OpenEuphoria

2. Re: type checking ?

• Posted by Matt Lewis <matthewwalkerlewis at ?mail.c?m> Nov 21, 2007
• 629 views

Bernie Ryan wrote:
> 
> Suppose you have a function/procedure and one of its
> parameters is a sequence.
> 
> How can you type check the parameter to be a CONSTANT SEQUENCE NAME.

Could you elaborate on what you mean by "CONSTANT SEQUENCE NAME?" This
sounds like you want the parameter to be a specific value.  If this is
accurate, then I can't see the utility of this, but here's an example:

with type_check
type my_constant_sequence_name( object m )
    return equal( m, "My Constant Sequence Name" )
end type

procedure foo( my_constant_sequence_name bar )
    -- ...
end procedure
foo("My Constant Sequence Name")  -- works
foo("Ha Ha!")                     -- fails

Matt

4. Re: type checking ?

• Posted by Matt Lewis <matthewwalkerlewis at gm?i?.com> Nov 21, 2007
• 633 views
• Last edited Nov 22, 2007

Bernie Ryan wrote:
> 
> > Bernie Ryan wrote:
> > > 
> > > Suppose you have a function/procedure and one of its
> > > parameters is a sequence.
> > > 
> > > How can you type check the parameter to be a CONSTANT SEQUENCE NAME.

> }}}
<eucode>
> constant
>   MySEQ = {1,2,3,4,5,6,7,8,9}
> 
> procedure useit(sequence seq_name)
>   -- do stuff.
> end procedure
> 
> -- The user can enter this which is WRONG
> useit("MySEQ")
> 
> -- Or the user can enter this is CORRECT
> useit(MySEQ)
> 
> -- NOTE they are both sequences so procedure will accept either.
> 
> </eucode>
{{{


Unfortunately, this hasn't cleared it up for me.  I guess that I have a
couple of responses.  If the passed value is incorrect, then you can
simply validate it using equal().  Also, if the only correct value is a
specific constant, then why pass it as a parameter at all?  That seems
to be just increasing typing for no benefit.

I suspect that there's something more to this that you haven't made clear
yet.  What is the effect of one being WRONG and the other CORRECT?

What about (in the above example):

useit({1,2,3,4,5,6,7,8,9})

Matt

6. Re: type checking ?

• Posted by Matt Lewis <matthewwalkerlewis at gma?l.c?m> Nov 22, 2007
• 641 views

Bernie Ryan wrote:
> 
> The useit() procedure will try to process the sequence weather it is
> a constant name sequence or the actual constant sequence because they
> depending how the user calls the procedure.
> I do not know in advance what the constant sequence will be because it is
> added by the user via include file. 
> Of course if user passes the name as a sequence the procedure will crash. 
> I will just have to spell it out in the users manual and
> HOPE that they read it. 

Ok, I give up.  I still have no clue what you're asking.

Matt

8. Re: type checking ?

• Posted by Derek Parnell <ddparnell at big?o?d.com> Nov 22, 2007
• 630 views

Bernie Ryan wrote:
> The useit() procedure will try to process the sequence weather it is
> a constant name sequence or the actual constant sequence because they
> depending how the user calls the procedure.
> I do not know in advance what the constant sequence will be because it is
> added by the user via include file. 
> Of course if user passes the name as a sequence the procedure will crash. 
> I will just have to spell it out in the users manual and
> HOPE that they read it. 


I'm still trying to work out Bernie's issue but here's what I've got so far...

Bernie has a file that is something like this ...

------------ start of bernie's file
include userfileA.e

global function/procedure useit(sequence x)
 <some processing goes here>
end function/procedure

include userfileB.e
------------- end of file

And a user of Bernie's application must supply a couple of include files.

------ start of userfileA.e
global constant WhatEver = "some text"
------ end of  userfileA.e

------ start of userfileB.e
useit(WhatEver)
------ end of  userfileB.e

Now the problem is that Bernie want to make sure that in userfileB, the user
codes ...

   useit(WhatEver)

and never codes ...

   useit("WhatEver")

plus allow the user to code ...

   useit("any other text")


-- 
Derek Parnell
Melbourne, Australia
Skype name: derek.j.parnell

10. Re: type checking ?

• Posted by CChris <christian.cuvier at agr?cu?ture.gouv.fr> Nov 22, 2007
• 629 views

Bernie Ryan wrote:
> 
> Derek Parnell wrote:
> > 
> > Bernie Ryan wrote:
> > > The useit() procedure will try to process the sequence weather it is
> > > a constant name sequence or the actual constant sequence because they
> > > depending how the user calls the procedure.
> > > I do not know in advance what the constant sequence will be because it is
> > > added by the user via include file. 
> > > Of course if user passes the name as a sequence the procedure will crash. 
> > > I will just have to spell it out in the users manual and
> > > HOPE that they read it. 
> > 
> > 
> > I'm still trying to work out Bernie's issue but here's what I've got so
> > far...
> > 
> > Bernie has a file that is something like this ...
> > 
> > ------------ start of bernie's file
> > include userfileA.e
> > 
> > global function/procedure useit(sequence x)
> >  <some processing goes here>
> > end function/procedure
> > 
> > include userfileB.e
> > ------------- end of file
> > 
> > And a user of Bernie's application must supply a couple of include files.
> > 
> > ------ start of userfileA.e
> > global constant WhatEver = "some text"
> > ------ end of  userfileA.e
> > 
> > ------ start of userfileB.e
> > useit(WhatEver)
> > ------ end of  userfileB.e
> > 
> > Now the problem is that Bernie want to make sure that in userfileB, the user
> > codes ...
> > 
> >    useit(WhatEver)
> > 
> > and never codes ...
> > 
> >    useit("WhatEver")
> > 
> 
> Derek:
> 
>    Thanks for explaining it.
> 
>    That is exactly what I mean.
> 
>    How can you be sure that a user enters the token WhatEver which
> 
>    represents a string constant and not the string "WhatEver"
> 
> Bernie
> 
> My files in archive:
> WMOTOR, XMOTOR, W32ENGIN, MIXEDLIB, EU_ENGIN, WIN32ERU, WIN32API 
> 
> Can be downloaded here:
> <a
> href="http://www.rapideuphoria.com/cgi-bin/asearch.exu?dos=on&win=on&lnx=on&gen=on&keywords=bernie+ryan">http://www.rapideuphoria.com/cgi-bin/asearch.exu?dos=on&win=on&lnx=on&gen=on&keywords=bernie+ryan</a>

Only the parser will have this info when it processes calls to useit().
Some possibilities I can think of:
1/ define a list of identifiers user is supposed to type. Then useit() will look
its argument up in that table and substitute the right value if the name was
found. Emit a warning in that event as seen fit.
2/ Shroud user code and check the IL for a call to oseit() using a named symbol
rather than a manifest string constant. Tougher, of course. And if user codes

constant myString="WhatEver"
useit(myString)

this approach won't work.
It all depends on what level of safety you want/need. The more, the more
expensive.

CChris

12. Re: type checking ?

• Posted by Matt Lewis <matthewwalkerlewis at gmail.c??> Nov 24, 2007
• 646 views
• Last edited Nov 25, 2007

Pete Lomax wrote:
> 
> Bernie Ryan wrote:
> > Derek Parnell wrote:
> > > A user of Bernie's application must supply a couple of include files.
> > > 
> > > global constant WhatEver = "some text"
> > 
> >    Thanks for explaining it.
> >    That is exactly what I mean.
> >    How can you be sure that a user enters the token WhatEver which
> >    represents a string constant and not the string "WhatEver"
> 
> Is the missing bit the way that constant is defined?

I'm still a bit baffled about all of this.  I suppose that Bernie has
a sorta legitimate reason for doing all this, but it really strikes me
as the kind of thing that is the wrong solution.  There's probably a
better way.

The main question that keeps popping up for me is:

Why do you need to pass a parameter if you want to force them to 
pass a specific constant?

Matt

14. Re: type checking ?

• Posted by Derek Parnell <ddparnell at b?g?ond.com> Nov 24, 2007
• 646 views
• Last edited Nov 25, 2007

Here is how how I would do it...

<code>
---- File1
constant
strConstant1 = defineit("This a string constant from file 1")
---- end of File1

---- File2
constant
strConstant2 = defineit("This a string constant from file 2")
---- end of File2

---- File3
constant
strConstant3 = defineit("This a string constant from file 3")
---- end of File3

---- defstr.e ---
global type goodstr(object s)
    if atom(s) then return 0 end if
    is length(s) != 2 then return 0 end if
    if compare(s[1], {{"goodstr"}}) != 0 then return 0 end if
    if atom(s[2]) then return 0 end if
    for i = 1 to length(s[2]) do
        if not integer(s[2][i]) then return 0 end if
        if s[2][i] < 0 then return 0 end if
        if s[2][i] > 255 then return 0 end if
    end for
    return 1
end type

global function defineit(sequence s)
    return {{{"goodstr"}}, s}
end function
---- end of defstr.e


---- MAIN FILE
include defstr.e
include file1
include file2
include file3

procedure useit(goodstring s)
  -- process s here
  if goodstr(s) = 0 then return end if
end procedure

-- These are ok
useit(strConstant1)
useit(strConstant2)
useit(strConstant3)

-- THIS IS WRONG BECAUSE OF THE QUOTES, I DO NOT WANT TO PROCESS THIS.

useit("strConstant1")

</code>

-- 
Derek Parnell
Melbourne, Australia
Skype name: derek.j.parnell

16. Re: type checking ?

• Posted by Pete Lomax <petelomax at blu??onder.co.uk> Nov 25, 2007
• 631 views

I wrote:
> }}}
<eucode>
> global function getstr(integer idx) -- or make defset global
>   if idx<1 or idx> length(defset) then ?9/0 end if
>   return defset[idx]
> end function
> procedure useit(integer idx)
> </eucode>
{{{


My OCD says: better typewise/error reporting is of course:

global type valididx(object idx)
   return integer(idx) and idx>= and idx<= length(defset)
end type
global function getstr(integer idx)
  return defset[idx]
end function
procedure useit(valididx idx)

 

Thataway any error should occur on the useit call itself, not two levels down in
the call stack...

Pete

18. Re: type checking ?

• Posted by Bernie Ryan <xotron at blu?frog.c?m> Nov 25, 2007
• 638 views

Matt Lewis wrote:
> 
> Bernie Ryan wrote:
> > 
> > Matt Lewis wrote:
> > > 
> > 
> > > Why do you need to pass a parameter if you want to force them to 
> > > pass a specific constant?
> >  
> > Matt:
> > 
> > <code>
> 
> <snipped>
> 
> > -- These are ok
> > useit(strConstant1)
> > useit(strConstant2)
> > useit(strConstant3)
> > 
> > -- THIS IS WRONG BECAUSE OF THE QUOTES, I DO NOT WANT TO PROCESS THIS.
> > 
> > useit("strConstant1")
> > 
> > </code>
> 
> OK, once again, you've answered the what, but not the why.  I'll play 
> dentist now and ask some more focused questions.
> 
> Where did file1, etc come from?  Are these user files?  Are they part
> of your library?

file1 is a resource file created by the user using a utility program. 
 
> Why is the distinction between a constant and a literal sequence important
> to useit?
>

useit() is a procedure in a library that is being used by the user.
 
> You say that you don't want to process a literal sequence.  Please explain 
> the reason behind this.
> 

I do not know in advance what constant name will generated by the user

generating the file.

So I was trying to type-check so the user entered the constant token name.

I think a figured away around it by having the utility embed a unique

indentifier in the generated sequence constant string.     


Bernie

My files in archive:
WMOTOR, XMOTOR, W32ENGIN, MIXEDLIB, EU_ENGIN, WIN32ERU, WIN32API 

Can be downloaded here:
http://www.rapideuphoria.com/cgi-bin/asearch.exu?dos=on&win=on&lnx=on&gen=on&keywords=bernie+ryan