Re: Please Help.

[Dale Stanbrough <dale@goanna.cs.rmit.EDU.AU>]

Robert Dewar writes:
"<<(note that Unbounded_IO is a simple package that i wrote). In my
 experience variable length string handling is one thing that has
 turned students off Ada a lot. Unbounded_String is a godsend in
 this respect. It's a pity that a standard I/O package wasn't
 defined in the standard for this type.>>

(This is a little ambiguous. It should say "attempting variable length
string handling with type String" (i.e. slices, pointers to strings, 
discriminated records etc)).


"I actually find such claims incredible. I would never introduce
 Unbounded_String to students till quite late in the class, since
 this kind of concentration on featurism is exactly what you do NOT
 want to teach students. Sure you introduce examples of abstractions
 to teach students, but this is a bad example, because it has too
 much complexity (particularly the reliance on controlled types)."

I don't see how 

	"if you want to process variable length character data, use
	 this type"

should be described as featurism. I think it took around 15 minutes
to introduce this in the first lecture of 2nd semester. The rest
was devoted to the text_io input model, command line arguments, and
general new subject stuff. Not a great amount of time.
For most students the complexity is completey hidden (only a
handful of them even know about controlled types, and _I_ certainly
haven't told them).

"To me, the idea that a student can be turned off because of a lack of
 some particular feature in a language is like saying that students
 are turned off chemistry because they have trouble with the analysis
 of one particular compound."

Students constantly see the C model of strings (bounded length variable
length strings) and the associated I/O, and want to know "why can't i
do this in Ada?" Well, you can _if_ you include an "no_of_chars" field
with your string (yes, i understand about slices - i'm talking about
storing values in records and the like).
Like it or not, this is what students tell me. UBS's make them happy.


"Dale, are you really speaking from experience here? your own perhaps?
 or from experience teaching. My own experience is that the one thing
 that turns on or turns off students most is the professor. A bad
 professor can make Ada a catastrophe from the students point of view,
 a good one could teach 1401 Autocoder, and the students would be happy.
 Of course students are not the ones to be able to judge curriculum
 content in any case."

7 years teaching programming with Ada at the 1st, 2nd and 3rd year level.
UBS's make my job easier in this respect, why ignore it?


"I do think that it is nice for students to be able to write interesting
 programs without too much fuss, but unbounded strings are hardly a
 prerequisite to this!"

I reckon i'ld have ~400 students who would disagree with you! :-)


Dale