prse/
lending_parse.rs

1use core::num::*;
2use core::str::FromStr;
3
4use crate::parse_error::ParseError;
5
6/// Parse a string into the implemented type, unlike [`FromStr`] this trait allows
7/// you to borrow the string. It can be automatically derived using
8/// [`Parse`](prse_derive::Parse).
9pub trait Parse<'a> {
10    /// Parses a string `s` to a return value of this type.
11    ///
12    /// If parsing succeeds, return the value inside [`Ok`], otherwise
13    /// when the string is ill-formatted return a [`ParseError`].
14    ///
15    /// ```
16    /// # use prse::{parse, Parse, ParseError};
17    /// # #[derive(PartialEq, Debug)]
18    /// struct Count<'b>(&'b str, u32);
19    ///
20    /// impl<'a> Parse<'a> for Count<'a> {
21    ///     fn from_str(s: &'a str) -> Result<Self, ParseError> {
22    ///         let (fruit, count) = s.split_once(':').ok_or_else(|| ParseError::new("expected a colon."))?;    
23    ///         Ok(Count(<&'a str>::from_str(fruit)?, <u32>::from_str(count.trim())?))
24    ///     }
25    /// }
26    ///
27    /// let c: Count = parse!("I have: {apple: 8}.", "I have: {{{}}}.");
28    /// assert_eq!(c, Count("apple", 8));
29    /// ```
30    ///
31    /// It also allows you to add your own custom parsing function.
32    ///
33    /// ```
34    /// # use prse::{parse, Parse, ParseError};
35    /// # #[derive(PartialEq, Debug)]
36    /// struct Hex(i32);
37    ///
38    /// impl<'a> Parse<'a> for Hex {
39    ///     fn from_str(s: &'a str) -> Result<Self, ParseError> {
40    ///         Ok(Hex(i32::from_str_radix(s, 16)?)) // Using 16 for Hexadecimal numbers
41    ///     }
42    /// }
43    ///
44    /// let v: Hex = parse!("A", "{}");
45    /// assert_eq!(v, Hex(10));
46    /// ```
47    fn from_str(s: &'a str) -> Result<Self, ParseError>
48    where
49        Self: Sized;
50}
51
52impl<'a> Parse<'a> for &'a str {
53    fn from_str(s: &'a str) -> Result<Self, ParseError> {
54        Ok(s)
55    }
56}
57
58macro_rules! impl_parse {
59    ( $( $Ty: ty )+) => {
60        $(
61            impl<'a> Parse<'a> for $Ty {
62                fn from_str(s: &'a str) -> Result<Self, ParseError> {
63                    <Self as FromStr>::from_str(s.trim()).map_err(|e| e.into())
64                }
65            }
66        )+
67    };
68}
69
70#[cfg(feature = "alloc")]
71macro_rules! impl_parse_infallible {
72    ( $( $Ty: ty )+) => {
73        $(
74            impl<'a> Parse<'a> for $Ty {
75                fn from_str(s: &'a str) -> Result<Self, ParseError> {
76                    Ok(<Self as FromStr>::from_str(&s).unwrap())
77                }
78            }
79        )+
80    };
81}
82
83impl_parse!(isize i8 i16 i32 i64 i128 usize u8 u16 u32 u64 u128);
84impl_parse!(bool char f32 f64);
85impl_parse!(NonZeroU8 NonZeroU16 NonZeroU32 NonZeroU64 NonZeroU128 NonZeroUsize);
86impl_parse!(NonZeroI8 NonZeroI16 NonZeroI32 NonZeroI64 NonZeroI128 NonZeroIsize);
87
88#[cfg(feature = "alloc")]
89mod impl_alloc {
90    extern crate alloc;
91
92    use alloc::string::String;
93
94    use super::{FromStr, Parse, ParseError};
95
96    impl_parse_infallible!(String);
97}
98
99#[cfg(feature = "std")]
100mod impl_std {
101    use std::ffi::OsString;
102    use std::net::*;
103    use std::path::PathBuf;
104
105    use super::{FromStr, Parse, ParseError};
106
107    impl_parse_infallible!(OsString PathBuf);
108    impl_parse!(IpAddr SocketAddr Ipv4Addr Ipv6Addr SocketAddrV4 SocketAddrV6);
109}
110
111/// An str extension trait to allow you to call the `from_str` from [`Parse`]
112/// without specifying the type.
113///
114/// The trait is sealed and cannot be implemented on any other type.
115pub trait ExtParseStr: __private::Sealed {
116    /// Parses the string slice into another type.
117    ///
118    /// lending_parse can parse into any type that implements the [`Parse`] trait.
119    fn lending_parse<'a, F: Parse<'a>>(&'a self) -> Result<F, ParseError>;
120}
121
122impl ExtParseStr for str {
123    fn lending_parse<'a, F: Parse<'a>>(&'a self) -> Result<F, ParseError> {
124        Parse::from_str(self)
125    }
126}
127
128#[doc(hidden)]
129mod __private {
130    pub trait Sealed {}
131
132    impl Sealed for str {}
133}
prse/lending_parse.rs

prse/
lending_parse.rs
