Path: utzoo!utgpu!jarvis.csri.toronto.edu!clyde.concordia.ca!uunet!aplcen!haven!udel!new
From: new@udel.edu (Darren New)
Newsgroups: comp.lang.smalltalk
Subject: Re: How does the Smalltalk compiler work?
Message-ID: <7677@nigel.udel.EDU>
Date: 8 Jan 90 19:20:31 GMT
References: <1340@mit-amt.MEDIA.MIT.EDU> <5478@netcom.UUCP>
Sender: usenet@udel.EDU
Reply-To: new@udel.edu (Darren New)
Organization: University of Delaware
Lines: 35

In article <5478@netcom.UUCP> schang@netcom.UUCP (Sehyo Chang) writes:
>In article <1340@mit-amt.MEDIA.MIT.EDU> adamk@media-lab.media.mit.edu.UUCP (Adam Kao) writes:
>For example, expression 'x > 1 ifTrue: [exp1] ifFalse: [exp2]' are normal
>smalltalk expression with no control structure.  Both 'ifTrue' and 'ifFalse'
>methods are in implemented in 'Boolean' class, but differently in 'True'
>and 'False' class.  For reference, read 1981 Byte articles on smalltalk.

True up to a point, but then did you ever look at the whileTrue: message
works?  In actuallity, the compiler (at least the original ST-80 compiler)
had special-case code for ifTrue:, whileTrue:, et al, and generated
inline jump instructions (primarily for efficiency).  Otherwise,
such common stuff would be difficult to do efficiently and while-loops
would require recursive implementation, quickly running you out
of stack space. 


>>Basically I just need to know how the Smalltalk compiler is similar to
>>(for example) an ordinary C compiler, and how it is different.  I also
>It is not matter of difference in compliler, it is matter of difference
>between compiler(source-host machine) to interpreter(source-VM bytecodes),

All the Smalltalk compilers I have studied the internals of use 
recursive-descent parsing; this topic should be findable in any
reasonable compiler book.  No tables are used -- basically the 
program-counter encodes the major state of the parsing.

>...  There are two cheap ways to do it. (1) Get "little Smalltalk
>", or (2) Smalltalk/V from Digitalk.  But if you have some money, get  a
>ParcPlace's Smalltalk, they are more true to the original smalltalk-80.

Actually, Smalltalk-80 is only about $200 for Macs and IBMclones and
about $400 for Suns if you can get the educational discount; e.g.,
if your school buys it.  I think it is well worth it, myself, and their
support is super.  Don't quote me on prices. Send mail to
info@parcplace.com or info@parcplace.uucp.   LossaLuck -- Darren