Main rules
- Variables or functions must be declared before their first use.
- Variables or functions can be defined more than once. It is called redefinition.
- In variable redefinition, the rule of consequence of expressions in the document occurs: the expression uses the variable or function declaration located in the nearest upper position.
- Redeclaring the function as a variable and vice versa is impossible.
- Functions can have any number of parameters defined with a comma.
- Built-in variables and functions can be redefined.
- Functions can be redefined for any number of arguments.