//! A parser library designed for Advent of Code.
//!
//! This library mainly provides a macro, `parser!`, that lets you write
//! a custom parser for your [AoC] puzzle input in seconds.
//!
//! For example, my puzzle input for [December 2, 2015][example] looked like this:
//!
//! ```text
//! 4x23x21
//! 22x29x19
//! 11x4x11
//! 8x10x5
//! 24x18x16
//! ...
//! ```
//!
//! The parser for this format is a one-liner:
//! `parser!(lines(u64 "x" u64 "x" u64))`.
//!
//! # How to use aoc-parse
//!
//! It's pretty easy.
//!
//! ```
//! use aoc_parse::{parser, prelude::*};
//!
//! let p = parser!(lines(u64 "x" u64 "x" u64));
//! assert_eq!(
//!     p.parse("4x23x21\n22x29x19\n").unwrap(),
//!     vec![(4, 23, 21), (22, 29, 19)]
//! );
//! ```
//!
//! If you're using [aoc-runner], it might look like this:
//!
//! ```
//! use aoc_runner_derive::*;
//! use aoc_parse::{parser, prelude::*};
//!
//! #[aoc_generator(day2)]
//! fn parse_input(text: &str) -> Vec<(u64, u64, u64)> {
//!     let p = parser!(lines(u64 "x" u64 "x" u64));
//!     p.parse(text).unwrap()
//! }
//! ```
//!
//! # Patterns
//!
//! The argument you need to pass to the `parser!` macro is a *pattern*;
//! all aoc-parse does is **match** strings against your chosen pattern
//! and **convert** them into Rust values.
//!
//! Here are some examples of patterns:
//!
//! ```
//! # use aoc_parse::{parser, prelude::*};
//! # let _p1 = parser!(
//! lines(i32)      // matches a list of integers, one per line
//!                 // converts them to a Vec<i32>
//! # );
//!
//! # let _p2 = parser!(
//! line(lower+)    // matches a single line of one or more lowercase letters
//!                 // converts them to a Vec<char>
//! # );
//!
//! # let _p3 = parser!(
//! lines({         // matches lines made up of the characters < = >
//!     "<" => -1,  // converts them to a Vec<Vec<i32>> filled with -1, 0, and 1
//!     "=" => 0,
//!     ">" => 1
//! }+)
//! # );
//! ```
//!
//! Here are the pieces that you can use in a pattern:
//!
//! *   `i8`, `i16`, `i32`, `i64`, `i128`, `isize`, `big_int` - These match an integer,
//!     written out using decimal digits, with an optional `+` or `-` sign
//!     at the start, like `0` or `-11474`.
//!
//!     It's an error if the string contains a number too big to fit in the
//!     type you chose. For example, `parser!(i8).parse("1000")` is an error.
//!     (It matches the string, but fails during the "convert" phase.)
//!
//!     `big_int` parses a [`num_bigint::BigInt`].
//!
//! *   `u8`, `u16`, `u32`, `u64`, `u128`, `usize`, `big_uint` - The same, but
//!     without the sign.
//!
//! *   `i8_bin`, `i16_bin`, `i32_bin`, `i64_bin`, `i128_bin`, `isize_bin`, `big_int_bin`,
//!     `u8_bin`, `u16_bin`, `u32_bin`, `u64_bin`, `u128_bin`, `usize_bin`, `big_uint_bin`,
//!     `i8_hex`, `i16_hex`, `i32_hex`, `i64_hex`, `i128_hex`, `isize_hex`, `big_int_hex`,
//!     `u8_hex`, `u16_hex`, `u32_hex`, `u64_hex`, `u128_hex`, `usize_hex`, `big_uint_hex` -
//!     Match an integer in base 2 or base 16. The `_hex` parsers allow both
//!     uppercase and lowercase digits `A`-`F`.
//!
//! *   `f32` ,`f64` - These match a floating-point number written out using
//!     decimal digits, in [this
//!     format](https://doc.rust-lang.org/std/primitive.f64.html#impl-FromStr-for-f64).
//!     (No Advent of Code puzzle has ever hinged on floating-point numbers,
//!     but it doesn't hurt to be prepared.)
//!
//! *   `bool` - Matches either `true` or `false` and converts it to the
//!     corresponding `bool` value.
//!
//! *   `'x'` or `"hello"` - A Rust character or string, in quotes, is a pattern
//!     that matches that exact text only.
//!
//!     Exact patterns don't produce a value.
//!
//! *   <code><var>pattern1 pattern2 pattern3</var>...</code> - Patterns can be
//!     concatenated to form larger patterns. This is how
//!     `parser!(u64 "x" u64 "x" u64)` matches the string `4x23x21`. It simply
//!     matches each subpattern in order. It converts the match to a tuple if
//!     there are two or more subpatterns that produce values.
//!
//! *   <code><var>parser_var</var></code> - You can use previously defined
//!     parsers that you've stored in local variables.
//!
//!     For example, the `amount` parser below makes use of the `fraction` parser
//!     defined on the previous line.
//!
//!     ```
//!     # use aoc_parse::{parser, prelude::*};
//!     let fraction = parser!(i64 "/" u64);
//!     let amount = parser!(fraction " tsp");
//!
//!     assert_eq!(amount.parse("1/4 tsp").unwrap(), (1, 4));
//!     ```
//!
//!     An identifier can also refer to a string or character constant.
//!
//! Repeating patterns:
//!
//! *   <code><var>pattern</var>*</code> - Any pattern followed by an asterisk
//!     matches that pattern zero or more times. It converts the results to a
//!     `Vec`. For example, `parser!("A"*)` matches the strings `A`, `AA`,
//!     `AAAAAAAAAAAAAA`, and so on, as well as the empty string.
//!
//! *   <code><var>pattern</var>+</code> - Matches the pattern one or more times, producing a `Vec`.
//!     `parser!("A"+)` matches `A`, `AA`, etc., but not the empty string.
//!
//! *   <code><var>pattern</var>?</code> - Optional pattern, producing a Rust `Option`. For
//!     example, `parser!("x=" i32?)` matches `x=123`, producing `Some(123)`;
//!     it also matches `x=`, producing the value `None`.
//!
//!     These behave just like the `*`, `+`, and `?` special characters in
//!     regular expressions.
//!
//! *   <code>repeat_sep(<var>pattern</var>, <var>separator</var>)</code> -
//!     Match the given *pattern* any number of times, separated by the *separator*.
//!     This converts only the bits that match *pattern* to Rust values, producing
//!     a `Vec`. Any parts of the string matched by *separator* are not converted.
//!
//! Matching single characters:
//!
//! *   `alpha`, `alnum`, `upper`, `lower` - Match single characters of
//!     various categories. (These use the Unicode categories, even though
//!     Advent of Code historically sticks to ASCII.)
//!
//! *   `digit`, `digit_bin`, `digit_hex` - Match a single ASCII character
//!     that's a digit in base 10, base 2, or base 16, respectively.
//!     The digit is converted to its numeric value, as a `usize`.
//!
//! *   `any_char` - Match the next character, no matter what it is (like `.`
//!     in a regular expression, except that `any_char` matches newline
//!     characters too).
//!
//! *   <code>char_of(<var>str</var>)</code> - Match the next character if it's
//!     one of the characters in *str*. For example, `char_of(">^<v")` matches
//!     exactly one character, either `>`, `^`, `<`, or `v`. Returns the index
//!     of the character within the list of options (in this case, `0`, `1`,
//!     `2`, or `3`).
//!
//! Matching multiple characters:
//!
//! *   <code>string(<var>pattern</var>)</code> - Matches the given *pattern*,
//!     but instead of converting it to some value, simply return the matched
//!     characters as a `String`.
//!
//!     By default, `alpha+` returns a `Vec<char>`, and sometimes that is handy
//!     in AoC, but often it's better to have it return a `String`.
//!
//! Custom conversion:
//!
//! *   <code>... <var>name1</var>:<var>pattern1</var> ... => <var>expr</var></code> -
//!     On successfully matching the patterns to the left of `=>`, evaluate the Rust
//!     expression *expr* to convert the results to a single Rust value.
//!
//!     Use this to convert input to structs. For instance, suppose your puzzle input
//!     contains each elf's name and height:
//!
//!     ```text
//!     Holly=33
//!     Ivy=7
//!     DouglasFir=1093
//!     ```
//!
//!     and you'd like to turn this into a vector of `struct Elf` values. The
//!     code you need is:
//!
//!     ```
//!     # use aoc_parse::{parser, prelude::*};
//!     struct Elf {
//!         name: String,
//!         height: u32,
//!     }
//!
//!     let p = parser!(lines(
//!         elf:string(alpha+) '=' ht:u32 => Elf { name: elf, height: ht }
//!     ));
//!     ```
//!
//!     The name `elf` applies to the pattern `string(alpha+)` and the name
//!     `ht` applies to the pattern `i32`. The bit after the `=>` is
//!     plain old Rust code.
//!
//!     The *name*s are in scope only for the following *expr* in the same
//!     set of matching parentheses or braces.
//!
//! Alternatives:
//!
//! *   <code>{<var>pattern1</var>, <var>pattern2</var>, ...}</code> -
//!     Matches any one of the *patterns*. First try matching *pattern1*; if it
//!     matches, stop. If not, try *pattern2*, and so on. All the patterns must
//!     produce the same type of Rust value.
//!
//!     This is sort of like a Rust `match` expression.
//!
//!     For example, `parser!({"<" => -1, ">" => 1})` either matches `<`,
//!     returning the value `-1`, or matches `>`, returing `1`.
//!
//!     Alternatives are handy when you want to convert the input into an enum.
//!     For example, my puzzle input for December 23, 2015 was a list of instructions
//!     that looked (in part) like this:
//!
//!     ```text
//!     jie a, +4
//!     tpl a
//!     inc a
//!     jmp +2
//!     hlf a
//!     jmp -7
//!     ```
//!
//!     This can be easily parsed into a vector of beautiful enums, like so:
//!
//!     ```
//!     # use aoc_parse::{parser, prelude::*};
//!     enum Reg {
//!         A,
//!         B,
//!     }
//!
//!     enum Insn {
//!         Hlf(Reg),
//!         Tpl(Reg),
//!         Inc(Reg),
//!         Jmp(isize),
//!         Jie(Reg, isize),
//!         Jio(Reg, isize),
//!     }
//!
//!     use Reg::*;
//!     use Insn::*;
//!
//!     let reg = parser!({"a" => A, "b" => B});
//!     let p = parser!(lines({
//!         "hlf " r:reg => Hlf(r),
//!         "tpl " r:reg => Tpl(r),
//!         "inc " r:reg => Inc(r),
//!         "jmp " offset:isize => Jmp(offset),
//!         "jie " r:reg ", " offset:isize => Jie(r, offset),
//!         "jio " r:reg ", " offset:isize => Jio(r, offset),
//!     }));
//!     ```
//!
//! Rule sets:
//!
//! *   <code>rule <var>name1</var>: <var>type1</var> = <var>pattern1</var>;</code> -
//!     Introduce a "rule", a named subparser.
//!
//!     This supports parsing text with nesting brackets.
//!
//!     ```
//!     # use aoc_parse::{parser, prelude::*};
//!     enum Formation {
//!         Elf(char),
//!         Stack(Vec<Formation>),
//!     }
//!
//!     let p = parser!(
//!         // First rule: A "formation" has return type Formation and is either
//!         // a letter or a stack.
//!         rule formation: Formation = {
//!             s:alpha => Formation::Elf(s),
//!             v:stack => Formation::Stack(v),
//!         };
//!
//!         // Second rule: A "stack" is one or more formations, wrapped in
//!         // matching parentheses.
//!         rule stack: Vec<Formation> = '(' v:formation+ ')' => v;
//!
//!         // After all rules, the pattern that .parse() will actually match.
//!         lines(formation+)
//!     );
//!
//!     assert!(p.parse("px(fo(i)(RR(c)))j(Q)zww\n").is_ok());
//!
//!     assert!(p.parse("x(fo))\n").is_err());  // parens not balanced
//!     ```
//!
//!     Ordinarily `let` suffices for parsers used by other parsers; but `rule`
//!     is needed for parsers that refer to themselves or to each other,
//!     cyclically, like `formation` and `stack` above. Rust's `let` doesn't
//!     support that.
//!
//!     Note: Left-recursive grammars don't work, as usual for PEG parsers.
//!
//! Lines and sections:
//!
//! *   <code>line(<var>pattern</var>)</code> - Matches a single line of text that
//!     matches *pattern*, and the newline at the end of the line.
//!
//!     This is like <code>^<var>pattern</var>\n</code> in regular expressions,
//!     with two minor differences:
//!
//!     -   <code>line(<var>pattern</var>)</code> will only ever match exactly
//!         one line of text, even if *pattern* could match more newlines.
//!
//!     -   If your input does not end with a newline,
//!         <code>line(<var<pattern</var>)</code> can still match the
//!         non-newline-terminated "line" at the end.
//!
//!     `line(string(any_char+))` matches a line of text, strips off the newline
//!     character, and returns the rest as a `String`.
//!
//!     `line("")` matches a blank line.
//!
//! *   <code>lines(<var>pattern</var>)</code> - Matches any number of lines of
//!     text matching *pattern*. Each line must be terminated by a newline, `'\n'`.
//!
//!     Equivalent to <code>line(<var>pattern</var>)*</code>.
//!
//!     ```
//!     # use aoc_parse::{parser, prelude::*};
//!     let p = parser!(lines(repeat_sep(digit, " ")));
//!     assert_eq!(
//!         p.parse("1 2 3\n4 5 6\n").unwrap(),
//!         vec![vec![1, 2, 3], vec![4, 5, 6]],
//!     );
//!     ```
//!
//! *   <code>section(<var>pattern</var>)</code> - Matches zero or more nonblank lines,
//!     followed by either a blank line or the end of input. The nonblank lines must match
//!     *pattern*.
//!
//!     `section()` consumes the blank line. *pattern* should not expect to see it.
//!
//!     It's common for an AoC puzzle input to have several lines of data, then
//!     a blank line, and then a different kind of data. You can parse this with
//!     <code>section(<var>p1</var>) section(<var>p2</var>)</code>.
//!
//!     `section(lines(u64))` matches a section that's a list of numbers, one per line.
//!
//! *   <code>sections(<var>pattern</var>)</code> - Matches any number of sections
//!     matching *pattern*. Equivalent to <code>section(<var>pattern</var>)*</code>
//!
//!     Bringing it all together to parse a complex example:
//!
//!     ```
//!     # use aoc_parse::{parser, prelude::*};
//!     let example = "\
//!     Wiring Diagram #1:
//!     a->q->E->z->J
//!     D->f->D
//!
//!     Wiring Diagram #2:
//!     g->r->f
//!     g->B
//!     ";
//!
//!     let p = parser!(sections(
//!         line("Wiring Diagram #" usize ":")
//!         lines(repeat_sep(alpha, "->"))
//!     ));
//!     assert_eq!(
//!         p.parse(example).unwrap(),
//!         vec![
//!             (1, vec![vec!['a', 'q', 'E', 'z', 'J'], vec!['D', 'f', 'D']]),
//!             (2, vec![vec!['g', 'r', 'f'], vec!['g', 'B']]),
//!         ],
//!     );
//!     ```
//!
//! [AoC]: https://adventofcode.com/
//! [example]: https://adventofcode.com/2015/day/2
//! [aoc-runner]: https://lib.rs/crates/aoc-runner

#![deny(missing_docs)]

mod context;
mod error;
#[doc(hidden)]
pub mod macros;
mod parsers;
#[cfg(test)]
mod testing;
mod traits;
mod types;
mod util;

pub use context::{ParseContext, Reported};
pub use error::ParseError;
use error::Result;
pub use traits::{ParseIter, Parser};

/// A giant sack of toys and goodies to import along with `parser!`.
///
/// The `parser!()` macro will work fine without this, so you can explicitly
/// import the names you want to use instead of doing `use aoc_parse::{parser,
/// prelude::*};`.
///
/// This includes some constants that have the same name as a built-in Rust
/// type: `i32`, `usize`, `bool`, and so on. There's no conflict because Rust
/// types and constants live in separate namespaces.
pub mod prelude {
    pub use crate::traits::Parser;

    pub use crate::util::aoc_parse;

    pub use crate::parsers::{
        alnum, alpha, any_char, big_int, big_int_bin, big_int_hex, big_uint, big_uint_bin,
        big_uint_hex, bool, char_of, digit, digit_bin, digit_hex, f32, f64, i128, i128_bin,
        i128_hex, i16, i16_bin, i16_hex, i32, i32_bin, i32_hex, i64, i64_bin, i64_hex, i8, i8_bin,
        i8_hex, isize, isize_bin, isize_hex, lower, u128, u128_bin, u128_hex, u16, u16_bin,
        u16_hex, u32, u32_bin, u32_hex, u64, u64_bin, u64_hex, u8, u8_bin, u8_hex, upper, usize,
        usize_bin, usize_hex,
    };

    pub use crate::parsers::{line, lines, repeat_sep, section, sections};

    /// Parse using `parser`, but instead of converting the matched text to a
    /// Rust value, simply return it as a `String`.
    ///
    /// By default, `parser!(alpha+)` returns a `Vec<char>`, and sometimes that
    /// is handy in AoC, but often it's better to have it return a `String`.
    /// That can be done with `parser!(string(alpha+))`.
    pub fn string<P: Parser>(parser: P) -> crate::parsers::StringParser<P> {
        crate::parsers::StringParser { parser }
    }
}