Instantiate a control using macros

All controls can be built via their constructors, but also via specialized macros meant to ease setting up a control. The general format is as follows: controller!("<parameter_list>"), where controller! is a specialized macro (for example button!) and parameter_list is a JSON-like/Python-like format made up of:

• positional parameters — for example, in this case "10,20,30" has three positional parameters: 10, 20, and 30.
• named parameters — parameters described using a name and a value. The usual format is name:value, but name=value is also supported.

All parameters are separated from one another using , or ;. The overall format of a parameter list is:

PositionalParam-1, ... PositionalParam-n, NamedParam-1, ... NamedParam-m

Both positional parameters and named parameters are optional. Their order is not arbitrary: positional parameters (if used) must always appear before named parameters.

Values

The values used as parameters can be:

• regular words (e.g. align:center)
• numerical values (e.g. x=10 or y=-2)
• percentages (e.g. width:10% or height=25%)
• strings — a string can be wrapped in double quotes or single quotes and can contain newlines (e.g. "..." or '...'). If both single quotes and double quotes must appear inside a string, three consecutive double or single quotes can be used (e.g. """...""" or '''...''').
• lists of values — written using [ and ]. The general format is [value-1, value-2, ... value-n]; for example [10,20,30] is a list with three values: 10, 20, and 30.
• nested parameter lists — written using { and }. For example, point={x:10,y:20} means parameter point is defined as two parameters: x with value 10 and y with value 20.
• flags — a meta-interpretation of the parameters described above. Flags can be a regular word or string, or a list of values. If using a word, you can separate flags with | or +. Additionally, when using strings, spaces, ,, and ; can also be used as separators. When using a list of values, each value is a separate flag. For example, the following declarations are equivalent:
  • flags=[flag1,flag2]
  • flags=flag1+flag2
  • flags=flag1|flag2
  • flags="flags1,flags2"
  • flags="flags1;flags2"
  • flags="flags1 flags2"

Common parameters

All controls have a set of common parameters that are required for layout or to change some of their states (such as visibility or if a control is enabled - can receive input).