handle errors better, using features

4 files changed, 33 insertions, 12 deletions

diff --git a/src/java/org/anarres/cpp/Feature.java b/src/java/org/anarres/cpp/Feature.java
index 2fc7a61..2f80245 100644
--- a/src/java/org/anarres/cpp/Feature.java
+++ b/src/java/org/anarres/cpp/Feature.java
@@ -21,9 +21,14 @@ package org.anarres.cpp;
  * Features of the Preprocessor, which may be enabled or disabled.
  */
 public enum Feature {
+	/** Supports ANSI digraphs. */
 	DIGRAPHS,
+	/** Supports ANSI trigraphs. */
 	TRIGRAPHS,
+	/** Outputs linemarker tokens. */
 	LINEMARKERS,
+	/** Reports tokens of type INVALID as errors. */
 	CSYNTAX,
+	/** Preserves comments in the lexed output. */
 	KEEPCOMMENTS,
 }
diff --git a/src/java/org/anarres/cpp/JoinReader.java b/src/java/org/anarres/cpp/JoinReader.java
index 4e1a376..91908a7 100644
--- a/src/java/org/anarres/cpp/JoinReader.java
+++ b/src/java/org/anarres/cpp/JoinReader.java
@@ -68,6 +68,8 @@ import java.io.IOException;
 	private void _unread(int c) {
 		if (c != -1)
 			unget[uptr++] = c;
+		assert uptr <= unget.length :
+				"JoinReader ungets too many characters";
 	}
 
 	protected void warning(String msg)
diff --git a/src/java/org/anarres/cpp/LexerSource.java b/src/java/org/anarres/cpp/LexerSource.java
index 44c6224..0eea1c3 100644
--- a/src/java/org/anarres/cpp/LexerSource.java
+++ b/src/java/org/anarres/cpp/LexerSource.java
@@ -235,6 +235,19 @@ public class LexerSource extends Source {
 		}
 	}
 
+	/* Consumes the rest of the current line into an invalid. */
+	private Token invalid(StringBuilder text, String reason)
+						throws IOException,
+								LexerException {
+		int	d = read();
+		while (!isLineSeparator(d)) {
+			text.append((char)d);
+			d = read();
+		}
+		unread(d);
+		return new Token(INVALID, text.toString(), reason);
+	}
+
 	private Token ccomment()
 						throws IOException,
 								LexerException {
@@ -325,19 +338,17 @@ public class LexerSource extends Source {
 		}
 		else if (isLineSeparator(d)) {
 			unread(d);
-			// error("Unterminated character literal");
 			return new Token(INVALID, text.toString(),
 							"Unterminated character literal");
 		}
 		else if (d == '\'') {
 			text.append('\'');
-			// error("Empty character literal");
 			return new Token(INVALID, text.toString(),
 							"Empty character literal");
 		}
 		else if (!Character.isDefined(d)) {
 			text.append('?');
-			error("Illegal unicode character literal");
+			return invalid(text, "Illegal unicode character literal");
 		}
 		else {
 			text.append((char)d);
@@ -348,17 +359,17 @@ public class LexerSource extends Source {
 			// error("Illegal character constant");
 			/* We consume up to the next ' or the rest of the line. */
 			for (;;) {
-				if (e == '\'')
-					break;
 				if (isLineSeparator(e)) {
 					unread(e);
 					break;
 				}
 				text.append((char)e);
+				if (e == '\'')
+					break;
 				e = read();
 			}
 			return new Token(INVALID, text.toString(),
-							"Illegal character constant");
+							"Illegal character constant " + text);
 		}
 		text.append('\'');
 		/* XXX It this a bad cast? */
diff --git a/src/java/org/anarres/cpp/Preprocessor.java b/src/java/org/anarres/cpp/Preprocessor.java
index a1a72d9..82e636b 100644
--- a/src/java/org/anarres/cpp/Preprocessor.java
+++ b/src/java/org/anarres/cpp/Preprocessor.java
@@ -497,7 +497,7 @@ public class Preprocessor {
 					return new Token(EOF);
 				Source	t = inputs.remove(0);
 				push_source(t, true);
-				if (features.contains(Feature.LINEMARKERS))
+				if (getFeature(Feature.LINEMARKERS))
 					return line_token(t.getLine(), t.getName(), " 1");
 				continue;
 			}
@@ -506,7 +506,7 @@ public class Preprocessor {
 				// System.out.println("Autopop " + s);
 				pop_source();
 				Source	t = getSource();
-				if (features.contains(Feature.LINEMARKERS)
+				if (getFeature(Feature.LINEMARKERS)
 						&& s.isNumbered()
 						&& t != null) {
 					/* XXX Don't we mean t.isNumbered() as well? */
@@ -1082,7 +1082,7 @@ public class Preprocessor {
 
 			/* 'tok' is the 'nl' after the include. We use it after the
 			 * #line directive. */
-			if (features.contains(Feature.LINEMARKERS))
+			if (getFeature(Feature.LINEMARKERS))
 				return line_token(1, name, " 1");
 			return tok;
 		}
@@ -1498,13 +1498,16 @@ public class Preprocessor {
 						/* The preprocessor has to take action here. */
 						break;
 					case WHITESPACE:
+						return tok;
 					case CCOMMENT:
 					case CPPCOMMENT:
 						// Patch up to preserve whitespace.
-						/* XXX We might want to return tok here in C */
+						if (getFeature(Feature.KEEPCOMMENTS))
+							return tok;
 						return toWhitespace(tok);
 					default:
 						// Return NL to preserve whitespace.
+						/* XXX This might lose a comment. */
 						return source_skipline(false);
 				}
 			}
@@ -1578,12 +1581,12 @@ public class Preprocessor {
 					return tok;
 
 				case P_LINE:
-					if (features.contains(Feature.LINEMARKERS))
+					if (getFeature(Feature.LINEMARKERS))
 						return tok;
 					break;
 
 				case INVALID:
-					if (features.contains(Feature.CSYNTAX))
+					if (getFeature(Feature.CSYNTAX))
 						error(tok, String.valueOf(tok.getValue()));
 					return tok;