REPL: transpose/indent multiple lines at once when highlighted

[rfourquet]

No description provided.

[andyferris]

@rfourquet I couldn't infer the functionality from the title, but I am curious. Do you have an example of what this does, or an issue or discussion to refer to?

[rfourquet]

Thanks for asking! I realize the tiltle must be quite opaque for anyone having not noticed the introduction of two recent features (pretty much everyone I guess 😉 ), at the intersection of which this PR lies:

1. you can indent the current line left/right with Alt-ArrowLeft and Alt-ArrowRight (REPL: indent line left-right with Meta-Arrow{Left,Right} #24726), and 1'. you can transpose the current line with the one above/below with Alt-ArrowUp and Alt-ArrowRight (REPL: implement transpose current line with line above/below #24687).

2. there is always a "region" in the input area delimited by the "mark" and the current position (REPL: implement a kill ring #23377); the mark is at position 0 by default, and can be set by Ctrl-Space; this region can be "copied" for example with Alt-w (and then pasted with C^y). Now, a region can be "activated", which is indicated by it being "highlighted", either repeating by Ctrl-Space twice, or with "shift-Arrow" keys, which is more known as "shift-selection" (REPL: enable visual selection #24725). This is still experimental, but the goal was to make the concept of region more discoverable (shift-selection is common in GUIs), and to allow some commands to have two modes of operations "simple" and "region", like this PR does. Another example would be having "backspace" delete the whole region when it's active (PR to come).

[andyferris]

Cool, thanks, nice features! I love the repl but for creating long functions it was tedious. This suite of changes should help enormously!

I’m curious about some of the keybindings - are these inspired by something?

(PS providing refs to those previous PRs would aid in navigabity. Thanks for taking your time to explain)

[rfourquet]

Thanks!

I’m curious about some of the keybindings - are these inspired by something?

The Ctrl-Space binding is inspired by emacs and readline, the Ctrl-Space twice by emacs (and more generally the concept of "active region"), (IPython has it too), the shif-selection by pretty much all GUIs, the alt-arrow keys are just ad-hoc, the bindings were free! but still it makes some sense: when alt is pressed, you can play with the arrow keys, and see your line or region moving accordingly. These bindings could be reclaimed though, if a better functionality pops in.

I updated the post above with references to PRs.