maketrans and translate

[Jonathan M Davis]

On Monday, February 13, 2012 08:09:06 bearophile wrote:
> Stewart Gordon:
> > Use an associative array for the translation table.
> 
> A new version of the code:
> 
> import std.stdio, std.string, std.range;
> void main() {
> char[] text = "dssdadsdasdas".dup; // lots of MBs of pure 7 bit ASCII
> text dchar[dchar] aa = ['A':'5', 'a':'5', 'B':'7', 'b':'7', 'C':'6',
> 'c':'6', 'D':'3', 'd':'3', 'E':'0', 'e':'0', 'F':'4', 'f':'4', 'G':'9',
> 'g':'9', 'H':'9', 'h':'9', 'I':'6', 'i':'6', 'J':'1', 'j':'1', 'K':'7',
> 'k':'7', 'L':'8', 'l':'8', 'M':'5', 'm':'5', 'N':'1', 'n':'1', 'O':'8',
> 'o':'8', 'P':'8', 'p':'8', 'Q':'1', 'q':'1', 'R':'2', 'r':'2', 'S':'3',
> 's':'3', 'T':'4', 't':'4', 'U':'7', 'u':'7', 'V':'6', 'v':'6', 'W':'2',
> 'w':'2', 'X':'2', 'x':'2', 'Y':'3', 'y':'3', 'Z':'9', 'z':'9'];
> auto text3 = text.translate(aa, "\"");
> writeln(text3);
> }
> 
> > Or write your own functions that work in the same way as
> > maketrans/translate.
> The code with the associative array is longer, and every char in the
> original string requires one or two associative array lookups. This is
> quite inefficient for ASCII strings.
> 
> Instead of writing my own string functions, or copying them from an older
> Phobos, what about the idea of keeping both the old maketrans and translate
> functions too and to un-deprecate them (maybe moving them in std.ascii)?
> They are not UTF-safe, but I have large amounts of biological data text
> that is not Unicode.

Do you have data to backup that there is a significant speed difference? We're 
trying to not have any ASCII-only string stuff.

- Jonathan M Davis