FRONT_2.3 How to Read the Syntax Diagrams
Throughout this book, syntax is described using the structure defined below.
- Read the syntax diagrams from left to right, from top to bottom,
following the path of the line.
The >>___ symbol indicates the beginning of a syntax diagram.
The ___> symbol indicates that the syntax diagram is continued on the next line.
The >___ symbol indicates that the syntax diagram is continued from the previous line.
The ___>< symbol indicates the end of a syntax diagram.
Diagrams of syntactical units other than complete statements start with the >___ symbol and end with the ___> symbol. - Required items appear on the horizontal line (the main path).
___ Format _________________________________________________________ | | | >>__STATEMENT__required item____________________________________>< | | | |____________________________________________________________________| - Optional items appear below the main path.
___ Format _________________________________________________________ | | | >>__STATEMENT__ _______________ ________________________________>< | | |_optional item_| | | | |____________________________________________________________________| - When you can choose from two or more items, they appear vertically, in
a stack.
If you must choose one of the items, one item of the stack appears on the main path.___ Format _________________________________________________________ | | | >>__STATEMENT__ _required choice 1_ ____________________________>< | | |_required choice 2_| | | | |____________________________________________________________________|If choosing one of the items is optional, the entire stack appears below the main path.___ Format _________________________________________________________ | | | >>__STATEMENT__ ___________________ ____________________________>< | | |_optional choice 1_| | | |_optional choice 2_| | | | |____________________________________________________________________| - An arrow returning to the left above the main line indicates an item
that can be repeated.
___ Format _________________________________________________________ | | | <_________________ | | >>__STATEMENT____repeatable item_|______________________________>< | | | |____________________________________________________________________|A repeat arrow above a stack indicates that you can make more than one choice from the stacked items, or repeat a single choice. - Variables appear in all lowercase letters (for example, parmx). They
represent user-supplied names or values.
- If punctuation marks, parentheses, arithmetic operators, or such
symbols are shown, they must be entered as part of the syntax.
___ Format _____________________________________________________________
| |
| (1) (2) <___________________ |
| >>__STATEMENT_____ _identifier-1____ ____ _______________ _|_________> |
| |_literal-1_______| | (3)| |
| |_| item 1 |____| |
| |
| <_______________________________ (4) |
| >____TO__identifier-3__ _________ _|_________________________________> |
| |_ROUNDED_| |
| |
| (5) |
| >__ ____________________________________________ ____________________> |
| |_ ____ __SIZE ERROR__imperative-statement-1_| |
| |_ON_| |
| |
| >__ __________________ _____________________________________________>< |
| | (6)| |
| |_END-STATEMENT____| |
| |
| item 1: |
| |__ _identifier-2_________________ __________________________________| |
| |_literal-2____________________| |
| | (7)| |
| |_ arithmetic-expression-1 ____| |
| |
| Notes: |
| (1) The STATEMENT key word must be specified and coded as shown. |
| |
| (2) This operand is required. Either identifier-1 or literal-1 must |
| be coded. |
| |
| (3) The item 1 fragment is optional; it can be coded or not, as |
| required by the application. If item 1 is coded, it can be |
| repeated with each entry separated by one or more COBOL |
| separators. Entry selections allowed for this fragment are |
| described at the bottom of the diagram. |
| |
| (4) The operand identifier-3 and associated TO key word are required |
| and can be repeated with one or more COBOL separators separating |
| each entry. Each entry can be assigned the key word ROUNDED. |
| |
| (5) The ON SIZE ERROR phrase with associated imperative-statement-1 |
| are optional. If the ON SIZE ERROR phrase is coded, the key word |
| ON is optional. |
| |
| (6) The END-STATEMENT key word can be coded to end the statement. It |
| is not a required delimiter. |
| |
X | (7) The reverse highlighting indicates that arithmetic-expression-1 |
X | is an IBM extension. This operand is optional. |
| |
|________________________________________________________________________|
© Copyright IBM Corp. 1991, 1998
IBM Library Server Copyright 1989, 2005 IBM Corporation. All rights reserved.
Return to library: z/OS | z/OS.e | TPF | z/VSE | z/VM | IBM Hardware | IBM System z Redbooks
Glossary: IBM terminology
Publications: How to order publications
Readers: Download IBM Library Reader | Download IBM Softcopy Reader | Download Adobe® Acrobat® Reader®
Library management: Download IBM Softcopy Librarian
Contacts: Contact z/OS
Adobe, the Adobe logo, Acrobat, the Acrobat logo, and Acrobat Reader are registered trademarks of Adobe Systems incorporated.