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User Defined ConversionsOne of the most common forms of user defined conversion is that which takes a code and using it extracts a description from a code table for display. For example: 0001 SUBROUTINE CODE_LOOKUP(TYPE, PASSED, BRANCH, RETURNED) 0002 BEGIN CASE 0003 CASE TYPE = "ICONV" 0004 * Assuming codes are MVs in field 5 and descs in 6 0005 CODES = XLATE("CODES", BRANCH[-1,"B*"],5,"X") 0006 LOCATE PASSED IN CODES USING @VM SETTING POS THEN 0007 STATUS() = 0 0008 END ELSE 0009 STATUS() = 1 ; PASSED = "" 0010 END 0011 RETURNED = PASSED 0012 CASE TYPE = "OCONV" 0013 CODES = XLATE("CODES", BRANCH[-1,"B*"],"","X") 0014 LOCATE PASSED IN CODES<5> USING @VM SETTING POS THEN 0015 RETURNED = CODES<6,POS> 0016 END ELSE 0017 RETURNED = PASSED 0018 END 0019 END CASE 0020 RETURN Note that in this example the DATA logic is kept separate from the APPLICATION logic (the ICONV itself does not suggest replacements, it flags that an error has occurred and lets the application logic suggest alternatives. This leads to more portable code (see future articles on system design)). However when the user presses Ctrl-F10 and then F2 the uncoded version shows up. If the user then chooses the uncoded version, the OCONV logic is invoked and it redisplays as the coded version. If the user then selects this version and F9s it, the system attempts to re-ICONV the OCONVed value - even though the internal form is available - fails to ICONV it and thus finds no hits. To fix this problem amend the code as follows :- 0001 CODES = XLATE("CODES", BRANCH[-1,"B*"], "", "X") 0002 LOCATE PASSED IN CODES<5> USING @VM SETTING POS THEN 0003 RETURNED = PASSED 0004 END ELSE 0005 LOCATE PASSED IN CODES<6> USING @VM SETTING POS THEN 0006 RETURNED = CODES<5,POS> 0007 END ELSE 0008 STATUS() = 1 ; RETURNED = "" 0009 END 0010 END (Volume 3, Issue 1, Page 7) |
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