variables, and function static variables, must be Plain Old Data (POD): only ints, chars, floats, or pointers, or arrays/structs of POD. The order in which class constructors and initializers for static function (such as getenv(), or getpid()) does not itself depend on any other globals. However, a static POD variable within function scope may be initialized with the result of a function, since its initialization quick_exit(), you need to register it in both places.) As a result we only allow static variables to contain POD data. This rule completely disallows vector (use C arrays instead), or string (use const char []).

prefer to break at a higher syntactic level. Also: 1. When a line is broken at a non-assignment operator the break comes before the symbol. (Note that this is not the same practice used in Google style style for other languages, such as C++ and JavaScript.) • This also applies to the following “operator-like” symbols: the dot separator (.), the two colons of a method reference (::), the amper- sand in type When a line is broken at an assignment operator the break typically comes after the symbol, but either way is acceptable. • This also applies to the “assignment-operator-like” colon in an en- hanced for (“foreach”)

common operations like multiplication, use the functions from the operator module instead of lambda functions. For example, prefer operator.mul to lambda x, y: x * y. Conditional Expressions link￿ Okay the @property decorator - see below). Must inherit from object. Can hide side-effects much like operator overloading. Can be confusing for subclasses. Decision: Use properties in new code to access or around arithmetic operators but always be consistent about whitespace on either side of a binary operator. Yes: x == 1 No: x<1 Don’t use spaces around the ‘=’ sign when used to indicate a keyword argument

-XX:-DontCompileHugeMethods Presentation – Result Interpretation [Matthias Boehm et al: On Optimizing Operator Fusion Plans for Large-Scale Machine Learning in SystemML. PVLDB 11(12) 2018] 19 706.015 Introduction

Afraid to Ask. PVLDB 11(13) 2018  #15.2 Prashanth Menon, Andrew Pavlo, Todd C. Mowry: Relaxed Operator Fusion for In- Memory Databases: Making Compilation, Vectorization, and Prefetching Work Together