[FEATURE] Allow to pass pairs to pairwise alignment

[Irallia]

Resolves #1516

[codecov]

Codecov Report

Merging #1913 into master will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master    #1913   +/-   ##
=======================================
  Coverage   97.77%   97.77%           
=======================================
  Files         258      258           
  Lines        9687     9688    +1     
=======================================
+ Hits         9471     9472    +1     
  Misses        216      216           

Impacted Files	Coverage Δ
...clude/seqan3/alignment/pairwise/align_pairwise.hpp	100.00% <100.00%> (ø)

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[joergi-w]

Thank you, looks good!

[rrahn]

Ok, I thought about it, and this is how I'd like to tackle this.
Replace this definition:

seqan3/include/seqan3/alignment/pairwise/detail/concept.hpp

Line 109 in cbced42

SEQAN3_CONCEPT align_pairwise_single_input =

with the following code:

SEQAN3_CONCEPT align_pairwise_single_input =
    sequence_pair<std::remove_reference_t<t>> &&
    std::is_lvalue_reference_v<t> ||
    (std::ranges::viewable_range<std::tuple_element_t<0, std::remove_reference_t<t>>> &&
     std::ranges::viewable_range<std::tuple_element_t<1, std::remove_reference_t<t>>>);

Then replace this line:

seqan3/include/seqan3/alignment/pairwise/align_pairwise.hpp

Line 134 in cbced42

requires detail::align_pairwise_single_input<std::remove_reference_t<sequence_t>> &&

with this:

    requires detail::align_pairwise_single_input<sequence_t> &&

And then you can rewrite the body above as:

    using std::get;

    if constexpr (std::is_lvalue_reference_v<sequence_t>)  // Forward tuple elements as references.
        return align_pairwise(std::tie(get<0>(seq), get<1>(seq)), config);

    static_assert(std::tuple_size_v<std::remove_reference_t<sequence_t>> == 2,
                  "Alignment configuration error: Expects exactly two sequences for pairwise alignments.");

    static_assert(std::ranges::viewable_range<std::tuple_element_t<0, std::remove_reference_t<sequence_t>>> &&
                  std::ranges::viewable_range<std::tuple_element_t<1, std::remove_reference_t<sequence_t>>>,
                  "Alignment configuration error: The tuple elements must model std::ranges::viewable_range.");

    return align_pairwise(std::views::single(std::forward<sequence_t>(seq)), config);

[rrahn]

Then we don't need the this additional interface.

[rrahn]

Many thanks for tackling this 👍 . I would approach the thing a little differently, though 😁 .

[rrahn]

Suggested change

[rrahn]

Suggested change

[rrahn]

Suggested change

[rrahn]

Looks good so far. Please rebase onto current master to resolve the merge conflict.