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Let's say I print a cell like so.

  BoxData[" "], "Input", Evaluatable -> True, 
  CellEvaluationFunction -> Function[Print[#];]

Now I type in several lines of text in the Cell in Mathematica.

For example



I hit Shift+Enter and get the following output.


But when I do Ctrl+Shift+e, the Cells content is really

  RowBox[{" ", 
       "1", "\[IndentingNewLine]", "\[IndentingNewLine]", "3"}]}]]

Why doesn't CellEvaluationFuction receive the actual cell data? Is there a hidden function/argument that might give me such information?

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According to the docs, "CellEvaluationFunction is applied to the BoxData expression representing the input to be evaluated." [Emphasis mine.] The docs do not say that the Front End won't substitute some simplification of the expression in the cell. I believe for TagBox and InterpretationBox, the difference might be quite a bit different. At the least, one should not be surprised that any "typesetting" differences are stripped. –  Michael E2 Aug 1 '13 at 23:34
@MichaelE2 Okay then a workaround would be appreciated to achieve such functionality. I am working on a workaround using CellTags right now, but I have some doubts on how dependable it will be with multiple cells. –  William Aug 1 '13 at 23:37
Related: (13317) -- UndocumentedTestFEParserPacket[string, False] would give the unmodified Box form for that string. This is not directly applicable but it may be useful at some point. –  Mr.Wizard Aug 6 '13 at 7:31

1 Answer 1

up vote 6 down vote accepted

Make your CellEvaluationFunction this:


Note that EvaluationCell (and the CellObject it creates) are new to version 9.

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John, would you please take a look at my question here? Also, can this answer be made to work in v7 by using SelectionMove and EvaluationCell? –  Mr.Wizard Aug 6 '13 at 7:34
@Mr.Wizard I don't have version 7 to test but I willing to be this works in v7 also. Basically I just read the entire notebook and extract the needed Cell. You could probably use CellIds in replacement of CellTags. pastebin.com/FmCEPju6 –  William Aug 6 '13 at 15:31
@Mr.Wizard The use of EvaluationCell as a selector for SelectionMove, while no longer supported in v9, still seems to work, and also works in older versions. E.g., SelectionMove[EvaluationNotebook[], All, EvaluationCell] –  John Fultz Aug 6 '13 at 16:25
@JohnFultz Sorry for the confusion I was talking about my linked code. pastebin.com/FmCEPju6 I was responding to Mr.Wizard's comment. It doesn't use EvaluationCell but NoteebokRead[InputNotebook[]] –  William Aug 6 '13 at 16:26
@Liam Actually, my comment was confused and didn't make much sense. SE wouldn't let me edit it anymore, so I just deleted it. –  John Fultz Aug 6 '13 at 16:28

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