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Re: this is ridiculous...

• To: mathgroup at smc.vnet.net
• Subject: [mg61815] Re: [mg61798] this is ridiculous...
• From: Selwyn Hollis <sh2.7183 at earthlink.net>
• Date: Mon, 31 Oct 2005 01:17:08 -0500 (EST)
• References: <200510300443.AAA09812@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

Chris,

Equal[x__] evaluates to True (as does Equal[]). HoldPattern is the fix:

In:    Equal[d, 2] /. HoldPattern[Equal[x__]] :> tree[x]

Out:   tree[d,2]

---
  Selwyn Hollis


On Oct 30, 2005, at 12:43 AM, Chris Chiasson wrote:

> Can anyone replicate the pattern replacement problem I am having  
> with Equal?
>
> Cell[CellGroupData[{Cell[BoxData[{
>     RowBox[{
>       RowBox[{"Equal", "[",
>         RowBox[{"d", ",", "2"}], "]"}], "/.",
>       RowBox[{
>         RowBox[{"Equal", "[", "x__", "]"}], "\[RuleDelayed]",
>         RowBox[{"tree", "[", "x", "]"}]}]}], "\[IndentingNewLine]",
>     RowBox[{
>       RowBox[{"willow", "[",
>         RowBox[{"d", ",", "2"}], "]"}], "/.",
>       RowBox[{
>         RowBox[{"willow", "[", "x__", "]"}], "\[RuleDelayed]",
>         RowBox[{"tree", "[", "x", "]"}]}]}], "\[IndentingNewLine]",
>   "$Version"}], "Input",
>   CellLabel->"In[1]:="],
>
> Cell[BoxData[
>     RowBox[{"d", "\[Equal]", "2"}]], "Output",
>   CellLabel->"Out[1]="],
>
> Cell[BoxData[
>     RowBox[{"tree", "[",
>       RowBox[{"d", ",", "2"}], "]"}]], "Output",
>   CellLabel->"Out[2]="],
>
> Cell[BoxData["\<\"5.2 for Microsoft Windows (June 20, 2005)\"\>"], \
> "Output",
>   CellLabel->"Out[3]="]
> }, Open  ]]
>
> --
> http://chrischiasson.com/contact/chris_chiasson
>
>

• References:
  • this is ridiculous...
    • From: Chris Chiasson <chris.chiasson@gmail.com>