# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1205972028 -3600
# Node ID 999f14fecba913a74f2d353fdae1d561c452b427
# Parent  a7cbfb7bb92b4931bfdd6c560ad75aba978c4a74
Added some tests of argument compatibility for predictable cases.
Improved the ProcessingError __repr__ string.
Added failure tests for keyword arguments.

diff -r a7cbfb7bb92b -r 999f14fecba9 README.txt
--- a/README.txt	Wed Mar 19 20:57:38 2008 +0100
+++ b/README.txt	Thu Mar 20 01:13:48 2008 +0100
@@ -269,6 +269,19 @@
 argument, in order to optimise instance attribute access in methods, we should
 seek to restrict the object type.
 
+Verifying Supplied Arguments
+----------------------------
+
+In order to ensure a correct invocation, it is also necessary to check the
+number of supplied arguments. If the target of the invocation is known at
+compile-time, no additional instructions need to be emitted; otherwise, the
+generated code must test for the following situations:
+
+ 1. That the number of supplied arguments is equal to the number of expected
+    parameters.
+
+ 2. That no keyword argument overwrites an existing positional parameter.
+
 Tuples, Frames and Allocation
 -----------------------------
 
diff -r a7cbfb7bb92b -r 999f14fecba9 micropython/ast.py
--- a/micropython/ast.py	Wed Mar 19 20:57:38 2008 +0100
+++ b/micropython/ast.py	Thu Mar 20 01:13:48 2008 +0100
@@ -262,11 +262,14 @@
         # Evaluate the arguments.
 
         positional = 1
+        start_keywords = None
+        employed_keywords = set()
 
         for i, arg in enumerate(args):
             if isinstance(arg, compiler.ast.Keyword):
                 if positional:
                     self.new_op(ReserveFrame(len(args) - i))
+                    start_keywords = i
                     positional = 0
 
                 self.dispatch(arg.expr)
@@ -294,6 +297,17 @@
                             raise
 
                     pos = table_entry[arg.name]
+
+                    # Test for illegal conditions.
+
+                    if pos < start_keywords:
+                        raise TranslateError(self.module.full_name(), node,
+                            "Keyword argument %r overwrites parameter %r." % (arg.name, pos))
+                    elif pos in employed_keywords:
+                        raise TranslateError(self.module.full_name(), node,
+                            "Keyword argument %r is repeated, overwriting parameter %r." % (arg.name, pos))
+
+                    employed_keywords.add(pos)
                     self.new_op(StoreFrame(pos))
 
                 # Otherwise, generate the code needed to obtain the details of
diff -r a7cbfb7bb92b -r 999f14fecba9 micropython/common.py
--- a/micropython/common.py	Wed Mar 19 20:57:38 2008 +0100
+++ b/micropython/common.py	Thu Mar 20 01:13:48 2008 +0100
@@ -29,7 +29,7 @@
         self.message = message
 
     def __repr__(self):
-        return "ProcessingError in %r at line %d: %s" % (self.unit_name, self.node.lineno, self.message)
+        return "Error in %r at line %d: %s" % (self.unit_name, self.node.lineno, self.message)
 
     def __str__(self):
         return repr(self)
diff -r a7cbfb7bb92b -r 999f14fecba9 tests/failure/keyword_conflict.py
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tests/failure/keyword_conflict.py	Thu Mar 20 01:13:48 2008 +0100
@@ -0,0 +1,18 @@
+#!/usr/bin/env python
+
+def f(a, b, c):
+    pass
+
+g = f
+g(1, a=3, b=2) # uncertain target - not detected
+
+def g(a, c, b):
+    pass
+
+g(1, a=3, b=2)
+
+f(1, 2, 3)
+f(1, a=2, c=3)
+f(c=3, b=2, a=1)
+
+# vim: tabstop=4 expandtab shiftwidth=4
diff -r a7cbfb7bb92b -r 999f14fecba9 tests/failure/keyword_repeat.py
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/tests/failure/keyword_repeat.py	Thu Mar 20 01:13:48 2008 +0100
@@ -0,0 +1,19 @@
+#!/usr/bin/env python
+
+def f(a, b, c):
+    pass
+
+g = f
+g(1, b=3, b=2)
+g(c=3, b=2, a=1, b=0) # uncertain target - not detected
+
+def g(a, c, b):
+    pass
+
+g(1, a=3, b=2)
+
+f(1, 2, 3)
+f(1, b=2, c=3)
+f(c=3, b=2, a=1, b=0)
+
+# vim: tabstop=4 expandtab shiftwidth=4