Add-ED

The standard editor, now as a library

Some time ago I decided to write an ED clone with syntax highlighting, hired. On my way to that I found that the macro commands ('g', 'v', 'G', 'V') pretty much require that you write an ED library for them. So I did, and here it is.

Differences from GNU Ed

I have taken some liberties in the commands I have found less than ergonomic, so especially advanced commands have some differences (both syntax and behaviour) from GNU Ed. This strives to be a list of these changes.

• 'g' and related commands take command list in input mode (with the regex separator as terminator instead of '.'). (Also, the 'I' suffix for case insensitive matching isn't implemented)
• '!' accepts a selection and will pipe those lines through the given shell command, replacing them with the output. Without a selection it acts as in GNU Ed.
• '#' accepts a selection and will set state.selection to it without printing anything. This is added to be able to set selection without printing.

Early APIs

Currently it is based on both my experiences with hired and the hired repo specifically (a manual fork, so it has the whole history). This may well mean the API is ill suited for your use. If that is the case I'd be happy to make some changes to make it more general.

In line with this, the help text is often a bit outdated. I'll get to that, and improve on the error type, before the first stable release.

Core concepts

The selection:

The original ED keeps track of the last line you interacted with and defaults to working on that for most commands. I felt this deserved expanding, so add-ed instead tracks the last span of lines you interacted with. My hope is that this is more intuitive. (To avoid unpleasantries such as partial saving some commands default to the whole buffer instead. Such as 'w', the save command.)

Flexible APIs

The library has been designed with clear traits to enable changing out most components easily. For example it should be somewhat easy to create a SSH/SFTP IO implementation for remote editing, or a GUI frontend implementing the UI trait.

New features compared to Ed

• 'A' and 'I' commands, which first 'a'/'i' and then 'j' the preceding/following line. Perfect for commenting out a single line or adding a forgotten ;.
• 'C' command, acts as 'c' but hands out previous value to the Ui's input method. This enables you to edit the selection instead of replacing it (depends on UI).
• 'N' and 'L' commands, toggle the default print conf. Line numbers and escapes respectively.
• ':' command, runs the macro with the name given as argument (whitespace trimmed). Macro execution behaves like 'g' execution. 'q' or error returns early.
• 'J' command, joins all lines in selection and then splits them so they all are shorter than the number of columns given after 'J'. Splits on word boundaries. It doesn't understand indentation, but improvement PRs are very welcome.

Feature flags:

local_io:

Include and expose a simple local fs and shell IO implementation.

initial_input_data:

Add 'C' command. This modifies the UI trait.

Attributions:

This project is essentially built upon the regex crate, as regex is the heart of Ed.