Sporadic work done in an airport

- Initial ErrorBuilder class
 - Random documentation

src/main/java/com/jozufozu/flywheel/backend/pipeline/SourceFile.java

@@ -113,9 +113,9 @@ public class SourceFile {
 			int lastEnd = 0;
 
 			for (Span elision : elisions) {
-				out.append(source, lastEnd, elision.getStart());
+				out.append(source, lastEnd, elision.getStartPos());
 
-				lastEnd = elision.getEnd();
+				lastEnd = elision.getEndPos();
 			}
 
 			out.append(source, lastEnd, source.length());

src/main/java/com/jozufozu/flywheel/backend/pipeline/error/ErrorBuilder.java

@@ -0,0 +1,30 @@
+package com.jozufozu.flywheel.backend.pipeline.error;
+
+import com.jozufozu.flywheel.backend.pipeline.SourceFile;
+
+public class ErrorBuilder {
+
+	private StringBuilder internal;
+
+	public ErrorBuilder header(CharSequence msg) {
+		internal.append("error: ")
+				.append(msg);
+		return endLine();
+	}
+
+	public ErrorBuilder errorIn(SourceFile file) {
+		internal.append("--> ")
+				.append(file.name);
+		return endLine();
+	}
+
+	public ErrorBuilder line(int no, CharSequence content) {
+
+		return endLine();
+	}
+
+	public ErrorBuilder endLine() {
+		internal.append('\n');
+		return this;
+	}
+}

src/main/java/com/jozufozu/flywheel/backend/pipeline/error/ErrorReporter.java

@@ -1,4 +1,4 @@
-package com.jozufozu.flywheel.backend.pipeline.parse;
+package com.jozufozu.flywheel.backend.pipeline.error;
 
 import com.jozufozu.flywheel.backend.pipeline.SourceFile;
 import com.jozufozu.flywheel.backend.pipeline.span.Span;
@@ -9,6 +9,8 @@ public class ErrorReporter {
 	public String generateSpanError(Span span, String message) {
 		SourceFile file = span.getSourceFile();
 
+
+
 		return "";
 	}
 }

src/main/java/com/jozufozu/flywheel/backend/pipeline/parse/AbstractShaderElement.java

@@ -1,5 +1,6 @@
 package com.jozufozu.flywheel.backend.pipeline.parse;
 
+import com.jozufozu.flywheel.backend.pipeline.error.ErrorReporter;
 import com.jozufozu.flywheel.backend.pipeline.span.Span;
 
 public abstract class AbstractShaderElement {

src/main/java/com/jozufozu/flywheel/backend/pipeline/parse/Include.java

@@ -3,6 +3,7 @@ package com.jozufozu.flywheel.backend.pipeline.parse;
 import java.util.Optional;
 
 import com.jozufozu.flywheel.backend.ShaderSources;
+import com.jozufozu.flywheel.backend.pipeline.error.ErrorReporter;
 import com.jozufozu.flywheel.backend.pipeline.SourceFile;
 import com.jozufozu.flywheel.backend.pipeline.span.Span;
 

src/main/java/com/jozufozu/flywheel/backend/pipeline/parse/ShaderFunction.java

@@ -6,6 +6,7 @@ import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 import java.util.stream.Collectors;
 
+import com.jozufozu.flywheel.backend.pipeline.error.ErrorReporter;
 import com.jozufozu.flywheel.backend.pipeline.span.Span;
 
 public class ShaderFunction extends AbstractShaderElement {

src/main/java/com/jozufozu/flywheel/backend/pipeline/parse/ShaderStruct.java

@@ -1,9 +1,5 @@
 package com.jozufozu.flywheel.backend.pipeline.parse;
 
-import java.util.ArrayList;
-import java.util.HashMap;
-import java.util.List;
-import java.util.Map;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
@@ -11,6 +7,7 @@ import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
 import com.jozufozu.flywheel.backend.loading.Program;
 import com.jozufozu.flywheel.backend.loading.TypeHelper;
+import com.jozufozu.flywheel.backend.pipeline.error.ErrorReporter;
 import com.jozufozu.flywheel.backend.pipeline.span.Span;
 
 public class ShaderStruct extends AbstractShaderElement {

src/main/java/com/jozufozu/flywheel/backend/pipeline/parse/StructField.java

@@ -1,9 +1,8 @@
 package com.jozufozu.flywheel.backend.pipeline.parse;
 
-import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
-import com.jozufozu.flywheel.backend.loading.LayoutTag;
+import com.jozufozu.flywheel.backend.pipeline.error.ErrorReporter;
 import com.jozufozu.flywheel.backend.pipeline.span.Span;
 
 public class StructField extends AbstractShaderElement {

src/main/java/com/jozufozu/flywheel/backend/pipeline/parse/Variable.java

@@ -1,5 +1,6 @@
 package com.jozufozu.flywheel.backend.pipeline.parse;
 
+import com.jozufozu.flywheel.backend.pipeline.error.ErrorReporter;
 import com.jozufozu.flywheel.backend.pipeline.span.Span;
 
 public class Variable extends AbstractShaderElement {

src/main/java/com/jozufozu/flywheel/backend/pipeline/span/CharPos.java

@@ -1,7 +1,8 @@
 package com.jozufozu.flywheel.backend.pipeline.span;
 
-import com.jozufozu.flywheel.backend.pipeline.SourceFile;
+/**
-
+ * A position in a file.
+ */
 public class CharPos {
 
 	private final int idx;

src/main/java/com/jozufozu/flywheel/backend/pipeline/span/ErrorSpan.java

@@ -2,6 +2,9 @@ package com.jozufozu.flywheel.backend.pipeline.span;
 
 import com.jozufozu.flywheel.backend.pipeline.SourceFile;
 
+/**
+ * Represents a (syntactically) malformed segment of code.
+ */
 public class ErrorSpan extends Span {
 	public ErrorSpan(SourceFile in, int loc) {
 		super(in, loc, loc);

src/main/java/com/jozufozu/flywheel/backend/pipeline/span/Span.java

@@ -23,31 +23,49 @@ public abstract class Span implements CharSequence {
 		this.end = end;
 	}
 
+	/**
+	 * @return The file that contains this code segment.
+	 */
 	public SourceFile getSourceFile() {
 		return in;
 	}
 
-	public int getStart() {
+	/**
+	 * @return the string index at the (inclusive) beginning of this code segment.
+	 */
+	public int getStartPos() {
 		return start.getPos();
 	}
 
-	public int getEnd() {
+	/**
+	 * @return the string index at the (exclusive) end of this code segment.
+	 */
+	public int getEndPos() {
 		return end.getPos();
 	}
 
+	/**
+	 * @return true if this span has no width.
+	 */
 	public boolean isEmpty() {
 		return start == end;
 	}
 
+	/**
+	 * Get a span referring to a code segment inside this code segment.
+	 */
 	public abstract Span subSpan(int from, int to);
 
+	/**
+	 * @return the portion of code represented by this span.
+	 */
 	public abstract String get();
 
 	public abstract boolean isErr();
 
 	@Override
 	public int length() {
-		return end.getPos() - start.getPos();
+		return getEndPos() - getStartPos();
 	}
 
 	@Override