Added parametric polymorphism to l1

2024-08-16 00:40:22 +03:00 · 2020-02-02 17:48:36 +03:00 · 2020-02-02 17:48:36 +03:00 · de99d7e2f3
commit de99d7e2f3
parent 6bdc0f59b2
4 changed files with 127 additions and 1 deletions
--- a/1.html
+++ b/1.html
@ -666,6 +666,52 @@

 <p><code>filter</code> тоже есть в стандартной библиотеке.</p>
 </section>
+<section id="еще-немного-структур" class="slide level1">
+<h1>Еще немного структур</h1>
+</section>
+<section class="slide level1">
+
+<h2 id="параметрмческий-полиморфизм">Параметрмческий полиморфизм</h2>
+<h3 id="дженерики">(Дженерики)</h3>
+<div class="sourceCode" id="cb123"><pre class="sourceCode haskell fragment"><code class="sourceCode haskell"><span id="cb123-1"><a href="#cb123-1"></a><span class="kw">data</span> <span class="dt">IntList</span> <span class="ot">=</span> <span class="dt">Cons</span> <span class="dt">Int</span> <span class="dt">IntList</span> <span class="op">|</span> <span class="dt">Nil</span></span></code></pre></div>
+<aside class="notes">
+<p>Мы научиоись делать список интов. А что если мы хотим сделать просто список. Чего-нибудь.</p>
+</aside>
+<div class="sourceCode" id="cb124"><pre class="sourceCode haskell fragment"><code class="sourceCode haskell"><span id="cb124-1"><a href="#cb124-1"></a><span class="kw">data</span> <span class="dt">List</span> a <span class="ot">=</span> <span class="dt">Cons</span> a (<span class="dt">List</span> a) <span class="op">|</span> <span class="dt">Nil</span></span></code></pre></div>
+<div class="sourceCode" id="cb125"><pre class="sourceCode haskell fragment"><code class="sourceCode haskell"><span id="cb125-1"><a href="#cb125-1"></a><span class="ot">ints ::</span> <span class="dt">List</span> <span class="dt">Int</span></span>
+<span id="cb125-2"><a href="#cb125-2"></a>ints <span class="ot">=</span> <span class="dt">Cons</span> <span class="dv">1</span> (<span class="dt">Cons</span> <span class="dv">2</span> (<span class="dt">Cons</span> <span class="dv">3</span> <span class="dt">Nil</span>))</span></code></pre></div>
+<div class="sourceCode" id="cb126"><pre class="sourceCode haskell fragment"><code class="sourceCode haskell"><span id="cb126-1"><a href="#cb126-1"></a><span class="co">-- Типы как всегда можно не писать</span></span>
+<span id="cb126-2"><a href="#cb126-2"></a><span class="ot">strings ::</span> <span class="dt">List</span> <span class="dt">String</span></span>
+<span id="cb126-3"><a href="#cb126-3"></a>strings <span class="ot">=</span> <span class="dt">Cons</span> <span class="st">&quot;one&quot;</span> (<span class="dt">Cons</span> <span class="st">&quot;two&quot;</span> (<span class="dt">Cons</span> <span class="st">&quot;three&quot;</span> <span class="dt">Nil</span>))</span></code></pre></div>
+<div class="sourceCode" id="cb127"><pre class="sourceCode haskell fragment"><code class="sourceCode haskell"><span id="cb127-1"><a href="#cb127-1"></a><span class="ot">strings ::</span> <span class="dt">List</span> <span class="dt">String</span></span>
+<span id="cb127-2"><a href="#cb127-2"></a>strings <span class="ot">=</span> <span class="dt">Cons</span> <span class="st">&quot;one&quot;</span> (<span class="dt">Cons</span> <span class="st">&quot;two&quot;</span> (<span class="dt">Cons</span> <span class="st">&quot;three&quot;</span> <span class="dt">Nil</span>))</span></code></pre></div>
+</section>
+<section class="slide level1">
+
+<div class="sourceCode" id="cb128"><pre class="sourceCode haskell"><code class="sourceCode haskell"><span id="cb128-1"><a href="#cb128-1"></a>things <span class="ot">=</span> <span class="dt">Cons</span> (<span class="st">&quot;one&quot;</span><span class="ot"> ::</span> <span class="dt">String</span>) (<span class="dt">Cons</span> (<span class="dv">2</span><span class="ot"> ::</span> <span class="dt">Int</span>) <span class="dt">Nil</span>)</span></code></pre></div>
+<pre class="fragment"><code>    • Couldn&#39;t match type ‘Int’ with ‘String’
+      Expected type: List String
+        Actual type: List Int
+   |
+10 | things = Cons (&quot;one&quot; :: String) (Cons (2 :: Int) Nil)
+   |                                  ^^^^^^^^^^^^^^^^^^^</code></pre>
+<div class="sourceCode" id="cb130"><pre class="sourceCode haskell fragment"><code class="sourceCode haskell"><span id="cb130-1"><a href="#cb130-1"></a><span class="kw">data</span> <span class="dt">List</span> a <span class="ot">=</span> <span class="dt">Cons</span> a (<span class="dt">List</span> a) <span class="op">|</span> <span class="dt">Nil</span></span></code></pre></div>
+<p><span class="fragment"><code>a</code> должен всегда быть <code>a</code>.</span></p>
+</section>
+<section class="slide level1">
+
+<div class="sourceCode" id="cb131"><pre class="sourceCode haskell"><code class="sourceCode haskell"><span id="cb131-1"><a href="#cb131-1"></a><span class="fu">take</span><span class="ot"> ::</span> <span class="dt">Int</span> <span class="ot">-&gt;</span> <span class="dt">IntList</span> <span class="ot">-&gt;</span> <span class="dt">IntList</span></span>
+<span id="cb131-2"><a href="#cb131-2"></a><span class="fu">take</span> _ <span class="dt">Nil</span> <span class="ot">=</span> <span class="dt">Nil</span></span>
+<span id="cb131-3"><a href="#cb131-3"></a><span class="fu">take</span> <span class="dv">0</span> _ <span class="ot">=</span> <span class="dt">Nil</span></span>
+<span id="cb131-4"><a href="#cb131-4"></a><span class="fu">take</span> n (<span class="dt">Cons</span> x xs) <span class="ot">=</span> <span class="dt">Cons</span> x (<span class="fu">take</span> (n <span class="op">-</span> <span class="dv">1</span>) xs)</span></code></pre></div>
+<div class="sourceCode" id="cb132"><pre class="sourceCode haskell fragment"><code class="sourceCode haskell"><span id="cb132-1"><a href="#cb132-1"></a><span class="fu">take</span><span class="ot"> ::</span> <span class="dt">Int</span> <span class="ot">-&gt;</span> <span class="dt">List</span> a <span class="ot">-&gt;</span> <span class="dt">List</span> a</span>
+<span id="cb132-2"><a href="#cb132-2"></a><span class="fu">take</span> _ <span class="dt">Nil</span> <span class="ot">=</span> <span class="dt">Nil</span></span>
+<span id="cb132-3"><a href="#cb132-3"></a><span class="fu">take</span> <span class="dv">0</span> _ <span class="ot">=</span> <span class="dt">Nil</span></span>
+<span id="cb132-4"><a href="#cb132-4"></a><span class="fu">take</span> n (<span class="dt">Cons</span> x xs) <span class="ot">=</span> <span class="dt">Cons</span> x (<span class="fu">take</span> (n <span class="op">-</span> <span class="dv">1</span>) xs)</span></code></pre></div>
+<aside class="notes">
+<p>Поменялся только тип!</p>
+</aside>
+</section>
 <section id="где-и-как-смотреть-стандартную-библиотеку" class="slide level1">
 <h1>Где и как смотреть “стандартную библиотеку”</h1>
 </section>
--- a/1.md
+++ b/1.md
@ -958,6 +958,85 @@ quicksort [2, 1, 3, 4]

 ---

+# Еще немного структур
+
+---
+
+## Параметрмческий полиморфизм
+
+### (Дженерики)
+
+```{ .haskell .fragment }
+data IntList = Cons Int IntList | Nil
+```
+
+:::notes
+Мы научиоись делать список интов. А что если мы хотим сделать просто список. Чего-нибудь.
+:::
+
+```{ .haskell .fragment }
+data List a = Cons a (List a) | Nil
+```
+
+```{ .haskell .fragment }
+ints :: List Int
+ints = Cons 1 (Cons 2 (Cons 3 Nil))
+```
+
+```{ .haskell .fragment }
+-- Типы как всегда можно не писать
+strings :: List String
+strings = Cons "one" (Cons "two" (Cons "three" Nil))
+```
+
+```{ .haskell .fragment }
+strings :: List String
+strings = Cons "one" (Cons "two" (Cons "three" Nil))
+```
+
+---
+
+```{ .haskell }
+things = Cons ("one" :: String) (Cons (2 :: Int) Nil)
+```
+
+```fragment
+    • Couldn't match type ‘Int’ with ‘String’
+      Expected type: List String
+        Actual type: List Int
+   |
+10 | things = Cons ("one" :: String) (Cons (2 :: Int) Nil)
+   |                                  ^^^^^^^^^^^^^^^^^^^
+```
+
+```{ .haskell .fragment }
+data List a = Cons a (List a) | Nil
+```
+
+[`a` должен всегда быть `a`.]{.fragment}
+
+---
+
+```{ .haskell }
+take :: Int -> IntList -> IntList
+take _ Nil = Nil
+take 0 _ = Nil
+take n (Cons x xs) = Cons x (take (n - 1) xs)
+```
+
+```{ .haskell .fragment }
+take :: Int -> List a -> List a
+take _ Nil = Nil
+take 0 _ = Nil
+take n (Cons x xs) = Cons x (take (n - 1) xs)
+```
+
+:::notes
+Поменялся только тип!
+:::
+
+---
+
 # Где и как смотреть "стандартную библиотеку"

 ---
--- a/README.md
+++ b/README.md
@ -11,3 +11,4 @@
  - Currying
  - Lists
  - Quicksort
+  - Parametric polymorphism in structures
--- a/build.sh
+++ b/build.sh
@ -3,7 +3,7 @@
 for file in *.md
 do
  base=$(basename $file .md)
-  if [base != "README"]
+  if [ $base != "README" ]
  then
    pandoc -i $file -t revealjs -s --highlight-style=breezeDark --include-in-header=style.html >"$base.html"
  fi