Abou Seven Languages In Seven Weeks Io,Day 2. Use js as extension name so the code can be highlighted.

deepsum.js

//For 3.3
//Create a nested list
li := list(1,2,3,list(3,4),"str")
//Flatten and only operate on Number and then sum them
List deepsum := method(
  self flatten select(isKindOf(Number)) sum
)
li deepsum

division.js

//For 3.2
if(Number getSlot("originalDivision"), //First check if the method have already been changed
  "Already changed" println, //Print message
  Number setSlot("originalDivision", Number getSlot("/")); //Save the original method
  //And then changed method to add code about "* / 0"
  Number setSlot("/", 
     method(denominator, 
	   if(denominator==0, 0, return(self   originalDivision(denominator))))))
//Test case  
3/0 println
5/2 println

fib.js

//For 3.1
Test := Object clone

Test fib := method(val, 
  if(val > 2, fib(val-1)+fib(val-2), 
  if(val <= 0, 0, 1)))

list(1,2,3,4,5,6,7,8) foreach(val, Test fib(val) print; ", " print);
  "Finished" println

Test fib_loop := method(val,
  if(val==1, return(1))
  p := 0
  n := 1
  c := 0
  for(i, 1, val-1, c=p+n;p=n;n=c); c)
list(1,2,3,4,5,6,7,8) foreach(val, Test fib_loop(val) print; ", " print);
  "Finished" println 

guess.js

//For 3.8
randomNumber := (Random value( 99 ) + 1) floor();
standardIO := File standardInput;
triedTimes := 0

10 repeat(
    "Guess number (1..100): " println;
    guess := standardIO readLine asNumber;
	triedTimes = triedTimes+1;
    if(
        (guess == randomNumber),
        break;
    );
	if(
	  guess > randomNumber,
	  "Too big" println,
	  "Too small" println
	);
);
if(
    (guess == randomNumber),
    (
        "Awesome! Excellent guess! You have tried #{triedTimes} times in total." interpolate println;
    ),
    (
        "Sorry, better luck next time. The answer is #{randomNumber}." interpolate println;
    )
);

matrix.js

//For 3.5
Matrix := List clone
Matrix dim := method(x, y,
  self setSize(x) map(list() setSize(y))
)
Matrix set := method(x, y, v,
  self at(x) atPut(y, v); self
)
Matrix get := method(x, y,
  self at(x) at(y)
)

matrix_io_file.js

//For 3.7
matrix := list(
    list( "A", 0, 0 ),
    list( "0", "B", "0" ),
    list( "0", "0", "C" )
);
filePath := "./data.txt"
dataFile := File open(filePath)
dataFile write(matrix serialized)
dataFile close
doMatrix := doFile(filePath)
("Matrix (size: " .. matrix size() .. ")") println();
matrix println();

("doFile Matrix (size: " .. doMatrix size() .. ")") println();
doMatrix println();

my_average.js

//For 3.4
//if any item is not kind of Number then raise an Exception
List myAverage := method(if(self size==0, return, 
  self flatten select(isKindOf(Number) 
  ifFalse(Exception raise("NaN")))
  average))

transpose.js

//For 3.6
Matrix transpose := method(
  new_x := self at(0) size;
  new_y := self size;
  new := Matrix dim(new_x, new_y);
  self foreach(x, xarray, 
    xarray foreach(y, yv, new set(y, x, self get(x, y))));
  return(new)
)