Bert and Bob --

Thanks for being so helpful, even though this is a classic case of RTFM.  I gotta say, I love the Squeak list.  

-----Original Message-----
From: Bert Freudenberg [mailto:bert at isg.cs.uni-magdeburg.de]
Sent: Thursday, December 27, 2001 10:48 AM
To: Brent Vukmer
Cc: squeak-dev at lists.squeakfoundation.org
Subject: Re: the magic behind "do it"


On Thu, 27 Dec 2001, Brent Vukmer wrote:

> Selecting "2 halt" and inspecting brought me to the method
> Compiler#evalute:in:to:notifying:ifFail.  I wrote a script to access
> this method directly ( see below ).  I am getting nil instead of 3.  
> When I debugged, it looks like the Parser is generating the following
> MethodNode:  DoIt
> 	^ nil
> 
> What do I need to do to get Compiler-love?
> 
> 
> | exprStream result failBlock |
> 
> exprStream  _ ReadWriteStream on: ''.
> exprStream nextPutAll: '1 + 2'.
> failBlock _ [ Transcript show: 'ArithmeticExpression#eval FAILED: ', exprStream contents. ].
> result _ Compiler new evaluate: exprStream in: nil to: nil notifying: nil ifFail: failBlock.
> ^ result

You need to reset the stream's position after writing to it:

	exprStream nextPutAll: '1 + 2'.
	exprStream reset.     "<--- insert"
	failBlock ...

Btw, on the class side of Compiler there are some handy methods to make 
live easier, try:

	 Compiler evaluate: '3 + 4'

-- Bert