Crate nom [] [src]

nom, eating data byte by byte

nom is a parser combinator library with a focus on safe parsing, streaming patterns, and as much as possible zero copy.

The code is available on Github

There are a few guides with more details about the design of nom, how to write parsers, or the error management system.

If you are upgrading to nom 2.0, please read the migration document.

See also the FAQ.

What are parser combinators?

Parser combinators are a way to build parsers out of small functions. instead of writing a huge grammar file then generaing code, like you would do with lex and yacc, you write small functions, to parse small things like a character, or a number, and then you assemble them in larger and larger functions, that can parse larger parts of your formats.

You end up with a list of small functions that you can reuse everywhere you need. Each of them can be unit tested anf fuzzed separately.

nom parser design

All nom parsers follow the same convention. They are all functions with the following signature:

Be careful when using this code, it's not being tested!
fn parser(input: I) -> IResult<I,O> { ... }

Here is the definition of that IResult type:

pub type IResult<I,O,E=u32> = Result<(I,O), Err<I,E>>;

pub enum Err<I,E=u32> {
  Incomplete(Needed),
  Error(Context<I,E>),
  Failure(Context<I,E>),
}

What it means:

  • Ok((i,o)) means the parser was successful. i is the remaining part of the input (called remainder), o is the correctly parsed value The remaining part can then be used as input for other parsers called in a sequence
  • Err(Err::Error(e)) indicates the parser encountered an error. The Context<I,E> type is an enum of possible parser errors, that can also contain a custom error that you'd specify, by redefining the E error type
  • Err(Err::Failure(e)) indicates the parser encountered an error that we cannot recover from (to prevent alt and other combinators from trying alternatives. The Context<I,E> type is an enum of possible parser errors, that can also contain a custom error that you'd specify, by redefining the E error type
  • Err(Err::Incomplete(i)) means the parser did not have enough information to decide, and tells you, if possible, how much data it needs

That way, you could write your own parser that recognizes the letter 'a' like this:

#[macro_use] extern crate nom;
use nom::{IResult,Needed,Err,ErrorKind};

fn a(input: &[u8]) -> IResult<&[u8], char> {
 // if there is not enough data, we return Ìncomplete
 if input.len() == 0 {
   Err(Err::Incomplete(Needed::Size(1)))
 } else {
   if input[0] == 'a' as u8 {
     // the first part of the returned value is the remaining slice
     Ok((&input[1..], 'a'))
   } else {
     Err(Err::Error(error_position!(input, ErrorKind::Custom(42))))
   }
 }
}

Writing all the parsers manually, like this, is dangerous, despite Rust's safety features. There are still a lot of mistakes one can make. That's why nom provides a list of macros to help in developing parsers. As an example, here is a parser that would recognize the phrase "Hello " and return the name of the person we hail:

#[macro_use] extern crate nom;
use nom::alpha;

named!(hello, preceded!(tag!("Hello "), alpha));

Let's deconstruct it:

  • named! generates a function with the correct type. Without named here, we could write the parser as follows:
#[macro_use] extern crate nom;
use nom::{alpha,IResult};

fn hello(input: &[u8]) -> IResult<&[u8], &[u8]> {
  preceded!(input,
    tag!("Hello "), alpha)
}

By default, named makes a function that takes &[u8] as input type, and returns &[u8] as output type. You can override it like this:

  • named!(hello<&str>, ...): would take &[u8] as input type, and return &str as output type.
  • named!(hello<&str, &str>, ...): would take &str as input type, and return &str as output type.

Note : when we don't use named!, we must pass the input as first argument of the top level combinator (see the line preceded!(input, in the preceding code example). This is a macro trick in nom to pass input from one combinator to the next by rewriting the call.

Next part of the parser: preceded!(tag!("Hello "), alpha)). Here, tag! is a combinator that recognizes a specific serie of bytes or characters. alpha is a function that recognizes alphabetical characters. The preceded! combinator assembles them in a more complex parser: if both parsers are successful, it returns the result of the second one (alpha is preceded by tag!).

Note : combinators can assemble other combinators (macros), or parser functions, as long as they follow the same interface. Here, alpha is a parser function already implemented in nom.

List of parsers and combinators

Basic elements

Those are used to recognize the lowest level elements of your grammar, like, "here is a dot", or "here is an big endian integer".

  • char!: matches one character: char!('a') will make a parser that recognizes the letter 'a' (works with non ASCII chars too)
  • eof!: eof!() returns its input if it is at the end of input data
  • is_a!, is_a_s!: matches a sequence of any of the characters passed as arguments. is_a!("ab1") could recognize ababa or 1bb. is_a_s! is a legacy combinator, it does exactly the same thing as is_a
  • is_not!, is_not_s!: matches a sequence of none of the characters passed as arguments
  • one_of!: matches one of the provided characters. one_of!("abc") could recognize 'a', 'b', or 'c'. It also works with non ASCII characters
  • none_of!: matches anything but the provided characters
  • tag!, tag_s!: recognizes a specific suite of characters or bytes. tag!("hello") matches "hello"
  • tag_no_case!: recognizes a suite of ASCII characters, case insensitive. tag_no_case!("hello") could match "hello", "Hello" or even "HeLlO"
  • tag_no_case_s! works like tag_no_case but on UTF-8 characters too (uses &str as input). Note that case insensitive comparison is not well defined for unicode, and that you might have bad surprises. Also, this combinator allocates a new string for the comparison. Ponder for a bit before using this combinator
  • take!, take_s!: takes a specific number of bytes or characters. take!(5) would return "hello" from the string "hello world"
  • take_str!: same as take! but returning a &str
  • take_till!, take_till_s!: returns the longest list of bytes until the provided function succeeds. take_till!(is_alphabetic) with input "123abc" would return "123"
  • take_till1!, take_till1_s!: same as take_till!, but the result must not be empty: take_till1!(is_alphabetic) would fail on "abc"
  • take_until!, take_until_s!: returns the longest list of bytes until the provided tag is found. take_until!("world") with input "Hello world!" would return "Hello " and leave "world!" as remaining input
  • take_until1!: same as take_until!, but cannot return an empty result
  • take_until_and_consume!, take_until_and_consume_s!: same as take_until! but consumes the tag. take_until_and_consume!("world") with input "Hello world!" would return "Hello " and leave "!" as remaining input
  • take_until_and_consume1!: same as take_until_and_consume!, but cannot return an empty result
  • take_until_either!: returns the longest list of bytes until any of the provided characters are found
  • take_until_either_and_consume!: same as take_until_either!, but consumes the terminating character
  • take_while!, take_while_s!: returns the longest list of bytes for which the function is true. take_while!(is_alphabetic) with input "abc123" would return "abc"
  • take_while1!, take_while1_s!: same as take_while!, but cannot return an empty result
  • value!: you can use value! to always return the same result value without consuming input, like this: value!(42). Or you can replace the result of a child parser with a predefined value, like this: value!(42, tag!("abcd")) which would replace, if successful, the return value from "abcd", to 42

Parsing integers from binary formats can be done in two ways: with parser functions, or combinators with configurable endianness:

  • configurable endianness: i16!, i32!, i64!, u16!, u32!, u64! are combinators that take as argument a nom::Endianness, like this: i16!(endianness). If the parameter is nom::Endianness::Big, parse a big endian i16 integer, otherwise a little endian i16 integer
  • fixed endianness: the functions are prefixed by "be_" for big endian numbers, and by "le_" for little endian numbers, and the suffix is the type they parse to. As an example, "be_u32" parses a big endian unsigned integer stored in 32 bits.
    • be_f32, be_f64, le_f32, le_f64: recognize floating point numbers
    • be_i8, be_i16, be_i32, be_i24, be_i32, be_i64: big endian signed integers
    • be_u8, be_u16, be_u32, be_u24, be_u32, be_u64: big endian unsigned integers
    • le_i8, le_i16, le_i32, le_i24, le_i32, le_i64: little endian signed integers
    • le_u8, le_u16, le_u32, le_u24, le_u32, le_u64: little endian unsigned integers

Modifiers

  • complete!: replaces a Incomplete returned by the child parser with an Error
  • cond!: conditional combinator
  • cond_reduce!: Conditional combinator with error
  • cond_with_error!: Conditional combinator
  • expr_opt!: evaluates an expression that returns a Option and returns a Ok((I,T)) if Some
  • expr_res!: evaluates an expression that returns a Result and returns a Ok((I,T)) if Ok
  • flat_map!:
  • map!: maps a function on the result of a parser
  • map_opt!: maps a function returning an Option on the output of a parser
  • map_res!: maps a function returning a Result on the output of a parser
  • not!: returns a result only if the embedded parser returns Error or Incomplete does not consume the input
  • opt!: make the underlying parser optional
  • opt_res!: make the underlying parser optional
  • parse_to!: uses the parse method from std::str::FromStr to convert the current input to the specified type
  • peek!: returns a result without consuming the input
  • recognize!: if the child parser was successful, return the consumed input as produced value
  • return_error!: prevents backtracking if the child parser fails
  • tap!: allows access to the parser's result without affecting it
  • verify!: returns the result of the child parser if it satisfies a verification function

Error management and debugging

  • add_return_error!: Add an error if the child parser fails
  • dbg!: Prints a message if the parser fails
  • dbg_dmp!: Prints a message and the input if the parser fails
  • error_code!: creates a parse error from a nom::ErrorKind
  • error_node!: creates a parse error from a nom::ErrorKind and the next error in the parsing tree. if "verbose-errors" is not activated, it default to only the error code
  • error_node_position!: creates a parse error from a nom::ErrorKind, the position in the input and the next error in the parsing tree. if "verbose-errors" is not activated, it default to only the error code
  • error_position!: creates a parse error from a nom::ErrorKind and the position in the input if "verbose-errors" is not activated, it default to only the error code
  • fix_error!: translate parser result from IResult to IResult with a custom type

Choice combinators

  • alt!: try a list of parsers and return the result of the first successful one
  • alt_complete!: is equivalent to the alt! combinator, except that it will not returns Incomplete when one of the constituting parsers returns Incomplete. Instead, it will try the next alternative in the chain.
  • switch!: choose the next parser depending on the result of the first one, if successful, and returns the result of the second parser

Sequence combinators

  • delimited!: delimited(opening, X, closing) returns X
  • do_parse!: do_parse applies sub parsers in a sequence. it can store intermediary results and make them available for later parsers
  • pair!: pair(X,Y), returns (x,y)
  • permutation!: applies its sub parsers in a sequence, but independent from their order This parser will only succeed if all of its sub parsers succeed
  • preceded!: preceded(opening, X) returns X
  • separated_pair!: separated_pair(X,sep,Y) returns (x,y)
  • terminated!: terminated(X, closing) returns X
  • tuple!: chains parsers and assemble the sub results in a tuple.

Applying a parser multiple times

  • count!: Applies the child parser a specified number of times
  • count_fixed!: Applies the child parser a fixed number of times and returns a fixed size array. The type must be specified and it must be Copy
  • fold_many0!: Applies the parser 0 or more times and folds the list of return values
  • fold_many1!: Applies the parser 1 or more times and folds the list of return values
  • fold_many_m_n!: Applies the parser between m and n times (n included) and folds the list of return value
  • length_count!: gets a number from the first parser, then applies the second parser that many times
  • many0!: Applies the parser 0 or more times and returns the list of results in a Vec
  • many1!: Applies the parser 1 or more times and returns the list of results in a Vec
  • many_m_n!: Applies the parser between m and n times (n included) and returns the list of results in a Vec
  • many_till!: Applies the first parser until the second applies. Returns a tuple containing the list of results from the first in a Vec and the result of the second.
  • separated_list!: separated_list(sep, X) returns Vec will return Incomplete if there may be more elements
  • separated_list_complete!: This is equivalent to the separated_list! combinator, except that it will return Error when either the separator or element subparser returns Incomplete.
  • separated_nonempty_list!: separated_nonempty_list(sep, X) returns Vec will return Incomplete if there may be more elements
  • separated_nonempty_list_complete!: This is equivalent to the separated_nonempty_list! combinator, except that it will return Error when either the separator or element subparser returns Incomplete.

Text parsing

  • escaped!: matches a byte string with escaped characters.
  • escaped_transform!: matches a byte string with escaped characters, and returns a new string with the escaped characters replaced

Binary format parsing

  • length_data!: gets a number from the first parser, than takes a subslice of the input of that size, and returns that subslice
  • length_bytes!: alias for length_data
  • length_value!: gets a number from the first parser, takes a subslice of the input of that size, then applies the second parser on that subslice. If the second parser returns Incomplete, length_value will return an error

Bit stream parsing

  • bits!: transforms the current input type (byte slice &[u8]) to a bit stream on which bit specific parsers and more general combinators can be applied
  • bytes!: transforms its bits stream input back into a byte slice for the underlying parsers.
  • tag_bits!: matches an integer pattern to a bitstream. The number of bits of the input to compare must be specified
  • take_bits!: generates a parser consuming the specified number of bits

Whitespace delimited formats parsing

  • eat_separator!: helper macros to build a separator parser
  • sep!: sep is the parser rewriting macro for whitespace separated formats
  • wrap_sep!:
  • ws!:

Remaining combinators

  • apply!: emulate function currying: apply!(my_function, arg1, arg2, ...) becomes my_function(input, arg1, arg2, ...)
  • apply_m!: emulate function currying for method calls on structs apply_m!(self.my_function, arg1, arg2, ...) becomes self.my_function(input, arg1, arg2, ...)
  • call!: Used to wrap common expressions and function as macros
  • call_m!: Used to called methods then move self back into self
  • closure!: Wraps a parser in a closure
  • method!: Makes a method from a parser combination
  • named!: Makes a function from a parser combination
  • named_args!: Makes a function from a parser combination with arguments.
  • named_attr!: Makes a function from a parser combination, with attributes
  • try_parse!: A bit like std::try!, this macro will return the remaining input and parsed value if the child parser returned Ok, and will do an early return for Error and Incomplete this can provide more flexibility than do_parse! if needed

Character test functions

use those functions with a combinator like take_while!:

  • is_alphabetic: Tests if byte is ASCII alphabetic: A-Z, a-z
  • is_alphanumeric: Tests if byte is ASCII alphanumeric: A-Z, a-z, 0-9
  • is_digit: Tests if byte is ASCII digit: 0-9
  • is_hex_digit: Tests if byte is ASCII hex digit: 0-9, A-F, a-f
  • is_oct_digit: Tests if byte is ASCII octal digit: 0-7
  • is_space: Tests if byte is ASCII space or tab

Remaining functions (sort those out in the other categories)

  • alpha: Recognizes one or more lowercase and uppercase alphabetic characters: a-zA-Z
  • alphanumeric: Recognizes one or more numerical and alphabetic characters: 0-9a-zA-Z
  • anychar:
  • begin:
  • crlf:
  • digit: Recognizes one or more numerical characters: 0-9
  • double: Recognizes floating point number in a byte string and returns a f64
  • double_s: Recognizes floating point number in a string and returns a f64
  • eol:
  • float: Recognizes floating point number in a byte string and returns a f32
  • float_s: Recognizes floating point number in a string and returns a f32
  • hex_digit: Recognizes one or more hexadecimal numerical characters: 0-9, A-F, a-f
  • hex_u32: Recognizes a hex-encoded integer
  • line_ending: Recognizes an end of line (both '\n' and "\r\n")
  • multispace: Recognizes one or more spaces, tabs, carriage returns and line feeds
  • newline: Matches a newline character '\n'
  • non_empty: Recognizes non empty buffers
  • not_line_ending:
  • oct_digit: Recognizes one or more octal characters: 0-7
  • rest: Return the remaining input.
  • rest_s: Return the remaining input, for strings.
  • shift:
  • sized_buffer:
  • space: Recognizes one or more spaces and tabs
  • tab: Matches a tab character '\t'
  • tag_cl:

Example

Be careful when using this code, it's not being tested!
#[macro_use]
extern crate nom;

use nom::{IResult,digit};

// Parser definition

use std::str;
use std::str::FromStr;

// We parse any expr surrounded by parens, ignoring all whitespaces around those
named!(parens<i64>, ws!(delimited!( tag!("("), expr, tag!(")") )) );

// We transform an integer string into a i64, ignoring surrounding whitespaces
// We look for a digit suite, and try to convert it.
// If either str::from_utf8 or FromStr::from_str fail,
// we fallback to the parens parser defined above
named!(factor<i64>, alt!(
    map_res!(
      map_res!(
        ws!(digit),
        str::from_utf8
      ),
      FromStr::from_str
    )
  | parens
  )
);

// We read an initial factor and for each time we find
// a * or / operator followed by another factor, we do
// the math by folding everything
named!(term <i64>, do_parse!(
    init: factor >>
    res:  fold_many0!(
        pair!(alt!(tag!("*") | tag!("/")), factor),
        init,
        |acc, (op, val): (&[u8], i64)| {
            if (op[0] as char) == '*' { acc * val } else { acc / val }
        }
    ) >>
    (res)
  )
);

named!(expr <i64>, do_parse!(
    init: term >>
    res:  fold_many0!(
        pair!(alt!(tag!("+") | tag!("-")), term),
        init,
        |acc, (op, val): (&[u8], i64)| {
            if (op[0] as char) == '+' { acc + val } else { acc - val }
        }
    ) >>
    (res)
  )
);

fn main() {
  assert_eq!(expr(b"1+2"),         Ok((&b""[..], 3)));
  assert_eq!(expr(b"12+6-4+3"),    Ok((&b""[..], 17)));
  assert_eq!(expr(b"1+2*3+4"),     Ok((&b""[..], 11)));

  assert_eq!(expr(b"(2)"),         Ok((&b""[..], 2)));
  assert_eq!(expr(b"2*(3+4)"),     Ok((&b""[..], 14)));
  assert_eq!(expr(b"2*2/(5-1)+3"), Ok((&b""[..], 4)));
}

Reexports

pub use self::simple_errors::*;
pub use self::methods::*;
pub use self::bits::*;
pub use self::whitespace::*;

Modules

bits

Bit level parsers and combinators

methods

Method macro combinators

simple_errors

Error management

types
whitespace

Support for whitespace delimited formats

Macros

add_return_error

Add an error if the child parser fails

alt

Try a list of parsers and return the result of the first successful one

alt_complete

Is equivalent to the alt! combinator, except that it will not return Incomplete when one of the constituting parsers returns Incomplete. Instead, it will try the next alternative in the chain.

apply

emulate function currying: apply!(my_function, arg1, arg2, ...) becomes my_function(input, arg1, arg2, ...)

apply_m

emulate function currying for method calls on structs apply_m!(self.my_function, arg1, arg2, ...) becomes self.my_function(input, arg1, arg2, ...)

bits

Transforms its byte slice input into a bit stream for the underlying parser. This allows the given bit stream parser to work on a byte slice input.

bytes

Counterpart to bits, bytes! transforms its bit stream input into a byte slice for the underlying parser, allowing byte-slice parsers to work on bit streams.

call

Used to wrap common expressions and function as macros

call_m

Used to called methods then move self back into self

char

matches one character: `char!(char) => &[u8] -> IResult<&[u8], char>

closure

Wraps a parser in a closure

complete

replaces a Incomplete returned by the child parser with an Error

cond

cond!(bool, I -> IResult<I,O>) => I -> IResult<I, Option<O>> Conditional combinator

cond_reduce

cond_reduce!(bool, I -> IResult<I,O>) => I -> IResult<I, O> Conditional combinator with error

cond_with_error

cond_with_error!(bool, I -> IResult<I,O>) => I -> IResult<I, Option<O>> Conditional combinator

count

count!(I -> IResult<I,O>, nb) => I -> IResult<I, Vec<O>> Applies the child parser a specified number of times

count_fixed

count_fixed!(O, I -> IResult<I,O>, nb) => I -> IResult<I, [O; nb]> Applies the child parser a fixed number of times and returns a fixed size array The type must be specified and it must be Copy

dbg

Prints a message if the parser fails

dbg_dmp

Prints a message and the input if the parser fails

delimited

delimited!(I -> IResult<I,T>, I -> IResult<I,O>, I -> IResult<I,U>) => I -> IResult<I, O> delimited(opening, X, closing) returns X

do_parse

do_parse!(I->IResult<I,A> >> I->IResult<I,B> >> ... I->IResult<I,X> , ( O ) ) => I -> IResult<I, O> do_parse applies sub parsers in a sequence. it can store intermediary results and make them available for later parsers

eat_separator

helper macros to build a separator parser

eof

eof!() returns its input if it is at the end of input data

error_node_position

creates a parse error from a nom::ErrorKind, the position in the input and the next error in the parsing tree. if "verbose-errors" is not activated, it default to only the error code

error_position

creates a parse error from a nom::ErrorKind and the position in the input if "verbose-errors" is not activated, it default to only the error code

escaped

escaped!(T -> IResult<T, T>, U, T -> IResult<T, T>) => T -> IResult<T, T> where T: InputIter, U: AsChar matches a byte string with escaped characters.

escaped_transform

escaped_transform!(&[T] -> IResult<&[T], &[T]>, T, &[T] -> IResult<&[T], &[T]>) => &[T] -> IResult<&[T], Vec<T>> matches a byte string with escaped characters.

exact

exact!() will fail if the child parser does not consume the whole data

expr_opt

expr_opt!(Option<O>) => I -> IResult<I, O> evaluate an expression that returns a Option and returns a IResult::Done(I,T) if Some

expr_res

expr_res!(Result<E,O>) => I -> IResult<I, O> evaluate an expression that returns a Result and returns a IResult::Done(I,T) if Ok

fix_error

translate parser result from IResult to IResult with a custom type

flat_map

flat_map!(R -> IResult<R,S>, S -> IResult<S,T>) => R -> IResult<R, T>

fold_many0

fold_many0!(I -> IResult<I,O>, R, Fn(R, O) -> R) => I -> IResult<I, R> Applies the parser 0 or more times and folds the list of return values

fold_many1

fold_many1!(I -> IResult<I,O>, R, Fn(R, O) -> R) => I -> IResult<I, R> Applies the parser 1 or more times and folds the list of return values

fold_many_m_n

fold_many_m_n!(usize, usize, I -> IResult<I,O>, R, Fn(R, O) -> R) => I -> IResult<I, R> Applies the parser between m and n times (n included) and folds the list of return value

i16

if the parameter is nom::Endianness::Big, parse a big endian i16 integer, otherwise a little endian i16 integer

i32

if the parameter is nom::Endianness::Big, parse a big endian i32 integer, otherwise a little endian i32 integer

i64

if the parameter is nom::Endianness::Big, parse a big endian i64 integer, otherwise a little endian i64 integer

is_a

is_a!(&[T]) => &[T] -> IResult<&[T], &[T]> returns the longest list of bytes that appear in the provided array

is_a_s

is_a_s!(&str) => &str -> IResult<&str, &str> returns the longest list of characters that appear in the provided array

is_not

is_not!(&[T:AsBytes]) => &[T] -> IResult<&[T], &[T]> returns the longest list of bytes that do not appear in the provided array

is_not_s

is_not_s!(&str) => &str -> IResult<&str, &str> returns the longest list of characters that do not appear in the provided array

length_bytes

length_bytes!(&[T] -> IResult<&[T], nb>) => &[T] -> IResult<&[T], &[T]> Gets a number from the first parser, then extracts that many bytes from the remaining stream

length_count

length_count!(I -> IResult<I, nb>, I -> IResult<I,O>) => I -> IResult<I, Vec<O>> gets a number from the first parser, then applies the second parser that many times

length_data

length_data!(I -> IResult<I, nb>) => O

length_value

length_value!(I -> IResult<I, nb>, I -> IResult<I,O>) => I -> IResult<I, Vec<O>> gets a number from the first parser, takes a subslice of the input of that size, then applies the second parser on that subslice. If the second parser returns Incomplete, length_value will return an error

many0

many0!(I -> IResult<I,O>) => I -> IResult<I, Vec<O>> Applies the parser 0 or more times and returns the list of results in a Vec

many1

many1!(I -> IResult<I,O>) => I -> IResult<I, Vec<O>> Applies the parser 1 or more times and returns the list of results in a Vec

many_m_n

many_m_n!(usize, usize, I -> IResult<I,O>) => I -> IResult<I, Vec<O>> Applies the parser between m and n times (n included) and returns the list of results in a Vec

many_till

many_till!(I -> IResult<I,O>, I -> IResult<I,P>) => I -> IResult<I, (Vec<O>, P)> Applies the first parser until the second applies. Returns a tuple containing the list of results from the first in a Vec and the result of the second.

map

map!(I -> IResult<I,O>, O -> P) => I -> IResult<I, P> maps a function on the result of a parser

map_opt

map_opt!(I -> IResult<I,O>, O -> Option<P>) => I -> IResult<I, P> maps a function returning an Option on the output of a parser

map_res

map_res!(I -> IResult<I,O>, O -> Result<P>) => I -> IResult<I, P> maps a function returning a Result on the output of a parser

method

Makes a method from a parser combination

named

Makes a function from a parser combination

named_args

Makes a function from a parser combination with arguments.

named_attr

Makes a function from a parser combination, with attributes

none_of

matches anything but the provided characters

not

not!(I -> IResult<I,O>) => I -> IResult<I, O> returns a result only if the embedded parser returns Error or Err(Err::Incomplete) does not consume the input

one_of

matches one of the provided characters

opt

opt!(I -> IResult<I,O>) => I -> IResult<I, Option<O>> make the underlying parser optional

opt_res

opt_res!(I -> IResult<I,O>) => I -> IResult<I, Result<nom::Err,O>> make the underlying parser optional

pair

pair!(I -> IResult<I,O>, I -> IResult<I,P>) => I -> IResult<I, (O,P)> pair(X,Y), returns (x,y)

parse_to

parse_to!(O) => I -> IResult<I, O> uses the parse method from std::str::FromStr to convert the current input to the specified type

peek

peek!(I -> IResult<I,O>) => I -> IResult<I, O> returns a result without consuming the input

permutation

permutation!(I -> IResult<I,A>, I -> IResult<I,B>, ... I -> IResult<I,X> ) => I -> IResult<I, (A,B,...X)> applies its sub parsers in a sequence, but independent from their order this parser will only succeed if all of its sub parsers succeed

preceded

preceded!(I -> IResult<I,T>, I -> IResult<I,O>) => I -> IResult<I, O> preceded(opening, X) returns X

recognize

recognize!(I -> IResult<I, O> ) => I -> IResult<I, I> if the child parser was successful, return the consumed input as produced value

return_error

Prevents backtracking if the child parser fails

sep

sep is the parser rewriting macro for whitespace separated formats

separated_list

separated_list!(I -> IResult<I,T>, I -> IResult<I,O>) => I -> IResult<I, Vec<O>> separated_list(sep, X) returns Vec will return Incomplete if there may be more elements

separated_list_complete

separated_list_complete!(I -> IResult<I,T>, I -> IResult<I,O>) => I -> IResult<I, Vec<O>> This is equivalent to the separated_list! combinator, except that it will return Error when either the separator or element subparser returns Incomplete.

separated_nonempty_list

separated_nonempty_list!(I -> IResult<I,T>, I -> IResult<I,O>) => I -> IResult<I, Vec<O>> separated_nonempty_list(sep, X) returns Vec will return Incomplete if there may be more elements

separated_nonempty_list_complete

separated_nonempty_list_complete!(I -> IResult<I,T>, I -> IResult<I,O>) => I -> IResult<I, Vec<O>> This is equivalent to the separated_nonempty_list! combinator, except that it will return Error when either the separator or element subparser returns Incomplete.

separated_pair

separated_pair!(I -> IResult<I,O>, I -> IResult<I, T>, I -> IResult<I,P>) => I -> IResult<I, (O,P)> separated_pair(X,sep,Y) returns (x,y)

switch

switch!(I -> IResult<I,P>, P => I -> IResult<I,O> | ... | P => I -> IResult<I,O> ) => I -> IResult<I, O> choose the next parser depending on the result of the first one, if successful, and returns the result of the second parser

tag

tag!(&[T]: nom::AsBytes) => &[T] -> IResult<&[T], &[T]> declares a byte array as a suite to recognize

tag_bits

Matches the given bit pattern.

tag_no_case

tag_no_case!(&[T]) => &[T] -> IResult<&[T], &[T]> declares a case insensitive ascii string as a suite to recognize

tag_no_case_s

tag_no_case_s!(&str) => &str -> IResult<&str, &str> declares a case-insensitive string as a suite to recognize

tag_s

tag_s!(&str) => &str -> IResult<&str, &str> declares a string as a suite to recognize

take

take!(nb) => &[T] -> IResult<&[T], &[T]> generates a parser consuming the specified number of bytes

take_bits

Consumes the specified number of bits and returns them as the specified type.

take_s

take_s!(nb) => &str -> IResult<&str, &str> generates a parser consuming the specified number of characters

take_str

take_str!(nb) => &[T] -> IResult<&[T], &str> same as take! but returning a &str

take_till

take_till!(T -> bool) => &[T] -> IResult<&[T], &[T]> returns the longest list of bytes until the provided function succeeds

take_till1

take_till1!(T -> bool) => &[T] -> IResult<&[T], &[T]> returns the longest non empty list of bytes until the provided function succeeds

take_till1_s

take_till1_s!(char -> bool) => &str -> IResult<&str, &str> returns the longest non empty list of characters until the provided function succeeds

take_till_s

take_till_s!(char -> bool) => &str -> IResult<&str, &str> returns the longest list of characters until the provided function succeeds

take_until

take_until!(tag) => &[T] -> IResult<&[T], &[T]> consumes data until it finds the specified tag.

take_until1

take_until1!(tag) => &[T] -> IResult<&[T], &[T]> consumes data (at least one byte) until it finds the specified tag

take_until_and_consume

take_until_and_consume!(tag) => &[T] -> IResult<&[T], &[T]> generates a parser consuming bytes until the specified byte sequence is found, and consumes it

take_until_and_consume1

take_until_and_consume1!(tag) => &[T] -> IResult<&[T], &[T]> generates a parser consuming bytes (at least 1) until the specified byte sequence is found, and consumes it

take_until_and_consume_s

take_until_and_consume_s!(&str) => &str -> IResult<&str, &str> generates a parser consuming all chars until the specified string is found and consumes it

take_until_either

take_until_either!(tag) => &[T] -> IResult<&[T], &[T]> consumes data until it finds any of the specified characters

take_until_either1

take_until_either1!(tag) => &[T] -> IResult<&[T], &[T]> consumes data (at least one byte) until it finds any of the specified characters

take_until_either_and_consume

take_until_either_and_consume!(chars) => &[T] -> IResult<&[T], &[T]> consumes data until it finds any of the specified characters, and consume it

take_until_either_and_consume1

take_until_either_and_consume1!(chars) => &[T] -> IResult<&[T], &[T]> consumes data (at least one byte) until it finds any of the specified characters, and consume it

take_until_s

take_until_s!(&str) => &str -> IResult<&str, &str> generates a parser consuming all chars until the specified string is found and leaves it in the remaining input

take_while

take_while!(T -> bool) => &[T] -> IResult<&[T], &[T]> returns the longest list of bytes until the provided function fails.

take_while1

take_while1!(T -> bool) => &[T] -> IResult<&[T], &[T]> returns the longest (non empty) list of bytes until the provided function fails.

take_while1_s

take_while1_s!(char -> bool) => &str -> IResult<&str, &str> returns the longest (non empty) list of characters until the provided function fails.

take_while_m_n

take_while_m_n!(m: usize, n: usize, T -> bool) => &[T] -> IResult<&[T], &[T]> returns a list of bytes or characters for which the provided function returns true. the returned list's size will be at least m, and at most n

take_while_s

take_while_s!(char -> bool) => &str -> IResult<&str, &str> returns the longest list of characters until the provided function fails.

tap

tap!(name: I -> IResult<I,O> => { block }) => I -> IResult<I, O> allows access to the parser's result without affecting it

terminated

terminated!(I -> IResult<I,O>, I -> IResult<I,T>) => I -> IResult<I, O> terminated(X, closing) returns X

try_parse

A bit like std::try!, this macro will return the remaining input and parsed value if the child parser returned Done, and will do an early return for Error and Incomplete this can provide more flexibility than do_parse! if needed

tuple

tuple!(I->IResult<I,A>, I->IResult<I,B>, ... I->IResult<I,X>) => I -> IResult<I, (A, B, ..., X)> chains parsers and assemble the sub results in a tuple.

u16

if the parameter is nom::Endianness::Big, parse a big endian u16 integer, otherwise a little endian u16 integer

u32

if the parameter is nom::Endianness::Big, parse a big endian u32 integer, otherwise a little endian u32 integer

u64

if the parameter is nom::Endianness::Big, parse a big endian u64 integer, otherwise a little endian u64 integer

value

value!(T, R -> IResult<R, S> ) => R -> IResult<R, T>

verify

verify!(I -> IResult<I,O>, O -> bool) => I -> IResult<I, O> returns the result of the child parser if it satisfies a verification function

wrap_sep
ws

ws!(I -> IResult<I,O>) => I -> IResult<I, O>

Enums

CompareResult

indicates wether a comparison was successful, an error, or if more data was needed

Endianness

Configurable endianness

Err

The Err enum indicates the parser was not successful, and has three cases:

ErrorKind

indicates which parser returned an error

Needed

Contains information on needed data if a parser returned Incomplete

Traits

AsBytes
AsChar

transforms common types to a char for basic token parsing

AtEof
Compare

abstracts comparison operations

Convert
ExtendInto

abtracts something which can extend an Extend

FindSubstring

look for a substring in self

FindToken

look for self in the given input stream

HexDisplay
InputIter

abstracts common iteration operations on the input type

InputLength

abstract method to calculate the input length

InputTake

abstracts slicing operations

Offset

useful functions to calculate the offset between slices and show a hexdump of a slice

ParseTo

used to integrate str's parse() method

Slice

slicing operations using ranges

Functions

alpha

Recognizes one or more lowercase and uppercase alphabetic characters: a-zA-Z

alpha0

Recognizes zero or more lowercase and uppercase alphabetic characters: a-zA-Z

alpha1

Recognizes one or more lowercase and uppercase alphabetic characters: a-zA-Z

alphanumeric

Recognizes one or more numerical and alphabetic characters: 0-9a-zA-Z

alphanumeric0

Recognizes zero or more numerical and alphabetic characters: 0-9a-zA-Z

alphanumeric1

Recognizes one or more numerical and alphabetic characters: 0-9a-zA-Z

anychar

matches one byte as a character. Note that the input type will accept a str, but not a &[u8], unlike many other nom parsers.

be_f32

Recognizes big endian 4 bytes floating point number

be_f64

Recognizes big endian 8 bytes floating point number

be_i8

Recognizes a signed 1 byte integer (equivalent to take!(1)

be_i16

Recognizes big endian signed 2 bytes integer

be_i24

Recognizes big endian signed 3 bytes integer

be_i32

Recognizes big endian signed 4 bytes integer

be_i64

Recognizes big endian signed 8 bytes integer

be_u8

Recognizes an unsigned 1 byte integer (equivalent to take!(1)

be_u16

Recognizes big endian unsigned 2 bytes integer

be_u24

Recognizes big endian unsigned 3 byte integer

be_u32

Recognizes big endian unsigned 4 bytes integer

be_u64

Recognizes big endian unsigned 8 bytes integer

begin
code_from_offset
crlf
digit

Recognizes one or more numerical characters: 0-9

digit0

Recognizes zero or more numerical characters: 0-9

digit1

Recognizes one or more numerical characters: 0-9

double

Recognizes floating point number in a byte string and returns a f64

double_s

Recognizes floating point number in a string and returns a f64

eol
error_to_u32
float

Recognizes floating point number in a byte string and returns a f32

float_s

Recognizes floating point number in a string and returns a f32

hex_digit

Recognizes one or more hexadecimal numerical characters: 0-9, A-F, a-f

hex_digit0

Recognizes zero or more hexadecimal numerical characters: 0-9, A-F, a-f

hex_digit1

Recognizes one or more hexadecimal numerical characters: 0-9, A-F, a-f

hex_u32

Recognizes a hex-encoded integer

is_alphabetic

Tests if byte is ASCII alphabetic: A-Z, a-z

is_alphanumeric

Tests if byte is ASCII alphanumeric: A-Z, a-z, 0-9

is_digit

Tests if byte is ASCII digit: 0-9

is_hex_digit

Tests if byte is ASCII hex digit: 0-9, A-F, a-f

is_oct_digit

Tests if byte is ASCII octal digit: 0-7

is_space

Tests if byte is ASCII space or tab

le_f32

Recognizes little endian 4 bytes floating point number

le_f64

Recognizes little endian 8 bytes floating point number

le_i8

Recognizes a signed 1 byte integer (equivalent to take!(1)

le_i16

Recognizes little endian signed 2 bytes integer

le_i24

Recognizes little endian signed 3 bytes integer

le_i32

Recognizes little endian signed 4 bytes integer

le_i64

Recognizes little endian signed 8 bytes integer

le_u8

Recognizes an unsigned 1 byte integer (equivalent to take!(1)

le_u16

Recognizes little endian unsigned 2 bytes integer

le_u24

Recognizes little endian unsigned 3 byte integer

le_u32

Recognizes little endian unsigned 4 bytes integer

le_u64

Recognizes little endian unsigned 8 bytes integer

line_ending

Recognizes an end of line (both '\n' and '\r\n')

multispace

Recognizes one or more spaces, tabs, carriage returns and line feeds

multispace0

Recognizes zero or more spaces, tabs, carriage returns and line feeds

multispace1

Recognizes one or more spaces, tabs, carriage returns and line feeds

need_more
need_more_err
newline

Matches a newline character '\n'

non_empty

Recognizes non empty buffers

not_line_ending
oct_digit

Recognizes one or more octal characters: 0-7

oct_digit0

Recognizes zero or more octal characters: 0-7

oct_digit1

Recognizes one or more octal characters: 0-7

print
print_codes
recognize_float
reset_color
rest

Return the remaining input.

rest_s

Return the remaining input, for strings.

sized_buffer
slice_to_offsets
space

Recognizes one or more spaces and tabs

space0

Recognizes zero or more spaces and tabs

space1

Recognizes one or more spaces and tabs

tab

Matches a tab character '\t'

tag_cl
write_color

Type Definitions

IResult

Holds the result of parsing functions