A few years back, Dr. Dobb’s posted a pretty great series of articles on some of the techniques RBK Dewar employed when building the original SPITBOL compiler: http://www.drdobbs.com/cpp/some-programs-are-poorly-designed...
(I was lucky enough to study compilers under Prof. Dewar when I was a grad student at NYU - I still have my notes on SPITBOL’s architecture, somewhere…)