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.

3 files changed, 110 insertions, 13 deletions

diff --git a/src/main/java/bjc/rgens/parser/templates/GrammarTemplate.java b/src/main/java/bjc/rgens/parser/templates/GrammarTemplate.java
index 8a99188..64db166 100644
--- a/src/main/java/bjc/rgens/parser/templates/GrammarTemplate.java
+++ b/src/main/java/bjc/rgens/parser/templates/GrammarTemplate.java
@@ -2,25 +2,58 @@ package bjc.rgens.parser.templates;
 
 import bjc.rgens.parser.ConfigSet;
 import bjc.rgens.parser.GenerationState;
+import bjc.rgens.parser.LoadOptions;
+
+import bjc.utils.data.ITree;
+import bjc.utils.data.Tree;
 
 import java.io.Reader;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Scanner;
 
+/**
+ * Represents a grammar template.
+ *
+ * @author Ben Culkin
+ */
 public class GrammarTemplate {
+	/**
+	 * The config set the template belongs to.
+	 */
 	public ConfigSet belongsTo;
 
+	/**
+	 * The name of the template.
+	 */
 	public String name;
 
+	/**
+	 * The elements in the template.
+	 */
 	public final List<TemplateElement> elements;
 
+	/**
+	 * Whether or not to do spacing of elements.
+	 */
 	public boolean doSpacing = true;
 
+	/**
+	 * Create a new grammar template.
+	 *
+	 * @param elements
+	 * 		The elements that belong to the template.
+	 */
 	public GrammarTemplate(List<TemplateElement> elements) {
 		this.elements = elements;
 	}
 
+	/**
+	 * Generate the template.
+	 *
+	 * @param state
+	 * 		The state for generating a template.
+	 */
 	public void generate(GenerationState state) {
 		for(TemplateElement element : elements) {
 			element.generate(state);
@@ -30,7 +63,18 @@ public class GrammarTemplate {
 		}
 	}
 
-	public static GrammarTemplate readTemplate(Reader rdr) {
+	/**
+	 * Read a template from an input source.
+	 *
+	 * @param rdr
+	 * 		The reader to get input from.
+	 *
+	 * @param errs
+	 * 		The errors/information to generate during loading.
+	 *
+	 * @return The generated template.
+	 */
+	public static GrammarTemplate readTemplate(Reader rdr, ITree<String> errs) {
 		List<TemplateElement> elements = new ArrayList<>();
 		GrammarTemplate template = new GrammarTemplate(elements);
 
@@ -42,34 +86,46 @@ public class GrammarTemplate {
 			String ln = scn.nextLine();
 			lno += 1;
 
+			ITree<String> kid = new Tree<>(String.format("INFO: Line %d", lno));
 			switch(ln.charAt(0)) {
 			case '#':
 				// Ignore comments
 				break;
 			case '/':
-				handlePragma(elements, template, ln.substring(1));
+				handlePragma(elements, template, ln.substring(1), kid);
 				break;
 			default:
-				handleLine(elements, template, ln);
+				handleLine(elements, template, ln, kid);
 			}
-		}
 
+			if (kid.size() > 0) {
+				errs.addChild(kid);
+			}
+		}
 
 		return template;
 	}
 
-	private static void handleLine(List<TemplateElement> elements, GrammarTemplate template, String ln) {
+	private static void handleLine(List<TemplateElement> elements, GrammarTemplate template, String ln, ITree<String> errs) {
 		if(ln.matches("^.*?\\$@.+?@\\$.*$")) {
 			/*
 			 * Handle live templates
 			 */
-			elements.add(new LiveTemplateElement(ln));
+			elements.add(new LiveTemplateElement(ln, errs));
 		} else {
-			elements.add(new LiteralTemplateElement(ln));
+			elements.add(new LiteralTemplateElement(ln, errs));
 		}
 	}
 
-	private static void handlePragma(List<TemplateElement> elements, GrammarTemplate template, String ln) {
-
+	private static void handlePragma(List<TemplateElement> elements, GrammarTemplate template, String ln, ITree<String> errs) {
+		/*
+		 * @TODO 2/8/2019 Ben Culkin :TemplatePragmas
+		 * Implement template pragmas.
+		 *
+		 * Implement template pragmas. Mainly, this means that the 'choose'
+		 * based ones need to be implemented based off of the provided sample
+		 * template.
+		 */
+		errs.addChild("ERROR: Template pragmas are not yet implemented");
 	}
 }
diff --git a/src/main/java/bjc/rgens/parser/templates/LiteralTemplateElement.java b/src/main/java/bjc/rgens/parser/templates/LiteralTemplateElement.java
index ca4b32f..2f0a571 100644
--- a/src/main/java/bjc/rgens/parser/templates/LiteralTemplateElement.java
+++ b/src/main/java/bjc/rgens/parser/templates/LiteralTemplateElement.java
@@ -1,16 +1,33 @@
 package bjc.rgens.parser.templates;
 
+import bjc.utils.data.ITree;
+
 import bjc.rgens.parser.GenerationState;
 
+/**
+ * Represents a literal text element.
+ *
+ * @author Ben Culkin
+ */
 public class LiteralTemplateElement extends TemplateElement {
+	/**
+	 * The literal value of the element.
+	 */
 	public final String val;
 
-	public LiteralTemplateElement(String val) {
+	/**
+	 * Create a new literal template element.
+	 *
+	 * @param val
+	 * 		The string to insert.
+	 */
+	public LiteralTemplateElement(String val, ITree<String> errs) {
 		super(true);
 
 		this.val = val;
 	}
 
+	@Override
 	public void generate(GenerationState state) {
 		state.appendContents(val);
 	}
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);