Refactor to add backtracking support

This probably doesn't help w/ error messages, but it enables some cool
ideas where syntax can be reused in cases where it would otherwise be
invalid

1 files changed, 7 insertions, 3 deletions

diff --git a/JPratt/src/main/java/bjc/pratt/commands/impls/UnaryCommand.java b/JPratt/src/main/java/bjc/pratt/commands/impls/UnaryCommand.java
index 2e7365b..657c004 100644
--- a/JPratt/src/main/java/bjc/pratt/commands/impls/UnaryCommand.java
+++ b/JPratt/src/main/java/bjc/pratt/commands/impls/UnaryCommand.java
@@ -2,6 +2,8 @@ package bjc.pratt.commands.impls;
 
 import bjc.pratt.ParserContext;
 import bjc.pratt.commands.AbstractInitialCommand;
+import bjc.pratt.commands.CommandResult;
+import bjc.pratt.commands.CommandResult.Status;
 import bjc.pratt.tokens.Token;
 import bjc.data.Tree;
 import bjc.data.SimpleTree;
@@ -37,10 +39,12 @@ public class UnaryCommand<K, V, C> extends AbstractInitialCommand<K, V, C> {
 	}
 
 	@Override
-	protected Tree<Token<K, V>> intNullDenotation(final Token<K, V> operator, final ParserContext<K, V, C> ctx)
+	protected CommandResult<K, V> intNullDenotation(final Token<K, V> operator, final ParserContext<K, V, C> ctx)
 			throws ParserException {
-		final Tree<Token<K, V>> opr = ctx.parse.parseExpression(nullPwer, ctx.tokens, ctx.state, false);
+		CommandResult<K,V> result = ctx.parse.parseExpression(nullPwer, ctx.tokens, ctx.state, false);
+		if (result.status != Status.SUCCESS) return result;
+		final Tree<Token<K, V>> opr = result.success();
 
-		return new SimpleTree<>(operator, opr);
+		return CommandResult.success(new SimpleTree<>(operator, opr));
 	}
 }
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