Crate nom [] [src]

Nom, eating data byte by byte

The goal is to make a parser combinator library that is safe, supports streaming (push and pull), and as much as possible zero copy.

The code is available on Github

Example

#[macro_use]
extern crate nom;

use nom::{IResult,digit,multispace};
use nom::IResult::*;

// Parser definition

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

named!(parens<i64>, delimited!(
    delimited!(opt!(multispace), tag!("("), opt!(multispace)),
    expr,
    delimited!(opt!(multispace), tag!(")"), opt!(multispace))
  )
);

// We transform an integer string into a i64
// we look for a digit suite, and try to convert it.
// if either str::from_utf8 or FromStr::from_str fail,
// the parser will fail
named!(factor<i64>,
  alt!(
    map_res!(
      map_res!(
        delimited!(opt!(multispace), digit, opt!(multispace)),
        str::from_utf8
      ),
      FromStr::from_str
    )
  | parens
  )
);

// we define acc as mutable to update its value whenever a new term is found
named!(term <i64>,
  chain!(
    mut acc: factor  ~
             many0!(
               alt!(
                 tap!(mul: preceded!(tag!("*"), factor) => acc = acc * mul) |
                 tap!(div: preceded!(tag!("/"), factor) => acc = acc / div)
               )
             ),
    || { return acc }
  )
);

named!(expr <i64>,
  chain!(
    mut acc: term  ~
             many0!(
               alt!(
                 tap!(add: preceded!(tag!("+"), term) => acc = acc + add) |
                 tap!(sub: preceded!(tag!("-"), term) => acc = acc - sub)
               )
             ),
    || { return acc }
  )
);

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

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

Macros

alt!

alt!(I -> IResult<I,O> | I -> IResult<I,O> | ... | I -> IResult<I,O> ) => I -> IResult<I, O> try a list of parser, return the result of the first successful one

alt_parser!

Internal parser, do not use directly

apply!
call!

Used to wrap common expressions and function as macros

chain!

chain!(I->IResult<I,A> ~ I->IResult<I,B> ~ ... I->IResult<I,X> , || { return O } ) => I -> IResult<I, O> chains parsers and assemble the results through a closure

chaining_parser!

Internal parser, do not use directly

closure!

Wraps a parser in a closure

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

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!(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

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

delimited1!

Internal parser, do not use directly

delimited2!

Internal parser, do not use directly

error!

Prevents backtracking if the child parser fails

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 Ok

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

filter!

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

flat_map!

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

i16!

if parameter is true, parse a big endian i16 integer, otherwise a little endian i16 integer

i32!

if parameter is true, parse a big endian i32 integer, otherwise a little endian i32 integer

i64!

if parameter is true, 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_not!

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

length_value!

length_value!(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

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

map!

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

map_impl!

Internal parser, do not use directly

map_opt!

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

map_opt_impl!

Internal parser, do not use directly

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

map_res_impl!

Internal parser, do not use directly

named!

Makes a function from a parser combination

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)

peek!

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

preceded!

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

pusher!

Prepares a parser function for a push pipeline

separated_list!

separated_list!(I -> IResult<I,T>, I -> IResult<I,O>) => I -> IResult<I, Vec<O>> separated_list(sep, X) returns Vec

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

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)

separated_pair1!

Internal parser, do not use directly

separated_pair2!

Internal parser, do not use directly

tag!

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

take!

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

take_str!

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

take_until!

take_until!(tag) => &[T] -> IResult<&[T], &[T]>

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

take_until_either!

take_until_either!(tag) => &[T] -> IResult<&[T], &[T]>

take_until_either_and_consume!

take_until_either_and_consume!(tag) => &[T] -> IResult<&[T], &[T]>

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

u16!

if parameter is true, parse a big endian u16 integer, otherwise a little endian u16 integer

u32!

if parameter is true, parse a big endian u32 integer, otherwise a little endian u32 integer

u64!

if parameter is true, parse a big endian u64 integer, otherwise a little endian u64 integer

Structs

AccReader
FileProducer

Can produce data from a file

MemProducer

Can parse data from an already in memory byte array

ReadProducer

Can produce data from a struct implementing Read

Stepper

Enums

ConsumerState

Holds the current state of the consumer

Err
ErrorCode
IResult

Holds the result of parsing functions

Needed
ProducerState

Holds the data producer's current state

StepperState

Traits

AsBytes
Consumer

Implement the consume method, taking a byte array as input and returning a consumer state

GetInput
GetOutput
HexDisplay
Producer

A producer implements the produce method, currently working with u8 arrays

Functions

add_error_pattern
alpha

Recognizes lowercase and uppercase alphabetic characters: a-zA-Z

alphanumeric

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

be_f32

Recognizes big endian 4 bytes floating point number

be_f64

Recognizes big endian 8 bytes floating point number

be_i16

Recognizes big endian signed 2 bytes integer

be_i32

Recognizes big endian signed 4 bytes integer

be_i64

Recognizes big endian signed 8 bytes integer

be_i8

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

be_u16

Recognizes big endian unsigned 2 bytes integer

be_u32

Recognizes big endian unsigned 4 bytes integer

be_u64

Recognizes big endian unsigned 8 bytes integer

be_u8

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

begin
code_from_offset
compare_error_paths
digit

Recognizes numerical characters: 0-9

eof

Recognizes empty input buffers

error_to_list
generate_colors
is_alphabetic
is_alphanumeric
is_digit
is_space
le_i16

Recognizes little endian signed 2 bytes integer

le_i32

Recognizes little endian signed 4 bytes integer

le_i64

Recognizes little endian signed 8 bytes integer

le_i8

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

le_u16

Recognizes little endian unsigned 2 bytes integer

le_u32

Recognizes little endian unsigned 4 bytes integer

le_u64

Recognizes little endian unsigned 8 bytes integer

le_u8

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

length_value
line_ending

Recognizes a line feed

multispace

Recognizes spaces, tabs, carriage returns and line feeds

not_line_ending
prepare_errors
print
print_codes
print_error
print_offsets
reset_color
sized_buffer
slice_to_offsets
space

Recognizes spaces and tabs

tag_cl
write_color