So... You want an easy way to determine if a character is already defined as a digraph in Vim?
The easiest way I know to do this is to place your cursor over the character in question and then type ga . At the bottom of the Vim window you'll not only see the character, its decimal value, its hexadecimal value, and its octal value, but if it's a defined digraph you'll also see the character-pair that defines the digraph.
To illustrate, try this:
- Copy this text and paste it into Vim:
e è é ê ĕ ¿ ?
- In Vim, position your cursor over each of those characters and type:
ga
- For
e and ?, you should see a line at the bottom that lists its Unicode values in decimal, hexadecimal, and octal.
- But for the
è é ê ĕ ¿ characters, you should also see a Digr value that tells you what character-pair defines the digraph.
For example, when I put my cursor over ? and press ga, I see:
<¿> 191, Hex 00bf, Oct 277, Digr ?I
That final Digr ?I means that if you type <C-K>?I while in INSERT mode, Vim will output a ¿ character.
Note that a character may have more than one digraph associated with it. For instance, the ¿ can by typed with both <C-K>?I and <C-K>~? but the output of ga will only show you one of them.
Let me try this out on the Latin Cross:
When I position my cursor on ✝ and type ga, I see this at the bottom of my Vim window:
<✝> 10013, Hex 271d, Octal 23435
Since there is no Digr text in that output, I can assume that the Latin Cross does not have a pre-defined digraph.