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Programming manual (

Some useful tags

We list some useful tags here. Keep them in mind when you need to express your program's output in various ways. You can look up details on how to use them in the Tags section of this website.

putLn and put

These tags are used to get strings of data out of the ioL console. They are transmitted to your program's standard-input stream, which means that you can pick them up in your program using your language's standard input functions like scanf() in C, or input() in Python.

Both tags function in the same way. The only difference between <putLn> and <put> is that putLn automatically adds a newline character {</n>} to the end.

Depending on your programming lanugage environment, some input functions look for a newline after each input, since they assume the input is coming from a TTY terminal where a user is pressing enter after typing each command.

These tags are short-lived. They exist to carry out a procedure, rather than creating an object in the console environment. It is not useful to attach labels to them.

span and box

These tags act as containers to display content on the screen. A span tag works for a section of text which may be spread across multiple lines inside a larger paragraph, while a box tag keeps its contents in a rectangular box where the text does not flow with surrounding content.

There are dozens of fields you can set on these tags. For example, span is useful for making a single word bold within a paragraph, or creating a large heading, while box is good for positioning content on the screen.

If you attach a label to a span or box, you can manipulate or clear the content inside it at any time until the tag is destroyed. (A tag will be destroyed when its parent field is cleared.)


This creates a single-line input box where the user can type input. By attaching a label to this tag, you can manipulate and access the contents of this box


A button is an on-screen element that the user interacts with by a mouse click.

The button tag supports an onclick= field to which you can specify (or push) a list of actions (tags) to be executed each time the button is clicked.

Note that any on-screen element can accept mouse clicks, however the button tag has an intuitive appearence — it is easier for users to understand that they are supposed to click on something that looks like a button.


This allows you to place PNG, JPEG or GIF images on the screen. The default field takes in the binary contents of the image file you want to display.