Added programming language fundamentals code. More to come.

2025-11-09 21:51:15 +00:00 · 2018-01-06 23:10:08 -08:00
parent 51b0102711
commit 7b18f6a807
13 changed files with 1248 additions and 0 deletions
--- a/Fundamentals/Homework
+++ b/Fundamentals/Homework
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+-- | A module for rendering lines as an HTML5 file containing an SVG image.
+--   This can be used to visualize the denotational semantics of a MiniLogo
+--   program.
+--
+--   NOTE: You should not change the definitions in this file!
+--
+module Render (Point,Line,toHTML) where
+
+import Data.List (intercalate)
+
+
+-- | A point is a cartesian pair (x,y).
+type Point = (Int,Int)
+
+-- | A line is defined by its endpoints.
+type Line = (Point,Point)
+
+-- | Output a list of lines as an HTML5 file containing an SVG image.
+toHTML :: [Line] -> IO ()
+toHTML ls = writeFile "MiniMiniLogo.html" (header ++ content ls ++ footer)
+
+
+
+--
+-- Private definitions. All definitions below this point will not be visible
+-- from within a module that imports this module.
+--
+
+scale, margin, width, height :: Int
+scale  = 10
+margin = 10
+width  = 800
+height = 400
+
+style = "fill:white;stroke:red;stroke-width:2"
+
+title  = "<head><title>MiniLogo Semantics Viewer</title></head>"
+view   = "<svg width='100%' viewBox='0 0 "
+         ++ show (width + 2*margin) ++ " "
+         ++ show (height + 2*margin) ++ "'>"
+border = "<rect x='" ++ show (margin-3) ++
+             "' y='" ++ show (margin-3) ++
+         "' width='" ++ show (width +6) ++
+        "' height='" ++ show (height+5) ++
+         "' style='fill:none;stroke:black;stroke-width:2'/>"
+
+header = unlines ["<!DOCTYPE html>", "<html>", title, "<body>", view, border]
+footer = unlines ["</svg>","</body>","</html>"]
+
+content :: [Line] -> String
+content = unlines . map poly . chunk
+
+-- | A canvas-adjusted point as a string.
+point :: Point -> String
+point (x,y) = show xp ++ "," ++ show yp
+  where xp = x*scale + margin
+        yp = height - y*scale + margin
+
+-- | Chunk a bunch of lines into sequences of connected points.
+chunk :: [Line] -> [[Point]]
+chunk []         = []
+chunk [(p,q)]    = [[p,q]]
+chunk ((p,q):ls) | q == head ps = (p:ps) : pss
+                 | otherwise    = [p,q] : ps : pss
+  where (ps:pss) = chunk ls
+
+-- | Draw a sequence of connected points.
+poly :: [Point] -> String
+poly ps = "<polyline points='"
+       ++ intercalate " " (map point ps)
+       ++ "' style='" ++ style ++ "'/>"