Created report

I didn't forget this time

1 files changed, 144 insertions, 0 deletions

diff --git a/Douglas_Richardson.md b/Douglas_Richardson.md
new file mode 100644
index 0000000..af86b16
--- /dev/null
+++ b/Douglas_Richardson.md
@@ -0,0 +1,144 @@
+# Hermes project report
+
+## Douglas Richardson
+### April 28, 2017
+
+# Overview
+Hermes is a multi-user chat program that allows users to setup a server, connect to it
+and communicate with all other members of the server.
+
+Hermes uses TCP pipes to tread input and output like a port. Essentially, each client sends
+information to the server and depending on the input, the server decides what to do with it
+and usually sends output back to all the other users.
+
+# Libraries Used
+The code uses two non-default libraries:
+
+```
+(require racket/gui/base)
+(require math/base)
+```
+
+* The ```racket/gui/base``` library is the primary library for the GUI.
+* the ```math/base``` is used for random number generation.
+
+# Key Code Excerpts
+
+Here is a discussion of the most essential procedures, including a description of how they embody ideas from 
+UMass Lowell's COMP.3010 Organization of Programming languages course.
+
+Five examples are shown and they are individually numbered. 
+
+## 1. Initializing the gui
+
+This line of code allows us to wrap the gui into an object.
+
+```
+(define (make-gui)
+      ...
+      (cond ((eq? command 'show) (lambda () (send main-frame show #t)))
+            ((eq? command 'get-color) get-my-color)
+            ((eq? command 'set-color) set-color)
+            ((eq? command 'prompt-color) prompt-color)
+            ((eq? command 'prompt-username) prompt-username)
+            ((eq? command 'prompt-hostname) prompt-hostname)
+            ((eq? command 'send) send-message) ;; call to show a message in a gui
+            ((eq? command 'set-name) (lambda (newname) (if (string? newname)
+                                                  (set! name newname)
+                                                  (print "Thats not good"))))
+            ; ((eq? command 'recieve-message) user-message)
+            ; ((eq? command 'get-list) listy)
+            ; ((eq? command 'set-list) update)
+            ;;Something up with that
+            ; else should assume a message and output to screen we do not want it
+            ; to fail
+            ((eq? command 'get-message) get-message)
+            (else (error "Invalid Request" command))
+            ))
+    ;;dispatch goes below that
+    dispatch)```
+
+This allows us to make our code simpler and lets us treat the gui like an object in it's self.
+Giving the gui commands to change it's self rather than having to remember all the commands it has.
+
+## 2. Working with lists
+
+This code is code that allows us to append a new message onto the end of the list of messages using recursion
+
+```
+(define (appendlist listoflist add-to-end)
+  (if (null? listoflist)
+      (cons add-to-end '())
+      (cons (car listoflist) (appendlist (cdr listoflist) add-to-end))))```
+      
+Normally there is a function to just append onto the end of a list, however the problem is that if we attempt to append
+a list of elements onto the end of a list, it just appends the elements onto the end of the list. For example if I had
+a list of the following '(("Doug" "Hello World!" "Purple")) 
+and wanted to append the list '("Gordon" "No one else is here Doug." "Black") The list I want back would be
+'(("Doug" "Hello World!" "Purple")("Gordon" "No one else is here Doug." "Black")) but if I use the default
+list append I get'(("Doug" "Hello World!" "Purple")"Gordon" "No one else is here Doug." "Black")
+which is no good for the gui.
+
+This follows on our idea of working with lists and using recursion to walk down a list.
+
+## 3. Re-drawing messages
+
+The following procedure is used to re-draw messages onto the canvas after a screen move or resize.
+
+```
+    (define (update-helper given-list)
+      (if (null? given-list)
+          '()
+          (if (null? (car given-list))
+              '()
+              (begin (user-message
+                      (get-username-from-list (car given-list))
+                      (get-message-from-list (car given-list))
+                      (get-color-from-list (car given-list)))
+                     (update-helper (cdr given-list))))))```
+
+While it doesn't actually use the map function, this is a map as for every element of a list (each element is a list of three strings)
+it runs a procedure (or in this case a set of procedures) in the order of the list.
+
+## 4. Parsing Messages
+
+This line of code is used to parse a single string message into a three string message
+
+```
+    (define (user-message-parse string-i start)
+        (define (helper str index)
+          (if (eq? (string-ref str (+ start index)) #\~) ; regexes would allow us
+                                                         ; to avoid this #\~
+              (substring str start (+ start index))
+              (helper str (+ index 1))))
+        (helper string-i 0))```
+
+This was used to parse a string into smaller strings. In hermes we can only send one string to each client at one time, therefore
+the three elements that the gui uses to print messages need to be compressed together. We append a ~ inbetween each of these so we can
+parse them out at the client end. 
+
+While we don't run any commands off it (saved that part for the commands we do interpret from strings) 
+it is similar to the symbolic differentaitor.
+
+## 5. Color setting
+ Here we have an example of when we use a symbolic differentiator in the gui to determine when a user wants to run a command
+ rather than input text.
+ 
+ ```
+ (define (button-do-stuff b e);b and e do nothing :/
+    (if (color-change-request? (send input get-value))
+        (set! my-color (get-color-from-input (send input get-value)))
+...
+ 
+ (define (color-change-request? given-string)
+  (if (> (string-length given-string) 7)
+      (if (equal? (substring given-string 0 6) "/color")
+          #t
+          #f)
+      #f))```
+
+The procedure button-do-stuff is run every time the user presses the return key or presses the send button on the gui
+and what it will do is check to see if the user typed in "/color", and if they did it sets the internal color to be 
+what the user said after that. This is part of our symbolic differentiator that allows the user to use commands
+rather than the typical use of the input (which is just to send a message to other clients)
+