Added some notes
I'm in chapter 8, and this is what I'm thinking about the book...
Add inventory function

Now we can show which objects the player have collected while walking through
the scenario.
First version of a "help" command.

I guess that later on I should try to make Lisp print this in a more nice way
(lowercases) and such. It would be nice also to have a detailed help when the
user requires that so.
Frist version of a greeter.

Playing around with input/output console commands (print/read).
Second version of the greeter

I've just changed print for printc
Changed read for read-line

When using the regular "read" function, one need to specify the type of the
input. So, if in the example you wanted to introduce your name, and wanted it
to be treated as a string (as anyone would expect from a greeter), then you
need to specify is a string by adding double quotes when doing the input.

[1]> (say-hello)
Please type your name: Arturo
Nice to meet you, ARTURO
ARTURO
[2]> (say-hello)
Please type your name: "Arturo"
Nice to meet you, Arturo
"Arturo"
[3]>

Which is a bit of a hassle for the user. I have changed the read function for a
read-line function, so that it always expects a string as an input.

Print and Read functions in lisp has an interesting properties though, and it's
recommended to start with them before evolving the program to more targeted
options like princ, prin1, read-line, etc.
First version of the modified repl for the game
Changed the implementation of game-repl to be more flexible.

First step to customize the functions read, eval and print so that we offer a
custom and more human oriented repl.
Improving read to accept plain commands.

First step to make an easy to use interface for the game is to let the user put
plain commands forgeting about the parenthesis. He should not be aware he's
calling a lisp function.
Thus, I have modified the read-game function, with some tips, from the book,
now, it takes a commands, and it adds the "(" and ")", so that it is
interpreted correctly.
It is still a bit ugly though...
hardening the custom game-read function

Now it forces to interpret as a symbol every extra parameter passed to the
commands. In this manner we avoid the user to input arbitrary functions calls
in the parameters. I.E, if the user inputs the following bad intentioned
commands:
   walk (format-disk)

Read will transform this into:
   (walk '(format-disk))

So that when eval is called, it does not evaluate the parameter as data
'(format-disk) instead of calling the function format-disk.
Hardening of game-eval function

Now game-eval only filters the commands that are not defined for the game, in
this way, the game-repl only calls eval on the defined functions for the game.
Embelishment of the the print, 1st stage

Removing the parenthesis from the begining and end.
Printing embelishment :-)

After adding a couple of functions, the player is able to see the output from
the program as propper lowercases. In adition to this, the player does not need
to know which are objects and which are symbols, he just enters texts. Example
from a run:

[1]> (game-repl)
look
You are in the living-room. A wizzard is snoring loudly on the couch. There is a door going west from here. There is a ladder going upstairs from here. You see a whiskey on the
 floor. You see a bucket on the floor.
walk upstairs
You are in the attic. There is a gigant welding torch in the corner. There is a ladder going downstairs from here.
items
I do not know that command.
pickup torch
You cannot get that
pickup gigant
You cannot get that
walk downstairs
You are in the living-room. A wizzard is snoring loudly on the couch. There is a door going west from here. There is a ladder going upstairs from here. You see a whiskey on the
 floor. You see a bucket on the floor.
pickup whiskey
You are now carriying the whiskey
walk west
You are in a beatiful garden. There is a well in front of you there is a door going east from here. You see a chain on the floor.
pickup chain
You are now carriying the chain
walk east
You are in the living-room. A wizzard is snoring loudly on the couch. There is a door going west from here. There is a ladder going upstairs from here. You see a bucket on the
 floor.
inventory
Items- whiskey chain

Basically what I've done is to convert what needs to be printed into a string,
remove its parenthesis, and transform that into a list of characters. That is
passed to a "list eater" called tweak-text, that is putting the text in upper
or lower case. Last, the output from tweak-text is coerced back into string,
and passed to printc, which is printing it in the console.
Second version of the "help" command.

It is still a bit messy. Will see if I can refine it more in the future iterations