Live examples

Some examples on this site have a Run button. Such an example can be changed right on the page to see what comes of it. Here is the smallest one:

Text "Hello"

Click the code and it becomes a text field. Change the text in the quotes and press Run.

What the button does

1. The text of the example goes to this site's own server.
2. The server builds a page from it — with the same compiler that builds REEEL sites.
3. The page comes back and is shown in a frame under the example.

The colouring of the code goes away once you start editing: it is computed by the analyzer, which runs on the server, not in the browser.

Consent to cookies

Until you have agreed to cookies, nothing leaves the page. Run brings the consent banner back instead; after "Accept all" the example runs by itself.

Limits

An ordinary example is nowhere near them: the largest example in the documentation copies 12 elements with its macros and builds in a few milliseconds.

What an example cannot do

• Read files. import , Markdown src: , JsonData and an image of the project get nothing: an example has no project.
• Use the network. HttpData and an image by address build, and reach nothing.
• Take the site's theme and strings. $theme and $strings are empty for an example — colours are written as numbers, texts as strings.
• Touch this page. The result is shown in a separate frame with an origin of its own: the site's storage and cookies are out of its sight.

A macro that calls another one twice

The limit on macros comes from one example. A macro that calls the next one twice doubles the tree at every level:

@A
  Column
    $B
    $B
@B
  Column
    $C
    $C
@C
  Text "x"
$A

Three levels are four texts. Twenty-six are 67 million elements out of a hundred lines. So parsing counts how many elements were copied out of macros, and stops: at a thousand in an example on this site, at a hundred thousand in a real project. The widest page of a real site copies about twenty thousand.

Where else there is a Run button

Only on this site. A Copy button is on any block of code in Markdown whose author switched on copyable:true ; running examples is something the server offers on the documentation site only. More in the description of the Markdown element.