Hi
recently I started to read a book on machine learning and they
manipulate dictionary of dictionary. (So I started my own
implementation and I will switch to DataFrame).
Now it occurred to me that when we program complex objects we do not
need a compact literal syntax for our objects. But when we manipulate
data objects it is super handy.
I ended up doing a lot of
self new
addRow: 'Claudia Puig'
withTaggedValues:
{('Snakes on a Plane' -> 3.5). ('Just My Luck' -> 3.0).
('The Night Listener' -> 4.5). ('Superman Returns' -> 4.0). ('You, Me
and Dupree' -> 2.5)}.
And I was not in the mood to write a class for the taggedValues and
writing a class would not have really help me.
Now we also have STON but STON is not yet part of the language
grammar. So we have to have an explicit conversion call.
STON fromString: 'Point[10,20]'
We were brainstorming with marcus and we could have a first nice extension:
{ 'x' -> 10 .'y' -> 20 } asObjectOf: #Point.
>>> 10@20
Now in addition I think that there is a value in having an object
literal syntax.
I pasted the old mail of igor on object literals because I like the
idea since it does not add any change in the parser.
Do you remember what were the problem raised by this solution (beside
the fact that it had too many # and the order was like in ston not
explicit).
I would love to have another pass on the idea of Igor.
Stef
---------- Forwarded message ----------
From: Igor Stasenko <[email protected]>
Date: Fri, Oct 19, 2012 at 1:09 PM
Subject: [Pharo-project] Yet another Notation format: Object literals
To: Pharo Development <[email protected]>
Hi,
as i promised before, here the simple smalltalk-based literal format.
It based on smalltalk syntax, and so, unlike JSON, it doesn't needs to
have separate parser (a normal smalltalk parser used for that).
The idea is quite simple:
you can tell any object to represent itself as an 'object literal' ,
for example:
(1@3) asObjectLiteral
--> #(#Point 1 3)
{ 1@2. 3@4. true. false . nil } asObjectLiteral
-> #(#Array #(#Point 1 2) #(#Point 3 4) true false nil)
(Dictionary newFromPairs: { 1->#(1 2 3) . 'foo' -> 'bar' }) asObjectLiteral
->
#(#Dictionary 1 #(#Array 1 2 3) 'foo' 'bar')
Next thing, you can 'pretty-print' it (kinda):
#(#Dictionary 1 #(#Array 1 2 3) 'foo' 'bar') printObjectLiteral
'#(#Dictionary
1
(#Array 1 2 3)
''foo'' ''bar'')'
and sure thing, you can do reverse conversion:
'#(#Dictionary
1
(#Array 1 2 3)
''foo'' ''bar'')' parseAsObjectLiteral
a Dictionary('foo'->'bar' 1->#(1 2 3) )
Initially, i thought that it could be generic (by implementing default
Object>>#asObjectLiteral),
but then after discussing it with others, we decided to leave
Object>>#asObjectLiteral to be a subclass responsibility.
So, potentially the format allows to represent any object(s) as
literals, except from circular referencing objects, of course.
The implementation is fairly simple, as you may guess and contains no
new classes, but just extension methods here and there.
Take it with grain and salt, since it is just a small proof of
concept. (And if doing it for real it may need some changes etc).
Since i am far from areas right now, where it can be used, i don't
want to pursue it further or advocate if this is the right way to do
things.
Neither i having a public repository for this project..
So, if there anyone who willing to pick it up and pursue the idea
further, please feel free to do so and make a public repository for
project.
