Eliminate pylint warnings from generate_pins.py (#1731)

It also contains small refactoring steps:

* Added a main() function - instead of just writing all the code into the
  "if name" block - to avoids creating global variables that could affect
  other functions.

* Added a `write_pins_to_files` function - which writes the generated pins
  into the output JS and C++ files - to avoid too many local variables.

JerryScript-DCO-1.0-Signed-off-by: Robert Sipka rsipka.uszeged@partner.samsung.com

targets/mbedos5/tools/generate_pins.py

@@ -22,22 +22,38 @@ It's expecting to be run from the targets/mbedos5 directory.
 
 from __future__ import print_function
 
-from pycparser import parse_file, c_ast, c_generator
+import argparse
-from pycparserext.ext_c_parser import GnuCParser
-
-from simpleeval import SimpleEval, DEFAULT_OPERATORS
-
 import ast
 
-import argparse
-import json
 import sys
 import os
 
+from simpleeval import SimpleEval, DEFAULT_OPERATORS
+from pycparserext.ext_c_parser import GnuCParser
+from pycparser import parse_file, c_ast, c_generator
+
 # import mbed tools
 sys.path.append(os.path.join(os.path.dirname(__file__), '..', 'mbed-os'))
 from tools.targets import Target
 
+LICENSE = '''/* Copyright JS Foundation and other contributors, http://js.foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the \"License\");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an \"AS IS\" BASIS
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * This file is generated by generate_pins.py. Please do not modify.
+ */
+    '''
+
 
 def find_file(root_dir, directories, name):
     """
@@ -53,41 +69,49 @@ def find_file(root_dir, directories, name):
 
     for root, dirs, files in os.walk(root_dir, topdown=True):
         # modify dirs in place
-        dirs[:] = filter(lambda x: x in directories or not x.startswith('TARGET_'), dirs)
+        dirs[:] = [directory for directory in dirs if directory in directories or not directory.startswith('TARGET_')]
 
         if name in files:
             return os.path.join(root, name)
 
+
 def enumerate_includes(root_dir, directories):
     """
     Walk through the directory tree, starting at root_dir, and enumerate all
     valid include directories.
     """
-    for root, dirs, files in os.walk(root_dir, topdown=True):
+    for root, dirs, _ in os.walk(root_dir, topdown=True):
         # modify dirs in place
-        dirs[:] = filter(lambda x: x in directory_labels
+        dirs[:] = [dir_label for dir_label in dirs
-                                or (    not x.startswith('TARGET_')
+                   if dir_label in directories
-                                    and not x.startswith('TOOLCHAIN_')), dirs)
+                   or (not dir_label.startswith('TARGET_')
+                       and not dir_label.startswith('TOOLCHAIN_'))]
         yield root
 
 
 class TypeDeclVisitor(c_ast.NodeVisitor):
-    def __init__(self, filter_names=[]):
+    """
-        self.names = filter_names
+    A TypeDecl visitor class that walks the ast and calls a visitor function for every node found.
+    """
+    def __init__(self, filter_names=None):
+        self.names = filter_names or []
 
     def visit(self, node):
         value = None
 
         if node.__class__.__name__ == "TypeDecl":
-            value = self.visit_TypeDecl(node)
+            value = self.visit_typedecl(node)
 
         if value is None:
-            for name, c in node.children():
+            for _, child_node in node.children():
-                value = value or self.visit(c)
+                value = value or self.visit(child_node)
 
         return value
 
-    def visit_TypeDecl(self, node):
+    def visit_typedecl(self, node):
+        """
+        Visit a node.
+        """
         if node.declname in self.names:
             c_gen = c_generator.CGenerator()
             pins = {}
@@ -96,7 +120,7 @@ class TypeDeclVisitor(c_ast.NodeVisitor):
             operators[ast.BitOr] = lambda a, b: a | b
             operators[ast.LShift] = lambda a, b: a << b
             operators[ast.RShift] = lambda a, b: a << b
-            evaluator = SimpleEval(DEFAULT_OPERATORS )
+            evaluator = SimpleEval(DEFAULT_OPERATORS)
 
             for pin in node.type.values.enumerators:
                 expr = c_gen.visit(pin.value)
@@ -111,6 +135,7 @@ class TypeDeclVisitor(c_ast.NodeVisitor):
 
             return pins
 
+
 def enumerate_pins(c_source_file, include_dirs, definitions):
     """
     Enumerate pins specified in PinNames.h, by looking for a PinName enum
@@ -122,18 +147,56 @@ def enumerate_pins(c_source_file, include_dirs, definitions):
     gcc_args += ['-I' + directory for directory in include_dirs]
 
     gcc_args += ['-D' + definition for definition in definitions]
-    ast = parse_file(c_source_file,
+    parsed_ast = parse_file(c_source_file,
-                    use_cpp=True,
+                            use_cpp=True,
-                    cpp_path='arm-none-eabi-gcc',
+                            cpp_path='arm-none-eabi-gcc',
-                    cpp_args=gcc_args,
+                            cpp_args=gcc_args,
-                    parser=GnuCParser())
+                            parser=GnuCParser())
 
     # now, walk the AST
-    v = TypeDeclVisitor(['PinName'])
+    visitor = TypeDeclVisitor(['PinName'])
-    return v.visit(ast)
+    return visitor.visit(parsed_ast)
 
 
-if __name__ == "__main__":
+def write_pins_to_files(pins, out_js_file, out_cpp_file):
+    """
+    Write the generated pins for a specified mbed board into the output JS and C++ files.
+    """
+    out_js = '\r\n'.join(['var %s = %s;' % pin for pin in pins])
+    out_js_file.write(out_js)
+
+    count = '''
+unsigned int jsmbed_js_magic_string_count = {};
+    '''.format(len(pins))
+
+    lengths = ',\n    '.join(str(len(pin[0])) for pin in pins)
+    lenghts_source = '''
+unsigned int jsmbed_js_magic_string_lengths[] = {
+    %s
+};
+    ''' % lengths
+
+    magic_values = ',\n    '.join(str(pin[1]) for pin in pins)
+    magic_source = '''
+unsigned int jsmbed_js_magic_string_values[] = {
+    %s
+};
+    ''' % magic_values
+
+    magic_strings = ',\n    '.join('"' + pin[0] + '"' for pin in pins)
+    magic_string_source = '''
+const char * jsmbed_js_magic_strings[] = {
+    %s
+};
+    ''' % magic_strings
+
+    out_cpp_file.write(LICENSE + count + lenghts_source + magic_source + magic_string_source)
+
+
+def main():
+    """
+    Perform the main function of this program
+    """
     if not os.path.exists('./mbed-os'):
         print("Fatal: mbed-os directory does not exist.")
         print("Try running 'make getlibs'")
@@ -174,53 +237,11 @@ if __name__ == "__main__":
     pins = enumerate_pins(pins_file, ['./tools'] + list(includes), defines)
 
     # first sort alphabetically, then by length.
-    pins = [ (x, pins[x]) for x in pins] # turn dict into tuples, which can be sorted
+    pins = [(x, pins[x]) for x in pins]  # turn dict into tuples, which can be sorted
-    pins = sorted(pins, key = lambda x: (len(x[0]), x[0].lower()))
+    pins = sorted(pins, key=lambda x: (len(x[0]), x[0].lower()))
 
-    out_file = '\r\n'.join(['var %s = %s;' % pin for pin in pins])
+    write_pins_to_files(pins, args.o, args.c)
-    args.o.write(out_file)
 
-    LICENSE = '''/* Copyright JS Foundation and other contributors, http://js.foundation
- *
- * Licensed under the Apache License, Version 2.0 (the \"License\");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an \"AS IS\" BASIS
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- *
- * This file is generated by generate_pins.py. Please do not modify.
- */
-    '''
 
-    COUNT = '''
+if __name__ == "__main__":
-unsigned int jsmbed_js_magic_string_count = {};
+    main()
-    '''.format(len(pins))
-
-    LENGTHS = ',\n    '.join(str(len(pin[0])) for pin in pins)
-    LENGTHS_SOURCE = '''
-unsigned int jsmbed_js_magic_string_lengths[] = {
-    %s
-};
-    ''' % LENGTHS
-
-    MAGIC_VALUES = ',\n    '.join(str(pin[1]) for pin in pins)
-    MAGIC_SOURCE = '''
-unsigned int jsmbed_js_magic_string_values[] = {
-    %s
-};
-    ''' % MAGIC_VALUES
-
-    MAGIC_STRINGS = ',\n    '.join('"' + pin[0] + '"' for pin in pins)
-    MAGIC_STRING_SOURCE = '''
-const char * jsmbed_js_magic_strings[] = {
-    %s
-};
-    ''' % MAGIC_STRINGS
-
-    args.c.write(LICENSE + COUNT + LENGTHS_SOURCE + MAGIC_SOURCE + MAGIC_STRING_SOURCE)