On Thursday, 14 August 2014 at 16:01:05 UTC, Baz wrote:
On Thursday, 14 August 2014 at 13:19:36 UTC, Sergey Kozyr wrote:
Sorry for previous message. Once again:
I was reading D language reference and found some issue with
"case ... :" statement specifications.
Documentation http://dlang.org/statement#CaseStatement says
that after
case 1:
must be non-empty statement "ScopeStatementList". For example
case 1:
return true;
case 2: {
}
case 3: ;
But next example concerns me:
case 1:
case 2:
return true;
case 3:
return false;
After "case 1:" we see no statement at all. This conflicts
with "CaseStatement" rule of documentation. But this is right
D code.
I think language reference must be updated.
It's a "fall trough":
https://en.wikipedia.org/wiki/Switch_statement#Fallthrough
It's a fall trough but it is not the reason why it does works. It
does because (as Daniel already mentioned) a case is a valid
statement, therefore a case following other case is a totally
valid statement.
for example:
case 1:
case 2:
return true;
There are three statements. One which must be followed by another
(case keyword) and another by an expression (return keyword).
It is not even a special-case in the switch in C language. The
switch keyword accept a expression constant as argument and must
be followed by a statement, so:
switch(1) return 0;
is valid C code and no standard-compliant compiler must give an
error about that. The fact we can do:
switch(E)
{
case 1: ... break;
case 2: .... break;
default: ... break;
}
That's why compound-statement is a statement too (which switch
does accept same reason why break keyword is needed)
