mojo: Starting generator for python bindings.

mojo/public/tools/bindings/generators/mojom_python_generator.py

Index: mojo/public/tools/bindings/generators/mojom_python_generator.py
diff --git a/mojo/public/tools/bindings/generators/mojom_python_generator.py b/mojo/public/tools/bindings/generators/mojom_python_generator.py
new file mode 100644
index 0000000000000000000000000000000000000000..f1a7afe0c83fec9c51eba5a87bad0f78690e5925
--- /dev/null
+++ b/mojo/public/tools/bindings/generators/mojom_python_generator.py
@@ -0,0 +1,102 @@
+# Copyright 2014 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""Generates Python source files from a mojom.Module."""
+
+import re
+
+import mojom.generate.generator as generator
+import mojom.generate.module as mojom
+from mojom.generate.template_expander import UseJinja
+
+
+def NameToComponent(name):

[pkl (ping after 24h if needed), 2014/09/01 12:52:02]

style: Function names should be name_to_component().

[qsr, 2014/09/01 14:19:38]

 The style of all the python files in mojo/public/tools/bindings/generators use
UpperCamelCase for function names.

[pkl (ping after 24h if needed), 2014/09/01 14:35:10]

Ack. Chromium has it's own style guide
http://www.chromium.org/chromium-os/python-style-guidelines for python :(

+  # insert '_' between anything and a Title name (e.g, HTTPEntry2FooBar ->
+  # HTTP_Entry2_FooBar)
+  name = re.sub('([^_])([A-Z][^A-Z_]+)', r'\1_\2', name)
+  # insert '_' between non upper and start of upper blocks (e.g.,
+  # HTTP_Entry2_FooBar -> HTTP_Entry2_Foo_Bar)
+  name = re.sub('([^A-Z_])([A-Z])', r'\1_\2', name)
+  return [x.lower() for x in name.split('_')]
+
+def CapitalizeFirst(string):
+  return string[0].upper() + string[1:]
+
+def UpperCamelCase(name):
+  return ''.join([CapitalizeFirst(x) for x in NameToComponent(name)])

[pkl (ping after 24h if needed), 2014/09/01 12:52:02]

why not just use x.capitalize() ? No need to define CapitalizeFirst().

[qsr, 2014/09/01 14:19:38]

Done.

+
+def CamelCase(name):
+  uccc = UpperCamelCase(name)
+  return uccc[0].lower() + uccc[1:]
+
+def ConstantStyle(name):
+  components = NameToComponent(name)
+  if components[0] == 'k':
+    components = components[1:]
+  return '_'.join([x.upper() for x in components])
+
+def GetNameForElement(element):
+  if isinstance(element, (mojom.NamedValue,
+                          mojom.Constant)):
+    return ConstantStyle(element.name)
+  raise Exception("Unexpected element: " % element)

[pkl (ping after 24h if needed), 2014/09/01 12:52:02]

style: Please use " and ' for string constants consistently.

[qsr, 2014/09/01 14:19:38]

Done.

+
+def TranslateConstants(token):
+  if isinstance(token, (mojom.EnumValue, mojom.NamedValue)):
+    # Both variable and enum constants are constructed like:
+    # NamespaceUid.Struct[.Enum].CONSTANT_NAME
+    name = []
+    if token.imported_from:
+      name.append(token.imported_from["python_module"])
+    if token.parent_kind:
+      name.append(GetNameForElement(token.parent_kind))
+    if isinstance(token, mojom.EnumValue):
+      name.append(GetNameForElement(token))
+    else:
+      name.append(token.name)
+    return ".".join(name)
+
+  if isinstance(token, mojom.BuiltinValue):
+    if token.value == "double.INFINITY" or token.value == "float.INFINITY":
+      return "float('inf')";
+    if token.value == "double.NEGATIVE_INFINITY" or \

[pkl (ping after 24h if needed), 2014/09/01 12:52:02]

style: do not use backslash for continuation. Use:

  if (foo == a_long_value or
      bar == some_other_long_value):
    blah()

[qsr, 2014/09/01 14:19:38]

Done.

+       token.value == "float.NEGATIVE_INFINITY":
+      return "float('-inf')"
+    if token.value == "double.NAN" or token.value == "float.NAN":
+      return "float('nan')";
+
+  return token
+
+
+def ExpressionToText(value):
+  return TranslateConstants(value)
+
+
+class Generator(generator.Generator):
+
+  python_filters = {
+    "expression_to_text": ExpressionToText,
+    "name": GetNameForElement,
+  }
+
+  @UseJinja("python_templates/module.py.tmpl", filters=python_filters)
+  def GeneratePythonModule(self):
+    return {
+      "imports": self.GetImports(),
+      "module": self.module,
+    }
+
+  def GenerateFiles(self, args):
+    self.Write(self.GeneratePythonModule(), "%s.py" % self.module.name.replace('.mojom', '_mojom'))

[pkl (ping after 24h if needed), 2014/09/01 12:52:02]

line length > 80

[qsr, 2014/09/01 14:19:38]

Done.

+
+  def GetImports(self):
+    for each in self.module.imports:
+      each["python_module"] = each['module_name'].replace('.mojom', '_mojom')
+    return self.module.imports
+
+  def GetJinjaParameters(self):
+    return {
+      'lstrip_blocks': True,
+      'trim_blocks': True,
+    }