Method evaluate

src/speech.rs:1127–1139

(&'a self, context: &'r Context<'c>, mathml: Element<'c>)

    }
    
    pub fn evaluate<'a, 'c>(&'a self, context: &'r Context<'c>, mathml: Element<'c>) -> Result<Value<'c>> {
        // debug!("evaluate: {}", self);
        let result = self.rc.xpath.evaluate(context, mathml);
        return match result {
            Ok(val) => Ok( val ),
            Err(e) => {
                bail!( "{}\n\n",
                e.to_string()           // remove confusing parts of error message from xpath
                .replace("OwnedPrefixedName { prefix: None, local_part:", "")
                .replace(" }", "") );    
            }
        };
    }

    pub fn test_input<F>(self, f: F) -> bool where F: Fn(&str) -> bool {
        return f(self.rc.string.as_ref());