SPITBOL is a compiled implementation of SNOBOL4. The original version was written for the IBM 360/370. It was created by Robert Dewar and Ken Belcher at the Illinois Institute of Technology (IIT).

Until SPITBOL came along, SNOBOL4 was thought to be (1) slow, (2) a memory hog, and (3) impossible to compile due to its dynamic nature. While the delayed binding prevented everything from being determined at compile time, SPITBOL was very clever about doing as much as possible as early as possible. SNOBOL programs run under SPITBOL were indeed amazingly fast. Notable was the SPITBOL garbage collector which ran with almost no spare memory.

A contribution of SPITBOL to computer science was to demonstrate the clear distinction between a language and its implementation. To say that a language is slow is to reveal a lack of imagination. It's better to say that writing a fast implementation is hard. This same issue arises now in reference to Java, which is often erroneously called an interpreted language. Of course, it's an implementation that is an interpreter. The language is just the language.

Modern versions of the SPITBOL compiler can still be found and since 2001, the source code for the original SPITBOL 360 compiler has been made available under the GPL licence.

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