This must have come out of the ITA Software acquisition.... (Heading "Attention required" 'You must follow the ITA convention of using...')
They were a big common lisp user apparently.
Google is normally very specific on the languages allowed for internal projects. A product/company acquisition with large assets written in common lisp would necessitate this becoming the "Google Common lisp style guide" rather than what it was most likely originally the "ITA Software" common lisp style guide. Speculation of course, but looks likely.
Do you know this for a fact? That'd be quite impressive if the Lispers maintained strong against Google's policies.. I remember reading that they ported over
On the contrary, it would be impressive if Google managed to make them port half (or more of) their codebase from Lisp to Java and still keep the ITA employees, some of whom are hardcore lispers.
I have a friend who works for ITA/Google today, and he tells me they are still using Lisp and their Lisp codebase is huge and complicated and not likely to ever be ported to another language.
Google is normally very specific on the languages allowed for internal projects. A product/company acquisition with large assets written in common lisp would necessitate this becoming the "Google Common lisp style guide" rather than what it was most likely originally the "ITA Software" common lisp style guide. Speculation of course, but looks likely.