{"id":415770,"date":"2024-06-30T00:34:07","date_gmt":"2024-06-30T00:34:07","guid":{"rendered":"http:\/\/savepearlharbor.com\/?p=415770"},"modified":"-0001-11-30T00:00:00","modified_gmt":"-0001-11-29T21:00:00","slug":"","status":"publish","type":"post","link":"https:\/\/savepearlharbor.com\/?p=415770","title":{"rendered":"Modern COBOL: Package Tutorial<\/span>"},"content":{"rendered":"
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You will learn and create an application-level library in COBOL. You will structure the package, implement automatic tests, deploy on GitHub and enable Continuous Integration workflow. Finally, you will publish the package in the COBOL package registry.<\/p>\n

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Preconditions<\/h2>\n

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You have learned basic principles, methods and standards of COBOL. In this tutorial we\u2019ll use GnuCOBOL<\/strong> \u2014 a free COBOL compiler which implements a substantial part of the COBOL 85, COBOL 2002 and COBOL 2014 standards and X\/Open COBOL, as well as many extensions included in other COBOL compilers.<\/p>\n

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You have Docker<\/strong>, a command-line virtualization tool, installed.<\/p>\n

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You have NPM<\/strong>, a package manager for JavaScript programming language, installed.<\/p>\n

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You have Git<\/strong>, an open source distributed version control client, installed.<\/p>\n

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You have GitHub<\/strong> account for publishing of the package.<\/p>\n

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You may use any text editor you like, but I recommend Visual Studio Code<\/strong> (or its open-source version VSCodium<\/strong>) with COBOL-syntax extension bitlang.cobol<\/code> installed.
Package vs Library<\/p>\n

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Each programming language has standard set of functions or operators provided by default and included into installation package. In COBOL we call them Intrinsic functions. Intrinsics cover basic programming needs, but we\u2019ve used to extend default set by own functions every time writing something smarter than \u00b4Hello, world!\u00b4.<\/p>\n

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Gradually, custom functions form reusable COBOL libraries, Copybooks, for inclusion into other programs and services on-demand. Thanks to Version Control Systems, contributors are able to effectively cooperate and deliver the libraries to the programmers. The only problem was an integration with external source-code that might be casually written in other COBOL dialect, coding standard or approach. And package management is a solution here.<\/p>\n

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Similar to other application-level package managers, such as Yarn<\/strong> for JavaScript, Maven<\/strong> for Java, Packagist<\/strong> for PHP, NuGet<\/strong> for C# etc., in 2020 COBOL obtained its own public package manager that standardizes the way the contributors should treat the libraries \u2014 COBOLget. The tutorial explains how to create and publish your first COBOL package the modern way.<\/p>\n

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Specifications<\/h2>\n

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For financial applications we\u2019ll implement banking<\/code> package which exposes single iban-checksum<\/code> function \u2014 an IBAN<\/a> validator. The function accepts alphanumeric argument and returns numeric value 1<\/code> in case of success. The algorithm is as follows:<\/p>\n

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