Remove tag_invoke customization for buffer sequences (#262)

doc/modules/ROOT/pages/8.examples/8c.buffer-composition.adoc

@@ -5,7 +5,7 @@ Composing buffer sequences without allocation for scatter/gather I/O.
 == What You Will Learn
 
 * Creating buffers from different sources
-* Using `const_buffer_pair` and `mutable_buffer_pair` for scatter/gather I/O
+* Using `std::array<const_buffer, N>` and `std::array<mutable_buffer, N>` for scatter/gather I/O
 * Zero-allocation buffer sequence patterns
 
 == Prerequisites
@@ -44,15 +44,15 @@ void demonstrate_single_buffers()
     std::cout << "Vector buffer: " << vec_buf.size() << " bytes\n";
 }
 
-void demonstrate_buffer_pair()
+void demonstrate_two_buffer_scatter()
 {
-    std::cout << "\n=== Buffer Pair (Scatter/Gather) ===\n\n";
-    
-    // capy::const_buffer_pair is std::array<const_buffer, 2>
+    std::cout << "\n=== Two-Buffer Scatter/Gather ===\n\n";
+
+    // A 2-element buffer sequence is just a std::array
     std::string header = "Content-Type: text/plain\r\n\r\n";
     std::string body = "Hello, World!";
-    
-    capy::const_buffer_pair message = {{
+
+    std::array<capy::const_buffer, 2> message = {{
         capy::make_buffer(header),
         capy::make_buffer(body)
     }};
@@ -108,7 +108,7 @@ void demonstrate_mutable_buffers()
     char buf1[64];
     char buf2[64];
 
-    capy::mutable_buffer_pair recv_buffers = {{
+    std::array<capy::mutable_buffer, 2> recv_buffers = {{
         capy::mutable_buffer(buf1, sizeof(buf1)),
         capy::mutable_buffer(buf2, sizeof(buf2))
     }};
@@ -124,7 +124,7 @@ void demonstrate_mutable_buffers()
 int main()
 {
     demonstrate_single_buffers();
-    demonstrate_buffer_pair();
+    demonstrate_two_buffer_scatter();
     demonstrate_buffer_array();
     demonstrate_mutable_buffers();
 
@@ -152,17 +152,17 @@ auto arr_buf = capy::make_buffer(arr, sizeof(arr) - 1);  // mutable_buffer
 
 `make_buffer` creates buffer views from various sources. No data is copied—the buffers reference the original storage.
 
-=== Buffer Pairs
+=== Two-Buffer Scatter/Gather
 
 [source,cpp]
 ----
-capy::const_buffer_pair message = {{
+std::array<capy::const_buffer, 2> message = {{
     capy::make_buffer(header),
     capy::make_buffer(body)
 }};
 ----
 
-`const_buffer_pair` is `std::array<const_buffer, 2>` — a fixed-size buffer sequence for scatter/gather I/O. Similarly, `mutable_buffer_pair` holds two mutable buffers.
+Capy's buffer-sequence concepts accept any range of `const_buffer` or `mutable_buffer`, so `std::array<X, 2>` is a buffer sequence with no further wrapping required. Use `mutable_buffer` for receive paths.
 
 === Multi-Buffer Arrays
 
@@ -175,7 +175,7 @@ std::array<capy::const_buffer, 5> http_response = {{
 }};
 ----
 
-For more than two buffers, use `std::array` directly. Buffer sequences support `buffer_size()` and `buffer_length()` for querying total bytes and buffer count.
+For more than two buffers, the same pattern works with a larger `std::array`. Buffer sequences support `buffer_size()` and `buffer_length()` for querying total bytes and buffer count.
 
 === Scatter/Gather I/O
 
@@ -199,7 +199,7 @@ String buffer: 13 bytes
 Array buffer:  10 bytes
 Vector buffer: 6 bytes
 
-=== Buffer Pair (Scatter/Gather) ===
+=== Two-Buffer Scatter/Gather ===
 
 Total message size: 41 bytes
 Buffer count: 2

doc/modules/ROOT/pages/9.design/9m.WhyNotCobalt.adoc

@@ -433,14 +433,6 @@ Capy has one `DynamicBuffer` concept. The v1/v2 split in Asio exists because of
 | Yes
 |
 
-| `buffer_pair`
-| Yes
-|
-
-| `slice`
-| Yes
-|
-
 | `front`
 | Yes
 |
@@ -449,10 +441,6 @@ Capy has one `DynamicBuffer` concept. The v1/v2 split in Asio exists because of
 | Yes
 |
 
-| `buffer_array`
-| Yes
-|
-
 | Byte-level trimming
 | Yes
 |

doc/modules/ROOT/pages/why-capy.adoc

@@ -162,7 +162,7 @@ Asio got buffer sequences right. The concept-driven approach—`ConstBufferSeque
 
 Capy doesn't reinvent this. We adopt Asio's buffer sequence model because it works.
 
-But we improve on it. Asio provides the basics; Capy extends them. Need to trim bytes from the front of a buffer sequence? Asio makes you work for it. Capy provides `buffer_slice` and `front`—byte-range slicing primitives for efficient byte-level manipulation. Need a circular buffer for protocol parsing? Capy has `circular_dynamic_buffer`. Need to compose two buffers without copying? `buffer_pair`.
+But we improve on it. Asio provides the basics; Capy extends them. Need to trim bytes from the front of a buffer sequence? Asio makes you work for it. Capy provides `buffer_slice` and `front`—byte-range slicing primitives for efficient byte-level manipulation. Need a circular buffer for protocol parsing? Capy has `circular_dynamic_buffer`. Need to compose two buffers without copying? Use `std::array<const_buffer, 2>` (or any range of buffers) directly — Capy's buffer-sequence concepts accept arbitrary ranges.
 
 And then there's the `DynamicBuffer` mess. If you've used Asio, you've encountered the confusing split between `DynamicBuffer_v1` and `DynamicBuffer_v2`. This exists because of a fundamental problem: when an async operation takes a buffer by value and completes via callback, who owns the buffer? The original design had flaws. The "fix" created two incompatible versions. (See https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2018/p1100r0.html[P1100R0] for the full story.)
 
@@ -173,8 +173,8 @@ One more thing: `std::ranges` cannot help here. `ranges::size` returns the numbe
 === What Capy Offers
 
 * `ConstBufferSequence`, `MutableBufferSequence`, `DynamicBuffer` — core concepts (Asio-compatible)
-* `flat_dynamic_buffer`, `circular_dynamic_buffer`, `buffer_pair` — additional concrete types
-* `buffer_slice`, `front`, `buffer_array` — byte-level manipulation utilities
+* `flat_dynamic_buffer`, `circular_dynamic_buffer` — additional concrete buffer types
+* `buffer_slice`, `front` — byte-level manipulation utilities
 
 === Comparison
 
@@ -227,11 +227,6 @@ One more thing: `std::ranges` cannot help here. `ranges::size` returns the numbe
 |
 |
 
-| `buffer_pair`
-|
-|
-|
-
 | `buffer_slice`
 |
 |
@@ -247,11 +242,6 @@ One more thing: `std::ranges` cannot help here. `ranges::size` returns the numbe
 |
 |
 
-| `buffer_array`
-|
-|
-|
-
 | `buffer_copy`
 | `buffer_copy`
 |

example/asio/api/capy_streams.cpp

@@ -18,7 +18,6 @@
 
 #include <boost/capy/buffers.hpp>
 #include <boost/capy/buffers/asio.hpp>
-#include <boost/capy/buffers/buffer_array.hpp>
 #include <boost/capy/concept/stream.hpp>
 #include <coroutine>
 #include <boost/capy/ex/io_env.hpp>
@@ -108,7 +107,7 @@ class asio_socket
             cancel_ = std::make_shared<cancel_state>(env->stop_token);
 
             self_->socket_.async_read_some(
-                capy::to_asio(capy::mutable_buffer_array<8>(buffers_)),
+                capy::to_asio(buffers_),
                 net::bind_cancellation_slot(
                     cancel_->signal.slot(),
                     [this, ex = env->executor](
@@ -172,7 +171,7 @@ class asio_socket
             cancel_ = std::make_shared<cancel_state>(env->stop_token);
 
             self_->socket_.async_write_some(
-                capy::to_asio(capy::const_buffer_array<8>(buffers_)),
+                capy::to_asio(buffers_),
                 net::bind_cancellation_slot(
                     cancel_->signal.slot(),
                     [this, ex = env->executor](

example/buffer-composition/buffer_composition.cpp

@@ -34,15 +34,15 @@ void demonstrate_single_buffers()
     std::cout << "Vector buffer: " << vec_buf.size() << " bytes\n";
 }
 
-void demonstrate_buffer_pair()
+void demonstrate_two_buffer_scatter()
 {
-    std::cout << "\n=== Buffer Pair (Scatter/Gather) ===\n\n";
+    std::cout << "\n=== Two-Buffer Scatter/Gather ===\n\n";
 
-    // capy::const_buffer_pair is std::array<const_buffer, 2>
+    // Two-element scatter/gather sequence (just a std::array)
     std::string header = "Content-Type: text/plain\r\n\r\n";
     std::string body = "Hello, World!";
-    
-    capy::const_buffer_pair message = {{
+
+    std::array<capy::const_buffer, 2> message = {{
         capy::make_buffer(header),
         capy::make_buffer(body)
     }};
@@ -98,7 +98,7 @@ void demonstrate_mutable_buffers()
     char buf1[64];
     char buf2[64];
 
-    capy::mutable_buffer_pair recv_buffers = {{
+    std::array<capy::mutable_buffer, 2> recv_buffers = {{
         capy::mutable_buffer(buf1, sizeof(buf1)),
         capy::mutable_buffer(buf2, sizeof(buf2))
     }};
@@ -114,7 +114,7 @@ void demonstrate_mutable_buffers()
 int main()
 {
     demonstrate_single_buffers();
-    demonstrate_buffer_pair();
+    demonstrate_two_buffer_scatter();
     demonstrate_buffer_array();
     demonstrate_mutable_buffers();
 

include/boost/capy.hpp

@@ -37,15 +37,12 @@
 // Buffers
 #include <boost/capy/buffers.hpp>
 #include <boost/capy/buffers/buffer_copy.hpp>
-#include <boost/capy/buffers/buffer_pair.hpp>
 #include <boost/capy/buffers/buffer_param.hpp>
 #include <boost/capy/buffers/buffer_slice.hpp>
 #include <boost/capy/buffers/circular_dynamic_buffer.hpp>
 #include <boost/capy/buffers/flat_dynamic_buffer.hpp>
 #include <boost/capy/buffers/front.hpp>
 #include <boost/capy/buffers/make_buffer.hpp>
-#include <boost/capy/buffers/slice.hpp>
-#include <boost/capy/buffers/buffer_array.hpp>
 #include <boost/capy/buffers/string_dynamic_buffer.hpp>
 #include <boost/capy/buffers/vector_dynamic_buffer.hpp>