[e-lang] AST view of E program

[Kevin Reid]

On Oct 8, 2008, at 8:58, Marcelo D. Ré wrote:

>     I have problem to print the AST. I couldn't find the way to do  
> this. Where is the class or method makeEParse?

All Java classes are presented in E named as "makeX". The actual class  
name is org.erights.e.elang.syntax.EParser.

> I didn't find it in the JavaDoc (http://www.erights.org/javadoc/index.html 
> )

This is the method you want, for basic usage:

<http://www.erights.org/javadoc/org/erights/e/elang/syntax/EParser.html#run(org.erights.e.elib.tables.Twine) 
 >

> I need a program that print the on console AST view of a source.

There is no one true syntax for the AST besides normal Kernel-E  
syntax, but you can get a TermL form using a converter that's available:


? def convert := <elang:visitors.makeConvertENode2Term>()
# value: <convert>

? convert(e`def x4k3 := (x10 * 4).keep(3)`)
# value: term`def(finalP("x4k3"),
#                 call(call(noun("x10"),
#                           "multiply",
#                           [quote(4)]),
#                      "keep",
#                      [quote(3)]))`


If you must have this from Java, then provided that an E vat is  
already set up you can do this:


import org.erights.e.elib.tables.Twine;
import org.erights.e.elib.prim.E;
import org.erights.e.elang.syntax.EParser;
import org.erights.e.elang.evm.ENode;
import org.erights.e.elib.serial.Loader;

Object converter =
   E.call((Loader)(safeScope.get("import__uriGetter"))
            .get("org.erights.e.elang.visitors.makeConvertENode2Term"),
          "run");

ENode node = EParser.run(Twine.fromString(source_text, source_url));
System.out.print(E.call(converter, "run", node));


But really, I expect that a reasonably efficient IDE-support module  
would want to walk the ENode tree directly, not print it in any syntax.

-- 
Kevin Reid                            <http://homepage.mac.com/kpreid/>