grammar.txt

---------------- GRAMMAR BNF ----------------


Delcarations: 
program     -> declaration* EOF;
declaration -> var_decl | fn_decl | class_decl | statements;
var_decl    -> "var" IDENTIFIER "=" "expression" end;
fn_decl     -> "fn" function;
class_decl  -> "cls" IDENTIFIER ( "[" IDENTIFIER "]" )? "{" function* "}" end;

Statements: 
statement   -> expr_stmt | block | if_stmt | 
               during_stmt | expire_stmt | return_stmt;
expr_stmt   -> expression end;
block       -> "{" declaration* "}";
if_stmt     -> "if" expression block ( "else" statement )? ;
during_stmt -> "dur" expression block;
expire_stmt -> "exp" ( var_decl | expression )? ";" 
               expression? ";" expression? ";" block;
return_stmt -> "ret" expression end;

Expressions: 
expression -> assignment;
assignment -> IDENTIFIER "=" expression | logic_or;
logic_or   -> logic_and ( "or" logic_and )* ;
logic_and  -> equality ( "and" equality )* ;
equality   -> comparison ( ( "*=" | "==" ) comparison )* ;
comparison -> term ( ( ">" | ">=" | "<" | "<=" ) term )* ;
term       -> factor ( ( "+" | "-" ) factor )* ;
factor     -> unary ( ( "*" | "/" ) unary )* ;
unary      -> ( "-" | "*" ) unary | call;
call       -> primary ( "(" arguments? ")" | "->" IDENTIFIER )* ;
primary    -> NUMBER | STRING | "sel" | "tru" | "fal" | "nul" | "(" expression ")" | "sup" "->" IDENTIFIER;

Helpers:
arguments  -> expression ( "," expression )* ;
function   -> IDENTIFIER "[" parameters? "]" block;
parameters -> IDENTIFIER ( "," IDENTIFIER )* ;
end        -> ( ";" | NEWLINE )