Library Submission Ideas

From: Sean Parent (sparent_at_[hidden])
Date: 2001-10-25 21:30:54

I'm just getting started on a project using boost libraries and I've got a
fair amount of code that could be cleaned up to be submitted - I'm also
interested in hearing if there is overlap in the existing libraries that I'm
missing.

Ideas (I have all of these in various states of completeness):

1. Generalize mem_fn, mem_fun, ptr_fun... into a single make_function()
which uses template specialization to return an appropriate function object.
Include functionality to construct a function object from a data member
(given an object, returns the value of the data member).

1.1 Use make_function() to implement smarter versions of std algorithm
functions that don't require adaptors for many parameters.

2. Copy-on-write smart pointer. Useful in implementing data-types
efficiently with value semantics.

3. Transactional STL style containers - uses non-throwing swap member of
contained items to achieve efficient transactional operations.

4. Generalized notion of range to a single "object". A range is an
encapsulation of a pair of iterators (i.e.  [iter1, iter2) is a range ). An
array constitutes a range as do any of the STL containers. Push ranges
through the STL containers and the algorithms.

5. Some utility algorithms - for example, I have a template function
lookup(Range, Conv, Value). Takes a range (as described above), a conversion
function (which takes an item in the range and converts it to a value) and a
value. lookup performs a linear search similar to find and return an
iterator to an item in the range for wish Conv(item) == Value. You can use
it like this:

---
typedef std::pair<int, std::string> int_float;
int_float arr[] = {
    int_float(10, "Mark"),
    int_float(5, "Dave"),
    int_float(3, "John")
};
std::cout << lookup(arr, &int_float::first, 5) << std::endl;
std::cout << lookup(arr, &int_float::second, std::string("John")) <<
std::endl;
---
This prints:
---
Dave
3
---
You can call lookup with any range as the first parameter (any STL container
will work) and anything that can generate a conversion function with
make_function() - i.e. pointer to a member function, and external function,
a function object constructed with compose...
I have to run now so I'll stop here - just trying to gauge interest and get
ideas.
Thoughts?
-- 
Sean Parent
Sr. Computer Scientist II
Advanced Technology Group
Adobe Systems Incorporated
sparent_at_[hidden]