Sp, speaking of mathematical precedence and all that, anyone up to
looking at the IEEE-754 spec and making one's Smalltalk of choice comply
with _all_ the requirements? Or how about implementing decimal floats?
On 6/26/14 12:01 , [email protected] wrote:
Couldn't we just have an expression evaluator done with PetitParser
doing these things?
Tcl and Bash have this expr: thing.
(Expression parse: '5+3*2') value.
(Expression parse: ':a | 5+:a*2') value:10.
(Expression parse: ':a | 5+:a*2') value:self x.
With the thesis of Lukas Renggli these was this Helvetia story.
Is there any chance we see something around these lines now that there
is a new compiler thing inside Pharo?
So:
someMethod: anX
<expr>
^ 5 + anX * 2
Phil
On Thu, Jun 26, 2014 at 6:11 PM, Richard Sargent
<[email protected]
<mailto:[email protected]>> wrote:
Esteban A. Maringolo wrote
> If one thing confuses people in that realm is non arithmetic
precedence:
> Eg. 2 + 3 * 4 = 20 instead of the "expected" 14.
>
> And we're not going to change that either. It's not worthy, and I
> doubt if it is possible at all.
I'm probably late to the party with this reply. The primary reason
for not
changing this is that it would be incorrect. It comes down to intrinsic
versus extrinsic meaning. A multiple operator has an intrinsic
meaning: it
means multiple. But a message name does not have intrinsic meaning
(other
than it is a good idea to have the name represent what it does). The
meaning
of a message is determined by the receiver. e.g. if PetitParser
defines #*
to mean "0 or more repetitions", what happens when someone has
decided that
it should be evaluated before #+?
Message sending precedence can only be defined in terms of the type of
message: unary, binary (or infix), and keyword, since the
interpretation of
the message is the receiver's responsibility, not the compiler's.
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