[Haskell-cafe] Expression parsing problem

[Malcolm Wallace]

> The grammar:
> expression  = "get" | [ "+" | "-" ] term { ( "+" | "-" ) term }
>  term      = factor { ( "*" | "/" ) factor }
>    factor  = IDENTIFIER | VALUE | "(" expression ")"
>
> I can't make term parse, for instance "1 * 2 / 3"

Indeed, the grammar does not admit "1*2/3" as a sentence of that  
language although it will admit "(1*2)/3" or "1*(2/3)".

If you wish to allow sequences of infix operators without bracketting,  
then examples of the standard grammar for this can be found by  
searching the web for "expression term factor", e.g. http://en.wikipedia.org/wiki/Syntax_diagram 
  suggests:

expression ::= term | term "+" expression
term ::= factor | factor "*" term
factor ::= constant | variable | "(" expression ")"

Regards,
     Malcolm