{% comment %}

As discussed in /_posts/2017-01-03-pdp-11-tutorials.md, when a page (usually part of a tutorial)
wants to create a control that tests some feature of a machine, the page will define a machine command
using a Liquid-style include that looks like this:

    {% include machine-command.html type='button' label='Try It!' machine='vt100' component='Keyboard' command='sendString' value='Hello World' %}

and which should generate something like this:

<button type="button" onclick="commandMachine(this, false, 'vt100','Keyboard','sendString','Hello World')">Try It!</button>

Alternatively, if the command parameter is the name of a command string in the page's Front Matter, then this:

    {% include machine-command.html type='button' label='Try It!' machine='vt100' component='Keyboard' command='scriptName' %}

should generate something like this:

    <button type="button" onclick="commandMachine(this, false, 'vt100','Keyboard','script','...')">Try It!</button>

{% endcomment %}
{% if page.commands[include.command] != nil %}{% assign machine_command = "script" %}{% capture command_value %}{{ page.commands[include.command] | replace:'"','&quot;' | strip }}{% endcapture %}{% else %}{% capture machine_command %}{{ include.command }}{% endcapture %}{% capture command_value %}{{ include.value | replace:'"','&quot;' }}{% endcapture %}{% endif %}{% if include.type == "clickOnce" %}{% assign control_type = "button" %}{% assign control_single = "true" %}{% elsif include.type == "button" %}{% assign control_type = "button" %}{% assign control_single = "false" %}{% else %}{% assign control_type = "unknown" %}{% assign control_single = "false" %}{% endif %}{% if control_type == "button" %}<button type="button" onclick="commandMachine(this,{{ control_single }},'{{ include.machine }}','{{ include.component }}','{{ machine_command }}','{{ command_value }}')">{{ include.label }}</button>{% else %}<!-- Unrecognized machine control type: {{ include.type }} -->{% endif %}