On 21 May 2014 21:06, "Ned Batchelder"
** Implementation
Although it may seem like a big change to be able to disable the optimizer, the heart of it is quite simple. In compile.c is the only call to PyCode_Optimize. That function takes a string of bytecode and returns another. If we skip that call, the peephole optimizer is disabled.
** User Interface
Unfortunately, the -O command-line switch does not lend itself to a new value that means, "less optimization than the default." I propose a new switch -P, to control the peephole optimizer, with a value of -P0 meaning no optimization at all. The PYTHONPEEPHOLE environment variable would also control the option.
Since this is a CPython specific thing, a -X named command line option would be more appropriate.
There are about a dozen places internal to CPython where optimization
level is indicated with an integer, for example, in Py_CompileStringObject. Those uses also don't allow for new values indicating less optimization than the default: 0 and -1 already have meanings. Unless we want to start using -2 for less that the default. I'm not sure we need to provide for those values, or if the PYTHONPEEPHOLE environment variable provides enough control. I assume you want the environment variable so the setting can be inherited by subprocesses? Cheers, Nick.