Re: for or against equality, was Why are ambiguous grammars usually a bad idea?

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From	gah4 <gah4@u.washington.edu>
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Subject	Re: for or against equality, was Why are ambiguous grammars usually a bad idea?
Date	Mon, 3 Jan 2022 21:07:07 -0800 (PST)
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On Monday, January 3, 2022 at 11:58:39 AM UTC-8, mac wrote:
> > [Interesting take. In reality, of couse, BASIC borrowed that from Fortran. Algol
> > used := for assignment, different from = for equality comparison. -John]

> Indeed.
> Unfortunately, assignment is probably the single most common operator.
> The ASCII committee should have kept the left-arrow character instead of
> replacing it with underscore.

The assignment statement in BASIC, at least the ones I know, has an
(optional) LET keyword, so it might say:

10  LET A=3

Most people leave it off, though.

Is PL/I the only language that uses = for both assignment and the relational operator?
Since expressions are not statements, it avoids the ambiguity that would otherwise occur.
I believe some BASIC also use = for both.

Underscore is a pretty useful character.

The two ASCII characters that don't exist in EBCDIC are ^ and ~.
Two EBCDIC characters that don't exist in ASCII are 𝇍 (cent)
and ¬ (logical NOT sign).  Conversion tables usually cross
map those pairs.  (PL/I, at least, uses ¬ and ¬= operators.)

[In original Dartmouth BASIC the LET was mandatory, but it was a considerably
smaller and fully compiled language than the later dialects.  On the other
hand, PL/I made a fetish of nothing being a reserved word, e.g.

  IF IF = THEN THEN ELSE = BEGIN; ELSE END = IF;

-John]

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