Topher Cooper wrote:
Actually the difficulty is "easy". The basic precedence parser could be whipped out in an hour or so. Another day or a bit more to do the interfacing, define the expression data structures, and do the constant folding.
Operators also need associativity, or, more expressively, two precedences -- a left and a right precedence.
You don't really need to specify "allowed variables" any more than you need to specify allowed literals -- if the parser sees a variable it can use it.
Personally I would include templates rather than just an operator string and then depend on the arity to determine the type. Then you can handle ternary and postfix operators.
Topher
Isn't it somethign that cna be done in a few days using spirit anyway ? -- ___________________________________________ Joel Falcou - Assistant Professor PARALL Team - LRI - Universite Paris Sud XI Tel : (+33)1 69 15 66 35