Initial data commit

Task/URL-decoding/Icon/url-decoding.icon

@@ -0,0 +1,22 @@
+link hexcvt
+
+procedure main()
+ue := "http%3A%2F%2Ffoo%20bar%2F"
+ud := decodeURL(ue) | stop("Improperly encoded string ",image(ue))
+write("encoded = ",image(ue))
+write("decoded = ",image(ue))
+end
+
+procedure decodeURL(s)              #: decode URL/URI encoded data
+static de
+initial {                           # build lookup table for everything
+  de := table()
+  every de[hexstring(ord(c := !string(&ascii)),2)] := c
+  }
+
+c := ""
+s ? until pos(0) do                 # decode every %xx or fail
+   c ||:= if ="%" then \de[move(2)] | fail
+   else move(1)
+return c
+end