fee 0.2.4

Expression evaluator supporting numeric, logical and bitwise operators
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48

use std::borrow::Cow;

use thiserror::Error;

#[derive(Debug, Error, PartialEq)]
pub enum Error<'a>
{
    #[error("unknown variable '{0}'")]
    UnknownVar(Cow<'a, str>),

    #[error("unknown function '{0}'")]
    UnknownFn(Cow<'a, str>),

    #[error("parse error: {0}")]
    ParseError(ParseError<'a>),

    #[error("eval error: {0}")]
    EvalError(EvalError),

    #[error("internal invariant: {0}")]
    InternalInvariant(String),
}

#[derive(Debug, Error, PartialEq)]
pub enum ParseError<'a>
{
    #[error("unexpected character '{0}' at {1}")]
    UnexpectedChar(Cow<'a, char>, usize),

    #[error("invalid number '{0}' at {1}")]
    InvalidNumber(Cow<'a, str>, usize),

    #[error("unmatched parentheses at {0}")]
    UnmatchedParentheses(usize),

    #[error("unexpected expresison end")]
    UnexpectedEnd,
}

#[derive(Debug, Error, PartialEq)]
pub enum EvalError
{
    #[error("RPN stack underflow")]
    RPNStackUnderflow,

    #[error("malformed expression")]
    MalformedExpression,
}