CompletionType::List does not support completion candidates that are shorter than the input

[sharkdp]

Thank you for maintaining this crate — we use it in Numbat and it works great.

We want to implement a feature where a user could type something like \hbar in the REPL, press Tab and it would be replaced by ℏ. This seems to work fine when using CompletionType::Circular, but it does not work for CompletionType::List. Words will only be replaced if they are longer than the input. This is probably due to this check:

rustyline/src/lib.rs

Line 154 in fafa0b9

if lcp.len() > s.line.pos() - start {

Would it be possible to support this use case?

Remark: that check above should probably use lcp.unicode_width() instead of lcp.len() (?).

[gwenn]

Not strictly related to the issue but to your remark:

that check above should probably use lcp.unicode_width() instead of lcp.len() (?).

s.line.pos() and start are byte offsets so the difference between them is a number of bytes.
So lcp.len() seems right.
But maybe we should compare s.line[start..s.line.pos()].width() and lcp.width() instead.
I will try to do some tests...

[gwenn]

Ok,
If I remember correctly, I used replxx (or linenoise-ng) as a reference implementation.
But then I didn't backported this change:

if ( ( longestCommonPrefix > itemLength ) || ( completionsCount == 1 ) ) {

And the associated comment perfectly matches your issue:

Support replacement completions, e.g. substitute symbolic names (\alpha) with proper symbols (α).

[gwenn]

Could you please give #750 a try ?

[gwenn]

Version 13.0.0 released.

[sharkdp]

Thank you!