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//! Provides utilities for working with alphabets. //! //! Note: This package re-exports the alphabet!() macro defined by the crate [alphabet_macro](https://crates.io/crates/alphabet-macro). mod counter; mod util; mod word; #[doc(inline)] pub use alphabet_macro::alphabet; use util::VectorAccess; /// Represents an alphabet. pub trait Alphabet<'a> { /// The iterator type used by iter_words(). type IterWord: Iterator<Item = String>; /// The iterator type used by iter_words_counting(). type IterWordCounting: Iterator<Item = String>; /// Allows to iterate over words of this alphabet (i.e. Self\* in the mathematical sense). /// This returns an infinite iterator in most cases. /// /// The words returned by the iterator are sorted lexicographically if the alphabet imposes any particular order on its symbols. /// /// All alphabets generated by the alphabet!() macro impose an order on their symbols, namely the order in which the symbols are listed. /// `Vec<char>` uses the order of its contents. For other implementors, refer to the respective documentation. /// /// The iterator is not infinite for empty alphabets. In that case, the only word is the empty word. /// /// # Examples /// /// Basic usage: /// ``` /// use alphabet::*; /// /// alphabet!(SCREAM = "A"); /// let mut words = SCREAM.iter_words(); /// assert_eq!(words.next().unwrap(), ""); /// assert_eq!(words.next().unwrap(), "A"); /// assert_eq!(words.next().unwrap(), "AA"); /// assert_eq!(words.next().unwrap(), "AAA"); /// ``` /// /// Note that this can not be used for 'counting': /// ``` /// use alphabet::*; /// /// alphabet!(BINARY = "01"); /// let mut words = BINARY.iter_words(); /// assert_eq!(words.next().unwrap(), ""); /// assert_eq!(words.next().unwrap(), "0"); /// assert_eq!(words.next().unwrap(), "1"); /// /// // Note that this does not 'count' in binary, it operates on symbols: /// assert_eq!(words.next().unwrap(), "00"); /// assert_eq!(words.next().unwrap(), "01"); /// assert_eq!(words.next().unwrap(), "10"); /// assert_eq!(words.next().unwrap(), "11"); /// assert_eq!(words.next().unwrap(), "000"); /// ``` /// /// Special case for empty alphabets: /// ``` /// use alphabet::*; /// /// alphabet!(SILENCE = ""); /// let mut words = SILENCE.iter_words(); /// assert_eq!(words.next().unwrap(), ""); /// assert!(words.next().is_none()); /// ``` fn iter_words(&'a self) -> Self::IterWord; /// Allows to iterate over 'count words' of this alphabet. This returns an infinite iterator in most cases. /// /// 'Count words' are words that are not empty and that do not start in the first symbol of the alphabet, unless they have length 1. /// Note that this requires the alphabet imposing an order on its symbols. /// /// Intuitively speaking, 'count words' are numbers using the alphabet as digits. /// /// All alphabets generated by the alphabet!() macro impose an order on their symbols, namely the order in which the symbols are listed. /// `Vec<char>` uses the order of its contents. For other implementors, refer to the respective documentation. /// /// The iterator is not infinite for empty alphabets and singleton alphabets. /// In both cases, there are no valid 'count words' and the iterator is empty. /// /// # Panics /// /// When `Self` imposes no order on its symbols. /// /// # Examples /// /// Basic usage: /// ``` /// use alphabet::*; /// /// alphabet!(BINARY = "01"); /// let mut words = BINARY.iter_words_counting(); /// assert_eq!(words.next().unwrap(), "0"); /// assert_eq!(words.next().unwrap(), "1"); /// assert_eq!(words.next().unwrap(), "10"); /// assert_eq!(words.next().unwrap(), "11"); /// assert_eq!(words.next().unwrap(), "100"); /// ``` /// /// Special case empty and singleton alphabets: /// ``` /// use alphabet::*; /// /// alphabet!(SILENCE = ""); /// let mut words = SILENCE.iter_words_counting(); /// assert!(words.next().is_none()); /// ``` /// ``` /// use alphabet::*; /// /// alphabet!(SCREAM = "A"); /// let mut words = SCREAM.iter_words_counting(); /// assert!(words.next().is_none()); /// ``` fn iter_words_counting(&'a self) -> Self::IterWordCounting; } impl<'a> Alphabet<'a> for [char] { type IterWord = word::WordIterator<'a>; type IterWordCounting = word::CountingIterator<'a>; fn iter_words(&self) -> Self::IterWord { word::WordIterator::new(VectorAccess::Direct(self.to_vec())) } fn iter_words_counting(&self) -> Self::IterWordCounting { word::CountingIterator::new(VectorAccess::Direct(self.to_vec())) } } impl<'a> Alphabet<'a> for Vec<char> { type IterWord = word::WordIterator<'a>; type IterWordCounting = word::CountingIterator<'a>; fn iter_words(&'a self) -> Self::IterWord { word::WordIterator::new(VectorAccess::Indirect(&self)) } fn iter_words_counting(&'a self) -> Self::IterWordCounting { word::CountingIterator::new(VectorAccess::Indirect(&self)) } } #[cfg(test)] mod tests { use super::*; alphabet!(EMPTY = ""); alphabet!(SCREAM = "A"); alphabet!(BINARY = "01"); alphabet!(ENGLISH = "abcdefghijklmnopqrstuvwxyz"); alphabet!(GERMAN = "aäbcdefghijklmnoöpqrstuüvwxyzß"); #[test] fn test_many_words() { // Testing infinity is hard, so this has to be enough assert_eq!(10000, BINARY.iter_words().take(10000).count()); } #[test] fn test_many_words_counting() { // Testing infinity is hard, so this has to be enough assert_eq!(10000, BINARY.iter_words_counting().take(10000).count()); } #[test] fn test_binary_counting_works() { let mut iter = BINARY.iter_words_counting(); for i in 0..10000 { let real_bin = format!("{:b}", i); assert_eq!(real_bin, iter.next().unwrap()); } } #[test] fn test_empty_alphabet_has_only_empty_word() { let mut iter = EMPTY.iter_words(); assert_eq!("", iter.next().unwrap()); assert!(iter.next().is_none()); } #[test] fn test_empty_alphabet_has_no_count_words() { let mut iter = EMPTY.iter_words_counting(); assert!(iter.next().is_none()); } #[test] fn test_singleton_alphabet_has_many_words() { // Testing infinity is hard, so this has to be enough assert_eq!(500, SCREAM.iter_words().take(500).count()); } #[test] fn test_singleton_alphabet_has_no_count_words() { let mut iter = SCREAM.iter_words_counting(); assert!(iter.next().is_none()); } #[test] fn test_some_english_words() { let mut iter = ENGLISH.iter_words(); assert_eq!("i", iter.nth(9).unwrap()); assert_eq!("cu", iter.nth(99 - 10).unwrap()); } #[test] fn test_some_german_words() { let mut iter = GERMAN.iter_words(); assert_eq!("ß", iter.nth(30).unwrap()); assert_eq!("aä", iter.nth(32 - 31).unwrap()); } #[test] fn test_iter_words_does_not_count() { let mut iter_a = BINARY.iter_words(); let mut iter_b = BINARY.iter_words_counting(); for _ in 0..10000 { assert_ne!(iter_a.next().unwrap(), iter_b.next().unwrap()); } } }