Alphabet + letters¶

This page contains information about the functionality for manipulating the alphabet of a Presentation object.

inline word_type const &libsemigroups::Presentation::alphabet() const noexcept¶

Returns the alphabet of the presentation.

Throws: (None) – This function is noexcept and is guaranteed never to throw.
Parameters: (None) –
Returns: A const reference to Presentation::word_type

Presentation &libsemigroups::Presentation::alphabet(size_type n)¶

Set the alphabet by size.

Sets the alphabet to the range \([0, n)\) consisting of values of type letter_type

See: validate_alphabet, validate_rules, and validate

Warning

No checks are performed by this function, in particular, it is not verified that the rules in the presentation (if any) consist of letters belonging to the alphabet

Parameters: n – the size of the alphabet
Throws: (None) – This function guarantees not to throw a LibsemigroupsException.
Returns: A const reference to *this

Presentation &libsemigroups::Presentation::alphabet(word_type const &lphbt)¶

Set the alphabet const reference.

Sets the alphabet to be the letters in lphbt.

See: validate_rules and validate

Warning

This function does not verify that the rules in the presentation (if any) consist of letters belonging to the alphabet

Parameters: lphbt – the alphabet
Throws: LibsemigroupsException – if there are duplicate letters in lphbt
Returns: A const reference to *this

Presentation &libsemigroups::Presentation::alphabet(word_type &&lphbt)¶

Set the alphabet from rvalue reference.

Sets the alphabet to be the letters in lphbt.

See: validate_rules and validate

Warning

This function does not verify that the rules in the presentation (if any) consist of letters belonging to the alphabet

Parameters: lphbt – the alphabet
Throws: LibsemigroupsException – if there are duplicate letters in lphbt
Returns: A const reference to *this

Presentation &libsemigroups::Presentation::alphabet_from_rules()¶

Set the alphabet to be the letters in the rules.

Sets the alphabet to be the letters in rules.

See: validate_rules, and validate

Parameters: (None) –
Returns: A const reference to *this

inline bool libsemigroups::Presentation::contains_empty_word() const noexcept¶

Check if the presentation should contain the empty word.

Parameters: (None) –
Throws: (None) – This function is noexcept and is guaranteed never to throw.
Returns: A value of type bool

inline Presentation &libsemigroups::Presentation::contains_empty_word(bool val) noexcept¶

Specify that the presentation should (not) contain the empty word.

Parameters: val – whether the presentation should contain the empty word
Throws: (None) – This function is noexcept and is guaranteed never to throw.
Returns: A const reference to *this

inline size_type libsemigroups::Presentation::index(letter_type val) const¶

Get the index of a letter in the alphabet.

Complexity: Constant.

Warning

This function does not verify that its argument belongs to the alphabet.

Parameters: val – the letter
Throws: (None) – This function guarantees not to throw a LibsemigroupsException.
Returns: A value of type size_type

inline letter_type libsemigroups::Presentation::letter(size_type i) const¶

Get a letter in the alphabet by index.

Returns the letter of the alphabet in position i

Warning

This function performs no bound checks on the argument i

Parameters: i – the index
Throws: (None) – This function guarantees not to throw a LibsemigroupsException.
Returns: A value of type letter_type