Add exemplary hexyl plugin

plugins/hexyl.lua

@@ -0,0 +1,21 @@
+-- Note: this plugin depends on the existence of 'inspect' [1] and 'hexyl' [2]
+--
+-- [1] https://github.com/sharkdp/content_inspector
+-- [2] https://github.com/sharkdp/hexyl
+
+function is_binary(path)
+    local stream = assert(io.popen("inspect '" .. path .. "'"))
+    local output = stream:read('*all')
+    stream:close()
+    return string.find(output, ": binary\n")
+end
+
+function preprocess(path)
+    if is_binary(path) then
+        tmpfile = os.tmpname()
+        os.execute("hexyl --length 1024 --no-position --border=none --no-squeezing '" .. path .. "' > '" .. tmpfile .. "'")
+        return tmpfile
+    else
+        return path
+    end
+end