Ralph Griswold dies

Ralph Griswold died earlier this month of cancer. Griswold was an important, but unsung , pioneer of programming language design. He was the inventor of SNOBOL and Icon (now Unicon), two languages distinguished by unsurpassed string processing capabilities. And I do mean unsurpassed. No language since has had such extensive native support for string operations.

The other outstanding characteristics of SNOBOL and Icon were that they were very high-level languages. This color picker was written in 31 lines of easily readable code. It might be a simple tool, but I doubt many languages could come close to that level of brevity for this same functionality (much less maintain such readability). Languages today could use a bit more of Griswold's vision, I believe.

Useful links:

Icon (which is still actively supported.)

Unicon (Icon with objects, advanced network and file functions, plus ODBC)

Griswold obituary

Solving the problem of embedded comments

One problem language designers face is handling embedded comments. The basic problem is that if you comment out a large block, your intent might be thwarted by comments within the block. For example in C, the /* symbol marks the beginning of a block and */ the end. To comment out a block of code it's not sufficient to place these markers at the beginning or end of the block, because if a */ occurs inside the block, it will close the comment. So, most languages forbid the use of embedded comments. (As a result, various work-arounds are used. In C, for example, the #if 0 / #endif combo is used.)

Lua, which is a nifty dynamic language, is the first language I've seen to come up with a solution to this problem. Here goes:

In Lua, block comments start with: --[[ and end with --]] If you want to comment out a chunk that might contain block comments, you can add one or more = signs between the brackets: Open with --[=[ and close with ]=]. You can use any number of = signs between the brackets and Lua will comment out everything until it finds a pair of closing brackets with a matching number of equal signs. So, --[==[ and ]==] or --[===[ and ]===] are valid comment block markers. You can use as many equal signs as you want, as long as beginning and ending counts match. So, you can always block out your code regardless of how many embedded comments it might contain.

I think that's pretty clever. Anyone know of another language with a similar mechanism?

Interesting Uses Of Virtualization

Last week, I presented two sessions at InfoWorld's Virtualization Executive Forum 2006. One was a panel on best practices for virtual test-lab automation, with representatives from VMware/Akimbi and Surgient.

The other was a solo presentation on interesting uses of virtualization--that is, compelling use cases outside of server consolidation. While hardware consolidation is still the leading driver for adoption of virtualization by IT, it will be overtaken by a slew of very interesing applications that are as yet little known. To see what I mean, have a look at the slides from my presentation. I have kept the deck short and to the point.