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REBOL for COBOL programmers |
| Table of contents Generalities Introduction Reserved words What you may/must say Right-to-left evaluation Programming by side effects Code is data The Global Context Coding REBOL like COBOL IDENTIFICATION DIVISION ENVIRONMENT DIVISION FILE SECTION WORKING-STORAGE SECTION SCREEN SECTION PROCEDURE DIVISION COPY statement Printing Your own mezzanine Module testers Module documentation idea Program structure suggestion List of all code samples Some useful equivalencies ACCEPT ADD COMPUTE DISPLAY DIVIDE EXIT INSPECT MOVE MULTIPLY IF OCCURS PERFORM READ REMAINDER ROUNDED SEARCH SET TODAYS-DATE TIME VALUE What's in your head, Boy? Introduction Similar but not the same Colon is not assignment Be careful defining A shorter letter On punctuation Why so dense? Doing COBOLish things Fixed-format file Sample applications Introduction Source code as corporate asset NACHA list Introduction Global services modules Start writing |
PROCEDURE DIVISION
Date written: October 5, 2012 This explains the REBOL equivalent of the PROCEDURE DIVISION (if there is one). COBOL PROCEDURE DIVISIONIn COBOL, all code that is statements that do things is clustered in one place. The exeuction of the program "starts" at the PROCEDURE DIVISION header. You can have straight-line code and paragraphs that you PERFORM. Usually, the code at the beginning is sort of an overview of the whole program because it PERFORMs paragraphs that are defined later in the program. The REBOL equivalentIn REBOL, all its words are functions, so in effect every statement is a "procedure division" statement. Even if you pseudo-define data by setting an initial value, like FILE-NAME: %testfile.txtthat is a function that assigns a value to a word. So everything is "procedure" and you can put it in your program wherever you like. However, there are some things you can do that are not required but are helpful in organizing your thoughts. These are things you have done in COBOL, and can do in REBOL in similar ways. The biggest thing probably would be to locate those procedures that you would peform several times, or that logically could be encapsulated, and put them into functions. You would do this same thing in COBOL. You would group code in paragraphs and PERFORM it. In REBOL, you group code into functions and call the functions by just saying the name. It is assumed that you have looked over the REBOL documentation, or looked some samples, enough that you know what a function is. When you organize your program, put the functions at the beginning with some comments to mark them visually. Later in the program, identify what is in effect the "first executable instruction" (a concept from assembler language), where your program actually "starts" running, and call those functions as needed. Later examples will show this. |