Created
December 15, 2013 13:17
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The example problems have gone missing from the Io language website, so here’s a backup.
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#Sample code | |
#Hello world | |
"Hello world!" print | |
#Factorial | |
factorial := method(n, if(n == 1, 1, n * factorial(n - 1))) | |
99 bottles of beer | |
bottle := method(i, | |
if(i == 0, return "no more bottles") | |
if(i == 1, return "1 bottle") | |
return "" .. i .. " bottles" | |
) | |
for(i, 99, 1, | |
writeln(current, " of beer on the wall, ", current, " of beer,\n", | |
"take one down, pass it around,\n", | |
bottle(i - 1), " of beer on the wall.\n") | |
) | |
#Create a simple object and show how to use it | |
Account := Object clone | |
Account balance := 0 | |
Account deposit := method(v, balance = balance + v) | |
Account withdraw := method(v, balance = balance - v) | |
Account show := method( | |
writeln("Account balance: $", balance) | |
) | |
myAccount := Account clone | |
myAccount show | |
"Depositing $10\n" print | |
myAccount deposit(10) | |
myAccount show | |
#Concurrency example - the following will print "112233" | |
o1 := Object clone | |
o1 test := method(for(n, 1, 3, n print; yield)) | |
o2 := o1 clone | |
// @ means send an asynchronous message | |
o1 @test; o2 @test | |
// wait for the messages to get processed | |
while(Scheduler activeActorCount > 1, yield) | |
#Look up a class/prototype given its name as a string | |
Lobby getSlot("PrototypeName") | |
#Execute a method given its name as a string | |
anObject perform("SomeMethodName", arg1, arg2) | |
#Find out if a method with a given name (again a string) exists | |
anObject hasSlot("SomeMethodName") | |
#Given an arbitrary reference to a class/prototype, instantiate it | |
newInstance := objectRef clone | |
#Add a method to a primitive | |
Number double := method(self * 2) | |
1 double | |
==> 2 | |
#Subclass a primitive | |
MyList := List clone // Same as creating an instance | |
#Iterate through an inheritance hierarchy | |
Object printAllSlots := method( | |
self slotNames foreach(i, slotName, | |
writeln(slotName) | |
if(self hasSlot("proto"), self proto printAllSlots | |
) | |
) | |
Object printAllSlots | |
#Implement a generic proxy | |
Proxy = Object clone | |
Proxy forward := method( | |
methodName := thisMessage name | |
args := thisMessage argsEvaluatedIn(sender) | |
// When an unrecognized message is received, | |
// this method will be invoked. | |
// Do what you like with the message here - | |
// such as send it over a network, etc. | |
) | |
#Implement a singleton | |
Foo := Object clone | |
Foo clone := Foo | |
#Print the source code of a method | |
myMethod := method(return testing(1+2+3)) | |
getSlot("myMethod") code print | |
==> "return(testing(1+(2)+(3)))" | |
#Add an operator method to an object | |
MyObject := Object clone | |
MyObject setSlot("+", method(n, write("adding ", n, "\n"))) | |
MyObject + 123 | |
==> "adding 123" | |
#Mixins and Aspects | |
a := Object clone | |
Mix := Object clone | |
Mix logData := Buffer clone | |
Mix init := method(logData = logData clone) | |
Mix log := method(s, logData append(s)) | |
a parent := Mix clone // Now a also inherits the state and behavior of Mix | |
b := Object clone | |
b parent := Mix clone // Now multiple objects use it so it's an "aspect" | |
#An auto source file importer | |
Object searchPaths = List clone add(launchPath) | |
Object forward := method( | |
methodName := thisMessage name | |
if (methodName characterAt(0) isUpperCase, | |
searchPaths foreach(i, searchPath, | |
fileName := searchPath appendPath(methodName .. ".io") | |
sourceFile := File clone setPath(fileName) | |
if (sourceFile exists) then ( | |
Lobby doFile(path) | |
return Lobby getSlot(methodName) | |
) | |
) | |
) | |
raiseException("Importer", "Could not find slot for " .. methodName) | |
) | |
#A simple whois client | |
whois := method(host, | |
socket := Socket clone setHostName("rs.internic.net") setPort(43) | |
socket connect write(host, "\n") | |
while(socket readNextChunk, nil) // socket read auto yields to other coroutines | |
return socket readBuffer | |
) | |
#An echo server | |
Echo := Object clone | |
Echo handleSocket := method(socket, | |
while(socket isOpen, | |
if(socket read, socket write(socket readBuffer)) | |
socket readBuffer empty | |
) | |
) | |
EchoServer := Server clone setPort(8456) | |
EchoServer handleSocket := method(socket, | |
Echo clone @handleSocket(socket) | |
// async message so it's handled in separate coroutine | |
) | |
EchoServer start |
Also, working through 7 languages - thanks!
Thank you @jezen 👍
Also working through seven languages. Cheers!
@jezen Thanks a lot!
👍
Thanks for this great resource!!
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Thanks for the mirror, @jezen :) slowly working through 7 languages when I found this. Big help.