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<p>Hi Nathan,</p>
<p>Thank you for the explanation. Makes sense. I will pass this on in the workshop.</p>
<p>Andreas</p>
<p>On 2017-06-19 14:12, Nathan Woodrow wrote:</p>
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<div dir="ltr">Hey <span style="color: #000000; font-family: Verdana,Geneva,sans-serif; font-size: 13.3333px;">Andreas,</span>
<div><span style="color: #000000; font-family: Verdana,Geneva,sans-serif; font-size: 13.3333px;"> </span></div>
<div><span style="color: #000000; font-family: Verdana,Geneva,sans-serif; font-size: 13.3333px;">They are really two different things. $geometry is really a function that takes no arguments. This has been </span><span style="color: #000000; font-family: Verdana, Geneva, sans-serif;"><span style="font-size: 13.3333px;">deprecated in favour calling with () e.g </span></span><span style="color: #000000; font-family: Verdana,Geneva,sans-serif; font-size: 13.3333px;">geometry(). @ is only for variables.</span></div>
<div><span style="color: #000000; font-family: Verdana,Geneva,sans-serif; font-size: 13.3333px;"> </span></div>
<div><span style="color: #000000; font-family: Verdana,Geneva,sans-serif; font-size: 13.3333px;">So you can explain it that $ used to be a shorthand way of calling a function that took no arguments which has now been replaced with () at the end to call it. $area = area(). This becomes important because now we support optional arguments meaning you can take 0 to N arguments.</span></div>
<div><span style="color: #000000; font-family: Verdana,Geneva,sans-serif; font-size: 13.3333px;"> </span></div>
<div><span style="color: #000000; font-family: Verdana,Geneva,sans-serif; font-size: 13.3333px;">- Nathan </span></div>
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<div class="gmail_quote">On Mon, Jun 19, 2017 at 9:53 PM, Neumann, Andreas <span><<a href="mailto:a.neumann@carto.net">a.neumann@carto.net</a>></span> wrote:<br />
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<p>Hi,</p>
<p>While preparing for a workshop on expressions I wonder how to explain why some variables are referenced with the $ sign (like $geometry) while other variables start with the @ sign, like @row_number, @layer_name.</p>
<p>I know that it has historical reasons and that variables with the @ sign are newer and are implemented using a different technology.</p>
<p>But are there plans to get rid of the old $ sign notation and move everything to the @ sign notation?</p>
<p>Just wonder how I best explain this to the participants of the workshop.</p>
<p>Thanks for your reply,</p>
<p>Andreas</p>
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