In message Wed, 27 Jan 1999 20:40:23 +0100, Joachim Durchholz joachim.durchholz@munich.netsurf.de writes:
Eliot & Linda Miranda wrote:
What are the relative recidences of + - * / \ // < <= > >= = ~= ?
From my above remarks, a highest-to-lowest precedence table is actually easy to construct, and actually observed in multi-precedence languages like C and Prolog:
Exponentiation ^ (is this actually in Smalltalk?) Multiplicative * / // \ Relational < <= > >= Equality = == ~ ~~ Assignment :=
This is where I've always seen the benefit of the Smalltalk syntax. If there's precedence (besides, of course, left-to-right) then it wouldn't really be fair to make precedence something magical about the base syntax and inaccessable to user-created operators. That the user/programmer is a peer of the language designer/library creator is one of the most important things about Smalltalk, IMHO.
But if everyone can play with precedence, the syntax gets out of hand. If you aren't very familiar with all the operators used (and perhaps the context as well, since they are just messages) it becomes difficult to read code. The precedence of a single operator could change the meaning of an entire statement. (I get the impression that this was a capability and problem of Smalltalk 76...?)
So you have the Algols, which give power to the language designer, and Lisps, which give up on infix entirely.
I like that Smallktalk figured out a way to do infix without tyranny. I'm just wondering or hoping that there might be some way that does everything right without making compromises. That's what rethinking is about -- everyone knows the compromises, languages have divided and families have been formed around those compromises. But maybe there's a different way of thinking about it that lets you have it all. IMHO, that's what Squeak (not necessarily Smalltalk) is supposed to be about.
Or is maintaining readability less important than attempting to provide an inaccurate simulation of mathematical notation (e.g. * instead of adjacency)?
Bah. No rethorics please. I understand you are accustomed to Smalltalk tradition and don't want to learn new tricks for little gain, but that doesn't necessarily mean that the position of anybody with a different opinion is so ridiculous as you present it here.
I must say I too was quite annoyed with the nit-picking that "*" is not the same as adjacency. Be it an x, a dot, or * doesn't matter -- that confuses no one. Changing the symbols is unimportant -- changing the semantics *is* important.
I think very strongly that the current design of the infix rules is better than any other programming language I've used, that its easier to teach, that its easier to learn, and easier to use.
I'd like to point out that when I started this thread, I never meant that it was too hard to learn Smalltalk's left-to-right rule. Only that it could confuse children who will later have to learn about the order of precedence. Maybe the whole issue could be generalized and politicized: do we accept outside conventions? Is Squeak a world of its own? If it is, is that being high-minded or egotistic? But those aren't really the questions I wanted to ask... I was just hoping there was some way that I couldn't see that would allow precedence without making Smalltalk into C. Sigh.
-- Ian Bicking