Access to parse tree? about asteval HOT 2 CLOSED

@colmshell I'm glad it helps!

I also have a need to display these user defined formulae. It would be pretty great if this package could help with that by exposing the AST or something. I'm currently using "formulas", but I'm not a great fan of this package.

Don't you already have the user's expression that is sent to the interpreter?

For completeness, you can use the parse method to get back the AST, so that you could do something like

 >>> from asteval import Interpreter 
 >>> import ast
 >>> aeval = Interpreter()
 >>> ast.dump(aeval.parse('sin(x/3)')
"Module(body=[Expr(value=Call(func=Name(id='sin', ctx=Load()), args=[BinOp(left=Name(id='x', ctx=Load()), op=Div(), right=Constant(value=3, kind=None))], keywords=[]))], type_ignores=[])"

That is the AST represents 'sin(x/3)', but I'm not sure what else you would want to do with it (besides "evaluate it"!) that wasn't also represented by the string 'sin(x/3)'.

from asteval.

Ah, perfect, thanks. I think this probably does what I need.

I wanted to render the formula I'm parsing using HTML. If I have myfunction(x / y), with a parse tree I can hyperlink myfunction, x and y to explanations for users who view the formula.

from asteval.