{"id":851,"date":"2012-08-02T13:22:47","date_gmt":"2012-08-02T13:22:47","guid":{"rendered":"http:\/\/www.gennard.net\/blog\/?p=851"},"modified":"2012-08-02T13:22:47","modified_gmt":"2012-08-02T13:22:47","slug":"reusing-cobol","status":"publish","type":"post","link":"http:\/\/www.gennard.net\/blog\/2012\/08\/reusing-cobol\/","title":{"rendered":"Re-using COBOL rather than converting it to C#"},"content":{"rendered":"

While reading a article on-line about using “NACA transcoder<\/a>” to translate COBOL into Java
\nit got me thinking about modernizing COBOL. <\/p>\n

While I agree 100% about the actual code generated by the NACA transcoder is not
\nmaintainable, I disagree that converting it to C# helps you modernize the code is
\nthe only solution.<\/p>\n

Using Visual COBOL the same code can be cut-pasted into a Class that exposes itself
\nin the same way as the C# he produces. Moving a legacy COBOL program into a Class
\nis just one way of reusing COBOL but in order to compare like with like, below is
\nthe actual COBOL Class. This COBOL class can be compiled using Visual COBOL to
\na .Net assembly or Java bytecode.<\/p>\n

class-id Example public.\r\n\r\nworking-storage section.\r\n01 COMPANY.\r\n 05 COMPANY-NAME        PIC X(60) VALUE \"Semantic Designs\".\r\n 05 COMPANY-ADDRESS.\r\n  10 STREET PIC X(80)    VALUE \"13171 Pond Springs Rd.\".\r\n  10 CITY.\r\n   15 CITY-NAME           PIC X(40) VALUE \"Austin\".\r\n   15 FILLER              PIC XX VALUE \", \".\r\n   15 CITY-STATE          PIC XX VALUE \"TX\".\r\n   15 ZIP.\r\n    20 ZIP-5              PIC 9(5) VALUE 78729.\r\n    20 FILLER             PIC X VALUE \"-\".\r\n    20 ZIP-E4             PIC 9(4) VALUE 7102.\r\n01 LINE-ITEM.\r\n 05 ITEM                  PIC X(20) VALUE \"Item Description\".\r\n 05 AMOUNT                PIC 999 VALUE 217.\r\n 05 PRICE                 PIC 9999V99 VALUE 24.95.\r\n\r\n77 TOTAL-AMOUNT           PIC 999999V99.\r\n77 DISCOUNT-THRESHOLD     PIC 999999V99 VALUE 1111.11.\r\n77 DISCOUNT-PERCENT       PIC 99 VALUE 20.\r\n77 DISCOUNT-AMOUNT        PIC 99999999V99.\r\n\r\n01 TOTAL-AMOUNT-FORMAT    PIC 999999.99.\r\n01 TotalAmount            string public.\r\n\r\nmethod-id ComputeTotal.\r\nprocedure division.\r\n  MULTIPLY AMOUNT BY PRICE GIVING TOTAL-AMOUNT.\r\n  IF TOTAL-AMOUNT > DISCOUNT-THRESHOLD\r\n   MULTIPLY TOTAL-AMOUNT BY DISCOUNT-PERCENT\r\n    GIVING DISCOUNT-AMOUNT\r\n  DIVIDE 100 INTO DISCOUNT-AMOUNT\r\n  SUBTRACT DISCOUNT-AMOUNT FROM TOTAL-AMOUNT.\r\n\r\n  move TOTAL-AMOUNT to TOTAL-AMOUNT-FORMAT\r\n  set TotalAmount to TOTAL-AMOUNT-FORMAT\r\n goback.\r\nend method.\r\n\r\nmethod-id. DisplayTotal.\r\nprocedure division.\r\n DISPLAY COMPANY-NAME.\r\n DISPLAY \"Total: \", TOTAL-AMOUNT-FORMAT\r\nend method.\r\n\r\nmethod-id. PerformTask.\r\nprocedure division.\r\n invoke self::ComputeTotal()\r\n invoke self::DisplayTotal()\r\nend method.\r\n\r\nend class.<\/pre>\n
A C# program that uses the class above….  the same can also be done with Java…<\/p>\n
\r\nusing System;\r\nusing System.Collections.Generic;\r\nusing System.Linq;\r\nusing System.Text;\r\n\r\nnamespace UseExample\r\n{\r\n    class Program\r\n    {\r\n        static void Main(string[] args)\r\n        {\r\n            new Example().PerformTask();\r\n        }\r\n    }\r\n}\r\n\r\n<\/pre>\n
Another approach would be keep the legacy COBOL and create a wrapper class
\nthat just uses the legacy COBOL.<\/p>\n
\r\n       class-id Example2.\r\n\r\n       working-storage section.\r\n\r\n       method-id ComputeTotal.\r\n       procedure division.\r\n           call \"COMPUTE-TOTAL\".\r\n       goback.\r\n       end method.\r\n\r\n       method-id. DisplayTotal.\r\n       procedure division.\r\n           call \"DISPLAY-TOTAL\".\r\n       end method.\r\n       \r\n       method-id. PerformTask.\r\n       procedure division.\r\n           invoke self::ComputeTotal()\r\n           invoke self::DisplayTotal()\r\n       end method.\r\n\r\n       end class.\r\n<\/pre>\n
Then to make the DISPLAY-TOTAL, COMPUTE-TOTAL accessible to the class add two entry-points so
\nthey can be used with the CALL verb eg:<\/p>\n
\r\n        EXTERNAL-EPS.\r\n          \r\n        ENTRY \"DISPLAY-TOTAL\".\r\n           PERFORM DISPLAY-TOTAL.\r\n           GOBACK.\r\n           \r\n        ENTRY \"COMPUTE-TOTAL\".\r\n           PERFORM COMPUTE-TOTAL.\r\n           GOBACK.\r\n<\/pre>\n
I personally think this it is quite a reasonable way to reuse COBOL…. plus the same code works under CLR
\nand JVM…. bonus….<\/p>\n","protected":false},"excerpt":{"rendered":"
While reading a article on-line about using “NACA transcoder” to translate COBOL into Java it got me thinking about modernizing COBOL. While I agree 100% about the actual code generated by the NACA transcoder is not maintainable, I disagree that … Continue reading →<\/span><\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4,5],"tags":[74,205,208,209,216,204,206,188],"_links":{"self":[{"href":"http:\/\/www.gennard.net\/blog\/wp-json\/wp\/v2\/posts\/851"}],"collection":[{"href":"http:\/\/www.gennard.net\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.gennard.net\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.gennard.net\/blog\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"http:\/\/www.gennard.net\/blog\/wp-json\/wp\/v2\/comments?post=851"}],"version-history":[{"count":26,"href":"http:\/\/www.gennard.net\/blog\/wp-json\/wp\/v2\/posts\/851\/revisions"}],"predecessor-version":[{"id":877,"href":"http:\/\/www.gennard.net\/blog\/wp-json\/wp\/v2\/posts\/851\/revisions\/877"}],"wp:attachment":[{"href":"http:\/\/www.gennard.net\/blog\/wp-json\/wp\/v2\/media?parent=851"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.gennard.net\/blog\/wp-json\/wp\/v2\/categories?post=851"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.gennard.net\/blog\/wp-json\/wp\/v2\/tags?post=851"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}