name

Errors and messages

Keyword	Page	In one line
TRY, CATCH, RAISE	TRY, CATCH, RAISE	Class-based exceptions, and the three flavours the compiler treats differently
RETRY, RESUME, RESUMABLE	RETRY and RESUME	Going back after an exception — the batch that must not stop
RAISE SHORTDUMP	RAISE SHORTDUMP	A dump on purpose, carrying the facts (7.53)
MESSAGE	MESSAGE	Six types, and each one decides what happens to the program next
ASSERT	ASSERT	A claim that ends the program when it is false — on purpose
BREAK-POINT, LOG-POINT, ASSERT ID	Checkpoint groups	Debugging aids that stay in shipped code and never fire unless switched on

Objects and modularization

Keyword	Page	In one line
CLASS	CLASS	Definition and implementation, visibility, inheritance
INTERFACE, INTERFACES	INTERFACE and INTERFACES	The contract, and the ~ that names a method through it
METHODS	METHODS and parameters	IMPORTING, EXPORTING, CHANGING, RETURNING, and which to reach for
EVENTS, RAISE EVENT, SET HANDLER	Events	Objects that publish, and the handlers that subscribe
FRIENDS, ALIASES, ABSTRACT, FINAL	The class additions	Who may instantiate, inherit, see the private section, or use a short name
CALL FUNCTION	CALL FUNCTION	Function modules, DESTINATION, and classic exceptions
GET BADI, CALL BADI	GET BADI and CALL BADI	Calling an enhancement spot, and finding out whether yours will run
ENHANCEMENT-POINT, ENHANCEMENT-SECTION	Enhancement points	Source-level hooks in SAP's code, explicit and implicit

Programs, screens and output

Keyword	Page	In one line
INITIALIZATION, AT SELECTION-SCREEN, START-OF-SELECTION	Report events	A report is event blocks in a fixed order, not a script
PARAMETERS, SELECT-OPTIONS	PARAMETERS and SELECT-OPTIONS	The selection screen you get for free, and its ranges table
SUBMIT	SUBMIT	Running another report, with its parameters, its list, or as a job
CALL TRANSACTION, LEAVE TO TRANSACTION	CALL TRANSACTION	Running a transaction from code — with or without driving its screens
EXPORT, IMPORT, SET/GET PARAMETER	EXPORT and IMPORT	ABAP memory, SAP memory and the shared buffer
CALL SCREEN, MODULE, PROCESS BEFORE OUTPUT	Classic screens	Dynpros and flow logic — the model every classic transaction runs on
WRITE	WRITE	List output: still the fastest way to see a number, still not a UI

The system, and time

Keyword	Page	In one line
sy-subrc, sy-tabix, sy-index, …	System fields	The structure the kernel keeps for you, and the three fields that cause bugs
GET TIME, GET RUN TIME, GET TIME STAMP, WAIT	Asking what time it is	Refreshing the clock, timing a block, and the WAIT that commits

Legacy you will read

Keyword	Page	In one line
FORM, PERFORM	FORM and PERFORM	Obsolete, everywhere, and worth reading fluently
TABLES, OCCURS, WITH HEADER LINE, RANGES, TYPE-POOLS	Obsolete declarations	Recognise them, and the header line above all
MOVE, ADD, SUBTRACT, COMPUTE	Obsolete statements	Assignment and arithmetic before operators existed
DEFINE	Macros	Text substitution you cannot debug

See also

• Topics — the same language cut by idea instead of by keyword
• Modern versus classic — every construct on this shelf beside what replaced it
• Constructor expressions — the VALUE/NEW/COND family as a family
• Foundations — the pages that have a recorded run behind them
• Glossary — short definitions, each pointing at the page that earns it
• Which release am I writing for? — the question behind half the answers on this shelf