STL Adapters

Русская версия

Header-only C++23 pipeline library with lazy adapters for data processing — filter, transform, split, join, and file I/O, composed via |. Written as part of a C++ course at ITMO University.

Adapters are lazy by default (except AggregateByKey, Join, and SplitExpected).

Dir("./data", /*recursive=*/false)
  | Filter([](fs::path& p){ return p.extension() == ".txt"; })
  | OpenFiles()
  | Split("\n ,.;")
  | Out(std::cout);

Adapters

Adapter	Description
Dir(path, recursive)	files in a directory, optionally recursive
OpenFiles()	opens each path as a file stream, yields lines
Split(delimiters)	splits strings by a set of delimiter characters
Filter(pred)	filters elements by predicate
Transform(func)	applies a function to each element
AsDataFlow(vec)	wraps a std::vector into a stream
Out(ostream)	prints elements to a stream (terminal)
Write(ostream, delim)	same, but with a custom delimiter between elements (terminal)
AsVector()	collects stream into a std::vector (terminal)
Join(right, lkey, rkey)	LEFT JOIN of two streams by key
DropNullopt()	filters std::nullopt from an optional<T> stream
SplitExpected()	splits an expected<T,E> stream into values and errors
AggregateByKey(init, agg, key)	aggregates values by key via an accumulator function

Build

git clone https://github.com/notakeith/stl-adapters.git
cd stl-adapters
cmake -B build && cmake --build build
ctest --test-dir build

Requirements: CMake ≥ 3.12, GCC 13+ or Clang 17+.