scripting-team: add first part of the loops page (by mistake)

git-svn-id: svn+ssh://atelier.inf.usi.ch/home/bevilj/group-1@155 a672b425-5310-4d7a-af5c-997e18724b81

site/pages/scripts/loops.html

@@ -0,0 +1,57 @@
+---
+layout: page
+category-page: scripts
+category-title: Scripting
+tags: loop for while range do
+author: Marco Tereh
+title: Loops
+---
+
+A very useful feature for scripting is loops; that is, the ability to write a repeating piece of code.<br>
+Loops take this form:
+<pre>
+  [condition] do
+    [repeated code]
+  done
+</pre>
+
+
+In particular, there are two types of loops, for loops and while loops.<br>
+For loops are written like this:
+<pre>
+  for [variable] in [list] do
+    [code]
+  done
+</pre>
+Their function is to <i>iterate</i> over a list. The list can take various forms, but the variable will always be
+one of its elements. In particular, it will be the first element of the list on the first iteration and advance by
+one element in every iteration after that. Most importantly, it can be accessed from inside the repeating code.<br>
+<br>
+The most basic kind of list is a numerical range, written like this:
+<pre>
+  for i in {1..10}; do
+    [code]
+  done
+</pre>
+<code>{1..10}</code> means "the list of every number between 1 and 10 (inclusive)".
+<code>i</code> is the variable that will hold one of these numbers in every iteration.
+Here's a simple example of how to use it:
+<pre>
+  for i in {1..10}; do
+    echo $i;
+  done
+</pre>
+<!-- TODO: insert the correct link here once the variables page is up -->
+<a href="#"><code>$i</code> is how you access the variable i</a>.
+Ranges can also count backward like this: <code>{10..1}</code>.
+Another way to say what <code>{1..10}</code> means is "The numbers between 10 and 1, <i>in increments of 1</i>".
+What if you want increments of two, though? What if you want every <i>even</i> number in a range?<br>
+Numerical ranges also allow you to specify the size of the increments or decrements between each element in the list,
+more generally called the <i>step size</i>.
+Here's an example:
+<pre>
+  for i in {0..10..2}; do
+    echo $i;
+  done
+</pre>
+<!-- UNFINISHED -->