# <>  must choose
# []  can choose
# {}  can repeat 0 to infinite time(s)
# |   or
# ::= is defined as

<number> ::= <token_type_number>
<string> ::= <token_type_string>
<id> ::= <token_type_identifier>
<dynamic_id> ::= <token_type_dynamic_id>
<vector> ::= <[> { <scalar> <,> } <]>
<hash> ::= <{> { ( <id> ) | ( <string> ) <:> <scalar> <,> } <}>

<function> ::=<func> [ <(> { ( <id> [ <=> <scalar> ] ) | ( <dynamic_id> ) <,> } <)> ] ( <statement> ) | ( <{> { <statement> <;> } <}> )
<calculation> ::=

<definition> ::=
	<var> <id> <=> <scalar>
|	<var> <(> <id> { <,> <id> } <)> <=> <scalar>
|	<(> <var> <id> { <,> <id> } <) <=> <scalar>

<assignment> ::=

<if-else> ::=
	<if> <(> <scalar> <)> ( <statement> ) | ( <{> { <statement> <;> } <}> )
	{ ( <elsif> ) | ( <else> <if> ) } <(> <scalar> <)> ( <statement> ) | ( <{> { <statement> <;> } <}> )
	[<else> ( <statement> ) | ( <{> { <statement> <;> } <}> )
<loop> ::=
	<for> <(> <;> <;> <)> ( <statement> ) | ( <{> { <statement> <;> } <}> )
|	<foreach> <(> <;> <)> ( <statement> ) | ( <{> { <statement> <;> } <}> )
|	<forindex> <(> <;> <)> ( <statement> ) | ( <{> { <statement> <;> } <}> )
|	<while> <(> <scalar> <)> ( <statement> ) | ( <{> { <statement> <;> } <}> )

<statement> ::=
	<definition>
|	<assignment>
|	<if-else>
|	<loop>
|	<scalar>