#162: Reimplemented Sub with trampoline.

parsingdata · Apr 20, 2017 · bd24aa0 · bd24aa0
1 parent c4cb37f
commit bd24aa0
Showing 1 changed file with 11 additions and 9 deletions.
diff --git a/core/src/main/java/io/parsingdata/metal/token/Sub.java b/core/src/main/java/io/parsingdata/metal/token/Sub.java
@@ -25,13 +25,17 @@
 import java.util.Objects;
 import java.util.Optional;
 
+import io.parsingdata.metal.Util;
 import io.parsingdata.metal.data.Environment;
 import io.parsingdata.metal.data.ImmutableList;
 import io.parsingdata.metal.data.ParseReference;
 import io.parsingdata.metal.data.Source;
 import io.parsingdata.metal.encoding.Encoding;
 import io.parsingdata.metal.expression.value.Value;
 import io.parsingdata.metal.expression.value.ValueExpression;
+import io.parsingdata.metal.token.util.FinalTrampoline;
+import io.parsingdata.metal.token.util.IntermediateTrampoline;
+import io.parsingdata.metal.token.util.Trampoline;
 
 /**
  * A {@link Token} that specifies a token to be parsed at a specific location
@@ -64,25 +68,23 @@ protected Optional<Environment> parseImpl(final String scope, final Environment
         if (addresses.isEmpty()) {
             return failure();
         }
-        final Optional<Environment> result = iterate(scope, addresses, environment.addBranch(this), encoding);
+        final Optional<Environment> result = iterate(scope, addresses, environment.addBranch(this), encoding).computeResult();
         if (result.isPresent()) {
             return success(result.get().closeBranch().seek(environment.offset));
         }
         return failure();
     }
 
-    private Optional<Environment> iterate(final String scope, final ImmutableList<Optional<Value>> addresses, final Environment environment, final Encoding encoding) throws IOException {
+    private Trampoline<Optional<Environment>> iterate(final String scope, final ImmutableList<Optional<Value>> addresses, final Environment environment, final Encoding encoding) throws IOException {
         if (!addresses.head.isPresent()) {
-            return failure();
+            return (FinalTrampoline<Optional<Environment>>) Util::failure;
         }
-        final long offset = addresses.head.get().asNumeric().longValue();
-        final Source source = environment.source;
-        final Optional<Environment> result = parse(scope, offset, source, environment, encoding);
+        final Optional<Environment> result = parse(scope, addresses.head.get().asNumeric().longValue(), environment.source, environment, encoding);
         if (result.isPresent()) {
-            if (addresses.tail.isEmpty()) { return result; }
-            return iterate(scope, addresses.tail, result.get(), encoding);
+            if (addresses.tail.isEmpty()) { return (FinalTrampoline<Optional<Environment>>) () -> result; }
+            return (IntermediateTrampoline<Optional<Environment>>) () -> iterate(scope, addresses.tail, result.get(), encoding);
         }
-        return failure();
+        return (FinalTrampoline<Optional<Environment>>) Util::failure;
     }
 
     private Optional<Environment> parse(final String scope, final long offset, final Source source, final Environment environment, final Encoding encoding) throws IOException {