🪛Input Reader Internals

What's exactly going on?

When the Read() function gets called, it first creates a new instance of TermReaderState to store the state of the current terminal input session. Then, it writes the input prompt to the console.

Before prompting for input, it initializes the current terminal reader state. TermRead then waits for a struck key before processing it by the keybinding reader, BindingsReader, which calls Execute().

To execute, BindingsReader has to look for any matching keybindings in two places:

• Base bindings

• Custom bindings

...by checking the BindMatched() value. In case none of the bindings match the key pressed, it falls back to the InsertSelf() binding.

After the matching keybinding is found, it goes on to perform the action defined by the overridden DoAction(TermReaderState) function with the current TermReaderState instance.

It repeats the above steps for any key pressed until one of the keys is a terminating keybinding, which usually sets the IsExit value to true. In this case, when IsTerminate(ConsoleKeyInfo) returns true, TermReader stops processing any further keys.

It then seeks the console cursor to the end of the text and writes a new line to the console, signifying that the input is aborted.

Depending on the defaultValue argument, if there is no current text, it goes on to replace the input with the defaultValue.

Then, it checks to see if the terminal reading mode isn't a password mode and if the history is enabled. If it's satisfied, it adds the input to the history.

Finally, it resets the terminal state and returns the written input.