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digitalmars.D.learn - Why Throwable.message is not a property

reply uranuz <neuranuz gmail.com> writes:
The question is why Throwable.message is not a  property?! It 
looks strange now, because "message" is not a *verb*, but a 
*noun*. So it's expected to be a property. Also because it is not 
a property in some contexts when I try to concatenate it with 
string without parentheses using "~" operator it fails, because 
(as you could expect) it is a *regular* function, but not a 
property.

I wonder if it was made as *non-property* by some reason or by 
oversight?

Thanks
Mar 17
parent reply Adam D. Ruppe <destructionator gmail.com> writes:
On Wednesday, 17 March 2021 at 17:46:27 UTC, uranuz wrote:
 Also because it is not a property in some contexts when I try 
 to concatenate it with string without parentheses using "~" 
 operator it fails
Can you post some sample code that demonstrates this?
Mar 17
parent reply uranuz <neuranuz gmail.com> writes:
On Wednesday, 17 March 2021 at 17:52:20 UTC, Adam D. Ruppe wrote:
 On Wednesday, 17 March 2021 at 17:46:27 UTC, uranuz wrote:
 Also because it is not a property in some contexts when I try 
 to concatenate it with string without parentheses using "~" 
 operator it fails
Can you post some sample code that demonstrates this?
Seems that a problem with concatenation is because Throwable.message has const(char)[] type, but not string. This makes some inconvenience ;-) There is an example: import std; void main() { auto exc = new Exception("Test"); string longMsg = "The: " ~ exc.message; // Adding parentheses () after "message" actually doesn't change anything. Error is the same writeln(longMsg); } Compile error: onlineapp.d(6): Error: cannot implicitly convert expression "The: " ~ exc.message() of type char[] to string I could add cast(string), but it's not something I want to do. The reason, why I want to use "message" instead of "msg" is that I want to add some extra information to exception as separate typed fields. But I want it to be displayed when converting exception to string. So I shall override "message" and convert this extra info to string...
Mar 17
parent reply Adam D. Ruppe <destructionator gmail.com> writes:
On Wednesday, 17 March 2021 at 19:32:02 UTC, uranuz wrote:
 Seems that a problem with concatenation is because 
 Throwable.message has const(char)[] type, but not string. This 
 makes some inconvenience ;-)
Yes, that's what I thought. The concat operation tends to give the most flexible type of the arguments... and I wish it would then ACTUALLY use that flexibility... but it doesn't. Regardless though since you know you are concating it, which means you get a new string anyway, you can safely cast(string) it. string longMsg = "The: " ~ cast(string) exc.message; that's how i do it.
Mar 17
parent uranuz <neuranuz gmail.com> writes:
On Wednesday, 17 March 2021 at 19:38:48 UTC, Adam D. Ruppe wrote:
 On Wednesday, 17 March 2021 at 19:32:02 UTC, uranuz wrote:
 Seems that a problem with concatenation is because 
 Throwable.message has const(char)[] type, but not string. This 
 makes some inconvenience ;-)
Yes, that's what I thought. The concat operation tends to give the most flexible type of the arguments... and I wish it would then ACTUALLY use that flexibility... but it doesn't. Regardless though since you know you are concating it, which means you get a new string anyway, you can safely cast(string) it. string longMsg = "The: " ~ cast(string) exc.message; that's how i do it.
This is what I have done ;-)
Mar 17