LED is a dialog-specification language whose purpose is not to be a complete programming language, but rather to make dialog specification simpler than in C.

In LED, attributes and expressions follow this form:

elem = element[attribute1=value1,attribute2=value2,...](...expression...)

The names of the elements must not contain the “iup” prefix. Attribute values are always interpreted as strings, but they need to be in quotes (“…”) only when they include spaces. The “IUP_” prefix must not be added to the names of the attributes and predefined values. Expressions contain parameters for creating the element.

In LED there is no distinction between upper and lower case, except for attribute names.

Also there is no NULL definition, so there is no optional parameters, in arrays at least one parameter must exist .

The IupLoad function can parse a text file and create the IUP elements defined in it. Naturally, the same file cannot be loaded more than once, because the elements would be created again. The file parse does not map the elements to the native system.

The LED files are dynamically loaded and must be packaged together with the application’s executable. However, this often becomes an inconvenience. To deal with it, there is the LEDC compiler that creates a C module from the LED contents.

To simply view a LED file objects use the LED Viewer application called IupView, in the applications included in the distribution. Pre-compiled binaries are available at the Download.