Some comments on data structures.
Please let me know if I miss something, which is possible.

1. It should be possible to create an uninitialised array.
[It can be done for string]

2. Arrays are mutable, but not variable length.

3. It isn't clear to me how fast concatenation
of sub arrays (or substrings) is. If I write

	Array.append 
		(Array.sub x xfirst xlen) 
		(Array.sub y yfirst ylen)

it isn't clear if the intermediate subarrays are
needlessly constructed or not. 

-- 
John Skaller, mailto:skaller@maxtal.com.au
1/10 Toxteth Rd Glebe NSW 2037 Australia
homepage: http://www.maxtal.com.au/~skaller
downloads: http://www.triode.net.au/~skaller