--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/python/libs/compiler/core/errors.py	Fri Nov 02 14:05:00 2012 +0100
@@ -0,0 +1,47 @@
+""" Error handling routines """
+
+class CompilerException(Exception):
+  def __init__(self, msg, row=0, col=0, filename=None):
+    self.msg = msg
+    self.row = row
+    self.col = col
+    self.filename = filename
+  def __repr__(self):
+     return self.msg
+  def __str__(self):
+     return self.msg
+
+class ErrorNode:
+   def __init__(self, row, col, msg):
+      self.row, self.col = row,col
+      self.msg = msg
+
+def Error(msg, node=None):
+   if node is None:
+      raise CompilerException(msg)
+   else:
+      raise CompilerException(msg, node.row, node.col)
+
+def printError(source, e):
+     def printLine(row, txt):
+        print(str(row)+':'+txt)
+     if e.row == 0:
+        print('Error: {0}'.format(e.msg))
+     else:
+        lines = source.split('\n')
+        prerow = e.row - 3
+        if prerow < 1:
+           prerow = 1
+        afterrow = e.row + 3
+        if afterrow > len(lines):
+           afterrow = len(lines)
+
+        # print preceding source lines:
+        for r in range(prerow, e.row):
+           printLine(r, lines[r-1])
+        # print source line containing error:
+        printLine(e.row, lines[e.row-1])
+        print(' '*(len(str(e.row)+':')+e.col-1) + '^ Error: {0}'.format(e.msg))
+        # print trailing source line:
+        for r in range(e.row+1, afterrow+1):
+          printLine(r, lines[r-1])