Fix Reader errors

src/kiss/Kiss.hx

@@ -68,6 +68,10 @@ class Kiss {
     static function _try<T>(operation:() -> T):Null<T> {
         try {
             return operation();
+        } catch (err:StreamError) {
+            Sys.stderr().writeString(err + "\n");
+            Sys.exit(1);
+            return null;
         } catch (err:CompileError) {
             Sys.stderr().writeString(err + "\n");
             Sys.exit(1);

src/kiss/Reader.hx

@@ -105,7 +105,7 @@ class Reader {
     public static function nextToken(stream:Stream, expect:String) {
         var tok = stream.expect(expect, () -> stream.takeUntilOneOf(terminators));
         if (tok.length == 0) {
-            error(stream, 'Expected $expect');
+            stream.error('Expected $expect');
             return null;
         }
         return tok;
@@ -117,7 +117,7 @@ class Reader {
             case Some(exp):
                 exp;
             case None:
-                error(stream, 'Ran out of Kiss expressions');
+                stream.error('Ran out of Kiss expressions');
                 return null;
         };
     }
@@ -264,7 +264,7 @@ class Reader {
                         case '$':
                             currentStringPart += '$';
                         default:
-                            error(stream, 'unsupported escape sequence \\$escapeSequence');
+                            stream.error('unsupported escape sequence \\$escapeSequence');
                             return null;
                     }
                 case '"':
@@ -290,19 +290,13 @@ class Reader {
                 case '"':
                     break;
                 default:
-                    error(stream, 'Invalid syntax for raw string. Delete $next');
+                    stream.error('Invalid syntax for raw string. Delete $next');
                     return null;
             }
         } while (true);
         return StrExp(stream.expect('closing $terminator', () -> stream.takeUntilAndDrop(terminator)));
     }
 
-    public static function error(stream:Stream, message:String) {
-        Sys.stderr().writeString('Kiss reader error!\n');
-        Sys.stderr().writeString(stream.position().toPrint() + ': $message\n');
-        Sys.exit(1);
-    }
-
     public static function toString(exp:ReaderExpDef) {
         return switch (exp) {
             case CallExp(func, args):

src/kiss/Stream.hx

@@ -2,10 +2,10 @@ package kiss;
 
 import sys.io.File;
 import haxe.ds.Option;
-import kiss.Reader;
 
 using StringTools;
 using Lambda;
+using kiss.Stream;
 
 typedef Position = {
     file:String,
@@ -14,6 +14,22 @@ typedef Position = {
     absoluteChar:Int
 };
 
+class StreamError {
+    var position:Position;
+    var message:String;
+
+    public function new(position:Position, message:String) {
+        this.position = position;
+        this.message = message;
+    }
+
+    public function toString() {
+        return '\nKiss reader error!\n'
+            + position.toPrint()
+            + ': $message\n';
+    }
+}
+
 class Stream {
     public var content(default, null):String;
 
@@ -125,7 +141,7 @@ class Stream {
     public function dropString(s:String) {
         var toDrop = content.substr(0, s.length);
         if (toDrop != s) {
-            Reader.error(this, 'Expected $s');
+            error(this, 'Expected $s');
         }
         dropChars(s.length);
     }
@@ -168,8 +184,12 @@ class Stream {
             case Some(s):
                 return s;
             default:
-                Reader.error(this, 'Expected $whatToExpect');
+                error(this, 'Expected $whatToExpect');
                 return null;
         }
     }
+
+    public static function error(stream:Stream, message:String) {
+        throw new StreamError(stream.position(), message);
+    }
 }