PROGRAM: [FUNCTION]* FUNCTION: tok_def tok_identifier tok_lpar [FUNCTION_ARG]* tok_rpar tok_lbrak [BODY]* tok_rbrak FUNCTION_ARG: tok_identifier | tok_identifier tok_comma BODY: [CONDITIONAL | DEFINITION | RETURN_STATEMENT]
CONDITIONAL: IF_STATEMENT | IF_ELSE_STATEMENT IF_STATEMENT: tok_if tok_lpar [EXPRESSION] tok_rpar tok_lbrak [BODY]* tok_rbrak IF_ELSE_STATEMENT: IF_STATEMENT tok_else tok_lbrak [BODY]* tok_rbrak
DEFINITION: tok_identifier tok_equals EXPRESSION RETURN_STATEMENT: tok_return EXPRESSION EXPRESSION: [IDENTIFIER_EXPRESSION | PAREN_EXPRESSION | tok_number] [BIN_OP_EXPRESSION]? BIN_OP_EXPRESSION: [tok_add | tok_sub] EXPRESSION | MULT_EXPRESSION MULT_EXPRESSION: [tok_mult | tok_div] EXPRESSION | MOD_EXPRESSION MOD_EXPRESSION: [tok_mod] EXPRESSION IDENTIFIER_EXPRESSION = tok_identifier | tok_identifier tok_lpar EXPRESSION tok_rpar PAREN_EXPRESSION = tok_lpar EXPRESSION tok_rpar