On Mon, Jun 01, 2020 at 01:15:23AM -0700, ToddAndMargo via perl6-users wrote: > On 2020-05-31 17:13, Peter Pentchev wrote: > > On Mon, Jun 01, 2020 at 03:12:05AM +0300, Peter Pentchev wrote: > > > On Sun, May 31, 2020 at 04:29:55PM -0700, ToddAndMargo via perl6-users > > > wrote: > > > > On 2020-05-31 04:58, Peter Pentchev wrote: > > > > > > > So my beef is when you feed these guys an undefined > > > > > > > variable, that they needs to tell you it requires > > > > > > > a "defined" variable. Not a bunch of useless rubbish. > > > > > > > For example (useless rubbish): > > > > > And also... I thought I mentioned this before. You want a more clear > > > > > error message for*one* *single* specific case of a "can't find this > > > > > method, did you mean one of these?" error message. I tried to explain > > > > > that this error message is one that is displayed in many cases, not > > > > > only > > > > > for "you passed an undefined thing, I want a defined thing"; in my > > > > > opinion, it is actually quite helpful in that it actually lists > > > > > the candidates in a "did you mean one of these?" style. > > > > > > > > > > You want it to be clear if you pass an undefined value where a defined > > > > > value was expected; that would mean that somebody would have to write > > > > > the code to make it check whether it is this very specific case and > > > > > then > > > > > that code would have to be maintained for years and years. Tomorrow > > > > > you'll say "but can't it give me a more clear message when I pass an > > > > > integer and it expected a string?" and the day after tomorrow you'll > > > > > say > > > > > "but can't it give me a more clear message when I pass a string and it > > > > > expected a function?". > > > > > > > > > > The error message says "you passed an object of this type, and I can't > > > > > find this method for this type; here are a couple of types that have > > > > > this method, did you mean one of these?" It tells you what the types > > > > > are, and it doesn't have to have thousands of special cases. It tells > > > > > you what the types are. > > > > > > > > Hi Peter, > > > > > > > > I like that you in-line and bottom post. You are a lot > > > > easier to follow. > > > > > > > > I think are talking at cross purposes. Let me give an > > > > example: > > > > > > > > Q: is a "cow" a "Plant"? > > > > A: a "cow" in not a hazel nut > > > > A: a "cow" in not a radish > > > > A: a "cow" in not a carrot > > > > A: a "cow" in not a cabbage > > > > ... > > > > > > > > Are all of the answers a correct? > > > > Yes.. Evey answer is completely correct. > > > > > > > > Are any of the answers helpful? > > > > No > > > > > > Right. So, once again, just as I said, you are only interested in one of > > > the answers - "Str:U is not a Str:D, you want a Str:D". However, how > > > should Raku know *which* one of the answers you are interested in? > > > Tomorrow you may pass an integer to a function that only accepts strings > > > and floating-point numbers; should Raku tell you "you must pass a > > > string, not an integer" or "you must pass a floating-point number, not > > > an integer"? Raku doesn't know which one of those you meant. > > > > ...accepts strings *or* floating-point numbers, of course... > > > > G'luck, > > Peter > > > > > Hi Peter, > > I screw up A LOT. When something REQUIRES "Str:D" and I > send it a "Str:U", I want to be told such. Not all > the things it can't do, which I see thrashing around the > protuberance of the scrubbary. > > starts-with's invocant requires a defined value (Str:D) > > would be perfect. Not appreciated is a list of all the > things it can't do. This makes me have to BOTH troubleshoot > my screw up and the everything it can't do error message. > > I think what you are trying to do is help me fix my screw > ups, which is of course, much appreciated. You are trying > to help me understand what the error message means. > > What I am after in this thread is a better error message. > > Thank you for all the help and tips. > > -T > > p.s believe me, there will be a lot more screw ups on my > part in the future for you to help me fix! Of that you > can rest assured.
OK, so for the last time :)
Imagine the following code:
===================================================
#!/usr/bin/env raku
use v6.d;
class Thing {
multi method do-things(Int:D $value) {
say "A thing can do things with an integer: $value";
}
multi method do-things(Rational:D $value) {
say "A thing can do things with a rational number: $value";
}
}
my Thing:D $thing = Thing.new;
dd $thing;
$thing.do-things(5);
$thing.do-things(3/5);
# And now for the clincher...
$thing.do-things("what?!");
===================================================
Running it on my system does this:
[roam@straylight ~/tmp/v/roam/testwhee]$ raku functions.raku
Thing $thing = Thing.new
A thing can do things with an integer: 5
A thing can do things with a rational number: 0.6
Cannot resolve caller do-things(Thing:D: Str:D); none of these signatures match:
(Thing: Int:D $value, *%_)
(Thing: Rational:D $value, *%_)
in block <unit> at functions.raku line 23
[roam@straylight ~/tmp/v/roam/testwhee]$
In other words, Raku tells me "I don't know which of these methods you want".
It doesn't know.
You say "it should tell me exactly what to do" - well, what exactly
would you like Raku to tell you in this case? Should it assume that you
meant to pass an integer? Should it assume that you meant to pass a
rational number?
It cannot tell you anything more specific.
It just... doesn't... know.
You are the only one who knows what you're *trying* to do. Raku doesn't.
Hope that helps :)
G'luck,
Peter
--
Peter Pentchev r...@ringlet.net r...@debian.org p...@storpool.com
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