diff --git a/backend.py b/backend.py
index 17ce2ed..5dc3c69 100644
--- a/backend.py
+++ b/backend.py
@@ -1,4 +1,4 @@
-# 2.5.6 backend
+# 2.5.8 backend
 
 # written by VB.
 
@@ -232,6 +232,8 @@ class YF:
 
     def addValue(self, parm, value):
         if type(value) is str or type(value) is unicode:
+            if value[0] != "'" and value[0] != '"':
+                value = "'" + value + "'"
             self.values[parm] = u(evalPython(value))
         else:
             self.values[parm] = u(evalPython(u(value)))
diff --git a/heading.en.yhtml2 b/heading.en.yhtml2
index 1837621..fa73144 100644
--- a/heading.en.yhtml2
+++ b/heading.en.yhtml2
@@ -13,7 +13,7 @@ decl ne is a {
 div id=headline {
     p > YML – Why a Markup Language?!
     div class=small {
-        "YML 2.5.7 of Do 26 Apr 2018  –  Copyleft 2007-2018, "
+        "YML 2.5.8 of We 29 Aug 2018  –  Copyleft 2007-2018, "
         a "http://blog.fdik.org", "Volker Birk";
         " – "
         a "http://fdik.org/yml2.tar.bz2", "Download YML 2";
diff --git a/standardlib.ysl2 b/standardlib.ysl2
index 2e995fd..83dfe6e 100644
--- a/standardlib.ysl2
+++ b/standardlib.ysl2
@@ -1,3 +1,5 @@
+// YML2 standardlib version 2.5.8
+
 function "yml:hex2dec" {
     param "hex";
     param "_result", 0;
diff --git a/yml2.py b/yml2.py
index f8a98b2..c58ef63 100644
--- a/yml2.py
+++ b/yml2.py
@@ -1,4 +1,4 @@
-# YML 2.5.6 language definition
+# YML 2.5.8 language definition
 
 # written by VB.
 
@@ -66,7 +66,7 @@ def parm_eq():      return [xmlSymbol, pyExp, pointer, macro], "=", [value, poin
 parm_eq.__name__ = "parm"
 _func = [symbol, ppointer, pointer, reference], _if(newSyntax, (-1, ("[", listing(parm), "]"))), 0, ("(", listing(parm), ")"), 0, listing(parm), -1, parm_eq
 def pythonCall():   return keyword("python"), _func, [";", "."]
-def declParm():     return [pointer, macro, xmlSymbol], 0, ("=", literal)
+def declParm():     return [pointer, macro, xmlSymbol], 0, ("=", [literal, symbol])
 def alias():        return keyword("alias"), aliasSymbol
 def descend():      return r(r"[+@*]" + _symbol, re.U)
 def base():         return keyword("is"), symbol
diff --git a/yml2c b/yml2c
index e324dc1..70262c6 100755
--- a/yml2c
+++ b/yml2c
@@ -2,7 +2,7 @@
 # vim: set fileencoding=utf-8 :
 
 """\
-YML 2 compiler version 5.5
+YML 2 compiler version 5.8
 Copyleft (c), 2009-2011, Volker Birk  http://fdik.org/yml/
 
 """
diff --git a/yml2proc b/yml2proc
index d8c5225..5bcb78b 100755
--- a/yml2proc
+++ b/yml2proc
@@ -2,7 +2,7 @@
 # vim: set fileencoding=utf-8 :
 
 """\
-YML/YSLT 2 processor version 5.5
+YML/YSLT 2 processor version 5.8
 Copyleft (c), 2009-2011 Volker Birk  http://fdik.org/yml/
 
 """