NCL Statement Types and Syntax › NCL Conventions and Syntax

NCL Conventions and Syntax

The logic capabilities of procedures include the ability to define user and global variables, test the truth of conditions, and to make conditional branches on the basis of these tests. To achieve this, certain syntax rules must be obeyed:

• Procedure statements are stored in 80-character records. Columns 1 to 72 can be used to contain commands, statements, or comments. Columns 73 to 80 are reserved for optional sequence numbers. If present, these sequence numbers are used in error messages to pinpoint a statement in error.
• Comments can be included within procedures to assist in documentation and you are encouraged to use them freely.

  Comments can occur as separate statements or on other types of statement.

• Continuation of a statement onto the next record is supported if the last non-blank character on the line (excluding comments) is a plus sign (+). The total length of a statement including all continuations cannot exceed 2048 characters. &CONTROL CONT must be in effect.
• Syntax is free-format and can start in any column to improve presentation.
• A procedure can invoke other procedures. This process is called nesting. Nesting to 64 levels is supported. Variables can be passed to a procedure either when the procedure is invoked by the operator or when a nested procedure is invoked.
• No individual word or field within a statement can exceed 256 characters.
• The value of a variable cannot exceed 256 characters in length.
• The total length of an expanded statement after variable substitution must not be longer than 12288 characters.
• Statements can contain any number of leading or trailing blanks. A completely blank statement is ignored. No specific termination statement is required to signal the end of a procedure. When the end of the procedure is reached (end-of-file), the procedure terminates, unless terminated through other processing options (for example, &END) or errors.