[Io](http://www.iolanguage.com/)’s very self-documenting, at least when it comes to “what parameters does this and that take?” This is a little walk-through that gets you up and running in the interpreter. Get a binary from the downlaods page, and then come back here.
There is a docs slot — with some text about what the method does. First, let’s list a string (in Io, known as a Sequence, a sequence of characters, you know).
Whip out your Io interpreter, and write a string, and send the docs message to it:
Io> "olle" docs
==> Object_0x6d5020:
slots = Object_0x6d5060
There we go, a memory address for the docs, and a list of slots. Open that!
Io> "olle" docs slots
==> Object_0x6d5060:
alignCenter = Object_0x1120d90
alignLeft = Object_0x111fcf0
alignLeftInPlace = Object_0x111e810
alignRight = Object_0x1120530
findNthSeq = Object_0x1121870
interpolate = Object_0x11222f0
interpolateInPlace = Object_0x11226f0
removeSeq = Object_0x111f2d0
repeated = Object_0x6d4880
These contain documentation:
Io> "olle" docs slots repeated
==> Object_0x6d4880:
args = List_0x6d4e20
description = "Returns a new sequence containing the receiver repeated aNumber number of times."
That is nice. But, there are many more methods on a Sequence. Where are the rest? Answer: not yet documented like this. Let’s go find the others.
Io> Sequence slotSummary
==> "":
.. = method(arg, ...)
afterSeq = Sequence_afterSeq()
alignCenter = method(width, padding, ...)
alignLeft = method(width, padding, ...)
alignLeftInPlace = method(width, padding, ...)
alignRight = method(width, padding, ...)
append = Sequence_append()
appendPathSeq = Sequence_appendPathSeq()
appendSeq = Sequence_appendSeq()
asBinaryNumber = Sequence_asBinaryNumber()
asBuffer = Sequence_asBuffer()
asCapitalized = Sequence_asCapitalized()
asLowercase = Sequence_asLowercase()
asMessage = Sequence_asMessage()
asMutable = Sequence_asMutable()
asNumber = Sequence_asNumber()
asSimpleString = method(...)
asString = Sequence_asString()
asSymbol = Sequence_asSymbol()
asUppercase = Sequence_asUppercase()
at = Sequence_at()
atInsertSeq = Sequence_atInsertSeq()
atPut = Sequence_atPut()
--- SNIPPED, FOR HER PLEASURE ---
That’s more like it! Notice the difference in the right-hand listing.
asNumber = Sequence_asNumber()
asSimpleString = method(...)
asNumber has a fast C implementation (the function name is a hint there), but asSimpleString is pure Io.
The Io-implemented methods have their argument list with them, like alignRight. The ellipsis (…) stands for the method body.
It’s possible to return any Io slot, serialized as a string. That includes all Io-implemented methods! Use the getSlot() method:
Io> Sequence alignRight getSlot("serialized")
==> method(b, if(b ==(nil), setSlot("b", Sequence clone));
b appendSeq(self asMutable replaceSeq("\"", "\\\"") asSimpleString))
So, Io has some documentation, and you can read much of the code in the interpreter.
The [online reference docs](http://iolanguage.com/docs/reference/browser.cgi) are not to be trusted, but they are helpful at times.
