hub.darcs.net :: vincent -> align-equal -> issue

Joonkyu Park

The prefixLength function currently returns the length of the suffix when the input does not contain an = character.

This behavior causes misalignment when trying to align multiple lines containing = if at least one line does not have =.
In such cases, the = characters in other lines are pushed further to the right.

Steps to Reproduce:

prefixLength "test"
-- Expected: 0, an error, or a Maybe Int
-- Actual: 4 (length of the suffix)

Discussion on Expected Behavior:
There are multiple possible ways to handle this case:
1. Return 0 – Keeps it simple, but might hide errors.
2. Raise an error – Ensures incorrect input is caught early, but could be too strict.
3. Return Maybe Int – Explicitly distinguishes cases where = is missing.

I believe using Maybe Int would be the safest and most explicit approach, but I'm open to discussion on what the best behavior should be.

Proposed Solution:
Modify prefixLength to return Maybe Int, or alternatively, ensure that it returns 0 or raises an error when no = is found.