Without expression trees, its impossible to describe expressions in a descriptive format; the only description of them is IL, which is too low level to re-create the user's intent for the expression.

Furthermore if this person USES some words or expressions that you 're not familiar with, you can use the context of the rest of the conversation to help you figure out what they mean.

In contrast to re (regular expressions), string functions are generally much faster, and in most cases they are easier to understand and maintain.