Forgiving interactive mode: Do not terminate on invalid input

autoload/easy_align.vim

@@ -143,7 +143,9 @@ function! s:echon(l, n, r, d, o, warn)
   \ [['Identifier', a:d == ' ' ? '\ ' : (a:d == '\' ? '\\' : a:d)]])
   if a:r == -1 | call add(tokens, ['Comment', ')']) | endif
   call add(tokens, ['Statement', empty(a:o) ? '' : ' '.string(a:o)])
-  call add(tokens, ['WarningMsg', a:warn])
+  if !empty(a:warn)
+    call add(tokens, ['WarningMsg', ' ('.a:warn.')'])
+  endif
 
   call s:echon_(tokens)
 endfunction
@@ -561,7 +563,7 @@ function! s:atoi(str)
   return (a:str =~ '^[0-9]\+$') ? str2nr(a:str) : a:str
 endfunction
 
-function! s:interactive(modes, vis, opts)
+function! s:interactive(modes, vis, opts, delims)
   let mode = s:shift(a:modes, 1)
   let n    = ''
   let ch   = ''
@@ -607,9 +609,21 @@ function! s:interactive(modes, vis, opts)
     elseif ch == "\<C-I>"
       let opts['idt'] = s:shift(vals['indentation'], 1)
     elseif ch == "\<C-L>"
-      let opts['lm'] = s:atoi(s:input("Left margin: ", get(opts, 'lm', ''), a:vis))
+      let lm = s:input("Left margin: ", get(opts, 'lm', ''), a:vis)
+      if empty(lm)
+        let warn = 'Set to default. Input 0 to remove it'
+        silent! call remove(opts, 'lm')
+      else
+        let opts['lm'] = s:atoi(lm)
+      endif
     elseif ch == "\<C-R>"
-      let opts['rm'] = s:atoi(s:input("Right margin: ", get(opts, 'rm', ''), a:vis))
+      let rm = s:input("Right margin: ", get(opts, 'rm', ''), a:vis)
+      if empty(rm)
+        let warn = 'Set to default. Input 0 to remove it'
+        silent! call remove(opts, 'rm')
+      else
+        let opts['rm'] = s:atoi(rm)
+      endif
     elseif ch == "\<C-U>"
       let opts['iu'] = s:shift(vals['ignore_unmatched'], 1)
     elseif ch == "\<C-G>"
@@ -636,24 +650,40 @@ function! s:interactive(modes, vis, opts)
     elseif ch == "\<C-_>" || ch == "\<C-X>"
       let prompt = 'Regular expression: '
       let ch = s:input(prompt, '', a:vis)
-      if !empty(ch)
+      let s:prev_echon_len = len(prompt . ch)
+      if !empty(ch) && s:valid_regexp(ch)
         let regx = 1
-        let s:prev_echon_len = len(prompt . ch)
         break
+      else
+        let warn = 'Invalid regular expression: '.ch
       endif
     elseif ch =~ '[[:print:]]'
-      break
+      if has_key(a:delims, ch)
+        break
+      else
+        let warn = 'Unknown delimiter key: '.ch
+      endif
     else
-      let warn = ' - Invalid character'
+      let warn = 'Invalid character'
     endif
   endwhile
   return [mode, n, ch, s:normalize_options(opts), regx]
 endfunction
 
-function! s:test_regexp(regexp)
+function! s:valid_regexp(regexp)
-  try   | call matchlist('', a:regexp)
+  try
-  catch | call s:exit("Invalid regular expression: ". a:regexp)
+    call matchlist('', a:regexp)
+  catch
+    return 0
   endtry
+  return 1
+endfunction
+
+function! s:test_regexp(regexp)
+  if !s:valid_regexp(a:regexp)
+    call s:exit('Invalid regular expression: '. a:regexp)
+  endif
+  return a:regexp
 endfunction
 
 function! s:parse_args(args)
@@ -700,7 +730,7 @@ function! s:parse_args(args)
 
   " Found regexp
   if !empty(matches)
-    return [matches[1], matches[2], opts, 1]
+    return [matches[1], s:test_regexp(matches[2]), opts, 1]
   else
     let tokens = matchlist(args, '^\([1-9][0-9]*\|-[0-9]*\|\*\*\?\)\?\s*\(.\{-}\)\?$')
     return [tokens[1], tokens[2], opts, 0]
@@ -735,12 +765,17 @@ function! s:align(bang, first_line, last_line, expr)
   " Heuristically determine if the user was in visual mode
   let vis    = a:first_line == line("'<") && a:last_line == line("'>")
 
+  let delimiters = s:easy_align_delimiters_default
+  if exists('g:easy_align_delimiters')
+    let delimiters = extend(copy(delimiters), g:easy_align_delimiters)
+  endif
+
   if empty(a:expr)
-    let [mode, n, ch, opts, regexp] = s:interactive(copy(modes), vis, opts)
+    let [mode, n, ch, opts, regexp] = s:interactive(copy(modes), vis, opts, delimiters)
   else
     let [n, ch, opts, regexp] = s:parse_args(a:expr)
     if empty(n) && empty(ch)
-      let [mode, n, ch, opts, regexp] = s:interactive(copy(modes), vis, opts)
+      let [mode, n, ch, opts, regexp] = s:interactive(copy(modes), vis, opts, delimiters)
     elseif empty(ch)
       " Try swapping n and ch
       let [n, ch] = ['', n]
@@ -757,13 +792,7 @@ function! s:align(bang, first_line, last_line, expr)
     let nth = n
   endif
 
-  let delimiters = s:easy_align_delimiters_default
-  if exists('g:easy_align_delimiters')
-    let delimiters = extend(copy(delimiters), g:easy_align_delimiters)
-  endif
-
   if regexp
-    call s:test_regexp(ch)
     let dict = { 'pattern': ch }
   else
     " Resolving command-line ambiguity

test/basic.script

@@ -1 +1 @@
-4Gvipjyvip
+4Gvipjyvip

test/regexp.script

@@ -1 +1 @@
-4Gvipjyvip:EasyAlign:
+4Gvipjyvip:EasyAlign: