Moved evaluation into its own module

2 files changed, 71 insertions, 51 deletions

diff --git a/examples/console/evalcontext.py b/examples/console/evalcontext.py
new file mode 100644
index 0000000..70cd35f
--- /dev/null
+++ b/examples/console/evalcontext.py
@@ -0,0 +1,65 @@
+from cStringIO import StringIO
+import traceback
+import threading
+import pdb
+import sys
+
+exec_lock = threading.Lock()
+
+class EvalContext(object):
+
+    """
+    Class that represents a interactive interface.  It has its own
+    namespace.  Use eval_context.exec_expr(expr) to run commands; the
+    output of those commands is returned, as are print statements.
+
+    This is essentially what doctest does, and is taken directly from
+    doctest.
+    """
+
+    def __init__(self):
+        self.namespace = {}
+
+    def exec_expr(self, s):
+        out = StringIO()
+        exec_lock.acquire()
+        save_stdout = sys.stdout
+        try:
+            debugger = _OutputRedirectingPdb(save_stdout)
+            debugger.reset()
+            pdb.set_trace = debugger.set_trace
+            sys.stdout = out
+            try:
+                code = compile(s, '<web>', "single", 0, 1)
+                exec code in self.namespace
+                debugger.set_continue()
+            except KeyboardInterrupt:
+                raise
+            except:
+                traceback.print_exc(file=out)
+                debugger.set_continue()
+        finally:
+            sys.stdout = save_stdout
+            exec_lock.release()
+        return out.getvalue()
+
+# From doctest
+class _OutputRedirectingPdb(pdb.Pdb):
+    """
+    A specialized version of the python debugger that redirects stdout
+    to a given stream when interacting with the user.  Stdout is *not*
+    redirected when traced code is executed.
+    """
+    def __init__(self, out):
+        self.__out = out
+        pdb.Pdb.__init__(self)
+
+    def trace_dispatch(self, *args):
+        # Redirect stdout to the given stream.
+        save_stdout = sys.stdout
+        sys.stdout = self.__out
+        # Call Pdb's trace dispatch method.
+        try:
+            return pdb.Pdb.trace_dispatch(self, *args)
+        finally:
+            sys.stdout = save_stdout
diff --git a/examples/console/web/index.py b/examples/console/web/index.py
index d181857..aec3498 100644
--- a/examples/console/web/index.py
+++ b/examples/console/web/index.py
@@ -1,34 +1,8 @@
-from cStringIO import StringIO
-import traceback
-import pdb
-import threading
-import sys
 from console.sitepage import SitePage
 from console.JSONComponent import JSONComponent
+from console.evalcontext import EvalContext
 
-global_namespace = {}
-namespace_lock = threading.Lock()
-
-# From doctest
-class _OutputRedirectingPdb(pdb.Pdb):
-    """
-    A specialized version of the python debugger that redirects stdout
-    to a given stream when interacting with the user.  Stdout is *not*
-    redirected when traced code is executed.
-    """
-    def __init__(self, out):
-        self.__out = out
-        pdb.Pdb.__init__(self)
-
-    def trace_dispatch(self, *args):
-        # Redirect stdout to the given stream.
-        save_stdout = sys.stdout
-        sys.stdout = self.__out
-        # Call Pdb's trace dispatch method.
-        try:
-            return pdb.Pdb.trace_dispatch(self, *args)
-        finally:
-            sys.stdout = save_stdout
+context = EvalContext()
 
 class index(SitePage):
 
@@ -41,26 +15,7 @@ class index(SitePage):
     def jsonMethods(self):
         return ['run']
     
-    def run(self, value):
-        out = StringIO()
-        namespace_lock.acquire()
-        save_stdout = sys.stdout
-        try:
-            debugger = _OutputRedirectingPdb(save_stdout)
-            debugger.reset()
-            pdb.set_trace = debugger.set_trace
-            sys.stdout = out
-            try:
-                code = compile(value, '<web>', "single", 0, 1)
-                exec code in global_namespace
-                debugger.set_continue()
-            except KeyboardInterrupt:
-                raise
-            except:
-                traceback.print_exc(file=out)
-                debugger.set_continue()
-        finally:
-            sys.stdout = save_stdout
-            namespace_lock.release()
-        value = out.getvalue()
-        return value
+    def run(self, expr):
+        if not expr.endswith('\n'):
+            expr += '\n'
+        return context.exec_expr(expr)