Re: [TCLCORE] Making Tcl 9 go (way) faster [IO]

[Jeff H. <je...@ac...>]

On 2012-11-23, at 7:28 PM, Larry McVoy <lm...@bi...> wrote:
> On Fri, Nov 23, 2012 at 06:45:18PM -0800, Larry McVoy wrote:
>>>> If that is the direction then I'd beg for two string types, unicode and
>>>> not.  Tcl could be kick ass fast if unicode was optional.
>>> 
>>> You keep harping on that, and it's just not quite true.
>>> Tcl is slower than it needs to be, because of all the conversion
>>> back and forth between UTF-8 (CESU-8, actually) and UCS-2 that it
>>> does.  That has to be revisited sometime fairly soon anyway, if we're
>>> to break the BMP barrier.  If we can get [string index] (and
>>> [string range] and friends), and [regexp] working on UTF-8 - which
>>> ought to be possible with a little bit of auxiliary indexing
>>> in place of the UCS-2 representation - then a lot of that disappears.
>>> 
>>> (And I repeat myself: your examples should be using byte arrays.)
>> 
>> OK, I might be wrong.  Can you write a cat(1) ans a grep(1) clone in
>> tcl that outperforms perl?
> 
> This might have come off as snarky, wasn't meant to be.  I did tcl
> versions of the above, can you make them faster?  I tried to do byte
> stuff with the fconfigure, is there some better way?
> 
> cat.tcl:
>    proc cat {file} {
> 	    set f [open $file rb]
> 	    while {[gets $f buf] >= 0} { puts $buf }
> 	    close $f
>    }
>    fconfigure stdout -buffering full -translation binary 
>    foreach file $argv {
> 	    cat $file
>    }

For cat, you can be faster than perl - just use fcopy.  Yes, it's a correct alternative, but only works for cat.

> grep.tcl:
>    proc grep {file} {
> 	    set f [open $file rb]
> 	    set buf ""
> 	    while {[gets $f buf] >= 0} {
> 		    if {[regexp -- {[^A-Za-z]fopen\(.*\)} $buf]} { puts $buf }
> 	    }
> 	    close $f
>    }
>    fconfigure stdout -translation binary 
>    foreach file $argv {
> 	    grep $file
>    }

Step 1: use PCRE, get 3x speedup.  Step 2 … maybe mark specially for non-utf-8 strings, and the speedup may be higher.

Jeff