A problem with special character in Vim script

Question

I'm trying to build a diacritic plugin which It's just a list of commands like

ia <leader>'e é " this one is source just fine
ia <leader>ae æ " This one causes error

But I'm seeing an error E474 when the file gets sourced.

I can't find a way to debug it, any help with this?

Answer 1

Not every character sequences are acceptable for abbreviation (see: :h abbreviation).

To determine if a sequence is supported the last character is important.

If the last character is a non-keyword character (usually a letter, a number or an underscore) the sequence is supported (non-id sequence). Example are: #foo#, foo#, bar##

If the last character is a keyword character there are two types of sequence supported:

1. The part before is only made of keyword characters (full-id sequence). Example are: foo, bar
2. The part before is only made of non-keyword characters (end-id sequence). Example are: #a, #.#b

If the last character is a keyword you can't mix keyword and non-keyword on the first part. Example are: \ae

Remark: The definition of what is a keyword character can be configured using the iskeyword option (more information with :h 'iskeyword')

I could recommend you to either use the suffix approach:

ia e'\ é
ia ae\ æ

Or use the following answer that propose to check the character before the abbreviation and delete it before inserting the abbreviation.