54 lines
4.3 KiB
Rexx
54 lines
4.3 KiB
Rexx
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/*┌───────────────────────────────────────────────────────────────────┐
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│ The REXX language doesn't allow for the changing or overriding of │
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│ syntax per se, but any of the built-in-functions (BIFs) can be │
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│ overridden by just specifying your own. │
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│ │
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│ To use the REXX's version of a built-in-function, you simply just │
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│ enclose the BIF in quotation marks (and uppercase the name). │
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│ │
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│ The intent is two-fold: the REXX language doesn't have any │
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│ reserved words, nor reserved BIFs (Built-In-Functions). │
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│ │
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│ So, if you don't know that VERIFY is a BIF, you can just code │
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│ a subroutine (or function) with that name (or any name), and not │
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│ worry about your subroutine being pre-empted. │
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│ │
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│ Second: if you're not satisfied how a BIF works, you can code │
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│ your own. This also allows you to front-end a BIF for debugging │
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│ or modifying the BIF's behavior. │
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└───────────────────────────────────────────────────────────────────┘ */
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yyy='123456789abcdefghi'
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rrr = substr(yyy,5) /*returns efghi */
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mmm = 'SUBSTR'(yyy,5) /*returns 56789abcdefgji */
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sss = "SUBSTR"(yyy,5) /* (same as above) */
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exit /*stick a fork in it, we're done.*/
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/*──────────────────────────────────SUBSTR subroutine───────────────────*/
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substr: return right(arg(1),arg(2))
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/*┌───────────────────────────────────────────────────────────────────┐
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│ Also, some REXX interpreters treat whitespace(s) as blanks when │
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│ performing comparisons. Some of the whitespace characters are: │
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│ │
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│ NL (newLine) │
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│ FF (formFeed) │
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│ VT (vertical tab) │
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│ HT (horizontal tab or TAB) │
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│ LF (lineFeed) │
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│ CR (carriage return) │
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│ EOF (end-of-file) │
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│ and/or others. │
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│ │
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│ Note that some of the above are ASCII or EBCDIC specific. │
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│ │
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│ Some REXX interpreters use the OPTIONS statement to force │
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│ REXX to only treat blanks as spaces. │
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│ │
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│ (Both the verb and option may be in lower/upper/mixed case.) │
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│ │
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│ REXX interpreters which don't recognize any option won't treat │
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│ the (below) statement as an error. │
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└───────────────────────────────────────────────────────────────────┘ */
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options strict_white_space_comparisons /*can be in lower/upper/mixed.*/
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