OpenEuphoria

2. Re: Stupid Newbie-sounding question.

• Posted by irv mullins <irvm at ellijay.com> May 29, 2004
• 554 views

Michelle wrote:

> but the problem with that is that it prints "John" as a string of the ascii
> codes,
> instead of an easily editable "John"..
>   if i add if sequence() it counts "John" as a sequence, just like the
>   sequence of
> flags..
> so my question is...
> how i can (within a loop) tell it to evaluate whether to puts or print?
> 
> bah..told you it was a stupid newbie question
> 
> Michelle Rogers
> 

Not stupid at all. 
What the Eu docs call "flexible", I call a design flaw.
Euphoria cannot tell the difference between "John" and {74,111,104,110}
where the latter might be a series of integers or flags or whatever. 

The easy way is to not try to write a universal "print" function which 
has to somehow detect how things are supposed to be printed, 
but just use printf(.. with the appropriate params to print the entire 
sequence at one time. Use \n as appropriate to break it up into lines.

If your flags are always either 0 or 1, (which aren't printable characters),
you might look for 0 or 1 in every sequence, and if found, consider this to 
be a sequence of flags, otherwise print as a string.

Irv.

4. Re: Stupid Newbie-sounding question.

• Posted by irv mullins <irvm at ellijay.com> May 29, 2004
• 578 views

Michelle wrote:
> 
> 
> bah...well..i will be (probably forever) adding variables to the
> sequence...and no...all
> of the sequences will not be "flags" that may be 0 or 1..
> As a matter of fact, some sequences may be sequences of text...
> I was trying to make it so that I never had to change the read/write
> procedures, even
> though I would be adding variables on...
> You seem to be saying that it may be impossible to do this?  That I may have
> to manually
> read/write every line, instead of making a loop?  So, that means that each
> time I add
> a new variable to the sequence, I have to also go add it to the read/write
> procedures...bah..was
> trying to get around that.
> 
> hmm..*thinking "out loud"*...this isn't the ideal way to do it..but maybe I
> could assign
> a fourth parameter to each "variable type" which is a 0 or a 1 to tell if the
> variable
> should be holding a string or just plain text...well..or even a 2 for atoms, I
> guess...although
> that I can check for

You could add a "tag" to each variable, to indicate the type:
For example, use 0 to indicate a string, -1 a flag, and 1 an integer:
Then your variables would look like:
{0,"John"}      -- var[2] is a string
{-1,{1,1,0,1}}   -- var[2] contains flags: TRUE, TRUE, FALSE, TRUE
{1,{1,2,3,4,5}} -- var[2] contains integers 1,2,3,4,5

Then your routine could pick off the "tag" and send the rest to the 
appropriate print formatting routine.
Kind of awkward, because you also have to remember to add the tag when 
the variable is created, and have to handle the data separately from the 
tag when doing anything with or to the variables - such as enter strings, 
compare strings, flags, etc. In the long run, probably more work than 
just modifying a single format string to use with a printf() statement.

Irv

6. Re: Stupid Newbie-sounding question.

• Posted by Allen V Robnett <alrobnett at alumni.princeton.edu> May 30, 2004
• 539 views

Michelle, Irv and Juergen have burst my bubble.
I had figured that, if I worked at it long enough, I could master the 
way Euphoria handles this sort of thing. Answer: it doesn't.

Allen

8. Re: Stupid Newbie-sounding question.

• Posted by Nicholas Koceja <Nickofurr at aol.com> May 30, 2004
• 580 views

Juergen Luethje wrote:
> 
> 
> Irv wrote:
> 
> > Michelle wrote:
> > 
> >> but the problem with that is that it prints "John" as a string of the ascii
> >> codes,
> >> instead of an easily editable "John"..
> >>   if i add if sequence() it counts "John" as a sequence, just like the
> >>   sequence
> of
> >> flags..
> >> so my question is...
> >> how i can (within a loop) tell it to evaluate whether to puts or print?
> >> 
> >> bah..told you it was a stupid newbie question
> >> 
> >> Michelle Rogers
> > 
> > Not stupid at all. 
> > What the Eu docs call "flexible", I call a design flaw.
> > Euphoria cannot tell the difference between "John" and {74,111,104,110}
> > where the latter might be a series of integers or flags or whatever.
> 
> [snip]
> 
> Yes, like "integer" is a special type of atom, there definitely should
> be a "string" datatype, which is a special type of sequence.
> 
> At the first glance, it might look as if an additional data type would
> make Euphoria more complicated, but (latest) at the second glance it
> is clear that Euphoria would become *much* more flexible (see Michelle's
> problem here), simpler, safer, and better readable.
> 
> Regards,
>    Juergen
> 
Well, I can see your problem, and I agree that that adding "string" would
do so, I must say something.  There is a way to tell if it is a string or
not.  In your program, ""'s and {},s mean the same thing, so they reccomend
using ""'s for text(a string of typeable characters), and {}'s for other
sequences.  However, for a way to find out, you can make two types, like this:

type char(object x)
    if integer(x) then
        if (x >= 'a' and x <= 'z') or        -- all lowercase characters
           (x >= 'A' and x <= 'Z') or        -- all uppercase characters
           (x >= '0' and x <= '9') or        -- all numericial characters
           find(x, "?<>,./\\|[]{}`" &            --\ all of the other symbols
                   "~!@#$%^&*()-=_" &            --- that you can type, even
                   "+:\'\"\t\r\n" & {32}) then   --/ with "Shift" held down.
            return 1 -- return true, since only one char. is checked.
        end if
    elsif sequence(x)    -- if x is not an integer
        return (length(x) = 1 and char(x[1]))
    end if
end type

global type string(sequence x)
    for elem = 1 to length(x) do
        if not char(x[elem]) then
            return 0
        end if
    end for
    return 1
end type

-------------------------------------------------
|         Name:         | Nicholas Koceja       |
|      Occupation:      | Computer genius       |
|     Programs  in:     | BASIC, HTML, Euphoria |
|  Programs Completed:  | 3-5                   |
| Programs  Incomplete: | 20-30                 |
|   Operating System:   | Windows XP            |
-------------------------------------------------

10. Re: Stupid Newbie-sounding question.

• Posted by Pete Lomax <petelomax at blueyonder.co.uk> May 30, 2004
• 562 views

>> > Michelle wrote:
>> > 
>> >> but the problem with that is that it prints "John" as a string of the
>> >> ascii codes,
>> >> instead of an easily editable "John"..

Michelle, before you dig a hole, if I'm not already too late, you may
like to try a quick play with my pretty print routine:

http://palacebuilders.pwp.blueyonder.co.uk/eppp.html

Eg:
include ppp.e
pp("fred")
pp({1,2,3,4,5})

will print:

"fred"
 {1,2,3,4,5}

without needing any extra hints.

Regards,
Pete

12. Re: Stupid Newbie-sounding question.

• Posted by "Patrick Barnes" <mistertrik at hotmail.com> May 31, 2004
• 551 views

My approach to this problem:

We need a new keyword; "of".
Usage:

type char ( integer c )
--  return 1 valid character, 0 otherwise
end type

--myStr is a string
sequence of char myStr

It is an extension to the type checking system on sequences, and is applied 
whenever an element of the sequence is changed. The existing type checks are 
slow because they have applied to the whole sequence whenever a single 
element is changed. This "of" typing would only check the elements that are 
changed in the sequence.

If you have a complex data structure list, you could have:

type myDataStructure( sequence s)
  --return 1 if valid myDataStructure, 0 otherwise
end type

--master_list is a 1-dimensional array of myDataStructures
sequence of myDataStructure master_list

This would not break any existing code, as "sequence" without an 'of' would 
mean no restrictions.

Multi-dimensional arrays are also possible:

--2d array of integers
sequence of sequence of integer 2d_array

type textpict_line( sequence s)
   if length(s) = 80 then return 1
   else return 0
   end if
end type

--2d array where the length of each line is fixed, and consists of 
characters
sequence of textpict_line of char text_picture


Rules:
--------
1. Only types that have sequence as a base can be listed before the last 
type.
So: sequence of sequence of char is ok.
and: sequence of char of sequence is NOT okay.
2. Whenever an element of a type is changed, the type that the element 
should be is checked. The rest of the variable was not affected, don't check 
it.
3. If using a custom type as the base, eg: textpict_line of char text_line, 
the textpict_line type checking will only be invoked when the length of the 
sequence changes. (If the of keyword is not used, it will be invoked as 
normal)
4. If casting between types: ie - generic sequence to sequence of char, then 
a full type check will be performed: The base type will be checked first, 
then the element type will be checked against each element.

Suggestion #2:
Allow some simple type defines, a la c/c++.
This could be done without adding extra code, perhaps like so:


type rgb (sequence of integer c)
    return length(c) = 3
end type

type rgb_map ( sequence of sequence of rgb x)
    return 1
end type

If no extra checking has to be done, then the type just returns 1.

That's my take on the situation. I can't see any problems with this right 
now, and Rob, I'd like to hear your thoughts on this.



Cheers.
MrTrick





>From: Juergen Luethje <j.lue at gmx.de>
>Reply-To: EUforum at topica.com
>To: EUforum at topica.com
>Subject: Re: Stupid Newbie-sounding question.
>Date: Mon, 31 May 2004 11:35:27 +0200
>
>
>Pete wrote:
>
> >> Juergen Luethje wrote:
> > <snip>
> >>> At the first glance, it might look as if an additional data type would
> >>> make Euphoria more complicated,
> >
> > Adding a string type takes the number of cases for the "&" operator
> > from 8 to 19, without considering unicode strings. Just so you know. I
> > agree that string types might be nice, but they are far from trivial.
>
>I think you are describing the point of view of the developer of the
>language, right? That's interesting. I didn't know that, but I truely
>believe that implementing a string datatype will mean considerable work.
>Well, I am willing to pay some extra $ for such an enhancement.
>
> >From the point of view of the user of the language, in most (if not all)
>cases the "&" operator should work with a built-in string type, like it
>currently works with our user-defined string types.
>
>[snipped in agreement]
>
>Regards,
>    Juergen
>
>
>
>

14. Re: Stupid Newbie-sounding question.

• Posted by "Patrick Barnes" <mistertrik at hotmail.com> Jun 01, 2004
• 563 views

>From: irv mullins <guest at RapidEuphoria.com>
>Subject: Re: Stupid Newbie-sounding question.
> > That's my take on the situation. I can't see any problems with this 
>right
> > now, and Rob, I'd like to hear your thoughts on this.
>
>The real problem is that it isn't all that useful because it only checks on
>assignment.

Actually, I guess it's a thread hijack. I wasn't trying to address the 
string debate in terms of printing... Like I said in the trace thread, I 
don't think it matters that much unless you're tracing.

>Why does Euphoria have different functions for outputting variables,
>depending on their type? If you choose the wrong one, you get a crash.
>Other languages handle this transparently.
>
>For example, if Euphoria actually used its type system, you could
>do this:
>
>a =  1
>b = 3.1415
>c = "Foo bar"
>d = {1,4,7,234}
>
>print(a,b,c,d)

Well, the printf function works properly, for what that's worth.

>All 4 should print the way you expect them to, IOW, 'c' doesn't look
>like a series of strange numbers, and 'd' doesn't try to print as
>a 4-letter word.

Okay, that is fair enough.... This could actually address the types a bit 
though (not var_arg_lists, that is another thing altogether)

Consider: If a variable is "cast" to a generic type:

type char( integer c)
     return (c <= 0) and (c >= 255) --Ignoring unicode matters, this is just 
an example.
end type
type string ( sequence of char s)
     return 1
end type

procedure print_variable( object x )
    if atom(x) then       --Print a number
        print(1,x)
   else if string(x) then --Print a string
        puts(1, x)
   else                       --Print a generic sequence
        print(1,x)
   end if
end procedure

Now, in the implementation of this, there would be some kind of tag on the 
variable (inside the interpreter) that would remain attached to the variable 
even if it was cast to a generic type (object, in this case). After all, the 
data hasn't changed. If any assignment is made to the variable, then there 
must be some checks as to whether the variable should retain its tag. So, no 
matter how complex the type, a type-check on a variable that has been cast 
to generic but not modified is trivial.

>I believe languages such as Lua and Python handle this without any
>problem, and they are untyped languages. Surely a language which forces
>you to declare specific types for a variable should actually make use
>of that information, shouldn't it?

After typing out the example above, I see what you mean... in that with 
default behaviour the above function would mistakenly take a 1-dimensional 
sequence of integers below 255 for a string, and print it. This *could* be 
fixed by creating a new built-in function that would check the tag on the 
variable, and return a 1 if the variable has that tag.

procedure print_variable( object x )
    if atom(x) then       --Print a number
        print(1,x)
   else if variable_tag(x, "string") then --Print a string
        puts(1, x)
   else                       --Print a generic sequence
        print(1,x)
   end if
end procedure

So, the variable_tag function would only check if the object x is already 
validated as a string, and would not attempt to cast from any other type.

>Why does Euphoria have any types at all, if it isn't going to use them to
>make the programmers job easier, and to reduce errors?

Because Rob is only one man, and has the same blinkers (think racehorses) as 
all of us do. Obviously no one person has a perfect paradigm, but by working 
together we can improve things.

MrTrick

16. Re: Stupid Newbie-sounding question.

• Posted by David Cuny <dcuny at lanset.com> Jun 01, 2004
• 575 views

Patrick Barnes wrote:

> Now, in the implementation of this, there would be some kind of tag on the
> variable (inside the interpreter) that would remain attached to the
> variable even if it was cast to a generic type (object, in this case).

For the case of literals and expressions, there is no tag to look up. For 
example:

   ? "a string"
   ? aString & " another string"

In these cases, the best Euphoria can do is determine that they are both 
sequences.

-- David Cuny

18. Re: Stupid Newbie-sounding question.

• Posted by Derek Parnell <ddparnell at bigpond.com> Jun 01, 2004
• 555 views

Patrick Barnes wrote:
> 
> >From: Robert Craig <guest at RapidEuphoria.com>
> >Subject: Re: Stupid Newbie-sounding question.
> >This idea has come up before.
> >I haven't ruled it out.
> >I was quite interested in this a few years ago.
> >As I recall, the thing that made me lose some
> >interest was the fear that few people
> >would use it, and it wouldn't provide a great deal
> >of benefit to those who did use it. It would
> >also make the language more complicated,
> >not to mention verbose.
> >
> >In other languages, you need types in order to
> >define the layout of your data in memory.
> >In Euphoria, a type is just a documentation
> >and debugging aid, and few people seem to
> >bother defining them.
> >
> Um, that's like saying "I don't need to replace the broken bicycle, no one 
> is using it"...
> 
> The main issue with Euphoria's sequences is that they're so damn flexible 
> that it can be confusing!
> Issue #1:
> function myFunc(sequence r1, sequence r2, sequence r3)
> 
> Okay Rob... What sort of structure do these sequences have to have? I don't 
> know! If we had the ability to use stronger typing, then function 
> myFunc(text_picture r1, string r2, flag_list r3) would make a lot more 
> sense. I could go and look at the type declaration, and figure out what to 
> pass to the function.
> People don't use the types like this at the moment because it's so damn 
> computationally expensive for sequences.

This is true. And there is the trade off - speed & flexibility against
structure and complexity. Think of it in terms of a bicycle without
training wheels and one with training wheels 

RDS has chosen speed. Meaning that the coder has more responsibility to
provide quality assurance than the translator does. Yes this does mean
more work for the coder and better discipline.

Would you prefer a slower Euphoria if it had structures, strings and
an improved type system? If so, you may have to wait until v2.5 comes out
and someone adds these to the slower version.

> Issue #2:
> Run-time slicing and sequence errors are my main cause of problems. The 
> primary error I make is missing a set of braces around a concatenation 
> command....
> type vector(sequence s)
>    return length(s) = 2 and atom(s[1]) and atom(s[2])
> end type
> type vector_list(sequence of vector s)
>    return 1
> end type
> vector_list vectors
> vectors = getVectors()
> Say I wanted to add a vector to that list (and I'm not quite paying enough 
> attention)
> vectors &= NewVector(30, 20)
> Hmm... Unbeknownst to me, the last two elements of vector are now 30 and 
> 20... not the last element being {30,20} like i'd hoped.
> 

Learn to love the append() function.

'append' adds ONE element, the source, to a sequence.  newlength = oldlength +
1.

'&' adds all the source elements to a sequence. newlength = oldlength +
sourcelength.

Another way of visualizing this is that '&' is like joining together two
sets of train carriges together. 'append' joins one new carriage and places
all the new stuff into that new carriage.
 
> Unfortunately, I only find out when I try to reference it, which may be a 
> long way from this error. At least with differential checking, an error 
> would show up at that point of error, and I can fix it quicker.

This is also an arguement for some type of 'assert' system that would help
trap errors during development and could be automatically removed for the
release version.

> While we're talking about types, it would be nice if:
> Should the checked variable be an incompatible type with the parameter, it 
> will just return 0, not crash the interpreter:
> type myStruct (sequence s)
>     if -------- return 1
>     else return 0
> end type
> 
> object x
> ...
> x = 0
> ...
> if myStruct(x) then return 1 end if
> ...
> This crashes.
> 
> That would actually help "of"s case.
> 
> I think that having types like this would make the language *easier* to 
> understand, not more complex. Especially, it would make someone elses code 
> easier to read.

Ummmm? Why not code so that it works?

 type myStruct (object s)
     if sequence(s) return 1
     else return 0
 end type

-- 
Derek Parnell
Melbourne, Australia

20. Re: Stupid Newbie-sounding question.

• Posted by "Patrick Barnes" <mistertrik at hotmail.com> Jun 02, 2004
• 558 views

>This is true. And there is the trade off - speed & flexibility against
>structure and complexity. Think of it in terms of a bicycle without
>training wheels and one with training wheels 
>
>RDS has chosen speed. Meaning that the coder has more responsibility to 
>provide quality assurance than the translator does. Yes this does mean more 
>work for the coder and better discipline.

So does that mean we peek and poke everything directly to memory?
None of those fancy atoms for me! I like dealing with my floats in raw
IEEE form!

MrTrick

22. Re: Stupid Newbie-sounding question.

• Posted by Derek Parnell <ddparnell at bigpond.com> Jun 02, 2004
• 544 views

Patrick Barnes wrote:
> 
> >This is true. And there is the trade off - speed & flexibility against
> >structure and complexity. Think of it in terms of a bicycle without
> >training wheels and one with training wheels 
> >
> >RDS has chosen speed. Meaning that the coder has more responsibility to 
> >provide quality assurance than the translator does. Yes this does mean more 
> >work for the coder and better discipline.
> 
> So does that mean we peek and poke everything directly to memory?
> None of those fancy atoms for me! I like dealing with my floats in raw
> IEEE form!

Now you're getting it 

But seriously, folks... the current internal structures used by Euphoria
mean that it is quick for Euphoria to distinguish between integers, atoms,
and sequences, but if you add any more 'native' types, things are going
to slow down a lot. RDS has given more priority to the speed aspect of
Euphoria than to providing assistance to coders to enhance application
quality. Coders can still produce quality Euphoria applications, but it
takes more effort to do so in Euphoria than some other languages (eg.
Ada, Eiffel, D). But on the other hand, when compared to still other languages,
Euphoria provides better QA (eg. C/C++, Assembler).

BTW, peek/poke for IEEE floating point is slower than using atom types!

-- 
Derek Parnell
Melbourne, Australia

24. Re: Stupid Newbie-sounding question.

• Posted by "Patrick Barnes" <mistertrik at hotmail.com> Jun 02, 2004
• 565 views

>From: Derek Parnell <guest at RapidEuphoria.com>
>Subject: Re: Stupid Newbie-sounding question.
> > So does that mean we peek and poke everything directly to memory?
> > None of those fancy atoms for me! I like dealing with my floats in raw
> > IEEE form!
>
>Now you're getting it 
>
>But seriously, folks... the current internal structures used by Euphoria
>mean that it is quick for Euphoria to distinguish between integers, atoms,
>and sequences, but if you add any more 'native' types, things are going
>to slow down a lot.

That's fine, we have integers, atoms, and sequences... but we can't easily 
know what is inside a sequence. I'm not trying to add any more native 
things.
MrTrick

26. Re: Stupid Newbie-sounding question.

• Posted by "Patrick Barnes" <mistertrik at hotmail.com> Jun 02, 2004
• 555 views

>From: Matt Lewis <guest at RapidEuphoria.com>
>Subject: Re: Stupid Newbie-sounding question.
> > Firstly, I agree with you totally. My opinion is that Euphoria is more
> > than fast enough for any of the application for which I would choose to=

> > use it. Making it 50% slower would still leave it more than fast enough=
.
>
>I agree that Euphoria is fast enough for *most* things that I like to
>do with it, however, it wouldn't be if it slowed down (especially by
>50%).  I write a lot of custom optimization code in Euphoria, and it's
>often right on the edge of being fast enough for some things.  If it
>slowed down, I'd have to stop using Euphoria for these tasks (yes,
>even running on 3Ghz machines).

Yes, you may think it doesn't matter whether a sub-routine takes 0.01=20
seconds or 0.0001...
But if your program needs to call this subroutine 1000 times at startup,=
=20
then those small differences are magnified 1000-fold.

Algorithmic efficiency is the most important thing now, not so much things=
=20
like how many bytes a primitive type is stored in (some exceptions), and=
=20
things like the processing time spent in the main portion of the code.






>
>It's mainly the flexibility/speed combination that I like.  I can
>develop these things very quickly, and more of my time is focused on the
>algorithms, rather than data structure or garbage collection, which
>can be really important when you're looking at, say, hundreds of thousands=

>or millions of possible solutions.
>
>I'm sure I'm in the minority on this (although going by User Contributions=
,
>not totally alone), but thought I'd speak up for those of us for whom
>speed still matters.
>
>Matt Lewis
>
>
>
>

28. Re: Stupid Newbie-sounding question.

• Posted by Pete Lomax <petelomax at blueyonder.co.uk> Jun 02, 2004
• 539 views

On Wed, 02 Jun 2004 04:34:18 -0700, Matt Lewis
<guest at RapidEuphoria.com> wrote:

>Derek Parnell wrote:
>> use it. Making it 50% slower would still leave it more than fast enough.
>> irv mullins wrote:
>slowed down, I'd have to stop using Euphoria for these tasks (yes,
>even running on 3Ghz machines).
>I'm sure I'm in the minority on this (although going by User Contributions,
>not totally alone), but thought I'd speak up for those of us for whom 
>speed still matters.

As I said before, I'll agree with an argument against this on
technical grounds. Non-string Eu is perfectly useable, and wonderfully
fast. I might favour string handling, but it is votes what count.

Regards,
Pete
PS I can be bribed )

30. Re: Stupid Newbie-sounding question.

• Posted by cklester <cklester at yahoo.com> Jun 02, 2004
• 552 views

Pete Lomax wrote:
> 
> On Wed, 02 Jun 2004 04:34:18 -0700, Matt Lewis
> <guest at RapidEuphoria.com> wrote:
> 
> >Derek Parnell wrote:
> >> use it. Making it 50% slower would still leave it more than fast enough.
> >> irv mullins wrote:
> >slowed down, I'd have to stop using Euphoria for these tasks (yes,
> >even running on 3Ghz machines).
> >I'm sure I'm in the minority on this (although going by User Contributions,
> >not totally alone), but thought I'd speak up for those of us for whom 
> >speed still matters.

I'm confused. Who said the last quote above (starting with
"slowed down" and ending with "still matters")? I can't figure out
if it was Derek or Matt or an unknown guest, and I can't find 
the original message in the list!

32. Re: Stupid Newbie-sounding question.

• Posted by irv mullins <irvm at ellijay.com> Jun 02, 2004
• 560 views

Pete Lomax wrote:

> PS I can be bribed )

Jeez, why are you programming, man? 
There's a great future for you in politics!

Irv