* Simplify @-patterns: only {attrs}@name' or name@{attrs}' are now

allowed.  So `name1@name2', `{attrs1}@{attrs2}' and so on are now no
  longer legal.  This is no big loss because they were not useful
  anyway.

  This also changes the output of builtins.toXML for @-patterns
  slightly.

tests/lang/eval-okay-patterns.exp

@@ -1 +1 @@
-Str("abcxyzDDDDEFghijk",[])
+Str("abcxyzDDDDEFijk",[])

tests/lang/eval-okay-patterns.nix

@@ -6,8 +6,6 @@ let
 
   h = {x ? "d", y ? x, z ? args.x}@args: x + y + z;
 
-  i = args@args2: args.x + args2.y;
-
   j = {x, y, z, ...}: x + y + z;
 
 in
@@ -15,5 +13,4 @@ in
   g {x = "x"; y = "y"; z = "z";} +
   h {x = "D";} +
   h {x = "D"; y = "E"; z = "F";} +
-  i {x = "g"; y = "h";} +
   j {x = "i"; y = "j"; z = "k"; bla = "bla"; foo = "bar";}

tests/lang/eval-okay-xml.exp.xml

@@ -6,14 +6,11 @@
     </attr>
     <attr name="at">
       <function>
-        <at>
-          <varpat name="args" />
-          <attrspat>
-            <attr name="x" />
-            <attr name="y" />
-            <attr name="z" />
-          </attrspat>
-        </at>
+        <attrspat name="args">
+          <attr name="x" />
+          <attr name="y" />
+          <attr name="z" />
+        </attrspat>
       </function>
     </attr>
     <attr name="b">
@@ -24,11 +21,10 @@
     </attr>
     <attr name="ellipsis">
       <function>
-        <attrspat>
+        <attrspat ellipsis="1">
           <attr name="x" />
           <attr name="y" />
           <attr name="z" />
-          <ellipsis />
         </attrspat>
       </function>
     </attr>

tests/lang/parse-okay-1.exp

@@ -1 +1 @@
-Function(AttrsPat([Formal("x",NoDefaultValue),Formal("y",NoDefaultValue),Formal("z",NoDefaultValue)],Bool(False)),OpPlus(OpPlus(Var("x"),Var("y")),Var("z")),NoPos)
+Function(AttrsPat([Formal("x",NoDefaultValue),Formal("y",NoDefaultValue),Formal("z",NoDefaultValue)],Bool(False),""),OpPlus(OpPlus(Var("x"),Var("y")),Var("z")),NoPos)

tests/lang/parse-okay-regression-20041027.exp

@@ -1 +1 @@
-Function(AttrsPat([Formal("stdenv",NoDefaultValue),Formal("fetchurl",NoDefaultValue)],Bool(False)),Call(Select(Var("stdenv"),"mkDerivation"),Attrs([Bind("name",Str("libXi-6.0.1",[]),NoPos),Bind("src",Call(Var("fetchurl"),Attrs([Bind("md5",Str("7e935a42428d63a387b3c048be0f2756",[]),NoPos),Bind("url",Str("http://freedesktop.org/~xlibs/release/libXi-6.0.1.tar.bz2",[]),NoPos)])),NoPos)])),NoPos)
+Function(AttrsPat([Formal("stdenv",NoDefaultValue),Formal("fetchurl",NoDefaultValue)],Bool(False),""),Call(Select(Var("stdenv"),"mkDerivation"),Attrs([Bind("name",Str("libXi-6.0.1",[]),NoPos),Bind("src",Call(Var("fetchurl"),Attrs([Bind("md5",Str("7e935a42428d63a387b3c048be0f2756",[]),NoPos),Bind("url",Str("http://freedesktop.org/~xlibs/release/libXi-6.0.1.tar.bz2",[]),NoPos)])),NoPos)])),NoPos)

tests/lang/parse-okay-subversion.exp

@@ -1 +1 @@
-Function(AttrsPat([Formal("localServer",DefaultValue(Var("false"))),Formal("httpServer",DefaultValue(Var("false"))),Formal("sslSupport",DefaultValue(Var("false"))),Formal("pythonBindings",DefaultValue(Var("false"))),Formal("javaSwigBindings",DefaultValue(Var("false"))),Formal("javahlBindings",DefaultValue(Var("false"))),Formal("stdenv",NoDefaultValue),Formal("fetchurl",NoDefaultValue),Formal("openssl",DefaultValue(Var("null"))),Formal("httpd",DefaultValue(Var("null"))),Formal("db4",DefaultValue(Var("null"))),Formal("expat",NoDefaultValue),Formal("swig",DefaultValue(Var("null"))),Formal("j2sdk",DefaultValue(Var("null")))],Bool(False)),Assert(OpNEq(Var("expat"),Var("null")),Assert(OpImpl(Var("localServer"),OpNEq(Var("db4"),Var("null"))),Assert(OpImpl(Var("httpServer"),OpAnd(OpNEq(Var("httpd"),Var("null")),OpEq(Select(Var("httpd"),"expat"),Var("expat")))),Assert(OpImpl(Var("sslSupport"),OpAnd(OpNEq(Var("openssl"),Var("null")),OpImpl(Var("httpServer"),OpEq(Select(Var("httpd"),"openssl"),Var("openssl"))))),Assert(OpImpl(Var("pythonBindings"),OpAnd(OpNEq(Var("swig"),Var("null")),Select(Var("swig"),"pythonSupport"))),Assert(OpImpl(Var("javaSwigBindings"),OpAnd(OpNEq(Var("swig"),Var("null")),Select(Var("swig"),"javaSupport"))),Assert(OpImpl(Var("javahlBindings"),OpNEq(Var("j2sdk"),Var("null"))),Call(Select(Var("stdenv"),"mkDerivation"),Attrs([Bind("builder",Path("/foo/bar"),NoPos),Bind("db4",If(Var("localServer"),Var("db4"),Var("null")),NoPos),Bind("expat",Var("expat"),NoPos),Bind("httpServer",Var("httpServer"),NoPos),Bind("httpd",If(Var("httpServer"),Var("httpd"),Var("null")),NoPos),Bind("j2sdk",If(Var("javaSwigBindings"),Select(Var("swig"),"j2sdk"),If(Var("javahlBindings"),Var("j2sdk"),Var("null"))),NoPos),Bind("javaSwigBindings",Var("javaSwigBindings"),NoPos),Bind("javahlBindings",Var("javahlBindings"),NoPos),Bind("localServer",Var("localServer"),NoPos),Bind("name",Str("subversion-1.1.1",[]),NoPos),Bind("openssl",If(Var("sslSupport"),Var("openssl"),Var("null")),NoPos),Bind("patches",If(Var("javahlBindings"),List([Path("/javahl.patch")]),List([])),NoPos),Bind("python",If(Var("pythonBindings"),Select(Var("swig"),"python"),Var("null")),NoPos),Bind("pythonBindings",Var("pythonBindings"),NoPos),Bind("src",Call(Var("fetchurl"),Attrs([Bind("md5",Str("a180c3fe91680389c210c99def54d9e0",[]),NoPos),Bind("url",Str("http://subversion.tigris.org/tarballs/subversion-1.1.1.tar.bz2",[]),NoPos)])),NoPos),Bind("sslSupport",Var("sslSupport"),NoPos),Bind("swig",If(OpOr(Var("pythonBindings"),Var("javaSwigBindings")),Var("swig"),Var("null")),NoPos)])),NoPos),NoPos),NoPos),NoPos),NoPos),NoPos),NoPos),NoPos)
+Function(AttrsPat([Formal("localServer",DefaultValue(Var("false"))),Formal("httpServer",DefaultValue(Var("false"))),Formal("sslSupport",DefaultValue(Var("false"))),Formal("pythonBindings",DefaultValue(Var("false"))),Formal("javaSwigBindings",DefaultValue(Var("false"))),Formal("javahlBindings",DefaultValue(Var("false"))),Formal("stdenv",NoDefaultValue),Formal("fetchurl",NoDefaultValue),Formal("openssl",DefaultValue(Var("null"))),Formal("httpd",DefaultValue(Var("null"))),Formal("db4",DefaultValue(Var("null"))),Formal("expat",NoDefaultValue),Formal("swig",DefaultValue(Var("null"))),Formal("j2sdk",DefaultValue(Var("null")))],Bool(False),""),Assert(OpNEq(Var("expat"),Var("null")),Assert(OpImpl(Var("localServer"),OpNEq(Var("db4"),Var("null"))),Assert(OpImpl(Var("httpServer"),OpAnd(OpNEq(Var("httpd"),Var("null")),OpEq(Select(Var("httpd"),"expat"),Var("expat")))),Assert(OpImpl(Var("sslSupport"),OpAnd(OpNEq(Var("openssl"),Var("null")),OpImpl(Var("httpServer"),OpEq(Select(Var("httpd"),"openssl"),Var("openssl"))))),Assert(OpImpl(Var("pythonBindings"),OpAnd(OpNEq(Var("swig"),Var("null")),Select(Var("swig"),"pythonSupport"))),Assert(OpImpl(Var("javaSwigBindings"),OpAnd(OpNEq(Var("swig"),Var("null")),Select(Var("swig"),"javaSupport"))),Assert(OpImpl(Var("javahlBindings"),OpNEq(Var("j2sdk"),Var("null"))),Call(Select(Var("stdenv"),"mkDerivation"),Attrs([Bind("builder",Path("/foo/bar"),NoPos),Bind("db4",If(Var("localServer"),Var("db4"),Var("null")),NoPos),Bind("expat",Var("expat"),NoPos),Bind("httpServer",Var("httpServer"),NoPos),Bind("httpd",If(Var("httpServer"),Var("httpd"),Var("null")),NoPos),Bind("j2sdk",If(Var("javaSwigBindings"),Select(Var("swig"),"j2sdk"),If(Var("javahlBindings"),Var("j2sdk"),Var("null"))),NoPos),Bind("javaSwigBindings",Var("javaSwigBindings"),NoPos),Bind("javahlBindings",Var("javahlBindings"),NoPos),Bind("localServer",Var("localServer"),NoPos),Bind("name",Str("subversion-1.1.1",[]),NoPos),Bind("openssl",If(Var("sslSupport"),Var("openssl"),Var("null")),NoPos),Bind("patches",If(Var("javahlBindings"),List([Path("/javahl.patch")]),List([])),NoPos),Bind("python",If(Var("pythonBindings"),Select(Var("swig"),"python"),Var("null")),NoPos),Bind("pythonBindings",Var("pythonBindings"),NoPos),Bind("src",Call(Var("fetchurl"),Attrs([Bind("md5",Str("a180c3fe91680389c210c99def54d9e0",[]),NoPos),Bind("url",Str("http://subversion.tigris.org/tarballs/subversion-1.1.1.tar.bz2",[]),NoPos)])),NoPos),Bind("sslSupport",Var("sslSupport"),NoPos),Bind("swig",If(OpOr(Var("pythonBindings"),Var("javaSwigBindings")),Var("swig"),Var("null")),NoPos)])),NoPos),NoPos),NoPos),NoPos),NoPos),NoPos),NoPos),NoPos)