Parser

Parsers for various probability expression grammars.

parse_causaleffect(s: str) → Expression

Parse a causaleffect probability expression.

parse_y0(s: str) → Expression

Parse a valid Python expression using the y0.dsl objects, written in a string.

Parameters:

s – The string to parse. Should be a valid Python expression given from y0.dsl import *. Variables of the form A-Z, A0-Z0, A_0-Z_0, A1-Z1, A_1-Z_1, …, A9-Z9, A_9-Z_9 are available.

Returns:

An expression object.

>>> from y0.parser import parse_y0
>>> from y0.dsl import P, PP, A, B, Sum, Pi1
>>> parse_y0("Sum[B](P(A|B) * P(B))") == Sum[B](P(A | B) * P(B))
True
>>> parse_y0("PP[π1](A)") == PP[Pi1](A)
True