(maxima.info)Introduction to alt-display

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39.1 Introduction to alt-display
================================

The _alt-display_ package provides a means to change the way that Maxima
displays its output.  The <*alt-display1d*> and <*alt-display2d*> Lisp
hooks were introduced to Maxima in 2002, but were not easily accessible
from the Maxima REPL until the introduction of this package.

   The package provides a general purpose function to define alternative
display functions, and a separate function to set the display function.
The package also provides customized display functions to produce output
in TeX, Texinfo, XML and all three output formats within Texinfo.

   Here is a sample session:

     (%i1) load("alt-display.mac")$
     (%i2) set_alt_display(2,tex_display)$

     (%i3) x/(x^2+y^2) = 1;
     \mbox{\tt\red({\it \%o_3}) \black}$${{x}\over{y^2+x^2}}=1$$

     (%i4) set_alt_display(2,mathml_display)$

     (%i5) x/(x^2+y^2) = 1;
     <math xmlns="http://www.w3.org/1998/Math/MathML"> <mi>mlabel</mi>
     <mfenced separators=""><msub><mi>%o</mi> <mn>5</mn></msub>
     <mo>,</mo><mfrac><mrow><mi>x</mi> </mrow> <mrow><msup><mrow>
     <mi>y</mi> </mrow> <mn>2</mn> </msup> <mo>+</mo> <msup><mrow>
     <mi>x</mi> </mrow> <mn>2</mn> </msup> </mrow></mfrac> <mo>=</mo>
     <mn>1</mn> </mfenced> </math>

     (%i6) set_alt_display(2,multi_display_for_texinfo)$

     (%i7) x/(x^2+y^2) = 1;

     @iftex
     @tex
     \mbox{\tt\red({\it \%o_7}) \black}$${{x}\over{y^2+x^2}}=1$$
     @end tex
     @end iftex
     @ifhtml
     @html

     <math xmlns="http://www.w3.org/1998/Math/MathML"> <mi>mlabel</mi>
     <mfenced separators=""><msub><mi>%o</mi> <mn>7</mn></msub>
     <mo>,</mo><mfrac><mrow><mi>x</mi> </mrow> <mrow><msup><mrow>
     <mi>y</mi> </mrow> <mn>2</mn> </msup> <mo>+</mo> <msup><mrow>
     <mi>x</mi> </mrow> <mn>2</mn> </msup> </mrow></mfrac> <mo>=</mo>
     <mn>1</mn> </mfenced> </math>
     @end html
     @end ifhtml
     @ifinfo
     @example
     (%o7) x/(y^2+x^2) = 1
     @end example
     @end ifinfo

   If the alternative display function causes an error, the error is
trapped and the display function is reset to the default display.  In
the following example, the 'error' function is set to display the
output.  This throws an error, which is handled by resetting the
2d-display to the default.

     (%i8) set_alt_display(2,?error)$

     (%i9) x;

     Error in *alt-display2d*.
     Messge: Condition designator ((MLABEL) $%O9 $X) is not of type (OR SYMBOL STRING
                                                                  FUNCTION).
     *alt-display2d* reset to nil.
      -- an error. To debug this try: debugmode(true);

     (%i10) x;
     (%o10)                                 x