An ABL statement is one complete instruction to the AVM at runtime. Within a statement, you use several language elements such as ABL keywords, variables, and operators. A statement may also contain constants, data class members, or database field names. Keywords are used to specify the syntax for a particular type of ABL statement. Variables are placeholders for values that are assigned at runtime. Constants are typically strings (in single or double quotes), logical values (true/false or yes/no), or numbers. An ABL statement always ends with a period. The following is an example of a single statement that displays "Hello, World!" in a message alert box.
MESSAGE "Hello, World!" VIEW-AS ALERT-BOX.
Running the code produces the following output:
Hello, World!

ABL is case-insensitive, meaning you can write either an ABL keyword or a reference to a variable name, or database table or field name, in any combination of uppercase and lowercase letters. There are circumstances when working with operating system-level commands or file system names when case must be correct. It is advisable to always write case correct code.

For more information, see An ABL procedure consists of statements and ABL combines procedural, database, and user interface statements in Develop ABL Applications.. The ABL Syntax Reference contains reference information on all the ABL statements.