Lua-Control.lsp

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<h1>Control Structure Tutorial</h1>


<p>Lua's control structures will feel familiar to most programmers. For detailed information, refer to Sections 2.4.4 and 2.4.5 of the <a target="_blank" href="https://realtimelogic.com/ba/doc/luaref_index.html">Lua Reference Manual</a>.</p>


<details open>
  <summary>while</summary>
  <p>The conditional looping statement "<code>while</code>" has the form: </p>
  <p><code>while</code> <em>exp</em> <strong><code>do</code></strong> <em>block</em> <strong><code>end</code></strong></p>
  <p>A simple loop:</p>
  <div class="lspeditor" extype="lua" example="3.1"></div>
  <p>We can exit the control of a while statement using the break
  keyword as in the following example.</p>
  <div class="lspeditor" extype="lua" example="3.2"></div>
</details>

<details open>
  <summary>repeat</summary>
  <p>The conditional looping statement "<code>repeat</code>" has the form:</p>
  <strong><code>repeat</code></strong> <em>block</em> <strong><code>until</code></strong> <em>exp</em>
  <p>A simple loop:</p>
  <div class="lspeditor" extype="lua" example="3.3"></div>
  <p>Like the while statement, we can exit a repeat loop using a break statement:</p>
  <div class="lspeditor" extype="lua" example="3.4"></div>
  <p>cows_come_home is a variable which is not defined. When we access it we get the value nil, so this code means "until false" or forever.</p>
</details>

<details open>
  <summary>for</summary>
  <p>The iterating statement "<code>for</code>" has two forms. The first is "<code>for</code>" numerical iteration:</p>
  <div class="lspeditor" extype="lua" example="3.5"></div>
  <p>The second is for sequential iteration, e.g. to print the contents of a table. In the example below, 'for' is passed the 'pairs()' iterator function, whose purpose is to supply the values of each iteration:</p>
  <div class="lspeditor" extype="lua" example="3.6"></div>
</details>

<details open>
  <summary>if ... then ... else ... end</summary>
  <p>The statement "<code>if</code>" has the form:</p>
  <strong><code>if</code></strong> <em>exp</em> <strong><code>then</code></strong> <em>block</em> <em>{</em> <strong><code>elseif</code></strong> <em>exp</em> <strong><code>then</code></strong> <em>block } [</em> <strong><code>else</code></strong> <em>block ]</em> <strong><code>end</code></strong>
  <p>For example,<code>if</code> ... <code>then</code> ... <code>end</code></p>
  <div class="lspeditor" extype="lua" example="3.7"></div>
  <p><code>if</code> ... <code>then</code> ... <code>else</code> ... <code>end</code></p>
  <div class="lspeditor" extype="lua" example="3.8"></div>
  <p><code>if</code> ... <code>then</code> ... <code>elseif</code> ... <code>else</code> ... <code>end</code></p>
  <div class="lspeditor" extype="lua" example="3.9"></div>
</details>

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