The reason for the question is strictly pedagogical. I am learning Smalltalk and i am playing with implementation of a Cells type package ala LISP or pyCells and Cellulose from the Python world.
I do not really expect complete this, as I said its just a learning exercise.
The question around the instance variables stems from the fact that they appear to be tantalizingly close to the surface given the fact that the Browser recognizes undeclared identifiers and asks if they are temps or instance and then plugs in the code for me.
I am just too new to be able to figure out how to intercept the messages being sent.
Thanks for the help and suggestions.
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Today's Topics:
- How to introspect method instance variables (rdmerrio)
- Re: How to introspect method instance variables (Michael van der Gulik)
- Re: How to introspect method instance variables (Yoshiki Ohshima)
Message: 1 Date: Mon, 24 Aug 2009 21:16:16 -0500 From: rdmerrio rdmerrio@gmail.com Subject: [Newbies] How to introspect method instance variables To: beginners@lists.squeakfoundation.org Message-ID: 4A934970.4070202@gmail.com Content-Type: text/plain; charset=ISO-8859-1; format=flowed
I have defined a method, i.e.,
someMethod anInstVariable := anotherInstVariable1 + anotherInstVariable2.
I would like to intercept the acceptance of this method by the browser and programatically determine what instance variables this method is using so that I can grab these names for other processing tasks.
Additionally, I would really like to be able to determine what instance variables are being assigned to, for instance, anInstVariable in this case and which ones are the "independent" instance variables, anotherInstVariable1 and anotherInstVariable2 in this case.
How can I do this?
Thanks
Message: 2 Date: Tue, 25 Aug 2009 14:34:18 +1200 From: Michael van der Gulik mikevdg@gmail.com Subject: Re: [Newbies] How to introspect method instance variables To: "A friendly place to get answers to even the most basic questions about Squeak." beginners@lists.squeakfoundation.org Message-ID: 1b61adf40908241934ve0f2ba1iacb768b3b122b94d@mail.gmail.com Content-Type: text/plain; charset="iso-8859-1"
On Tue, Aug 25, 2009 at 2:16 PM, rdmerrio rdmerrio@gmail.com wrote:
I have defined a method, i.e.,
someMethod anInstVariable := anotherInstVariable1 + anotherInstVariable2.
I would like to intercept the acceptance of this method by the browser and programatically determine what instance variables this method is using so that I can grab these names for other processing tasks.
Additionally, I would really like to be able to determine what instance variables are being assigned to, for instance, anInstVariable in this case and which ones are the "independent" instance variables, anotherInstVariable1 and anotherInstVariable2 in this case.
How can I do this?
Why? What are you trying to achieve? You're talking about some pretty intrusive techniques. Unless you're developing a code analyser of some sort, you probably should be looking at a better way of doing what you're doing.
To capture the acceptance of a method (assuming you mean the action that happens when you press alt+s), you insert a bit of code into PluggableTextMorph>>accept.
To determine which instance variables are being assigned to, you'll need to somehow look at the bytecodes. They're not too hard to analyse, but it can be a bit of work. Alternatively, maybe the refactory browser can help, or maybe you can look at the intermediate code that the compiler generates.
The bytecodes are described here: http://burks.bton.ac.uk/burks/language/smaltalk/goldberg/blueb003.htm. They're in the "Blue book chapter 28" if you need to Google it. You'll want the "store" bytecodes.
To see real bytecodes, either inspect "Morph>>#basicInitialize" to see a CompiledMethod, or use the "byteCodes" view in a Browser (hidden behind the "source" button).
Gulik.