OpenEuphoria

Big String Idea for v2.6

• Posted by Al Getz <Xaxo at aol.com> Jul 18, 2005
• 466 views

Hello all,

This could be very, very useful if it was implemented...

Take for example, a C function call:

String="ThisName"
pString=allocate_string(String)
retv=c_func(xSetName,{pString})
free(pString)

Granted we could have saved one line here by not declaring a string
sequence 'String' but a lot of times calls like this have a string
that originates outside the block of code that actually calls
the c function anyway, so this isnt a bad example.

If we take a close look at this, we can see we had to do quite a
bit of work just to pass the string to the c_func didnt we?
We had to allocate a string, then free it.  This is not only a
lot of additional work, it took more processor time also.
All one would need is a simple function that gets the pointer
to the sequence element and the above code would reduce to something
like this:

String="ThisName"
retv=c_func(xSetName,{pointer(String)})

pointer() of course returns the pointer to the first element
of String, and String would have to be a one dimensional sequence.
A variant would look like this:

retv=c_func(xSetName,{pointer(String[1])})

indicating the pointer should be the pointer to the first element
of String.

Of course sub-elements would still be indicated by indexes like:

pointer(MyStrings[3][1])


Now i know this brings up a few problems like the fact that
the sequences are stored as four byte C integers rather than
single bytes (like a C string) so here is a way around
that...

  pointer4a(String[1])
would take every 4th element and poke it into memory to create
a C string.  Upon return from the function call, the mem would
be free'd.  This wouldnt take any additional memory if the
call didnt return right away either...because right now poke's
do the same thing.

As a side effect, strings could be indexed to suite:

String="C:\\DirA\\Filename.txt"
c_proc(xSetFilename,{pointer(String[9])})
c_proc(xSetDirname,{pointer(String[1..8])})
--done


BTW, in the preceeding the name 'pointer' was arbitrary..
even 'allocate_string' would work as long as the function call
took note that it had to be free'd upon completion.  This 
wouldnt even add any additional keywords to the language.


Take care,
Al

And, good luck with your Euphoria programming!

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