#162: Simplified and unified parseImple() and iterate() methods in To…

…ken implementations.
parsingdata · Jun 13, 2017 · 4f0a8d9 · 4f0a8d9
1 parent a1e4bcc
commit 4f0a8d9
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Showing 8 changed files with 44 additions and 50 deletions.
diff --git a/core/src/main/java/io/parsingdata/metal/token/Post.java b/core/src/main/java/io/parsingdata/metal/token/Post.java
@@ -24,6 +24,7 @@
 import java.util.Objects;
 import java.util.Optional;
 
+import io.parsingdata.metal.Util;
 import io.parsingdata.metal.data.Environment;
 import io.parsingdata.metal.encoding.Encoding;
 import io.parsingdata.metal.expression.Expression;
@@ -52,12 +53,9 @@ public Post(final String name, final Token token, final Expression predicate, fi
 
     @Override
     protected Optional<Environment> parseImpl(final String scope, final Environment environment, final Encoding encoding) throws IOException {
-        final Optional<Environment> result = token.parse(scope, environment.addBranch(this), encoding);
-        if (result.isPresent()) {
-            final Environment newEnvironment = result.get();
-            return predicate.eval(newEnvironment.order, encoding) ? success(newEnvironment.closeBranch()) : failure();
-        }
-        return failure();
+        return token.parse(scope, environment.addBranch(this), encoding)
+            .map(nextEnvironment -> predicate.eval(nextEnvironment.order, encoding) ? success(nextEnvironment.closeBranch()) : failure())
+            .orElseGet(Util::failure);
     }
 
     @Override

diff --git a/core/src/main/java/io/parsingdata/metal/token/Pre.java b/core/src/main/java/io/parsingdata/metal/token/Pre.java
@@ -57,8 +57,7 @@ protected Optional<Environment> parseImpl(final String scope, final Environment
         if (!predicate.eval(environment.order, encoding)) {
             return failure();
         }
-        final Optional<Environment> result = token.parse(scope, environment.addBranch(this), encoding);
-        return result
+        return token.parse(scope, environment.addBranch(this), encoding)
             .map(resultEnvironment -> success(resultEnvironment.closeBranch()))
             .orElseGet(Util::failure);
     }

diff --git a/core/src/main/java/io/parsingdata/metal/token/Rep.java b/core/src/main/java/io/parsingdata/metal/token/Rep.java
@@ -49,14 +49,13 @@ public Rep(final String name, final Token token, final Encoding encoding) {
 
     @Override
     protected Optional<Environment> parseImpl(final String scope, final Environment environment, final Encoding encoding) throws IOException {
-        final Environment input = environment.addBranch(this);
-        return iterate(scope, Optional.of(input), encoding, input).computeResult();
+        return iterate(scope, environment.addBranch(this), encoding).computeResult();
     }
 
-    private Trampoline<Optional<Environment>> iterate(final String scope, final Optional<Environment> environment, final Encoding encoding, final Environment previous) {
-        return environment
-            .map(result -> intermediate(() -> iterate(scope, token.parse(scope, result, encoding), encoding, result)))
-            .orElseGet(() -> complete(() -> success(previous.closeBranch())));
+    private Trampoline<Optional<Environment>> iterate(final String scope, final Environment environment, final Encoding encoding) throws IOException {
+        return token.parse(scope, environment, encoding)
+            .map(nextEnvironment -> intermediate(() -> iterate(scope, nextEnvironment, encoding)))
+            .orElseGet(() -> complete(() -> success(environment.closeBranch())));
     }
 
     @Override

diff --git a/core/src/main/java/io/parsingdata/metal/token/RepN.java b/core/src/main/java/io/parsingdata/metal/token/RepN.java
@@ -63,17 +63,16 @@ protected Optional<Environment> parseImpl(final String scope, final Environment
         if (counts.size != 1 || !counts.head.isPresent()) {
             return failure();
         }
-        return iterate(scope, Optional.of(environment.addBranch(this)), encoding, counts.head.get().asNumeric().longValue()).computeResult();
+        return iterate(scope, environment.addBranch(this), encoding, counts.head.get().asNumeric().longValue()).computeResult();
     }
 
-    private Trampoline<Optional<Environment>> iterate(final String scope, final Optional<Environment> environment, final Encoding encoding, final long count) {
-        if (!environment.isPresent()) {
-            return complete(Util::failure);
-        }
+    private Trampoline<Optional<Environment>> iterate(final String scope, final Environment environment, final Encoding encoding, final long count) throws IOException {
         if (count <= 0) {
-            return complete(() -> success(environment.get().closeBranch()));
+            return complete(() -> success(environment.closeBranch()));
         }
-        return intermediate(() -> iterate(scope, token.parse(scope, environment.get(), encoding), encoding, count - 1));
+        return token.parse(scope, environment, encoding)
+            .map(nextEnvironment -> intermediate(() -> iterate(scope, nextEnvironment, encoding, count - 1)))
+            .orElseGet(() -> complete(Util::failure));
     }
 
     @Override

diff --git a/core/src/main/java/io/parsingdata/metal/token/Seq.java b/core/src/main/java/io/parsingdata/metal/token/Seq.java
@@ -53,17 +53,16 @@ public Seq(final String name, final Encoding encoding, final Token token1, final
 
     @Override
     protected Optional<Environment> parseImpl(final String scope, final Environment environment, final Encoding encoding) throws IOException {
-        return iterate(scope, Optional.of(environment.addBranch(this)), encoding, tokens).computeResult();
+        return iterate(scope, environment.addBranch(this), encoding, tokens).computeResult();
     }
 
-    private Trampoline<Optional<Environment>> iterate(final String scope, final Optional<Environment> environment, final Encoding encoding, final ImmutableList<Token> list) {
-        if (!environment.isPresent()) {
-            return complete(Util::failure);
-        }
+    private Trampoline<Optional<Environment>> iterate(final String scope, final Environment environment, final Encoding encoding, final ImmutableList<Token> list) throws IOException {
         if (list.isEmpty()) {
-            return complete(() -> success(environment.get().closeBranch()));
+            return complete(() -> success(environment.closeBranch()));
         }
-        return intermediate(() -> iterate(scope, list.head.parse(scope, environment.get(), encoding), encoding, list.tail));
+        return list.head.parse(scope, environment, encoding)
+            .map(nextEnvironment -> intermediate(() -> iterate(scope, nextEnvironment, encoding, list.tail)))
+            .orElseGet(() -> complete(Util::failure));
     }
 
     @Override

diff --git a/core/src/main/java/io/parsingdata/metal/token/Sub.java b/core/src/main/java/io/parsingdata/metal/token/Sub.java
@@ -68,19 +68,20 @@ protected Optional<Environment> parseImpl(final String scope, final Environment
         if (addresses.isEmpty()) {
             return failure();
         }
-        return iterate(scope, addresses, environment.offset, environment.addBranch(this), encoding).computeResult();
+        return iterate(scope, addresses, environment.addBranch(this), encoding).computeResult()
+            .flatMap(nextEnvironment -> success(nextEnvironment.seek(environment.offset)));
     }
 
-    private Trampoline<Optional<Environment>> iterate(final String scope, final ImmutableList<Optional<Value>> addresses, final long returnOffset, 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.isEmpty()) {
+            return complete(() -> success(environment.closeBranch()));
+        }
         if (!addresses.head.isPresent()) {
             return complete(Util::failure);
         }
-        final Optional<Environment> result = parse(scope, addresses.head.get().asNumeric().longValue(), environment.source, environment, encoding);
-        if (result.isPresent()) {
-            if (addresses.tail.isEmpty()) { return complete(() -> success(result.get().closeBranch().seek(returnOffset))); }
-            return intermediate(() -> iterate(scope, addresses.tail, returnOffset, result.get(), encoding));
-        }
-        return complete(Util::failure);
+        return parse(scope, addresses.head.get().asNumeric().longValue(), environment.source, environment, encoding)
+            .map(nextEnvironment -> intermediate(() -> iterate(scope, addresses.tail, nextEnvironment, encoding)))
+            .orElseGet(() -> complete(Util::failure));
     }
 
     private Optional<Environment> parse(final String scope, final long offset, final Source source, final Environment environment, final Encoding encoding) throws IOException {

diff --git a/core/src/main/java/io/parsingdata/metal/token/Tie.java b/core/src/main/java/io/parsingdata/metal/token/Tie.java
@@ -69,15 +69,15 @@ protected Optional<Environment> parseImpl(final String scope, final Environment
     }
 
     private Trampoline<Optional<Environment>> iterate(final String scope, final ImmutableList<Optional<Value>> values, final int index, final Environment returnEnvironment, final Environment environment, final Encoding encoding) throws IOException {
+        if (values.isEmpty()) {
+            return complete(() -> success(new Environment(environment.closeBranch().order, returnEnvironment.source, returnEnvironment.offset, returnEnvironment.callbacks)));
+        }
         if (!values.head.isPresent()) {
             return complete(Util::failure);
         }
-        final Optional<Environment> result = token.parse(scope, environment.source(dataExpression, index, environment, encoding), encoding);
-        if (result.isPresent()) {
-            if (values.tail.isEmpty()) { return complete(() -> success(new Environment(result.get().closeBranch().order, returnEnvironment.source, returnEnvironment.offset, returnEnvironment.callbacks))); }
-            return intermediate(() -> iterate(scope, values.tail, index + 1, returnEnvironment, result.get(), encoding));
-        }
-        return complete(Util::failure);
+        return token.parse(scope, environment.source(dataExpression, index, environment, encoding), encoding)
+            .map(nextEnvironment -> intermediate(() -> iterate(scope, values.tail, index + 1, returnEnvironment, nextEnvironment, encoding)))
+            .orElseGet(() -> complete(Util::failure));
     }
 
     @Override

diff --git a/core/src/main/java/io/parsingdata/metal/token/While.java b/core/src/main/java/io/parsingdata/metal/token/While.java
@@ -58,17 +58,16 @@ public While(final String name, final Token token, final Expression predicate, f
 
     @Override
     protected Optional<Environment> parseImpl(final String scope, final Environment environment, final Encoding encoding) throws IOException {
-        return iterate(scope, Optional.of(environment.addBranch(this)), encoding).computeResult();
+        return iterate(scope, environment.addBranch(this), encoding).computeResult();
     }
 
-    private Trampoline<Optional<Environment>> iterate(final String scope, final Optional<Environment> environment, final Encoding encoding) {
-        if (!environment.isPresent()) {
-            return complete(Util::failure);
+    private Trampoline<Optional<Environment>> iterate(final String scope, final Environment environment, final Encoding encoding) throws IOException {
+        if (predicate.eval(environment.order, encoding)) {
+            return token.parse(scope, environment, encoding)
+                .map(nextEnvironment -> intermediate(() -> iterate(scope, nextEnvironment, encoding)))
+                .orElseGet(() -> complete(Util::failure));
         }
-        if (predicate.eval(environment.get().order, encoding)) {
-            return intermediate(() -> iterate(scope, token.parse(scope, environment.get(), encoding), encoding));
-        }
-        return complete(() -> success(environment.get().closeBranch()));
+        return complete(() -> success(environment.closeBranch()));
     }
 
     @Override