[−][src]Macro nom::named_args

macro_rules! named_args {
    (pub $func_name:ident ( $( $arg:ident : $typ:ty ),* ) < $return_type:ty > , $submac:ident!( $($args:tt)* ) ) => { ... };
    (pub $func_name:ident < 'a > ( $( $arg:ident : $typ:ty ),* ) < $return_type:ty > , $submac:ident!( $($args:tt)* ) ) => { ... };
    (pub(crate) $func_name:ident ( $( $arg:ident : $typ:ty ),* ) < $return_type:ty > , $submac:ident!( $($args:tt)* ) ) => { ... };
    (pub(crate) $func_name:ident < 'a > ( $( $arg:ident : $typ:ty ),* ) < $return_type:ty > , $submac:ident!( $($args:tt)* ) ) => { ... };
    ($func_name:ident ( $( $arg:ident : $typ:ty ),* ) < $return_type:ty > , $submac:ident!( $($args:tt)* ) ) => { ... };
    ($func_name:ident < 'a > ( $( $arg:ident : $typ:ty ),* ) < $return_type:ty > , $submac:ident!( $($args:tt)* ) ) => { ... };
    (pub $func_name:ident ( $( $arg:ident : $typ:ty ),* ) < $input_type:ty, $return_type:ty > , $submac:ident!( $($args:tt)* ) ) => { ... };
    ($func_name:ident ( $( $arg:ident : $typ:ty ),* ) < $input_type:ty, $return_type:ty > , $submac:ident!( $($args:tt)* ) ) => { ... };
    (pub $func_name:ident < 'a > ( $( $arg:ident : $typ:ty ),* ) < $input_type:ty, $return_type:ty > , $submac:ident!( $($args:tt)* ) ) => { ... };
    ($func_name:ident < 'a > ( $( $arg:ident : $typ:ty ),* ) < $input_type:ty, $return_type:ty > , $submac:ident!( $($args:tt)* ) ) => { ... };
}

Makes a function from a parser combination with arguments.

ⓘThis example is not tested
//takes `&[u8]` as input
named_args!(tagged(open_tag: &[u8], close_tag: &[u8])<&str>,
  delimited!(tag!(open_tag), map_res!(take!(4), str::from_utf8), tag!(close_tag))
);
//takes `&str` as input
named_args!(tagged(open_tag: &str, close_tag: &str)<&str, &str>,
  delimited!(tag!(open_tag), take!(4), tag!(close_tag))
);

Note: if using arguments that way gets hard to read, it is always possible to write the equivalent parser definition manually, like this:

ⓘThis example is not tested
fn tagged(input: &[u8], open_tag: &[u8], close_tag: &[u8]) -> IResult<&[u8], &str> {
  // the first combinator in the tree gets the input as argument. It is then
  // passed from one combinator to the next through macro rewriting
  delimited!(input,
    tag!(open_tag), take!(4), tag!(close_tag)
  )
);