Make the length of a name roughly proportional to the length of its scope

Rationale: The larger the scope the greater the chance of confusion and of an unintended name clash.

Example

double sqrt(double x);   // return the square root of x; x must be non-negative

int length(const char* p);  // return the number of characters in a zero-terminated C-style string

int length_of_string(const char zero_terminated_array_of_char[])    // bad: verbose

int g;      // bad: global variable with a cryptic name

int open;   // bad: global variable with a short, popular name

The use of p for pointer and x for a floating-point variable is conventional and non-confusing in a restricted scope.

Enforcement

???