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* Added an experimental feature suggested by Andres: ellipses ("...")

in attribute set pattern matches.  This allows defining a function
  that takes *at least* the listed attributes, while ignoring
  additional attributes.  For instance,

    {stdenv, fetchurl, fuse, ...}:
    
    stdenv.mkDerivation {
      ...
    };
    
  defines a function that requires an attribute set that contains the 
  specified attributes but ignores others.  The main advantage is that
  we can then write in all-packages.nix

    aefs = import ../bla/aefs pkgs;

  instead of

    aefs = import ../bla/aefs {
      inherit stdenv fetchurl fuse;
    };

  This saves a lot of typing (not to mention not having to update
  all-packages.nix with purely mechanical changes).  It saves as much
  typing as the "args: with args;" style, but has the advantage that
  the function arguments are properly declared (not implicit in what
  the body of the "with" uses).
This commit is contained in:
Eelco Dolstra 2008-08-14 14:00:44 +00:00
parent db4f4a8425
commit 9279174dde
14 changed files with 57 additions and 23 deletions

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

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@ -8,9 +8,12 @@ let
i = args@args2: args.x + args2.y;
j = {x, y, z, ...}: x + y + z;
in
f {x = "a"; y = "b"; z = "c";} +
g {x = "x"; y = "y"; z = "z";} +
h {x = "D";} +
h {x = "D"; y = "E"; z = "F";} +
i {x = "g"; y = "h";}
i {x = "g"; y = "h";} +
j {x = "i"; y = "j"; z = "k"; bla = "bla"; foo = "bar";}

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@ -22,6 +22,16 @@
<attr name="c">
<string value="foobar" />
</attr>
<attr name="ellipsis">
<function>
<attrspat>
<attr name="x" />
<attr name="y" />
<attr name="z" />
<ellipsis />
</attrspat>
</function>
</attr>
<attr name="f">
<function>
<attrspat>

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@ -14,4 +14,6 @@ rec {
at = args@{x, y, z}: x;
ellipsis = {x, y, z, ...}: x;
}

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@ -1 +1 @@
Function(AttrsPat([Formal("x",NoDefaultValue),Formal("y",NoDefaultValue),Formal("z",NoDefaultValue)]),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)

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@ -1 +1 @@
Function(AttrsPat([Formal("stdenv",NoDefaultValue),Formal("fetchurl",NoDefaultValue)]),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)

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@ -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")))]),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)