> On Apr 26, 2022, at 4:41 PM, ben via cctalk <cctalk@classiccmp.org> wrote:
>
> ...
> PS: Did any common I/O devices have the ALGOL symbols Less than or Equals,
> Greater than or equals , not , arrows and other misc symbols?
Yes, the Flexowriters at TU Eindhoven used to punch ALGOL programs for the
Electrologica X8 machine there (late 1960s through early 1970s). As I recall,
Dijkstra made some comment somewhere about the usefulness of being able to
specify your own character set.
Those machines had upper/lower case letters, several special character such as
the logic symbols not, or, and, the subscript 10 for exponential notation
numbers, plus non-escaping underline and vertical bar. The underline was used
for keywords, so the ALGOL keyword "begin" was keyed as _b_e_g_i_n. It would
also make several other special characters, for example _= (underlined equal)
is the Boolean equivalence operator, and _ followed by the not symbol gives you
the "implies" operator, and _< is less-or-equal. The vertical bar would also
make several overstruck symbols, for example |= becomes not-equal, | followed
by the and symbol is uparrow (for exponentiation). The local inventions |< and
|> were used for string quotes.
Here's a sample of what it would look like printed on the Flexowriter. The
line printers were upper-case only; they'd print lower case letters as upper
case, upper case letters overprinted with a period. Ugh...
paul
