[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Open issues summary #1
Here is a list of the open issues on which I'd like to hear opinions and
discussion. (It's not an exhaustive list; feel free to raise other issues).
- STRING-APPEND accepts chars as well as strings?
Would give a kind of "string cons" for free...
If we altered STRING-APPEND to accept characters as well as strings,
we would get the ability to "cons" characters onto the head or tail of
strings, e.g. (string-append c1 c2 s).
No: bengt egorov
- Comparison functions n-ary?
No: shivers, bengt, egorov
Should the string comparison functions such as STRING= and STRING<
be generalised to be n-ary? E.g., should we be able to write
(string< s1 s2 s3)
I have specified these functions as dyadic only. You can certainly make
a case for greater generality. However,
- Unlike numeric inequalities, I do not think this generality will be
useful in practice.
- It doesn't extend well to the *sub*string comparison functions
or the three-way comparison functions. To get it to work for the
three-way comparison functions, you'd have to put the continuations
first, then the strings after. This is pretty ugly; the usual convention
is continuations last. This is not a completely compelling argument,
but it does weigh some.
Extending to the substring comparison functions -- both the predicates
and the 3-way continuation-based functions is even uglier.
Finally, if we were to do this, we ought to really follow through
and make the 8 prefix-count functions n-ary.
I think it's too much complexity.
Note that Rice's MzScheme provides n-ary string comparison.
- Include STRING-TOKENIZE?
Yes: bengt, shivers, egorov
- Include STRING-REDUCE and STRING-REDUCE-RIGHT ?
Yes: bengt, shivers
- SUBSTRING and copying/shared-text semantics:
Conservative: Egorov?, Bornstein?
The two choices are
+ Conservative -- Drop SUBSTRING. Add STRING-COPY & SUBSTRING/SHARED
+ Liberal -- Add STRING-COPY; alter SUBSTRING to allow shared-text
- STRING-ITER vs STRING-ITERATE
- -COUNT versus -LENGTH
No opinion: Shivers
These or these?