parser port

cases in exp	status
simple_exp	🆗
NOT exp	🆗
MINUS exp
exp PLUS exp
exp MINUS exp
exp EQUAL exp
exp LESS_GREATER exp
exp LESS exp
exp GREATER exp
exp LESS_EQUAL exp
exp GREATER_EQUAL exp
IF exp THEN exp ELSE exp
MINUS_DOT exp
exp PLUS_DOT exp
exp MINUS_DOT exp
exp AST_DOT exp
exp SLASH_DOT exp
LET IDENT EQUAL exp IN exp
LET REC fundef IN exp
exp actual_args	🆗
elems
LET LPAREN pat RPAREN EQUAL exp IN exp
simple_exp DOT LPAREN exp RPAREN LESS_MINUS exp
exp SEMICOLON exp
ARRAY_CREATE simple_exp simple_exp