2 files changed, 34 insertions, 26 deletions

diff --git a/src/paca.mjs b/src/paca.mjs
index 993d26c..380200a 100644
--- a/src/paca.mjs
+++ b/src/paca.mjs
@@ -36,12 +36,6 @@ const tokenizeRegexStep = chars => ({ out, state }, char, index) => {
 	}
 
 	if (char === "\\") {
-		if (next === undefined) {
-			throw new SyntaxError(
-				`bad trailing escape character: ${chars}`,
-			);
-		}
-
 		return {
 			out,
 			state: ConcatStep.ESCAPING,
@@ -61,8 +55,18 @@ const tokenizeRegexFn = chars =>
 		state: ConcatStep.ACCEPTING,
 	});
 
-const tokenizeRegex = chars =>
-	tokenizeRegexFn(chars).out;
+const tokenizeRegex = chars => {
+	const tokens = tokenizeRegexFn(chars);
+	if (!!tokens.error) {
+		throw tokens.error;
+	}
+
+	if (tokens.state !== ConcatStep.ACCEPTING) {
+		throw new SyntaxError("bad ending state: " + tokens.state);
+	}
+
+	return tokens.out;
+};
 
 const PRECEDENCE = {
 	"(":      4,
diff --git a/tests/paca.mjs b/tests/paca.mjs
index 0724bf2..aa7333b 100644
--- a/tests/paca.mjs
+++ b/tests/paca.mjs
@@ -178,24 +178,6 @@ const test_tokenizeRegexStep = t => {
 		}
 	});
 
-	t.testing("trailing escape errors", () => {
-		try {
-			t.assertEq(tokenizeRegexStep("\\")({
-				out:   [],
-				index: 0,
-				state: ConcatStep.ACCEPTING,
-			}, "\\"), null);
-			t.assertEq(true, false);
-		} catch (e) {
-			const message = "bad trailing escape character: ";
-			t.assertEq(
-				e.message.substring(0, message.length),
-				message,
-			);
-			t.assertEq(e instanceof SyntaxError, true);
-		}
-	});
-
 	t.testing("escape makes it enter escaping mode", () => {
 		const stepFn = tokenizeRegexStep("\\a\\*");
 		const steps = [{
@@ -474,6 +456,28 @@ const test_tokenizeRegex = t => {
 			);
 		}
 	});
+
+	t.testing("trailing escape errors", () => {
+		try {
+			t.assertEq(tokenizeRegex(explode("\\")), null);
+			t.assertEq(true, false);
+		} catch (e) {
+			const message = "bad ending state: escaping";
+			t.assertEq(e.message, message);
+			t.assertEq(e instanceof SyntaxError, true);
+		}
+	});
+
+	t.testing("trailing range errors", () => {
+		try {
+			t.assertEq(tokenizeRegex(explode("{")), null);
+			t.assertEq(true, false);
+		} catch (e) {
+			const message = "bad ending state: range";
+			t.assertEq(e.message, message);
+			t.assertEq(e instanceof SyntaxError, true);
+		}
+	});
 };
 
 const test_shouldPush = t => {