Does this class supposed to be inherrited or instantiated directly? Thanks Hilaire Le 28/01/2013 14:16, Guillaume Larcheveque a écrit :

look at PPExpressionParser class.

it's designed for that and you have a great example in the class comment

2013/1/28 Hilaire Fernandes <hilaire.fernandes@gmail.com <mailto:hilaire.fernandes@gmail.com>>

Hello

I try to extent the example of the arithmetic evaluator[1], I don't understand the magic underneath nor how you will make it works with substraction.

Changing method add to:

add ^ prod, ($+ asParser / $- asParser) trim, term

to parse mixture addition and substraction is wrong:

parser parse: '1 - 2 + 6' -> #(1 $- #(2 $+ 6))

The precedence is wrong.

How will you make it work? It seems to me the way to handle precedence in the example is not suited for extension

Thanks

Hilaire

[1] http://pharobooks.gforge.inria.fr/PharoByExampleTwo-Eng/latest/

-- *Guillaume Larcheveque*