diff --git a/lex.js b/lex.js
index d24183c..c49c67d 100644
--- a/lex.js
+++ b/lex.js
@@ -122,7 +122,7 @@
                 line = i + 1;
                 break;
             }
-            previousLinesLength += this.newlines[i] + 1;
+            previousLinesLength = this.newlines[i] + 1;
         }
         return {line:line, pos:pos - previousLinesLength + 1};
     }

diff --git a/lex.js b/lex.js
index d24183c..c49c67d 100644
--- a/lex.js
+++ b/lex.js
@@ -122,7 +122,7 @@
                 line = i + 1;
                 break;
             }
-            previousLinesLength += this.newlines[i] + 1;
+            previousLinesLength = this.newlines[i] + 1;
         }
         return {line:line, pos:pos - previousLinesLength + 1};
     }
diff --git a/parse.js b/parse.js
index 3af758c..b5f3041 100644
--- a/parse.js
+++ b/parse.js
@@ -43,7 +43,7 @@
 });
 
 // all reserved keywords
-const Keywords = Object.freeze([ "if" ]);
+const Keywords = Object.freeze([ "if", "on", "wait", "for", "map", "in" ]);
 
 // the types of AST nodes
 const ASTNode = Object.freeze({
@@ -59,6 +59,10 @@
     Block:10,           // a set of statements in a { } block
 });
 
+const StatementsWithSemicolon = Object.freeze([
+    ASTNode.ExprStatement,
+]);
+
 // all reserved words that represent literals
 const Literals = Object.freeze({
     "true": {node:ASTNode.Literal, value:true},
@@ -80,12 +84,12 @@
         if (openError) return this.getError(openError);
 
         let { ast:statements, error, numMatched } = this.attemptSubtree(this.statements);
-        if (error && numMatched > this.mustConsumeBeforeUsingError) return this.getError(this.error);
+        if (error && numMatched > this.mustConsumeBeforeUsingError) return this.getError(error);
 
         let { error:closeError } = this.tokenStream.consume(lex.TokenType.Op, "}");
         if (closeError) return this.getError(closeError);
 
-        return { ast: { node: ASTNode.Block, statements: statements }, error: null };
+        return { ast: { node: ASTNode.Block, statements: statements.statements }, error: null };
     }
 
     statements()
@@ -121,7 +125,7 @@
         {
             return this.getError(error);
         }
-        else
+        else if (StatementsWithSemicolon.includes(stmt.node))
         {
             if (error = this.tokenStream.consume(lex.TokenType.Op, ';').error)
             {