Re: [Help-smalltalk] Which parser to use to parse the gnu-smalltalk code

[Junsong Li]

Thanks. Using STClassLoader to load the class and then walking the AST of
the class is the way to go! Done!

On Sun, Apr 12, 2015 at 1:34 PM, Holger Freyther <address@hidden> wrote:

>
> > On 12 Apr 2015, at 16:56, Junsong Li <address@hidden> wrote:
> >
> > Thanks. Basically what I want is just a method that compile the .st
> file, give me the root node of the AST, then I can traverse the AST and
> print out each kind of expression. I have tried _various_ classes in
> STInST, none of them works. Here is what I got. There are basically Drivers
> and Parsers for parsing:
>
> The general approach is to look at the testcases. E.g. to parse a class the
> first thing I found is:
>
> > (STInST.STParsingDriver new parseSmalltalkStream: 'Object subclass: Test
> [ method [ ^1 ] ]' readStream
> >   with: STInST.GSTFileInParser) parser
>
> Did you have a look at the test cases? E.g. the STClassLoader? And did you
> look
> at scripts/Convert.st which is using STInST to parse and re-format? At the
> same
> also at the STCompiler which inherits from the RBProgramNodeVisitor?
>
> The STInST.STParsingDriver hierarchy will load the code and call
> >>#evaluate:
> on each node. So you don’t get an AST of ASTs with this.
>
> But if you start the other way around. E.g. with the RBParser you can
> parse simple
> expressions like STInST.RBParser parseExpression: '3+3’ or even entire
> methods
> using STInST.RBBracketedMethodParser parseMethod: 'abc [ ^ 3]’ which will
> give
> you RBMethodNode.
>
> But starting from the STFileInparser subclass you need to provide a driver
> that
> will be called whenever something has been parsed. It is then up to you to
> decide
> what to do with the RB nodes.
>
>
>
> >
> > Then I am stuck on getting AST out. It appears to having no methods to
> return the AST node.  Anything wrong with it?
>
> You looked at the driver. IIRC they go through the classes but don’t store
> them. E.g. the
> STClassLoader loads a class and you can access a representation of the
> class then.
>
>
>