Category: PHP
zval container & symbol table
zval container: all php variables’ value is store in the zval container, which also includes is_ref (boolean value, and default is false, this is indicated whether the variable point to this value is reference variable or not) and refcount (contains how many variables point to this value) symbol table: all variable name in different scope
function: extract()
Syntax extract ( array &$array [, int $flags = EXTR_OVERWRITE [, string $prefix = NULL ]] ) Description extract — Import variables into the current symbol table from an array, Checks each key to see whether it has a valid variable name. It also checks for collisions with existing variables in the symbol table. Code