grammar.ebnf

string_primitive  = STRING ;
null_primitive    = 'null' ;
bool_primitive    = 'true' | 'false' ;
decimal_primitive = DIGITS ;
floating_point    = DIGITS '.' DIGITS ;

identifier        = /[a-zA-Z_][a-zA-Z0-9_]* / ;

source_file         = type_declaration* ;

type_declaration    = ( 'class' | 'extension' | 'cutscene' | 'component' ) identifier type_block ;
type_block       = '{' type_member* '}' ;
type_member      = assignment | procedure_declaration ;

expression        = binary | unary | primary ;
binary            = expression ( '!=' | '==' | '>' | '>=' | '<' | '<=' | '-' | '+' | '/' | '*' ) expression;
unary             = ( '!' | '-' ) expression ;

primary           = string_primitive
                  | null_primitive
                  | bool_primitive
                  | decimal_primitive
                  | floating_point
                  | identifier
                  | field_access
                  | procedure_call
                  | 'self'
                  | paren_expr ;
paren_expr        = '(' expression ')' ;

TODO: rework these rules?
field_access      = primary '.' identifier ;
procedure_call    = ( field_access | identifier ) argument_list ;
argument_list     = '(' expression ( ',' expression )* ')' ;

procedure_decl    = 'function' identifier procedure_params procedure_block ;
procedure_params  = '(' identifier* ')' ;
procedure_block   = '{' statement* '}' ;

assignment        = ( field_access | identifier ) ( '=' | '+=' | '-=' | '*=' | '/=' ) expression ';' ;

compound_statement = if_statement | while_statement | for_statement ;
if_statement      = 'if' paren_expr block elif_clause* else_clause? ;
elif_clause       = 'elif' paren_expr ;
else_clause       = 'else' block ;

while_statement   = 'while' paren_expr block ;
for_statement     = 'for' '(' identifier 'in' expression ')' block ;

simple_statement  = ( procedure_call | return_statement | wait_statement ) ';' ;
return_statement  = 'return' expression ;
wait_statement    = 'wait' expression ;

statement         = assignment | compount_statement | simple_statement ;
block             = '{' statement* '}' ;