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//! Regular Expression Constructor - the recreational version of regular expressions //! //! `rec` is a Rust library that simplifies the process of writing, reading, and using regular //! expressions. This library is intended for all users working with regular expressions, no matter //! their familiarity with regular expression syntax. Below is a summary of the functionality //! provided by `rec`: //! //! - WYSIWYG: [`&str`] and [`char`] are interpreted exactly as written (i.e. no metacharacters); //! all metacharacters (as well as other useful patterns) are provided by the [`Class`] struct. //! - Simple to understand quantifier and capture group syntaxes. //! - Uses operators to provide easy to understand expressions. //! - [`Pattern`] expands on [`Regex`] API to simplify access to data. //! //! This library utilizes the [`regex`] crate. //! //! # Getting Started //! //! Add the following to your `Cargo.toml`: //! //! ```toml //! [dependencies] //! rec = "0.10.0" //! ``` //! //! # Examples //! ## Use Regex API. //! //! A [`Pattern`] is a smart pointer to a [`Regex`], so one can call the same functions. //! //! ``` //! use rec::{some, Class, Pattern}; //! //! let pattern = Pattern::new("hello" + some(Class::Whitespace) + (Class::Digit | "world")); //! //! assert!(pattern.is_match("hello world")); //! ``` //! //! ## Use Pattern to capture a group. //! //! [`Pattern`] additionally provides helper functions to reduce boilerplate. //! //! ``` //! use rec::{prelude::*, some, tkn, var, Class, Pattern}; //! //! let decimal_number = Pattern::new(tkn!("whole" => some(Class::Digit)) + "." + var(Class::Digit)); //! //! assert_eq!(decimal_number.name_str("23.2", "whole"), Some("23")); //! ``` //! //! # FAQ //! //! ## I know regular expression syntax; why should I use `rec`? //! //! In order for code to be easily maintainable, it should be as simple as possible. Even if the //! original developer understands their regular expression, it is beneficial for the project as a //! whole if all contributors are able to easily understand the function of a regular expression. #![warn( absolute_paths_not_starting_with_crate, anonymous_parameters, bare_trait_objects, box_pointers, deprecated_in_future, elided_lifetimes_in_paths, ellipsis_inclusive_range_patterns, explicit_outlives_requirements, keyword_idents, macro_use_extern_crate, missing_copy_implementations, missing_debug_implementations, missing_docs, missing_doc_code_examples, private_doc_tests, question_mark_macro_sep, single_use_lifetimes, trivial_casts, trivial_numeric_casts, unreachable_pub, unsafe_code, unstable_features, unused_extern_crates, unused_import_braces, unused_labels, unused_lifetimes, unused_qualifications, unused_results, variant_size_differences, clippy::cargo, clippy::nursery, clippy::pedantic, clippy::restriction )] #![allow( clippy::implicit_return, // Omitting the return keyword is idiomatic Rust code. clippy::missing_inline_in_public_items, // Generally not bad and there are issues with derived traits. )] #![allow(single_use_lifetimes)] // issue: rust-lang/rust/#55057 pub mod prelude; mod atom; mod repetition; pub use crate::{ atom::{Ch, Class}, repetition::{ btwn, exact, lazy_btwn, lazy_max, lazy_min, lazy_opt, lazy_some, lazy_var, max, min, opt, some, var, }, }; pub use regex::{Match, Regex}; use crate::prelude::{Element, Rec}; use core::{ops::Deref, str::FromStr}; use regex::Captures; /// Creates a [`Rec`] representing the given [`Element`] assigned a name. /// /// # Examples /// ``` /// use rec::{prelude::*, tkn, Class}; /// /// let a_rec = tkn!("digit" => Class::Digit); /// /// assert_eq!(a_rec, Rec::from(r"(?P<digit>\d)")) /// ``` /// /// `tkn!` utilizes named capture groups. /// ``` /// use rec::{prelude::*, Pattern, tkn, some, Class}; /// /// let pattern = Pattern::new("name: " + tkn!("name" => some(Class::Any))); /// let captured_name = pattern.name_str("name: Bob", "name"); /// /// assert_eq!(captured_name, Some("Bob")); /// ``` #[macro_export] macro_rules! tkn { ($name:expr => $elmt:expr) => { Rec::from(format!("(?P<{}>{})", $name, $elmt.to_regex()).as_str()) }; } /// Represents a regular expression to be matched against a target. #[derive(Clone, Debug)] pub struct Pattern { /// The [`Regex`] being used. re: Regex, } impl Pattern { /// Creates a [`Pattern`]. /// /// This is only safe to use with [`Element`]s that are known prior to runtime. /// /// # Panics /// /// Panics if `element` converts into a [`Rec`] with an invalid regular expression. #[allow(clippy::needless_pass_by_value)] // User interface is much better when passing by value. pub fn new<T: Element>(element: T) -> Self { Self { re: Rec::from(element.to_regex()).build(), } } /// Returns the [`str`] of the first [`Match`] in `text`. /// /// If no match is found, returns [`None`]. pub fn find_str<'t>(&self, text: &'t str) -> Option<&'t str> { self.find(text).map(|m| m.as_str()) } /// Returns the first [`Tokens`] found in `text`. pub fn tokenize<'t>(&self, text: &'t str) -> Option<Tokens<'t>> { self.captures(text).map(|captures| Tokens { captures }) } /// Returns the [`str`] of the [`Match`] for [`name`] of the first [`Tokens`] found in `text`. pub fn name_str<'t>(&self, text: &'t str, name: &str) -> Option<&'t str> { // Trying to do `self.tokenize(text).and_then(|t| t.name_str(name))` causes E0515. self.tokenize(text) .and_then(|t| t.name(name).map(|m| m.as_str())) } } impl Deref for Pattern { type Target = Regex; fn deref(&self) -> &Self::Target { &self.re } } impl FromStr for Pattern { type Err = regex::Error; fn from_str(s: &str) -> Result<Self, Self::Err> { Rec::from(s).try_build().map(|x| Self { re: x }) } } /// Stores the found capture groups. #[derive(Debug)] pub struct Tokens<'t> { /// The [`Captures`] matched from the [`Pattern`]. captures: Captures<'t>, } impl Tokens<'_> { /// Returns the [`str`] of the [`Match`] for the given capture name. /// /// If no match is found, returns [`None`]. pub fn name_str(&self, name: &str) -> Option<&str> { self.name(name).map(|m| m.as_str()) } } impl<'t> Deref for Tokens<'t> { type Target = Captures<'t>; fn deref(&self) -> &Self::Target { &self.captures } }