December 30, 2007 Implicit conversion of char[] to string struct | ||||
---|---|---|---|---|
| ||||
Hi, I would like to know if it is possible to convert a char[] to a struct that has a opCall(char[] str) function. For example: import std.stdio; char firstCharacterInString(pstring str) { return str[0]; } void main() { writefln("first char = '%s'", firstCharacterInString("Hello World!")); // should print "first char = 'H'" } pstring = http://www.dprogramming.com/dstring.php The above code will output something like this: Error: cannot implicitly convert expression ("Hello World!") of type char[12u] to pstring Is there any way to make D substitute "Hello World!" for pstring("Hello World!")? How do I get the above code to work without creating an instance of pstring like this: pstring str = "Hello World!"; writefln("first char = '%s'", firstCharacterInString(str)); All help is appreciated! Peace, Alan |
December 30, 2007 Re: Implicit conversion of char[] to string struct | ||||
---|---|---|---|---|
| ||||
Posted in reply to Alan Smith | Alan Smith wrote: > I would like to know if it is possible to convert a char[] to a struct that has a opCall(char[] str) function. For example: > > import std.stdio; > > char firstCharacterInString(pstring str) { return str[0]; } > > void main() { writefln("first char = '%s'", firstCharacterInString("Hello World!")); // should print "first char = 'H'" } > > pstring = http://www.dprogramming.com/dstring.php > > The above code will output something like this: > > Error: cannot implicitly convert expression ("Hello World!") of type > char[12u] to pstring > > Is there any way to make D substitute "Hello World!" for pstring("Hello World!")? How do I get the above code to work without creating an instance of pstring like this: > > pstring str = "Hello World!"; > > writefln("first char = '%s'", firstCharacterInString(str)); You can't do it with structs, as far as I can tell. If pstring were a class, you could do this: import std.stdio; class pstring { char[] foo; this(char[] s) { foo = s; } } // note the ellipsis char firstCharacterInString(pstring str...) { return str.foo[0]; } void main() { writefln("first char = '%s'", firstCharacterInString("Hello World!")); } Perhaps if, in the future, structs get constructors, you could do something like this with structs. Of course, you're free to make a wrapper class for your struct but that's somewhat self-defeating in my opinion. :-) -- E-mail address: matti.niemenmaa+news, domain is iki (DOT) fi |
Copyright © 1999-2021 by the D Language Foundation