Context sensitive insert mode mapping or abbreviation

Question

I'm planning to implement some utility mappings for my LaTeX plugin to simplify typing of mathematics. For instance, I want to create abbreviations similar to

`a : \alpha
`b : \beta
-> : \to
=> : \Rightarrow

And similar. I want (some of) the mappings only to be available inside math environments, and not outside.

I know that I can recognize math environments through the syntax groups, i.e. texMathZoneE and texMathZoneX. However, I do not know how to use this in order to make context sensitive mappings or abbreviations.

Answer 1

Perhaps like this:

let s:TeXmaps = {
    \ '`a': '\alpha',
    \ '`b': '\beta',
    \ '->': '\to',
    \ '=>': '\Rightarrow' }

function! <SID>IsTeXMath()
    return &ft ==# 'tex' && match(map( synstack(line('.'), col('.')), 'synIDattr(v:val, "name")' ), '\m^texMathZone[EX]$') >= 0
endfunction

for s:k in keys(s:TeXmaps)
    silent! exec 'inoremap <silent> ' . s:k . ' <C-r>=<SID>IsTeXMath()?' . string(s:TeXmaps[s:k]) . ':' . string(s:k) . '<CR>'
endfor

Answer 2

lh-brackets provides the Map4TheseContexts() function that takes care of detecting the context to do different things.

" To be defined in a tex ftplugin -> ~/.vim/ftplugin/tex/your-shortcuts.vim
:inoremap <buffer> <silent> `a <c-r>=Map4TheseContexts('`a', 'texMathZone', '\\alpha', '`a')<cr>
" or:
:inoremap <buffer> <silent> <expr> `a Map4TheseContexts('`a', 'texMathZone', '\\alpha', '`a')

Note: If you have installed latex-suite, you'll have instead to use its IMAP() function to define your new mappings -- this is because latex-suite is quite intrusive regarding mappings.