Nitpicking the D grammar

[Stewart Gordon]

"Jascha Wetzel" <"[firstname]"@mainia.de> wrote in message 
news:fbrk6q$1cv5$1 at digitalmars.com...
<snip>
> Disallowing expressions without an effect is nice, but wouldn't a warning 
> suffice? After all the compiler can't find all expressions that have no 
> effect. Besides, adding for example two integers and not saving the result 
> (which is classified as a no-effect-expression) still has the effect of 
> changing the eflags register, which may be read in an asm block. So it's 
> questionable what "no effect" actually means.

Not if the compiler optimises it away.  As such, the contents of any 
register after such a statement would be undefined, so you can't really do 
anything with it.

> Wouldn't it be more appropriate here to change the specs to
> "Expressions that can be interpreted as a declaration, like (a*b), are 
> illegal in expression statements. If such an expression is needed, casting 
> it to void will make it legal."
> (http://www.digitalmars.com/d/statement.html#ExpressionStatement)

Such a statement in the spec would be null, because it isn't even parsed as 
an ExpressionStatement.

What the spec needs to do is properly document the disambiguation rules.

Stewart.