Re: Using gpp preprocessor to create more easily svg code

On Tue, Feb 04, 2014 at 02:14:55AM -0800, [email protected] wrote:
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> Hello, i'am a french programmer since years, and i use often macro processors to give some facility to coding. 
>  SVG is not a functional langage, as JavaScript.
>  I think SVG is very powerful, and can be used alone, in some cases, without JS or external libraries.
>  So, i found GPP, a simple but powerful macro preprocessor, and write a 60 lines macros definitions to write easy SVG in texte files. GPP support #include and #define statements, so many usual svg definitions can be written in macros.
>  I give you some samples below :
>  
> 
>  The two following lines tell to use the macro user file (svg.inc), and create the xml and svg header, with x,y,width, height, and default viewport
>  
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>  #include "svg.inc"
>  SVG__("svg31",0,0,400,400)
>  
> 
>  Below is the SVG generated code (with GPP) :
>  
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>  <?xml version="1.0" encoding="utf-8"?><!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/D TD/svg11.dtd">
>  <svg version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" id="svg31" x="0" y="0" width="400" height="400" viewbox="0 0 400 400" xml:space="preserve">
>  
> 
>  The following lines create a <def> zone with some css statements :
>  
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>  DEF__
>  <!-- Css Defs -->
>  CSS__
>  _STY(_st1,_FSS(blue,1,red,2))
>  _STY(_st2,_FSS(red,0.5,green,4))
>  _STY(_st3,_FSS(none,1,black,1))
>  _STY(_st4,_FSS(green,1,yellow,1) _TSS("Comic sans Ms",1cm))
>  __CSS
>  __DEF
>  
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>  The _FSS macro define fill and stroke parameters
>  The _TSS macro define font-family and font-size parameters
>  
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>  The following lines define some graphic elements :
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>  _RCT("rec1",10,10,70,50,_st1,)
>  _CIR("cir1",120,120,30,_st2,)
>  _PTH("tri1","M120 20 L200 20 L150 50 L120 20",_st3,)
>  _TXT("txt1",10,100,_st4,Egc,)
>  
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>  _RCT is a <rect>, _CIR a circle, _PTH a path, _TXT a text
>  Each element have a style, and can integrate some animate tags as last argument.
>  
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>  I write the code as : source.txt
>  I use the console command : gpp source.txt -o result.svg
>  And i load result.svg in internet browser to see the svg file
>  Errors are very easy to see and correct.
>  
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> 
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>  I write some others macros to simplify gradients, filters, and animation tags.
>  
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>  Please, feedback if interested about this subject.
>  Thank you very much
>  
> 
>  Greetings to all svg'rs !
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And welcome to you, Yves.  Yes, I quite agree that SVG, even in isolation, has
remarkable potential.  While I probably won't myself adopt gpp as you've pre-
sented it here, I think your introduction to gpp is perfect:  you capture the
essentials of its use and hint at the benefits to coders, in just a few
easily-understood lines.  You surely influence the thinking of even those you
don't immediately "convert".

Yves, how do you express inclusion (nesting, hierarchy, ...) of elements (tags)
in your macro language?