Text Commands
MCCompiled's support for format strings entirely abstracts away the use of JSON raw-text. There are a couple of reasons why JSON was phased out, but most importantly:
Writing raw-text is hard and unnecessarily verbose.
More opportunities for MCCompiled to take the wheel, especially with types.
Better language support without having to extend rawtext's already convoluted syntax.
The commands in MCCompiled mirror the commands in regular Minecraft. With any command in Minecraft that accepts raw-text, its MCCompiled version accepts a format-string.
Syntax
Format strings use the same syntax as regular strings, but their contents are what dictate what should be shown. To insert an item inside a format-string, use curly braces {} surrounding the content to insert. You can insert values, expressions, or selectors.
Inserting Values
To insert a value, place it inside curly braces anywhere in the string you want it to show.
Inserting Expressions
If you want to evaluate an expression inside the curly braces, you can do that. The result will be stored in an automatically generated temporary value and displayed as expected!
Inserting Selectors
When inserting a selector, the name(s) of the entity it selects will be displayed. If multiple entities match the selector, their names will be separated by commas. The order in which the entities are displayed is not defined.
Escaping
If you don't want an item in curly braces to be evaluated, use a backslash \ to escape it, making it not be evaluated. Using two backslashes will escape the backslash, making it show as one backslash and not affect the proceeding insert.
Commands
The commands which support format-strings are listed in the cheat cheet here. If marked with the text " Supports format-strings ," then the command will properly process format-string inputs.