the ugly ocaml monstrosity powering my site
oppi.li
noodle on mainframe modernization
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posts/tales_from_mainframe_modernization.md
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posts/tales_from_mainframe_modernization.md
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some wonderful hacks to get around the limitations of the
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system. Mainframes are also chock full of history.
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### Base-2 numerics
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### Base-10 numerics
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This is the first thing that stood out to me when I looked
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at COBOL code, a data-definition (the phrase for "variable")
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That statement declares a variable called `HEIGHT` with type
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`9(3)`, which is shorthand for `999`, which indicates
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"3-digit number". Similarly `A(5)` indicates 5-character
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alphabetic string.
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"3-digit number". The possible values for this variable are
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`0` to `999`!
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### Internationalisation
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···
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01 DATE.
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05 DD PIC 9(2).
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05 FILLER PIC X.
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05 MM PIC 9(2).
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05 MMM PIC A(3).
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05 FILLER PIC X.
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05 YYYY PIC 9(4).
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···
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.
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.
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MOVE "03/04/2025" TO DATE.
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MOVE "03 MAR 2025" TO DATE.
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DISPLAY "DAY: " DD. *> DAY: 03
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DISPLAY "MONTH: " MM. *> MONTH: 04
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DISPLAY "MONTH: " MMM. *> MONTH: MAR
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DISPLAY "YEAR: " YYYY. *> YEAR: 2025
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*> also works:
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MOVE "03.04.2025" TO DATE.
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MOVE "03-MAR-2025" TO DATE.
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```
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### Early exit