On Wed, 2 Sep 2020 15:02:51 +0000, Seymour J Metz wrote:
>PL/I has no reserved words, so IBM can extend the language without breaking
>existing code. However, it is bad form to knowingly use a keyword as a
>procedure, label or variable name.
>
However, if IBM were to extend in that fashion it would be at the
cost of rendering possibly existing user code "bad form".
"No keywords" and "compatibly extensible" aren't equivalent. Some
decades ago a colleague and I extended a Pascal compiler, adding
constructs analogous to ITERATE and LEAVE by making them BIFs
declared in Pascal's mythical exterior block in which standard types
appear to be declared. The user can code overriding declarations
of the standard identifiers or our identifiers without error; the
outer declarations are then inaccessible in that inner block.
I considered it bad form when a user declared overiding:
TYPE INTEGER = -32768..32767;
The ability to do so is deemed a specification flaw by partisans
of other languages.
On Wed, 2 Sep 2020 17:47:27 +0000 [Wrong!], Robert Prins wrote:
> ...
>ISPF HILITE is just that highlight. It does not do any parsing of the language.
>I think EDOEND predated HILITE, and it also has an option to just show all
>"myproc: proc;" ... 'end myproc;' statements
>
>> "Language and logic hiliting is not supported for ASCII or UTF-8 editing
>> sessions and the HILITE command is not available during these edit sessions."
>>
Bummer. The user ought to be able to split the screen and HILITE an
EBCDIC PL/I program in one split and an ASCII C program in another.
-- gil
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