* Strings in Ada83
@ 1997-10-14 0:00 Scott Dick (CS)
1997-10-15 0:00 ` Michael F Brenner
1997-10-18 0:00 ` Matthew Heaney
0 siblings, 2 replies; 3+ messages in thread
From: Scott Dick (CS) @ 1997-10-14 0:00 UTC (permalink / raw)
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Hello,
My name is Scott Dick, and I am brand new on this discussion group.
I was wondering if someone might be able to answer a question for me.
For my undergraduate thesis, I wrote a string package for Ada83, and I
am now turning that thesis into a paper for Southeastcon '98. Is there
anywhere I might be able to find out the amount of Ada code that
currently exists? (e.g. # of lines of code currently in systems, # of
lines of code written each year, something along those lines?) Such a
number would really help for explaining the significance of my work for
the reviewers.
BTW, that strings package is at
http://www.csee.usf.edu/~dick/cstring.html . If anyone wants to take a
look at it, your comments would be most welcome. Thanks for your time!
--
*************************************************************************
* * *
* Scott Dick * *
* Research Assistant * Cool & brilliant thought *
* USF Computer Science * still under contruction *
* dick@morden.csee.usf.edu * *
* * *
*************************************************************************
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<HTML>
Hello,
<P> My name is Scott Dick, and I am brand new on this
discussion group. I was wondering if someone might be able to answer a
question for me. For my undergraduate thesis, I wrote a string package
for Ada83, and I am now turning that thesis into a paper for Southeastcon
'98. Is there anywhere I might be able to find out the amount of Ada code
that currently exists? (e.g. # of lines of code currently in systems, #
of lines of code written each year, something along those lines?) Such
a number would really help for explaining the significance of my work for
the reviewers.
<P>BTW, that strings package is at <A HREF="http://www.csee.usf.edu/~dick/cstring.html">http://www.csee.usf.edu/~dick/cstring.html</A>
. If anyone wants to take a look at it, your comments would be most welcome.
Thanks for your time!
<PRE>--
*************************************************************************
* * *
* Scott Dick * *
* Research Assistant * Cool & brilliant thought *
* USF Computer Science * still under contruction *
* dick@morden.csee.usf.edu * *
* * *
*************************************************************************</PRE>
</HTML>
--------------EAF2C630C8D9EDA010EB2FE1--
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: Strings in Ada83
1997-10-14 0:00 Strings in Ada83 Scott Dick (CS)
@ 1997-10-15 0:00 ` Michael F Brenner
1997-10-18 0:00 ` Matthew Heaney
1 sibling, 0 replies; 3+ messages in thread
From: Michael F Brenner @ 1997-10-15 0:00 UTC (permalink / raw)
Scott said: > ... strings package is at
> http://www.csee.usf.edu/~dick/cstring.html
> ... your comments would be most welcome. Thanks...
If you ever choose to revise it, you might consider these ideas:
(1) Separation of I/O from computation. For example,
The get_line and put_line could be put in a second package
(or a child package in Ada-95). With suitable revisions,
the package would then be a pure package which would be
subject to additional optimizations. In Ada-95 this pureness
can be celebrated with a specific pragma, but an Ada-83
optimizer can still do the data analysis to recoginize the
pureness of the code. Making the string manipulation portion
of the package dependent upon text_io makes it non-portable.
Realtime embedded systems may not have a text_io
connected, consider a satellite in orbit. In addition,
text_io usually brings in a lot of software which is
a memory hog. More important than the practical problems
with forcing the user to use text_io in order to use
strings is the lack of cohesion in the package caused by
mixing I/O with string manipulation; to increase the
cohesion, let the package do one thing (string manipulation)
without a very complex other thing (I/O).
(2) Use of a limited type. Since you chose to make it a limited type,
why not make INSERT and DELETE functions instead of procedures,
taking advantage of a fully functional style?
(3) Use of a limited private type. Consider making type cstrings
a limited private type, and convert all the functions to
procedures, except tostring, length, and the comparision
operators, taking advantage of the safety of limited private
thypes.
(4) Letting the user choose the size of each string. You might wish
to change the type definition to permit each string to have its
own size. Arrays, however, would have to have all strings of the
same maximum length.
(5) The exception cstring_null which is raised when the text_io file
is not open, does not inform the user what the real problem is.
(6) Have you tested this using the full capability of text_io to
process files with end-of-page markers in them?
(7) The loop in the less-than function would be easier to read, by
removing the boolean variable GO and experiencing the corresponding
lowering in the depth of nesting. To do this, replace the
statement IF LEFT... /= RIGHT ... with the statement
EXIT WHEN LEFT /= RIGHT. In most compilers, doing this would
result in faster code because the I:=I+1 would then be the
innermost nesting level of the loop and thus be slightly
better optimized. This would not matter so much in a machine
with a deep instruction pipeline or where the program cache
is not voided by jumps.
(8) The body of the function less-than-or-equal-to can be simplified
by noting that IF CONDITION THEN RETURN TRUE ELSE RETURN FALSE
is equivalent to RETURN CONDITION.
(9) There are no protection against uninitialized cstrings (as you
and this code may go into long or infinite loops when used
on uninitialized cstrings.
(10) Returning a maximum sized Ada string (say 1000000 characters
long) for a 1 character long cstring is not efficient and this
should be documented for the user. Better, why not return an
Ada string that is the same length as the cstring?
(11) In CSTRINGTONUMBER, the expression
IF NOT (('0'<=X) and (x<='9')) THEN
would be more readable if replaced with
IF X NOT IN '0'..'9' THEN
(12) The exception cstring_null in cstringtonumber does not
adequately inform the user that a minus sign, plus sign,
underline, or decimal point was used as part of a number
and this code prohibits those characters.
(13) It might be worth testing why MY_REVERSE does not actually
reverse all cstrings.
(14) The variable FLAG would be obviated by replacing
flag:=True;
WHILE FLAG LOOP
... code ...
if CONDITION then
flag := FALSE;
end if;
end loop
with the simpler loop
loop
... code ...
exit when CONDITION;
end loop;
(15) When back filling with ASCII null characters, some of the
loops fill the cstring up to max_size and some fill it
up to max_size+1. This is often the sign of a bug. In this
case, using suitable checks for non-initialized cstrings,
the appropriate thing to do is not to fill the cstrings at
all, but just add a single ASCII null at then end of the
meat of the string.
(16) The formal parameter INDEX could be renamed AFTER to indicate
its function in the procedure INSERT.
(17) What happens when inserting something at the beginning of
a cstring?
(18) What happens when deleting max_size characters from a string?
(19) Is it true that BM_scan only located strings correctly when
the pattern string being looked for (SUB) does not contain
repetitious strings withing itself? For example, will it
fail if INJINKINL is searched using the pattern INKINL, because
it notices that INKINL doesnot match INJINK (the first 6 letters)
and bumps up the count by 6, next trying to match INKINL against
INL which also fails?
(20) The test programs in your sample drivers do not flesh out all
the bugs. An IF statement is needed for each feature of the
package. This should only appear inside this package if it
done entirely with ASSERT statements and use no I/O.
procedure ASSERT (condition: boolean) is
Scott_made_an_error: exception;
begin
if not condition then
raise Scott_made_an_error;
end if;
end assert;
(21) The data integrity paragraph of the user documentation is not
accurate, promising that cstrings can only be accessed
through the operations defined in the package. In addition,
a private type can be access through the equality operator,
the assignment operator, and through non-initialized
elaboration.
(22) The Notes on Design and Implementation are not adequate to
fix the bugs or to maintain this software.
(23) The above comments, notwithstanding, this is a good piece
of work and, if you concentrate an equal amount of time
writing test programs as you do writing lines of code,
you will solve many problems during your long and happy
career.
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: Strings in Ada83
1997-10-14 0:00 Strings in Ada83 Scott Dick (CS)
1997-10-15 0:00 ` Michael F Brenner
@ 1997-10-18 0:00 ` Matthew Heaney
1 sibling, 0 replies; 3+ messages in thread
From: Matthew Heaney @ 1997-10-18 0:00 UTC (permalink / raw)
In article <3443D8AF.D9CD4393@morden.csee.usf.edu>, "Scott Dick (CS)"
<dick@morden.csee.usf.edu> wrote:
>Is there
>anywhere I might be able to find out the amount of Ada code that
>currently exists? (e.g. # of lines of code currently in systems, # of
>lines of code written each year, something along those lines?)
This is the kind of research Boehm et al did when they investigated the
issue of whether to get rid of the Ada mandate. Their report is called Ada
and Beyond, ISBN 0-309-05597-0, and I think it's available via the National
Academy Press.
<http://www.nap.com>
--------------------------------------------------------------------
Matthew Heaney
Software Development Consultant
<mailto:matthew_heaney@acm.org>
(818) 985-1271
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