Refactor for DRY with explanitory comments

Author: alerque

autoload/ledger.vim

@@ -341,9 +341,9 @@ function! s:goto_col(pos, min_spaces)
   if diff > 0 | exec "normal!" diff . "a " | endif
 endf
 
-" Return substring position (in chars).
-function! s:strpos(expr, pat)
-  let pos = match(a:expr, a:pat)
+" Return character position of decimal separator (multibyte safe)
+function! s:decimalpos(expr)
+  let pos = match(a:expr, '\V' . g:ledger_decimal_sep)
   if pos > 0
     let pos = strchars(a:expr[:pos]) - 1
   endif
@@ -378,7 +378,7 @@ function! ledger#align_commodity()
     let pos = -1
     if g:ledger_decimal_sep != ''
       " Find the position of the first decimal separator:
-      let pos = s:strpos(rhs, '\V' . g:ledger_decimal_sep)
+      let pos = s:decimalpos(rhs)
     endif
     if pos < 0
       " Find the position after the first digits
@@ -399,7 +399,7 @@ function! ledger#align_amount_at_cursor()
   " Select and cut text:
   normal! viWd
   " Find the position of the decimal separator
-  let pos = s:strpos(@", '\V' . g:ledger_decimal_sep) " Returns zero when the separator is the empty string
+  let pos = s:decimalpos(@") " Returns zero when the separator is the empty string
   if pos <= 0
     let pos = len(@")
   endif