diff --git a/misc/vim/syntax/factor.vim b/misc/vim/syntax/factor.vim
index 5cea099f45..ede8eb2707 100644
--- a/misc/vim/syntax/factor.vim
+++ b/misc/vim/syntax/factor.vim
@@ -48,8 +48,8 @@ syn keyword factorBoolean f t
 syn keyword factorBreakpoint B
 syn keyword factorFrySpecifier @ _ contained
 syn keyword factorDeclaration delimiter deprecated final flushable foldable inline recursive
-syn match factorCallQuotation /\<call(\s\(\S*\s\)\?--\(\s\S*\)\?\s)\>/
-syn match factorExecute /\<execute(\s\(\S*\s\)\?--\(\s\S*\)\?\s)\>/
+syn match factorCallQuotation /\<call(\s\+\(\S*\s\+\)*--\(\s\+\S*\)*\s\+)\>/ contained contains=factorStackEffect
+syn match factorExecute /\<execute(\s\+\(\S*\s\+\)*--\(\s\+\S*\)*\s\+)\>/ contained contains=factorStackEffect
 syn keyword factorCallNextMethod call-next-method
 
 syn keyword factorKeyword or 2bi 2tri while wrapper nip 4dip wrapper? bi* callstack>array both? hashcode die dupd callstack callstack? 3dup tri@ pick curry build ?execute 3bi prepose >boolean ?if clone eq? tri* ? = swapd 2over 2keep 3keep clear 2dup when not tuple? dup 2bi* 2tri* call tri-curry object bi@ do unless* if* loop bi-curry* drop when* assert= retainstack assert? -rot execute 2bi@ 2tri@ boa with either? 3drop bi curry? datastack until 3dip over 3curry tri-curry* tri-curry@ swap and 2nip throw bi-curry (clone) hashcode* compose 2dip if 3tri unless compose? tuple keep 2curry equal? assert tri 2drop most <wrapper> boolean? identity-hashcode identity-tuple? null new dip bi-curry@ rot xor identity-tuple boolean
@@ -148,8 +148,11 @@ syn match factorMultiStringContents /.*/ contained
 "syn match factorStackEffectErr /\<)\>/
 "syn region factorStackEffectErr start=/\<(\>/ end=/\<)\>/
 "syn region factorStackEffect start=/\<(\>/ end=/\<)\>/ contained
-syn match factorStackEffect /\<(\s\(\S*\s\)\?--\(\s\S*\)\?\s)\>/ contained
-syn match factorLiteralStackEffect /\<((\s\(\S*\s\)\?--\(\s\S*\)\?\s))\>/
+syn match factorStackEffect /(\s\+\(\S*\s\+\)*--\(\s\+\S*\)*\s\+)\>/ contained contains=factorStackDelims,factorStackItems,factorCallExecuteDelim
+syn match factorLiteralStackEffect /((\s\+\(\S*\s\+\)*--\(\s\+\S*\)*\s\+))\>/ contained contains=factorStackDelims,factorStackItems
+syn match factorStackItems contained "\<\S\+\>"
+syn keyword factorStackDelims contained ( ) (( )) --
+syn match factorCallExecuteDelim contained /(\s/
 
 "adapted from lisp.vim
 if exists("g:factor_norainbow")
@@ -199,6 +202,9 @@ if version >= 508 || !exists("did_factor_syn_inits")
     HiLink factorShebang                PreProc
     HiLink factorShebangErr             Error
     HiLink factorStackEffect            Typedef
+    HiLink factorStackDelims            Delimiter
+    HiLink factorCallExecuteDelim       Delimiter
+    HiLink factorStackItems             Identifier
     HiLink factorLiteralStackEffect     Typedef
     HiLink factorTodo                   Todo
     HiLink factorInclude                Include