Re: Decimal comma on input

• To: mathgroup at smc.vnet.net
• Subject: [mg60545] Re: Decimal comma on input
• From: "Jens-Peer Kuska" <kuska at informatik.uni-leipzig.de>
• Date: Tue, 20 Sep 2005 05:18:59 -0400 (EDT)
• Organization: Uni Leipzig
• References: <dgm112\$o3b\$1@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

```Hi,

don't do that ! or what is
lst={2,3,4,5}

a four element list of integers or a
two elemement list of floats ?
How knows ?

Regards
Jens

"Cca" <cca at gregosetroianos.mat.br> schrieb im
Newsbeitrag news:dgm112\$o3b\$1 at smc.vnet.net...
| Here in Brazil our decimal separator is a comma.
(This is the favoured convention in most non
English-speaking countries.) We also put dots
between each group of three digits. As an example,
the number whose numeral is
|
| 1234.56789
|
| in USA is represented in Brazil as
|
| NumberForm[1234.56789, DigitBlock->{3,3},
|  NumberPoint->",", NumberSeparator->"."]
|
| or also (following the SI)
|
| NumberForm[1234.56789, DigitBlock->{3,3},
|  NumberPoint->",", NumberSeparator->" "]
|
| This said, it is natutal to ask: how to instruct
Mathematica to recognize a decimal comma on input?
| solution is shown below, but I would be very
interested in knowing alternative approaches.
|
| ---------------------------------------------
| Instead of a "true" comma, I use one with hidden
information, namely
|
| TagBox[",", Identity, Editable->False,
SyntaxForm->"."] // DisplayForm
|
| with the following rule (which will work, of
course, only in the expected contexts):
|
| MakeExpression[RowBox[{a_,
| TagBox[",", Identity, Editable->False,
SyntaxForm->"."], b_}], form_] :=
MakeExpression[StringJoin[a, ".", b], form]
|
| Now we can try, for example, 2,3*3,5, 2,3+1,45,
etc.
| ---------------------------------------------
| Finally, to make it easy to insert the decimal
comma above I provide four ways to the user:
|
| (1) a button:
|
| ButtonBox[",", ButtonData->
|   TagBox[",", Identity, Editable->False,
SyntaxForm->"."]// DisplayForm
|
| (2) a rule for InputAliases (which overrides
\[InvisibleComma]);
|
| (3) a keyboard shortcut, for which I add the
following line to the file
KeyEventTranslations.tr:
|
|
{FrontEnd`NotebookWrite[FrontEnd`InputNotebook[],
| TagBox[",", Identity, Editable->False,
SyntaxForm->"."], After]}]]
|
| (4) a menu command (not well tested yet):
|
|     {Item["Decimal comma",
|         FrontEndExecute[{
|
FrontEnd`NotebookWrite[FrontEnd`InputNotebook[],
TagBox[",", Identity, Editable->False,
SyntaxForm->"."], After]}]]}]]
| ---------------------------------------------
|
| Carlos César de Araújo
| Gregos & Troianos Educacional
| www.gregosetroianos.mat.br
| Belo Horizonte, MG, Brazil
| (31) 3283-1122
|

```

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