--- a/runtime/indent/j.vim
+++ b/runtime/indent/j.vim
@@ -2,7 +2,7 @@
 " Language:	J
 " Maintainer:	David Bürgin <676c7473@gmail.com>
 " URL:		https://github.com/glts/vim-j
-" Last Change:	2014-03-17
+" Last Change:	2014-04-05
 
 if exists('b:did_indent')
   finish
@@ -10,8 +10,8 @@ endif
 let b:did_indent = 1
 
 setlocal indentexpr=GetJIndent()
-setlocal indentkeys-=0{,0},\:,0#
-setlocal indentkeys+=0),=case.,=catch.,=catchd.,=catcht.,=do.,=else.,=elseif.,=end.,=fcase.
+setlocal indentkeys-=0{,0},:,0#
+setlocal indentkeys+=0),0<:>,=case.,=catch.,=catchd.,=catcht.,=do.,=else.,=elseif.,=end.,=fcase.
 
 let b:undo_indent = 'setlocal indentkeys< indentexpr<'
 
@@ -19,19 +19,31 @@ if exists('*GetJIndent')
   finish
 endif
 
-function GetJIndent()
+" If g:j_indent_definitions is true, the bodies of explicit definitions of
+" adverbs, conjunctions, and verbs will be indented. Default is false (0).
+if !exists('g:j_indent_definitions')
+  let g:j_indent_definitions = 0
+endif
+
+function GetJIndent() abort
   let prevlnum = prevnonblank(v:lnum-1)
   if prevlnum == 0
     return 0
   endif
-
   let indent = indent(prevlnum)
-  if getline(prevlnum) =~# '^\s*\%(case\|catch[dt]\=\|do\|else\%(if\)\=\|fcase\|for\%(_\a\k*\)\=\|if\|select\|try\|whil\%(e\|st\)\)\.'
-    if getline(prevlnum) !~# '\<end\.'
-      let indent += shiftwidth()
-    endif
+  let prevline = getline(prevlnum)
+  if prevline =~# '^\s*\%(case\|catch[dt]\=\|do\|else\%(if\)\=\|fcase\|for\%(_\a\k*\)\=\|if\|select\|try\|whil\%(e\|st\)\)\.\%(\%(\<end\.\)\@!.\)*$'
+    " Increase indentation after an initial control word that starts or
+    " continues a block and is not terminated by "end."
+    let indent += shiftwidth()
+  elseif g:j_indent_definitions && (prevline =~# '\<\%([1-4]\|13\|adverb\|conjunction\|verb\|monad\|dyad\)\s\+\%(:\s*0\|def\s\+0\|define\)\>' || prevline =~# '^\s*:\s*$')
+    " Increase indentation in explicit definitions of adverbs, conjunctions,
+    " and verbs
+    let indent += shiftwidth()
   endif
-  if getline(v:lnum) =~# '^\s*\%(\%(case\|catch[dt]\=\|do\|else\%(if\)\=\|end\|fcase\)\.\)\|)'
+  " Decrease indentation in lines that start with either control words that
+  " continue or end a block, or the special items ")" and ":"
+  if getline(v:lnum) =~# '^\s*\%()\|:\|\%(case\|catch[dt]\=\|do\|else\%(if\)\=\|end\|fcase\)\.\)'
     let indent -= shiftwidth()
   endif
   return indent