Map a sequence of letters in insert mode

Question

I can already map a key combination in insert mode:

:inoremap abc <do stuff>

However, this has a few drawbacks:

• When typing a partial version of the sequence, such as ab, the characters aren't actually displayed for a short amount of time, since it's "waiting" to see whether you're going to type the full command. This is undesirable; I want to map a chain of letters without pausing if a partial substring of the chain is entered.

• If I type ab, then pause (and wait until the characters actually appear as mentioned in the above point), then type the c, the command is not executed. I want the command to be executed no matter how long I wait.

I would use an iab, but that doesn't work because:

1. It requires entering a space after the string
2. I can't execute arbitrary commands with it, only insert a string of text.

Is there any way to execute a command or keystrokes if a certain string is entered in insert mode, without using a map (which will annoyingly pause every time I type an a and not work if I wait too long)?

Answer 1

Here's one way to do that:

let s:inputBuffer = ''

augroup _silentInsertTrigger
    autocmd!
    autocmd InsertCharPre * call <sid>OnPreEnterChar()
    autocmd InsertLeave * call <sid>OnInsertLeave()
augroup END

function! s:OnPreEnterChar()
    let s:inputBuffer .= v:char

    if s:inputBuffer[-3:] ==# 'abc'
        echo '<do stuff>'
    endif

    return v:char
endfunction

function! s:OnInsertLeave()
    let s:inputBuffer = ''
endfunction