Streams.

jtomschroeder · Aug 6, 2016 · 1d86d5c · 1d86d5c
1 parent 9c1644a
commit 1d86d5c
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diff --git a/lib/lambda.hpp b/lib/lambda.hpp
@@ -23,4  23,6 @@
 
 #include "lambda/dollar.hpp"
 
 #include "lambda/stream.hpp"
 
 #endif // LAMBDA_LAMBDA_H
diff --git a/lib/lambda/stream.hpp b/lib/lambda/stream.hpp
@@ -0,0  1,69 @@
 
 #pragma once
 
 #include "maybe.hpp"
 
 namespace lambda {
 
 // pub trait Iterator {
 //     type Item;
 //     fn next(&mut self)->Option<Self::Item>;
 //
 // fn map<B, F>(self, f: F) -> Map<Self, F> where Self: Sized, F: FnMut(Self::Item) -> B { ... }
 //
 //
 // pub struct Map<I, F> {
 //     iter: I,
 //     f: F,
 // }
 //
 
 template <class T>
 class Stream : public std::enable_shared_from_this<Stream<T>> {
 public:
     using RawStream = std::shared_ptr<Stream>;
 
     Stream() {}
 
     virtual Maybe<T> next() = 0;
 
     template <class F>
     RawStream map(F &&f);
 };
 
 template <class T>
 using RawStream = typename Stream<T>::RawStream;
 
 template <class T, class F>
 class Map : public Stream<T> {
     RawStream<T> stream;
     F f;
 
 public:
     Map(RawStream<T> stream, F f) : stream(stream), f(f) {}
 
     virtual Maybe<T> next() { return stream->next() >> f; }
 };
 
 template <class T, class C>
 class IteratorStream : public Stream<T> {
     typename C::const_iterator begin, end;
 
 public:
     IteratorStream(C &collection) : begin(collection.cbegin()), end(collection.cend()) {}
 
     virtual Maybe<T> next() { return begin != end ? some(*begin  ) : none; }
 };
 
 template <class T, class C>
 static auto from(C &collection) {
     return RawStream<T>(new IteratorStream<T, C>{collection});
 }
 
 template <class T>
 template <class F>
 RawStream<T> Stream<T>::map(F &&f) {
     return RawStream(new Map<T, F>{Stream<T>::shared_from_this(), f});
 }
 
 } /* lambda */
diff --git a/test/test_dollar.cpp b/test/test_dollar.cpp
@@ -13,4  13,11 @@ TEST(lambda, dollar) {
     ASSERT_EQ(vector(2, 3, 4, 5), map(vector(1, 2, 3, 4), plus(1)));
 
     ASSERT_EQ(vector(1, 4), without(vector(1, 2, 3, 4), 2, 3));
 
     auto vec = vector(1, 2, 3, 4);
     // auto stream = IteratorStream<int, std::vector<int>>{vec}.map([](auto i) { return i; });
     auto stream = from<int>(vec)->map([](auto i) { return i * 25; });
     while (auto val = stream->next()) {
         printer << val;
     }
 }
Original file line number	Diff line number	Diff line change
Expand Up		@@ -23,4 23,6 @@

		#include "lambda/dollar.hpp"

		#include "lambda/stream.hpp"

		#endif // LAMBDA_LAMBDA_H