Refactor front-end error-handling

This refactors the front-end to use a tree for capturing errors, instead
of throwing exceptions.

This has the benefit that you will receive notifications about all of
the error messages you have, instead of only the first.

I'm a bit fuzzy on the details, since it's been a while since I wrote
these changes.

1 files changed, 27 insertions, 3 deletions

diff --git a/src/main/java/bjc/rgens/parser/templates/LiveTemplateElement.java b/src/main/java/bjc/rgens/parser/templates/LiveTemplateElement.java
index 8dbde05..0aa3bd0 100644
--- a/src/main/java/bjc/rgens/parser/templates/LiveTemplateElement.java
+++ b/src/main/java/bjc/rgens/parser/templates/LiveTemplateElement.java
@@ -1,7 +1,10 @@
 package bjc.rgens.parser.templates;
 
 import bjc.utils.data.BooleanToggle;
+import bjc.utils.data.ITree;
+import bjc.utils.data.Tree;
 import bjc.utils.funcdata.FunctionalList;
+import bjc.utils.funcdata.IList;
 
 import bjc.rgens.parser.GenerationState;
 import bjc.rgens.parser.RGrammarParser;
@@ -14,12 +17,30 @@ import java.util.List;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
+/**
+ * A template element that can contain rule elements.
+ *
+ * @author Ben Culkin.
+ */
 public class LiveTemplateElement extends TemplateElement {
+	// Pattern for matching elements (any number of characters bracketed by '$@' and '@$')
 	private static final Pattern INSERT_PAT = Pattern.compile("\\$@(.+?)@\\$");
 
+	/**
+	 * The sub-elements of this element.
+	 */
 	public final List<List<CaseElement>> elements;
 
-	public LiveTemplateElement(String val) {
+	/**
+	 * Create a new template element.
+	 *
+	 * @param val
+	 * 		The string to parse this element from.
+	 *
+	 * @param errs
+	 * 		A tree to add errors &amp; information to.
+	 */
+	public LiveTemplateElement(String val, ITree<String> errs) {
 		super(true);
 
 		elements = new ArrayList<>();
@@ -31,10 +52,12 @@ public class LiveTemplateElement extends TemplateElement {
 			mat.appendReplacement(sb, "");
 			String body = mat.group(1);
 
-			FunctionalList<CaseElement> elms = (FunctionalList<CaseElement>)RGrammarParser.parseElementString(body).getLeft();
+			List<CaseElement> elms = new ArrayList<>();
+
+			int weight = RGrammarParser.parseElementString(body, elms, errs);
 
 			elements.add(Arrays.asList(new LiteralCaseElement(sb.toString())));
-			elements.add(elms.getInternal());
+			elements.add(elms);
 
 			sb = new StringBuffer();
 		}
@@ -43,6 +66,7 @@ public class LiveTemplateElement extends TemplateElement {
 		elements.add(Arrays.asList(new LiteralCaseElement(sb.toString())));
 	}
 
+	@Override
 	public void generate(GenerationState state) {
 		BooleanToggle bt = new BooleanToggle(false);