From: "P.J. Hinton" <paulh@wolfram.com>
Subject: Re: Mathematica: Using "contexts"
Date: Fri, 24 Mar 2000 22:08:29 -0600
Newsgroups: sci.math.symbolic
Summary: [missing]

Questions specific to Mathematica may also be directed to the moderated
Usenet newsgroup comp.soft-sys.math.mathematica.  An information webpage
can be found at this URL:

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On 24 Mar 2000, Martin Johansson wrote:

<snip!>

> the "definition" of "UnitStep" is changed, i.e., there is not
> a new "UnitStep" in the SignalProcessing` context, but rather the
> version in the System` context is changed:
> 
> In[5]:= Attributes[UnitStep]
> Out[5]= {NumericFunction, Orderless, Protected}
> 
> In[6]:= Context[UnitStep]
> Out[6]= System`
> 
> In[7]:= UnitStep[{-1,0,1}]
> Out[7]= 0
> 
> Needless to say, the changed UnitStep function does not work with the
> rest of my code. Furthermore, Mathematica does not warn about the
> change of definition. This leads to the following questions:

<snip!>

> Q3. Is there are way of listing _all_ the contexts in which a function
>     exists?

You can use a wildcard operator (*) with the Information operation.
Continuing with our example above.

In[3]:= ? *`LogLogPlot
LogLogPlot                   Graphics`Graphics`LogLogPlot
  
> Q4. Is there a way of listing all functions defined in a given context?

Again, you can use a wildcard operator.

In[4]:= ? Graphics`Graphics`*
BarChart                     LogLinearPlot
BarEdges                     LogListPlot
BarEdgeStyle                 LogLogListPlot
BarGroupSpacing              Graphics`Graphics`LogLogPlot
BarLabels                    LogPlot
BarOrientation               LogScale
BarSpacing                   PercentileBarChart
BarStyle                     PieChart
BarValues                    PieExploded
DisplayTogether              PieLabels
DisplayTogetherArray         PieLineStyle
ErrorListPlot                PieStyle
GeneralizedBarChart          PiScale
Histogram                    PolarListPlot
LabeledListPlot              PolarPlot
LinearLogListPlot            ScaledListPlot
LinearLogPlot                ScaledPlot
LinearScale                  SkewGraphics
ListAndCurvePlot             StackedBarChart
LogGridMajor                 TextListPlot
LogGridMinor                 TransformGraphics
LogLinearListPlot            UnitScale
 
> Q5. Is the Signal and Systems package "compatible" with Mma v.4?

A revision that has been tested with Mathematica 4 is available for users
who have registered their copy of this software.  See this URL:

http://www.wolfram.com/products/applications/updates/

If you have further questions, you are encouraged to contact Wolfram
Research Technical Support.

http://www.wolfram.com/services/techsupport/contact.html

-- 
P.J. Hinton
Mathematica Programming Group           paulh@wolfram.com
Wolfram Research, Inc.
Disclaimer: Opinions expressed herein are those of the author alone.