* 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

View file

@ -84,11 +84,12 @@ static void patternMatch(EvalState & state,
ATerm name;
ATermList formals;
Pattern pat1, pat2;
ATermBool ellipsis;
if (matchVarPat(pat, name))
subs.set(name, arg);
else if (matchAttrsPat(pat, formals)) {
else if (matchAttrsPat(pat, formals, ellipsis)) {
arg = evalExpr(state, arg);
@ -122,8 +123,8 @@ static void patternMatch(EvalState & state,
}
/* Check that each actual argument is listed as a formal
argument. */
if (attrsUsed != nrAttrs)
argument (unless the attribute match specifies a `...'). */
if (ellipsis == eFalse && attrsUsed != nrAttrs)
throw TypeError(format("the function does not expect an argument named `%1%'")
% aterm2String(attrs.begin()->key));
}
@ -402,9 +403,10 @@ Expr autoCallFunction(Expr e, const ATermMap & args)
Pattern pat;
ATerm body, pos;
ATermList formals;
ATermBool ellipsis;
/* !!! this should be more general */
if (matchFunction(e, pat, body, pos) && matchAttrsPat(pat, formals)) {
if (matchFunction(e, pat, body, pos) && matchAttrsPat(pat, formals, ellipsis)) {
ATermMap actualArgs(ATgetLength(formals));
for (ATermIterator i(formals); i; ++i) {

View file

@ -45,15 +45,17 @@ static void printPatternAsXML(Pattern pat, XMLWriter & doc)
ATerm name;
ATermList formals;
Pattern pat1, pat2;
ATermBool ellipsis;
if (matchVarPat(pat, name))
doc.writeEmptyElement("varpat", singletonAttrs("name", aterm2String(name)));
else if (matchAttrsPat(pat, formals)) {
else if (matchAttrsPat(pat, formals, ellipsis)) {
XMLOpenElement _(doc, "attrspat");
for (ATermIterator i(formals); i; ++i) {
Expr name; ATerm dummy;
if (!matchFormal(*i, name, dummy)) abort();
doc.writeEmptyElement("attr", singletonAttrs("name", aterm2String(name)));
}
if (ellipsis == eTrue) doc.writeEmptyElement("ellipsis");
}
else if (matchAtPat(pat, pat1, pat2)) {
XMLOpenElement _(doc, "at");

View file

@ -95,6 +95,7 @@ let { return LET; }
in { return IN; }
rec { return REC; }
inherit { return INHERIT; }
\.\.\. { return ELLIPSIS; }
\=\= { return EQ; }
\!\= { return NEQ; }

View file

@ -66,7 +66,7 @@ PrimOp | int ATermBlob ATermList | Expr |
Attrs | ATermList | Expr |
Closed | Expr | Expr |
Rec | ATermList ATermList | Expr |
Bool | ATerm | Expr |
Bool | ATermBool | Expr |
Null | | Expr |
Bind | string Expr Pos | ATerm |
@ -76,7 +76,7 @@ Inherit | Expr ATermList Pos | ATerm |
Scope | | Expr |
VarPat | string | Pattern |
AttrsPat | ATermList | Pattern |
AttrsPat | ATermList ATermBool | Pattern | # bool = `...'
AtPat | Pattern Pattern | Pattern |
Formal | string DefaultValue | ATerm |
@ -84,8 +84,8 @@ Formal | string DefaultValue | ATerm |
DefaultValue | Expr | DefaultValue |
NoDefaultValue | | DefaultValue |
True | | ATerm |
False | | ATerm |
True | | ATermBool |
False | | ATermBool |
PrimOpDef | int ATermBlob | ATerm |

View file

@ -115,11 +115,12 @@ static void varsBoundByPattern(ATermMap & map, Pattern pat)
ATerm name;
ATermList formals;
Pattern pat1, pat2;
ATermBool ellipsis;
/* Use makeRemoved() so that it can be used directly in
substitute(). */
if (matchVarPat(pat, name))
map.set(name, makeRemoved());
else if (matchAttrsPat(pat, formals)) {
else if (matchAttrsPat(pat, formals, ellipsis)) {
for (ATermIterator i(formals); i; ++i) {
ATerm d1;
if (!matchFormal(*i, name, d1)) abort();

View file

@ -24,6 +24,7 @@ typedef ATerm Expr;
typedef ATerm DefaultValue;
typedef ATerm Pos;
typedef ATerm Pattern;
typedef ATerm ATermBool;
/* A STL vector of ATerms. Should be used with great care since it's

View file

@ -208,16 +208,22 @@ static void freeAndUnprotect(void * p)
%union {
ATerm t;
ATermList ts;
struct {
ATermList formals;
bool ellipsis;
} formals;
}
%type <t> start expr expr_function expr_if expr_op
%type <t> expr_app expr_select expr_simple bind inheritsrc formal
%type <t> pattern pattern2
%type <ts> binds ids expr_list formals string_parts ind_string_parts
%type <ts> binds ids expr_list string_parts ind_string_parts
%type <formals> formals
%token <t> ID INT STR IND_STR PATH URI
%token IF THEN ELSE ASSERT WITH LET IN REC INHERIT EQ NEQ AND OR IMPL
%token DOLLAR_CURLY /* == ${ */
%token IND_STRING_OPEN IND_STRING_CLOSE
%token ELLIPSIS
%nonassoc IMPL
%left OR
@ -326,7 +332,7 @@ pattern
pattern2
: ID { $$ = makeVarPat($1); }
| '{' formals '}' { $$ = makeAttrsPat($2); }
| '{' formals '}' { $$ = makeAttrsPat($2.formals, $2.ellipsis ? eTrue : eFalse); }
;
binds
@ -357,9 +363,14 @@ expr_list
;
formals
: formal ',' formals { $$ = ATinsert($3, $1); } /* idem - right recursive */
| formal { $$ = ATinsert(ATempty, $1); }
| { $$ = ATempty; }
: formal ',' formals /* idem - right recursive */
{ $$.formals = ATinsert($3.formals, $1); $$.ellipsis = $3.ellipsis; }
| formal
{ $$.formals = ATinsert(ATempty, $1); $$.ellipsis = false; }
|
{ $$.formals = ATempty; $$.ellipsis = false; }
| ELLIPSIS
{ $$.formals = ATempty; $$.ellipsis = true; }
;
formal
@ -401,13 +412,14 @@ static void checkPatternVars(ATerm pos, ATermMap & map, Pattern pat)
ATerm name;
ATermList formals;
Pattern pat1, pat2;
ATermBool ellipsis;
if (matchVarPat(pat, name)) {
if (map.get(name))
throw EvalError(format("duplicate formal function argument `%1%' at %2%")
% aterm2String(name) % showPos(pos));
map.set(name, name);
}
else if (matchAttrsPat(pat, formals)) {
else if (matchAttrsPat(pat, formals, ellipsis)) {
for (ATermIterator i(formals); i; ++i) {
ATerm d1;
if (!matchFormal(*i, name, d1)) abort();

View file

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

View file

@ -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";}

View file

@ -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>

View file

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

View file

@ -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)

View file

@ -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)

View file

@ -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)