Ranges

This page contains links to some classes and functions in libsemigroups that extend the functionality of range objects from rx::ranges.

Please consult the rx::ranges README file for more information about ranges in general and the existing functionality of rx::ranges.

Range objects are used extensively elsewhere in libsemigroups, and are returned by many functions.

Note

So that range classes in libsemigroups can be used efficiently with the functionality of rx::ranges, the usual naming conventions in libsemigroups are not used for the member functions of range objects. In particular, none of the member functions required by rx::ranges check their arguments, but they do not have the suffix _no_checks.

Classes
struct	Random
	Aggregator for choosing a single random item in a range. More...

Functions
template<typename S, typename T>
auto	chain (S const &x, T const &y)
	Chain objects (const references).
template<typename T>
auto	enumerate (T const &thing)
	Enumerate an object (by const reference).
template<typename Range1, typename Range2>
bool	equal (Range1 r1, Range2 r2)
	Check two ranges for equality.
template<typename Range>
bool	is_sorted (Range r)
	Check if a range is sorted according to std::less.
template<typename Range, typename Compare>
bool	is_sorted (Range r, Compare &&comp)
	Check if a range is sorted according to comp.
template<typename Range1, typename Range2>
bool	lexicographical_compare (Range1 r1, Range2 r2)
	Check if a range is lexicographically less than another.
template<typename Range, typename = std::enable_if_t<rx::is_input_or_sink_v<Range>>>
std::ostream &	operator<< (std::ostream &os, Range r)
	Insert a range into an output stream.
template<typename Range1, typename Range2>
bool	shortlex_compare (Range1 r1, Range2 r2)
	Check if a range is shortlex less than another.

Function Documentation

chain()

template<typename S, typename T>

auto chain	(	S const &	x,
		T const &	y )

Defined in ranges.hpp.

This function is just a wrapper for rx::chain but taking objects by reference rather than using iterators for convenience, and it returns a range objects where the items in x come before any of the items in y.

Template Parameters

S	the type of the first argument.
T	the type of the second argument.

Parameters

x	the first object to chain.
y	the second object to chain.

Returns

A range object.

enumerate()

template<typename T>

auto enumerate

(

T const &

thing

)

Defined in ranges.hpp.

This function is just a wrapper for rx::enumerate but taking objects by reference rather than using iterators for convenience, and it returns a a pair consisting of the index of an item and that item. This is similar to the function of the same name in python.

Template Parameters

T	the type of the argument.

Parameters

thing

the object to enumerate.

Returns

A range object.

equal()

template<typename Range1, typename Range2>

bool equal	(	Range1	r1,
		Range2	r2 )

Defined in ranges.hpp.

This function checks if the ranges r1 and r2 are equal, in that they contain the same items (compared using operator==) in the same order. This is analogous to std::equal.

Template Parameters

Range1	the type of the first range.
Range2	the type of the second range.

Parameters

r1	the first range.
r2	the second range.

Returns

true if the ranges are equal and false if not.

is_sorted() [1/2]

template<typename Range>

bool is_sorted

(

Range

r

)

Defined in ranges.hpp.

This function checks if a range is sorted according to the comparison function object comp, and is analogous to std::is_sorted.

Template Parameters

Range

the type of the range to check for sortedness.

Parameters

r	the input range.

Returns

true if the elements in the range are sorted in non-descending order according to std::less and false otherwise.

Note

This function returns true for ranges of size 0 and 1.

is_sorted() [2/2]

template<typename Range, typename Compare>

bool is_sorted	(	Range	r,
		Compare &&	comp )

Defined in ranges.hpp.

This function checks if a range is sorted according to the comparison function object comp, and is analogous to std::is_sorted.

Template Parameters

Range	the type of the range to check for sortedness.
Compare	the type of the comparison function object.

Parameters

r	the input range.
comp	the comparison function object which returns true if the first argument is less than the second.

Returns

true if the elements in the range are sorted in non-descending order according to comp and false otherwise.

Note

This function returns true for ranges of size 0 and 1.

lexicographical_compare()

template<typename Range1, typename Range2>

bool lexicographical_compare	(	Range1	r1,
		Range2	r2 )

Defined in ranges.hpp.

This function checks if the range r1 is lexicographically less than the range r2, using operator< on the items in the ranges. This is analogous to std::lexicographical_compare.

Template Parameters

Range1	the type of the first range.
Range2	the type of the second range.

Parameters

r1	the first range.
r2	the second range.

Returns

true if the range r1 is lexicographically less than the range r2, and false it not.

operator<<()

template<typename Range, typename = std::enable_if_t<rx::is_input_or_sink_v<Range>>>

std::ostream & operator<<	(	std::ostream &	os,
		Range	r )

Defined in ranges.hpp.

This function inserts a human readable representation of a range object into a std::ostream by applying std::to_string to each item in the range.

Template Parameters

Range

the type of the range (must satisfy rx::is_input_or_sink_v<Range>).

Parameters

os	the output stream.
r	the range object.

Returns

A reference to the first parameter os.

shortlex_compare()

template<typename Range1, typename Range2>

bool shortlex_compare	(	Range1	r1,
		Range2	r2 )

Defined in ranges.hpp.

This function checks if the range r1 is shortlex less than the range r2, using operator< on the items in the ranges. This is analogous to shortlex_compare.

Template Parameters

Range1	the type of the first range.
Range2	the type of the second range.

Parameters

r1	the first range.
r2	the second range.

Returns

true if the range r1 is shortlex less than the range r2, and false it not.