On Thu, 28 Feb 2013 12:02:53 -0500, Walter Bright
<[email protected]> wrote:
On 2/28/2013 7:40 AM, Steven Schveighoffer wrote:
If you look at lexer.c, case 0 is the first test.
No, it is not. It is actually a table lookup - all done in parallel.
jmp cases[character]
You are comparing the assembly output of your solution with uncompiled D
code. Apples and oranges.
Quoting directly from
https://github.com/D-Programming-Language/dmd/blob/master/src/lexer.c#L479:
switch (*p)
{
case 0:
As several others have pointed out, an optimizer can (and some do) make
this rewrite automatically.
The point is, if the lexer simply requires an input range, and not a
sentinel input range, it is more flexible for its input. But when it does
get called with a sentinel input range, the optimizer can reap the
benefits.
-Steve
