bevy_convars/
parse.rs

1//! Provides tools for parsing CVar overrides ([CVarOverride]) and config files.
2use std::{error::Error, fmt::Display, str::FromStr};
3
4/// A partially parsed CVar override. This ensures its in the correct format, but does not ensure it'll deserialize!
5#[derive(Clone, Debug)]
6pub struct CVarOverride(pub(crate) String, pub(crate) toml_edit::Value);
7
8/// Errors that can occur parsing a [CVarOverride]
9#[derive(Debug)]
10#[non_exhaustive]
11pub enum CVarOverrideParseError {
12    /// Error indicating the override is invalid as the left side is not a path.
13    InvalidPath,
14    /// Error indicating the override is invalid as the right side is not valid TOML.
15    InvalidToml,
16    /// Error indicating the override is invalid as it doesn't even look like an override (`left=right`)
17    DoesntLookLikeAnOverride,
18}
19
20impl Error for CVarOverrideParseError {}
21
22impl Display for CVarOverrideParseError {
23    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
24        match self {
25            CVarOverrideParseError::InvalidPath => write!(
26                f,
27                "Not a valid override, a CVar override must have a CVar path (a.b.c) on the left."
28            ),
29            CVarOverrideParseError::InvalidToml => write!(
30                f,
31                "Not a valid override, a CVar override must have TOML on the right."
32            ),
33            CVarOverrideParseError::DoesntLookLikeAnOverride => write!(
34                f,
35                "Not a valid override, a CVar override must be of form `left=right`"
36            ),
37        }
38    }
39}
40
41impl TryFrom<&str> for CVarOverride {
42    type Error = CVarOverrideParseError;
43
44    fn try_from(value: &str) -> Result<Self, Self::Error> {
45        let (left, right) = value
46            .split_once('=')
47            .ok_or(CVarOverrideParseError::DoesntLookLikeAnOverride)?;
48
49        let value =
50            toml_edit::Value::from_str(right).map_err(|_| CVarOverrideParseError::InvalidToml)?;
51
52        Ok(CVarOverride(left.to_owned(), value))
53    }
54}
55
56impl FromStr for CVarOverride {
57    type Err = CVarOverrideParseError;
58
59    fn from_str(s: &str) -> Result<Self, Self::Err> {
60        Self::try_from(s)
61    }
62}
bevy_convars/parse.rs

bevy_convars/
parse.rs
