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RowBox-es

• To: mathgroup at smc.vnet.net
• Subject: [mg21338] RowBox-es
• From: "Drago Ganic" <drago.ganic at in2.hr>
• Date: Sun, 26 Dec 1999 01:26:15 -0500 (EST)
• Sender: owner-wri-mathgroup at wolfram.com

Hi,

I've got two questions concerning RowBoxes.

FIRST QUESTION
==============

Try (Mathematica 4)

FullForm[?N]

and you get an error message.

Show at the internel representation (using Format | Show Expression)

Cell[BoxData[
    RowBox[{"FullForm", "[", 
      RowBox[{"?", "N]"}]}]], "Input",
  CellLabel->"In[1]:="]

and changing it (deleting the internal RowBox) into 

Cell[BoxData[
    RowBox[{"FullForm", "[", "?", "N]"}]], "Input",
  CellLabel->"In[1]:="]

we get the right answer.

or (better) moving the outer bracket outside the inner RowBox we get

Cell[BoxData[
    RowBox[{"FullForm", "[", 
      RowBox[{"?", "N"}], "]"}]], "Input",
  CellLabel->"In[1]:="]

I believe Mathematica has problems in correctly interpretating the expression. Any comments ?


SECOND QUESTION
==================

In the Book David B. Wagner: "Power Programming with Mathematica THE KERNEL" on page
46 ther is an exercise 2.

The question is "What will happen with this Input" - notice the missing 2'nd comma

{2 + 3,
 4 + 5
 6 + 7
} // Trace

Evaluating the expression with MathKernel 3 or 4 we get the expected answer

{{2 + 3, 5}, {{5 6, 30}, 4 + 30 + 7, 41}, {5, 41}}

BUT, evaluating the expression with the notebook (especcially v4.0) I get an 
unexpected anser (wrong ??)


Output in Notebook v3.0
Syntax::"tsntxi":  "2+3, 4+5" is incomplete; more input is needed."

Output in Notebook v4.0
{{2 + 3, 5}, {4 + 6 + 7, 17}, {5, 17}} (* !!????!! *)

Of course the Notebook v4.0 gives the expected answer for the input in ONE line
In  {2 + 3, 4 + 5 6 + 7} // Trace
Out {{2 + 3, 5}, {{5 6, 30}, 4 + 30 + 7, 41}, {5, 41}}


I believe that the wrong behaiviour is not because of the new symbol "\[IndentingNewLine]"
(in v3.0: "\n", "\t" was used instead). It's because of the wrong use of RowBox-es.

Cell[BoxData[
    RowBox[{"{", 
      RowBox[{
        RowBox[{"2", "+", "3"}], ",", "\[IndentingNewLine]", 
        RowBox[{"4", "+", 
          RowBox[{"5", "\[IndentingNewLine]", "6"}], "+", 
          "7"}]}], "\[IndentingNewLine]", "}"}]], "Input",
  CellLabel->"In[6]:="]


But I wasn' able to change it to get the same bahaviour like v3.0.
Am I right ?


Greeting from Croatia,
Drago Ganic