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
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
//! Error management
//!
//! Depending on a compilation flag, the content of the `Context` enum
//! can change. In the default case, it will only have one variant:
//! `Context::Code(I, ErrorKind<E=u32>)` (with `I` and `E` configurable).
//! It contains an error code and the input position that triggered it.
//!
//! If you activate the `verbose-errors` compilation flags, it will add another
//! variant to the enum: `Context::List(Vec<(I, ErrorKind<E>)>)`.
//! This variant aggregates positions and error codes as the code backtracks
//! through the nested parsers.
//! The verbose errors feature allows for very flexible error management:
//! you can know precisely which parser got to which part of the input.
//! The main drawback is that it is a lot slower than default error
//! management.
use util::{Convert, ErrorKind};
use lib::std::convert::From;

#[derive(Debug, Clone, PartialEq)]
pub enum Context<I, E = u32> {
  Code(I, ErrorKind<E>),
}

impl<I, F, E: From<F>> Convert<Context<I, F>> for Context<I, E> {
  fn convert(c: Context<I, F>) -> Self {
    let Context::Code(i, e) = c;

    Context::Code(i, ErrorKind::convert(e))
  }
}

impl<I, E> Context<I, E> {
  /// Convert Err into ErrorKind.
  ///
  /// This allows application code to use ErrorKind and stay independent from the verbose-errors features activation.
  pub fn into_error_kind(self) -> ErrorKind<E> {
    let Context::Code(_, e) = self;
    ErrorKind::convert(e)
  }
}

/*
impl<I,O,E> IResult<I,O,E> {
  /// Maps a `IResult<I, O, E>` to `IResult<I, O, N>` by appling a function
  /// to a contained `Error` value, leaving `Done` and `Incomplete` value
  /// untouched.
  #[inline]
  pub fn map_err<N, F>(self, f: F) -> IResult<I, O, N>
   where F: FnOnce(Err<E>) -> Err<N> {
    match self {
      Error(e)      => Error(f(e)),
      Incomplete(n) => Incomplete(n),
      Done(i, o)    => Done(i, o),
    }
  }

  /// Unwrap the contained `Error(E)` value, or panic if the `IResult` is not
  /// `Error`.
  pub fn unwrap_err(self) -> Err<E> {
    match self {
      Error(e)      => e,
      Done(_, _)    => panic!("unwrap_err() called on an IResult that is Done"),
      Incomplete(_) => panic!("unwrap_err() called on an IResult that is Incomplete"),
    }
  }

  /// Convert the IResult to a std::result::Result
  pub fn to_full_result(self) -> Result<O, IError<E>> {
    match self {
      Done(_, o)    => Ok(o),
      Incomplete(n) => Err(IError::Incomplete(n)),
      Error(e)      => Err(IError::Error(e))
    }
  }

  /// Convert the IResult to a std::result::Result, or panic if the `IResult` is `Incomplete`
  pub fn to_result(self) -> Result<O, Err<E>> {
    match self {
      Done(_, o)    => Ok(o),
      Error(e)      => Err(e),
      Incomplete(_) => panic!("to_result() called on an IResult that is Incomplete")
    }
  }
}

#[cfg(feature = "std")]
use $crate::lib::std::any::Any;
#[cfg(feature = "std")]
use $crate::lib::std::{error,fmt};
#[cfg(feature = "std")]
impl<E: fmt::Debug+Any> error::Error for Err<E> {
  fn description(&self) -> &str {
    self.description()
  }
}

#[cfg(feature = "std")]
impl<E: fmt::Debug> fmt::Display for Err<E> {
  fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
    write!(f, "{}", self.description())
  }
}
*/

/// translate parser result from IResult<I,O,u32> to IResult<I,O,E> with a custom type
///
/// ```
/// # #[macro_use] extern crate nom;
/// # use nom::IResult;
/// # use std::convert::From;
/// # use nom::Context;
/// # use nom::Err;
/// # use nom::ErrorKind;
/// # fn main() {
///     // will add a Custom(42) error to the error chain
///     named!(err_test, add_return_error!(ErrorKind::Custom(42u32), tag!("abcd")));
///
///     #[derive(Debug,Clone,PartialEq)]
///     pub struct ErrorStr(String);
///
///     // Convert to IResult<&[u8], &[u8], ErrorStr>
///     impl From<u32> for ErrorStr {
///       fn from(i: u32) -> Self {
///         ErrorStr(format!("custom error code: {}", i))
///       }
///     }
///
///     named!(parser<&[u8], &[u8], ErrorStr>,
///         fix_error!(ErrorStr, err_test)
///       );
///
///     let a = &b"efghblah"[..];
///     assert_eq!(parser(a), Err(Err::Error(Context::Code(a, ErrorKind::Custom(ErrorStr("custom error code: 42".to_string()))))));
/// # }
/// ```
#[macro_export]
macro_rules! fix_error (
  ($i:expr, $t:ty, $submac:ident!( $($args:tt)* )) => (
    {
      use $crate::lib::std::result::Result::*;
      use $crate::Err;
      use $crate::{Convert,Context,ErrorKind};

      match $submac!($i, $($args)*) {
        Ok((i,o)) => Ok((i,o)),
        Err(e) => {
          let e2 = match e {
            Err::Error(err) => {
              let Context::Code(i, code) = err;
              let code2: ErrorKind<$t> = ErrorKind::convert(code);
              Err::Error(Context::Code(i, code2))
            },
            Err::Failure(err) => {
              let Context::Code(i, code) = err;
              let code2: ErrorKind<$t> = ErrorKind::convert(code);
              Err::Failure(Context::Code(i, code2))
            },
            Err::Incomplete(e) => Err::Incomplete(e),
          };
          Err(e2)
        }
      }
    }
  );
  ($i:expr, $t:ty, $f:expr) => (
    fix_error!($i, $t, call!($f));
  );
);

/// `flat_map!(R -> IResult<R,S>, S -> IResult<S,T>) => R -> IResult<R, T>`
///
/// combines a parser R -> IResult<R,S> and
/// a parser S -> IResult<S,T> to return another
/// parser R -> IResult<R,T>
#[macro_export]
macro_rules! flat_map(
  ($i:expr, $submac:ident!( $($args:tt)* ), $submac2:ident!( $($args2:tt)* )) => (
    flat_map!(__impl $i, $submac!($($args)*), $submac2!($($args2)*));
  );
  ($i:expr, $submac:ident!( $($args:tt)* ), $g:expr) => (
    flat_map!(__impl $i, $submac!($($args)*), call!($g));
  );
  ($i:expr, $f:expr, $submac:ident!( $($args:tt)* )) => (
    flat_map!(__impl $i, call!($f), $submac!($($args)*));
  );
  ($i:expr, $f:expr, $g:expr) => (
    flat_map!(__impl $i, call!($f), call!($g));
  );
  (__impl $i:expr, $submac:ident!( $($args:tt)* ), $submac2:ident!( $($args2:tt)* )) => (
    {
      use $crate::lib::std::result::Result::*;
      use $crate::{Convert,Err};

      ($submac!($i, $($args)*)).and_then(|(i,o)| {
        match $submac2!(o, $($args2)*) {
          Err(e)      => Err(Err::convert(e)),
          Ok((_, o2)) => Ok((i, o2))
        }
      })
    }
  );
);