On 08/27/2015 09:25 AM, Dean Tribble wrote:
Ideally syntax proposals should include some frequency information to
motivate any change. Is there an easy search to estimate the frequency
of Math.pow? In my application codebase (financial app with only
modest JS use), there are very few uses, and there are as many uses of
Math.sin as there are of Math.pow.
Frequency relative to what, though? If code that does nontrivial math is
a very small proportion of total JS code, and yet the exponentiation
operator makes that code much more readable, then what is the
conclusion? I would argue that ** precedence confusion is irrelevant to
code that isn't going to use Math.pow in the first place. So it's a
question of whether ** is a big enough readability win in code that
computes exponents.
Anecdotally, my eyes caught on: "-Math.pow(2,-10*a/1)" (from a
charting library) which makes me not want to have to review code where
I'm worried about the precedence of exponentiation.
I'd have to write that out: -2**(-10*a/1). That doesn't seem too bad.
For myself, I do very much prefer Math.sqrt(a**2 + b**2) to
Math.sqrt(Math.pow(a, 2) + Math.pow(b, 2)). The verbosity and uneven
density of notation is really bothersome -- for any equation like the
second one, I guarantee that I'll rewrite it on paper to figure out what
it's saying. (Ok, maybe not for that specific formula, but even there
I'll mentally render it.) I would not need to do so with the first one.
Jumping between prefix and infix is jarring.
Then again, I could make the same argument for Math.sqrt(a**2 + b**2) vs
(a**2 + b**2) ** 0.5. And I don't like the second one much. But people
don't interchange those when handwriting formulas, either.
Math.sqrt(a.pow(2) + b.pow(2)) is an interesting middle point. I
initially thought it struck the right balance, but seeing it written
out, it still looks far inferior to me.
A more complex example might help:
a * (b - a)**(x - 1/2 * (b - a)**2)
vs
a * Math.pow(b - a, x - 1/2 * Math.pow(b - a, 2))
vs
a * (b - a).pow(x - 1/2 * (b - a).pow(2))
For me, the middle one is a mess. I can't make sense of it, and I can't
spot the common (b - a) expression at all. The first one is as readable
as such formulas ever are when written out with ASCII text. The third
one is somewhere in between. I can see the common (b - a), and perhaps
if I got more used to seeing .pow I could mentally make use of it
without writing it on paper, but for now I cannot. Part of the problem
is that I can easily translate "x**2" into "x squared", but "x.pow(2)"
is raising x to the power of 2.
_______________________________________________
es-discuss mailing list
es-discuss@mozilla.org
https://mail.mozilla.org/listinfo/es-discuss
