First :D

plugins/pycparser/cdecl.py

@@ -0,0 +1,98 @@
+#-----------------------------------------------------------------
+# pycparser: cdecl.py
+#
+# Example of the CDECL tool using pycparser. CDECL "explains"
+# C type declarations in plain English.
+#
+# The AST generated by pycparser from the given declaration is
+# traversed recursively to build the explanation.
+# Note that the declaration must be a valid external declaration
+# in C. All the types used in it must be defined with typedef,
+# or parsing will fail. The definition can be arbitrary, it isn't
+# really used - by pycparser must know which tokens are types.
+#
+# For example:
+#
+# 'typedef int Node; const Node* (*ar)[10];'
+# =>
+# ar is a pointer to array[10] of pointer to const Node
+#
+# Copyright (C) 2008, Eli Bendersky
+# License: LGPL
+#-----------------------------------------------------------------
+import sys
+
+from pycparser import c_parser, c_ast
+
+
+def explain_c_declaration(c_decl):
+    """ Parses the declaration in c_decl and returns a text
+        explanation as a string.
+
+        The last external node of the string is used, to allow
+        earlier typedefs for used types.
+    """
+    parser = c_parser.CParser()
+
+    node = parser.parse(c_decl, filename='<stdin>')
+
+    if (    not isinstance(node, c_ast.FileAST) or
+            not isinstance(node.ext[-1], c_ast.Decl)):
+        return "Last external node is invalid type"
+
+    return _explain_decl_node(node.ext[-1])
+
+
+def _explain_decl_node(decl_node):
+    """ Receives a c_ast.Decl note and returns its explanation in
+        English.
+    """
+    #~ print decl_node.show()
+    storage = ' '.join(decl_node.storage) + ' ' if decl_node.storage else ''
+
+    return (decl_node.name +
+            " is a " +
+            storage +
+            _explain_type(decl_node.type))
+
+
+def _explain_type(decl):
+    """ Recursively explains a type decl node
+    """
+    typ = type(decl)
+
+    if typ == c_ast.TypeDecl:
+        quals = ' '.join(decl.quals) + ' ' if decl.quals else ''
+        return quals + _explain_type(decl.type)
+    elif typ == c_ast.Typename or typ == c_ast.Decl:
+        return _explain_type(decl.type)
+    elif typ == c_ast.IdentifierType:
+        return ' '.join(decl.names)
+    elif typ == c_ast.PtrDecl:
+        quals = ' '.join(decl.quals) + ' ' if decl.quals else ''
+        return quals + 'pointer to ' + _explain_type(decl.type)
+    elif typ == c_ast.ArrayDecl:
+        arr = 'array'
+        if decl.dim: arr += '[%s]' % decl.dim.value
+
+        return arr + " of " + _explain_type(decl.type)
+
+    elif typ == c_ast.FuncDecl:
+        if decl.args:
+            params = [_explain_type(param) for param in decl.args.params]
+            args = ', '.join(params)
+        else:
+            args = ''
+
+        return ('function(%s) returning ' % (args) +
+                _explain_type(decl.type))
+
+
+if __name__ == "__main__":
+    if len(sys.argv) > 1:
+        c_decl  = sys.argv[1]
+    else:
+        c_decl = "char *(*(**foo[][8])())[];"
+
+    print "Explaining the declaration:", c_decl
+    print "\n", explain_c_declaration(c_decl)