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| package nuthatch.examples;
import static nuthatch.examples.xmpllang.full.XmplPatterns.*;
import nuthatch.examples.xmpllang.Stat;
import nuthatch.examples.xmpllang.Type;
import nuthatch.examples.xmpllang.XmplNode;
import nuthatch.examples.xmpllang.full.XmplActionFactory;
import nuthatch.examples.xmpllang.full.XmplCursor;
import nuthatch.examples.xmpllang.full.XmplWalker;
import nuthatch.library.Action;
import nuthatch.library.ActionBuilder;
import nuthatch.library.BaseAction;
import nuthatch.library.MatchBuilder;
import nuthatch.library.Walk;
public class EvalOrderWalk implements Walk<XmplWalker> {
final Action<XmplWalker> userAction;
final Action<XmplWalker> action;
public EvalOrderWalk(Action<XmplWalker> action) {
this.userAction = action;
XmplActionFactory af = XmplActionFactory.getInstance();
MatchBuilder<XmplNode, Type, XmplCursor, XmplWalker> mb = af.matchBuilder();
mb.add(Let(_, _, _), af.combine(
af.down(af.go(2)), // skip first child on way down
af.from(2, userAction), // perform action after visiting expression
af.from(3, userAction))); // also perform action after visiting body
mb.add(Declare(_, _, _), af.combine(
af.down(af.go(2)), // skip first child on way down
af.from(2, userAction), // perform action after visiting expression
af.from(3, userAction))); // also perform action after visiting body
mb.add(If(_, _, _), af.combine(
af.from(1, userAction), // perform action after visiting condition
af.from(2, af.go(PARENT)))); // skip else-branch if we took then-branch
mb.add(While(_, _), af.combine(
af.from(1, userAction), // perform action after visiting condition
af.from(2, userAction))); // also perform action after visiting body
mb.add(Assign(_, _), af.combine(//
af.down(af.go(2)), // skip first child on way down
af.from(2, userAction))); // perform action after visiting expression
mb.add(Seq(___), af.nop()); // don't visit sequences explicitly
mb.add(isExpr(), af.up(userAction));// any other expression, perform action on the way up
mb.add(isStat(), af.up(userAction));// any other statement, perform action on the way up
this.action = mb.first(); // do the first case that matches
}
@Override
public void init(XmplWalker walker) {
action.init(walker);
}
@Override
public int step(XmplWalker walker) {
int step = action.step(walker);
if(step == PROCEED) {
return NEXT;
}
else {
return step;
}
}
public static void main(String[] args) {
XmplActionFactory af = XmplActionFactory.getInstance();
final int[] i = new int[]{0};
Action<XmplWalker> printAction = new BaseAction<XmplWalker>(){
@Override
public int step(XmplWalker walker) {
System.out.printf(" %3d: %s\n", i[0]++, Printer.toTerm(walker.getData()));
return PROCEED;
}
};
ActionBuilder<XmplWalker> as = af.sequenceBuilder();
as.add(af.match(and(Var(var("x")), //
ancestor(and(Let(Var(var("x")), var("e"), _), from(3)))), //
af.replace(var("e")))); // replace by binding from matching Let
as.add(af.match(and(Var(var("x")), //
ancestor(and(Declare(Var(var("x")), var("e"), _), from(3)))), //
af.replace(var("e")))); // replace by binding from matching Let
as.add(af.down(af.match(Let(_, _, _), af.action(af.go(2)))));
// Drop all Lets on the way up
as.add(af.up(af.match(Let(_, _, var("e")), af.replace(var("e")))));
as.add(af.up(af.match(Declare(_, _, var("s")), af.replace(var("s")))));
Action<XmplWalker> inline = as.done();
for(Stat e : ExampleStat.allStats) {
i[0] = 0;
System.out.println(Printer.toTerm(e) + ":");
XmplWalker walker = new XmplWalker(e, new EvalOrderWalk(af.seq(printAction, inline)));
// run it
walker.start();
System.out.println(" => " + Printer.toTerm(walker.getData()));
System.out.println();
// print the contents of S
}
}
}
|
