OpenEuphoria

Re: Strings

• Posted by Jason Gade <jaygade at yahoo.com> Feb 18, 2006
• 649 views

Al Getz wrote:
> 
> Jason Gade wrote:
> > 
> > Ryan W. Johnson wrote:
> > > 
> > > Jason Gade wrote:
> > > > 
> > > > Okay, so I'm going to propose two things with regards to strings. Even
> > > > though
> > > > I said that I wouldn't propose new stuff. Plus, I suppose it could be
> > > > handled
> > > > by ESL (once we get around to it) if it isn't implemented internally
> > > > (preferred0.
> > > > 
> > > > A string built-in data type with:
> > > > Byte-size ASCII strings. For Kat, since she can't have goto.
> > > > Unicode UTF-8 strings.
> > > > One built-in type should be able to handle both.
> > > > 
> > > > Atom has integer as a subclass for efficiency. I think that sequence can
> > > > have
> > > > string as a subclass as well, since strings are a "basic" type in most
> > > > programming
> > > > projects. Strings can be up-cast to sequences, like integers can be
> > > > up-cast
> > > > to atoms.
> > > 
> > > I would be very happy if this was implemented!  Is there any
> > > reason to not have built-in strings?
> > 
> > I admit I was tired and bored last night when I posted that. I've been
> > thinking
> > about it all morning.
> > 
> > One reason for *not* having built-in strings is that sequences handle 99% of
> > the functionality of strings already.
> > 
> > This proposal would get more complicated when you want sequences of strings
> > as well. The string type would only be able to apply to a single-level
> > sequence.
> > 
> > But a question that occurs to me is what percentage of sequences in any
> > given
> > Euphoria application represent text strings?
> > 
> > I think it really only matters for efficiency when working with large
> > amounts
> > of text data. Because sequence elements are 4-bytes each.
> > 
> > So, basically, I retract my proposal. 
> > 
> > But it was helpful for reminding me of what features I want to see in an
> > Euphoria
> > Standard Library string module.
> > 
> > > ~Ryan W. Johnson
> > > 
> > > Fluid Application Environment
> > > <a href="http://www.fluidae.com/">http://www.fluidae.com/</a>
> > > 
> > > [cool quote here, if i ever think of one...]
> > 
> > 
> > --
> > "Any programming problem can be solved by adding a level of indirection."
> > --anonymous
> > "Any performance problem can be solved by removing a level of indirection."
> > --M. Haertel
> > "Premature optimization is the root of all evil in programming."
> > --C.A.R. Hoare
> > j.
> 
> 
> Hi again,
> 
> 
> You're right in that the main advantage to having a string type
> would be mostly in making a text editor, where there is so much
> text the memory savings would be great, but yes, quite a few
> apps wont benefit much with *that* kind of definition of 'string'.
> There is, however, another definition of 'string' where it's actually
> a memory element:
> 
> string s
> s="My Window"
> 
> where internally s is a pointer to the string, so it can be passed
> to a C function like:
> 
> x=CreateWindow(s,...)
> 
> without having the bother of s=allocate_string("My Window").

Well, using allocate_string doesn't seem like *too* much work to me. But you
lose a lot of the dynamics of sequences with manual allocation.

> 
> This would mean other function such as 'printf(..)' would
> have to also support this new kind of data type:
> 
> printf(1,"%s\n",{s})
> 
> where Euphoria would recognize 's' as a memory string object and
> make the necessary call to print that type of object rather than
> say a sequence string.
 
Well, you could always use C for stuff like that... But routines that convert
between static strings in memory and sequences would be useful. So if 's' was a
pointer to a string then you could do:

printf(1, "%s\n", stringz(s))

> 
> Al
> 
> 
> My bumper sticker: "I brake for LED's"

This is just a mental exercise, but something else occurs to me. Euphoria uses
bit-flags to determine the type of data that it is working with -- a pointer to a
sequence or a double, or a 31-bit integer. See
http://www.listfilter.com/cgi-bin/esearch.exu?fromMonth=A&fromYear=A&toMonth=A&toYear=A&postedBy=Robert+Craig&keywords=%22bit+fiddling%22

Euphoria *could* use bit flags to say "pointer to string".
 
--
"Any programming problem can be solved by adding a level of indirection."
--anonymous
"Any performance problem can be solved by removing a level of indirection."
--M. Haertel
"Premature optimization is the root of all evil in programming."
--C.A.R. Hoare
j.