# also includes quotes and format strings
STRING = !SPECIALS

NUMBER = 1-9
ALFA = a-zA-Z
EOL = \n
IDENT = ALFA (ALFA | NUMBER)*

VARIABLE = $IDENT
INDEX = VALUE ( "[" VALUE "]" ) +

PRIMITIVE_VALUES = NUMBER | STRING | VARIABLE | INDEX

# group and object destructors/bindings will be here
BINDABLE = PRIMITIVE_VALUES

VALUE = PRIMITIVE_VALUES | GROUP

# statements are expressions, so it is possible to write `echo (if true { echo true } else { echo false })`
GROUP = "(" STATEMENT ")"

# no padding can be here, must be TEXT=VALUE
ENV_VAR_SPECIFICATION = STRING = VALUE

COMMAND = ( ENV_VAR_SPECIFICATION WHITESPACE ) * ( VALUE WHITESPACE ) +

# in the future this could also support other ops like add+set
SET = set BINDABLE = VALUE

FUNCTION = fn STRING "(" ( BINDABLE , )* BINDABLE ")" { STATEMENTS }

FOR = for BINDABLE in VALUE { STATEMENTS } ( else { STATEMENTS } )?
IF = if VALUE { STATEMENTS } ( else if VALUE { STATEMENTS } ) * ( else { STATEMENTS } )?
WHILE = while VALUE { STATEMENTS } ( else { STATEMENTS } )?
LOOP = loop { STATEMENTS }

BREAK = break

STATEMENT = COMMAND | SET | FOR | IF | WHILE | LOOP | FUNCTION | BREAK
STATEMENTS = ( STATEMENT (; | EOL) )* STATEMENT?