digitalmars.D.bugs - [Issue 3217] New: std.functional.binaryFunImpl doesn't support UDT with string functions , therefore neither does many std.algorithm functions
- d-bugmail puremagic.com (147/147) Jul 30 2009 http://d.puremagic.com/issues/show_bug.cgi?id=3217
- d-bugmail puremagic.com (10/10) Jul 30 2009 http://d.puremagic.com/issues/show_bug.cgi?id=3217
- d-bugmail puremagic.com (12/12) Aug 28 2009 http://d.puremagic.com/issues/show_bug.cgi?id=3217
http://d.puremagic.com/issues/show_bug.cgi?id=3217
Summary: std.functional.binaryFunImpl doesn't support UDT with
string functions , therefore neither does many
std.algorithm functions
Product: D
Version: 2.031
Platform: x86
OS/Version: Windows
Status: NEW
Keywords: patch
Severity: major
Priority: P2
Component: Phobos
AssignedTo: nobody puremagic.com
ReportedBy: sandford jhu.edu
std.functional.binaryFunImpl doesn't support user defined data types. As this
is used by many functions in std.algorithm, it represents a major loss of
function.
import std.functional;
import std.algorithm;
struct foo{
foo opAdd(foo f) {
return this;
}
}
void main(char[][] args) {
foo[] foos = new foo[5];
// binaryFunImpl!("a + b","a","b").Body!(foo,foo);
// writeln( reduce!"a + b"(foos) );
// C:\dmd\windows\bin\..\..\src\phobos\std\functional.d|191|Error: static
assert "Bad binary function q{a + b}. You need to use a valid D expression
using symbols a of type foo and b of type foo."|
// This is the failed static if
// static if (__traits(compiles, mixin(testAsExpression)))
// and testAsExpression equals
// {foo a; foo b; return (a + b);}()
static assert(__traits(compiles, mixin("{foo a; foo b; return (a +
b);}()")) == true );
static if (__traits(compiles, mixin("{foo a; foo b; return (a + b);}()")))
// okay
static assert(true);
else
static assert(false);
return;
}
I tried replacing ElementType1.stringof with "ElementType1",
ElementType2.stringof with , "ElementType2" which seemed to work:
The patch in brief:
enum testAsExpression = "{ ElementType1 "
~parm1Name~"; ElementType2 "
~parm2Name~"; return ("~fun~");}()";
The patch in full:
template binaryFunImpl(alias fun,
string parm1Name, string parm2Name)
{
static if (is(typeof(fun) : string))
{
template Body(ElementType1, ElementType2)
{
enum testAsExpression = "{ ElementType1 "
~parm1Name~"; ElementType2 "
~parm2Name~"; return ("~fun~");}()";
enum testAsStmts = "{ "~ElementType1.stringof~" "
~parm1Name~"; "~ElementType2.stringof~" "
~parm2Name~"; "~fun~"}()";
static if (__traits(compiles, mixin(testAsExpression)))
{
enum string code = "return (" ~ fun ~ ");";
alias typeof(mixin(testAsExpression)) ReturnType;
}
// else static if (__traits(compiles, mixin(testAsStmts)))
// {
// enum string code = fun;
// alias typeof(mixin(testAsStmts)) ReturnType;
// }
else
{
// Credit for this idea goes to Don Clugston
enum string msg =
"Bad binary function q{" ~ fun ~ "}."
~" You need to use a valid D expression using symbols "
~parm1Name~" of type "~ElementType1.stringof~" and "
~parm2Name~" of type "~ElementType2.stringof~"."
~(fun.length && fun[$ - 1] == ';'
? " The trailing semicolon is _not_ needed."
: "")
~(fun.length && fun[$ - 1] == '}'
? " The trailing bracket is mistaken."
: "");
static assert(false, msg);
}
}
Body!(ElementType1, ElementType2).ReturnType
result(ElementType1, ElementType2)
(ElementType1 __a, ElementType2 __b)
{
mixin("alias __a "~parm1Name~";");
mixin("alias __b "~parm2Name~";");
mixin(Body!(ElementType1, ElementType2).code);
}
}
else
{
alias fun result;
}
// static if (is(typeof(comp) : string))
// {
// // BUG1816 : typeof(mixin(comp)) should work
// typeof({
// static ElementType1 a;
// static ElementType2 b;
// return mixin(comp);
// }())
// binaryFun(ElementType1, ElementType2)
// (ElementType1 a, ElementType2 b)
// {
// return mixin(comp);
// }
// }
// else
// {
// alias comp binaryFun;
// }
}
The patch passes the unittests in functional.d. i.e.
unittest
{
alias binaryFun!(q{a < b}) less;
assert(less(1, 2) && !less(2, 1));
assert(less("1", "2") && !less("2", "1"));
static int f1(int a, string b) { return a + 1; }
static assert(is(typeof(binaryFun!(f1)(1, "2")) == int));
assert(binaryFun!(f1)(41, "a") == 42);
string f2(int a, string b) { return b ~ "2"; }
static assert(is(typeof(binaryFun!(f2)(1, "1")) == string));
assert(binaryFun!(f2)(1, "4") == "42");
assert(binaryFun!("a + b")(41, 1) == 42);
// BUG
//assert(binaryFun!("return a + b;")(41, 1) == 42);
}
As a note, unaryFunImpl uses "{ ElementType " as well, and it looks like
testAsStmts is dead code in each (grepping the source tree only turned up he
definition in functional.d). As testAsStmts also uses .stringof, which seems to
be wrong, I'd recommend either fixing or removing it in both templates.
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d-bugmail puremagic.com
http://d.puremagic.com/issues/show_bug.cgi?id=3217
Andrei Alexandrescu <andrei metalanguage.com> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |ASSIGNED
CC| |andrei metalanguage.com
AssignedTo|nobody puremagic.com |andrei metalanguage.com
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http://d.puremagic.com/issues/show_bug.cgi?id=3217
Andrei Alexandrescu <andrei metalanguage.com> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|ASSIGNED |RESOLVED
Resolution| |FIXED
09:21:34 PDT ---
Ok, thanks. I've integrated the patch. As for testAsStmts, it used to crash the
compiler so I'm leaving it commented (albeit corrected) for now.
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Aug 28 2009