On Sunday, August 28, 2016 at 12:56:37 AM UTC+8, Michael Jones wrote: > > TL, I have been confused by this thread, your similar questions, and in > fact, most of your emails—until now. > > > > When you write ‘Why can’t X’ as you often do, I have presumed that this > was a casual and imprecise form of expressing the question “what is the > reason why a different path was chosen.” Now, based on this, I see it > differently. I think you mean it literally. I imagine myself walking beside > you and you saying, “Why can’t trees be blue? Why can’t dogs have square > heads? Why can’t cars have windows in the tires? Why don’t cats and pigs > swim?” Which is to say, it seems that you are writing email as a way to > share a stream of consciousness that every aspect of reality—every choice, > decision, evolutionary outcome, taste, desire—could in fact be different in > some other place or time or circumstance. > > > > Now that the question unfolds as “Why is it not possible that X” (as you > wrote from the start) then the answer to your emails is, “It is possible,” > possible as in, “in a different language, with a different goal, on a > hypothetical computer, if the most common programmer errors were not as > they are, etc.” In engineering, nearly everything is possible. Not all of > the possibilities are good, wise, or desirable though, so I think many here > thought these other attributes were implied as part of your question. I did > before but now do not. > > > > In your spirit of “Why can’t” as in “prove that it is impossible” (of > course such proofs are impossible), I offer examples of the uncommon but > possible. > > > > > > > > A different question, “Why is X disallowed in Go,” is actually much more > educational. The example below, that was given you by amkguo, is the > example that I thought of right at first—not about “why can’t bytes be > interchangeable” but “why are Types treated as separate species.” This is a > great topic. Because of huge human experience that mixing types by concept > (adding two kinds of temperature or mass) results in unfortunate outcomes > (many!) and similar experience in debugging as the result of many > languages, C and C++ among them, doing natural-seeming invisible coercion > between types. Type coercion in specific and invisible actions generally > are a trouble area in large-scale software development. This is why the Go > team (superstars with UNIX, C, major Gnu C/C++ implementation, Plan 9, > Inferno, and maybe more importantly, careful study of common software > development problems by 10,000+ programmers Google) disallowed it during > the design of Go and instead require explicit casts (as in “var a int = 3; > b := float64(a)”), why they treat Types as non-mixing species, and why the > affordances around this are very limited. > > > > I gave a talk in Madrid about Go as a software engineering approach > assisted by a computer language. This seems a nice educational way to avoid > many of the “but C allows …” or “it should be technically possible to…” > confusions. > > > > Michael >
I never deny the great work made by golang team. In fact, I'm a go lover. I just want to understand the reason for some golang syntax rules. :) > > > *From: *<golan...@googlegroups.com <javascript:>> on behalf of T L < > tapi...@gmail.com <javascript:>> > *Date: *Saturday, August 27, 2016 at 8:28 AM > *To: *golang-nuts <golan...@googlegroups.com <javascript:>> > *Cc: *<tapi...@gmail.com <javascript:>>, <amk...@gmail.com <javascript:>> > *Subject: *Re: [go-nuts] Re: Why can't convert []T to []T2 if T2 is a > copy definition of T? > > > > On Saturday, August 27, 2016 at 10:33:45 PM UTC+8, amk...@gmail.com wrote: > > Look at this example code from > https://talks.golang.org/2012/goforc/celsius.go and you'll know why. > > > > Although the underlying type of Celsius and Fahrenheit are the same - > float32. There will be no meaning if the language allow you to convert > these type to the underlying type float32. What's it mean for 0 = 273.15? ( > 273.15K = 0°C). > > > > Also, even for the Age type, I may use it for a person's age, you may use > it for a virus' age. > > The person may live 100 years, but some virus may live only several hours. > Although the > > underlying type is int, what does it mean when you compare a person's age > with a virus' age? > > "A type determines the set of values and operations specific to values of > that type." > > type Age is not the same as type int. > > > In this example, in fact, values of Celsius and Fahrenheit (including > float32) can be converted to other types. > > -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. To unsubscribe from this group and stop receiving emails from it, send an email to golang-nuts+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
