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#
#	File:     lindstrp.icn
#
#	Subject:  Procedure to interpret L-system output as striped pattern
#
#	Author:   Ralph E. Griswold
#
#	Date:     March 25, 2002
#
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#
#   This file is in the public domain.
#
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#
#  Lindenmayer systems are usually are interpreted as specifications
#  for drawing plant-like objects, fractals, or other geometric designs.
#  This procedure illustrates that L-systems can be interpreted in other
#  ways -- as striped patterns, for example.
#
#  The procedure is called as lindstrp(prod, band_tbl) where prod is a
#  "production" that is interpreted as being a sequence of one-character
#  symbols, and band_tbl is a table with these symbols as keys whose
#  corresponding values are specifications for bands of the form
#  "color:width". An example of a table for the symbols A, B, and C is:
#
#	band_tbl := table()
#
#	band_tbl["A"] := "blue:3"
#	band_tbl["B"] := "red:10"
#	band_tbl["C"] := "black:5"
#  
#  With a table default of null, as above, symbols in prod that are not
#  table keys are effectively ignored.  Other table defaults
#  can be used to produce different behaviors for such symbols.
#
#  An example of a production is:
#
#	"ABCBABC"
#
#  The result is a string of band specifications for the striped pattern
#  represented by prod.  It can be converted to an image by using
#  strplang.icn, but graphics are not necessary for the use of this
#  procedure itself.
#
#  One thing this procedure is useful for is developing an understanding
#  of how to construct L-systems for specific purpose:  L-systems for
#  plant-like objects and fractals are require specialized knowledge and
#  are difficult to construct, while stripes are simple enough for
#  anyone to understand and develop L-systems for.
#
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#
#  See also linden.icn and lindsys.icn.
#
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procedure lindstrp(prod, band_tbl)
   local result

   result := ""

   every result ||:= \band_tbl[!prod] || ";"

   return result

end