moving CGenerator from examples/c-to-c.py into its own class in pycparser/. c-to-c remains as a shell example over it

1 files changed, 9 insertions, 382 deletions

diff --git a/examples/c-to-c.py b/examples/c-to-c.py
index e1277ab..ca76cc5 100644
--- a/examples/c-to-c.py
+++ b/examples/c-to-c.py
@@ -1,15 +1,12 @@
-#-----------------------------------------------------------------
+#------------------------------------------------------------------------------
 # pycparser: c-to-c.py
 #
-# Example of a C code generator from pycparser AST nodes, serving 
-# as a simplistic translator from C to AST and back to C.
-# Note: at this stage, the example is "alpha release" and considered 
-# experimental. Please file any bugs you find in the Issues page on pycparser's
-# website.
+# Example of using pycparser.c_generator, serving as a simplistic translator
+# from C to AST and back to C.
 #
-# Copyright (C) 2008-2011, Eli Bendersky
+# Copyright (C) 2008-2012, Eli Bendersky
 # License: BSD
-#-----------------------------------------------------------------
+#------------------------------------------------------------------------------
 from __future__ import print_function
 import sys
 
@@ -18,382 +15,12 @@ import sys
 #
 sys.path.insert(0, '..')
 
-from pycparser import c_parser, c_ast, parse_file
-
-
-class CGenerator(object):
-    """ Uses the same visitor pattern as c_ast.NodeVisitor, but modified to
-        return a value from each visit method, using string accumulation in 
-        generic_visit.
-    """
-    def __init__(self):
-        self.output = ''
-        
-        # Statements start with indentation of self.indent_level spaces, using
-        # the _make_indent method
-        #
-        self.indent_level = 0
-    
-    def _make_indent(self):
-        return ' ' * self.indent_level
-    
-    def visit(self, node):
-        method = 'visit_' + node.__class__.__name__
-        return getattr(self, method, self.generic_visit)(node)
-    
-    def generic_visit(self, node):
-        #~ print('generic:', type(node))
-        if node is None:
-            return ''
-        else:
-            return ''.join(self.visit(c) for c in node.children())
-    
-    def visit_Constant(self, n):
-        return n.value
-        
-    def visit_ID(self, n):
-        return n.name
-
-    def visit_ArrayRef(self, n):
-        arrref = self._parenthesize_unless_simple(n.name)
-        return arrref + '[' + self.visit(n.subscript) + ']'
-
-    def visit_StructRef(self, n):
-        sref = self._parenthesize_unless_simple(n.name)
-        return sref + n.type + self.visit(n.field)
-
-    def visit_FuncCall(self, n):
-        fref = self._parenthesize_unless_simple(n.name)
-        return fref + '(' + self.visit(n.args) + ')'
-
-    def visit_UnaryOp(self, n):
-        operand = self._parenthesize_unless_simple(n.expr)
-        if n.op == 'p++':
-            return '%s++' % operand
-        elif n.op == 'p--':
-            return '%s--' % operand
-        elif n.op == 'sizeof':
-            # Always parenthesize the argument of sizeof since it can be 
-            # a name.
-            return 'sizeof(%s)' % self.visit(n.expr)
-        else:
-            return '%s%s' % (n.op, operand)
-
-    def visit_BinaryOp(self, n):
-        lval_str = self._parenthesize_if(n.left, 
-                            lambda d: not self._is_simple_node(d))
-        rval_str = self._parenthesize_if(n.right, 
-                            lambda d: not self._is_simple_node(d))
-        return '%s %s %s' % (lval_str, n.op, rval_str)
-    
-    def visit_Assignment(self, n):
-        rval_str = self._parenthesize_if(
-                            n.rvalue, 
-                            lambda n: isinstance(n, c_ast.Assignment))
-        return '%s %s %s' % (self.visit(n.lvalue), n.op, rval_str)
-    
-    def visit_IdentifierType(self, n):
-        return ' '.join(n.names)
-    
-    def visit_Decl(self, n, no_type=False):
-        # no_type is used when a Decl is part of a DeclList, where the type is
-        # explicitly only for the first delaration in a list.
-        #
-        s = n.name if no_type else self._generate_decl(n)
-        if n.bitsize: s += ' : ' + self.visit(n.bitsize)
-        if n.init:
-            if isinstance(n.init, c_ast.ExprList):
-                s += ' = {' + self.visit(n.init) + '}'
-            else:
-                s += ' = ' + self.visit(n.init)
-        return s
-    
-    def visit_DeclList(self, n):
-        s = self.visit(n.decls[0])
-        if len(n.decls) > 1:
-            s += ', ' + ', '.join(self.visit_Decl(decl, no_type=True) 
-                                    for decl in n.decls[1:])
-        return s
-    
-    def visit_Typedef(self, n):
-        s = ''
-        if n.storage: s += ' '.join(n.storage) + ' '
-        s += self._generate_type(n.type)
-        return s
-    
-    def visit_Cast(self, n):
-        s = '(' + self._generate_type(n.to_type) + ')' 
-        return s + ' ' + self._parenthesize_unless_simple(n.expr)
-    
-    def visit_ExprList(self, n):
-        visited_subexprs = []
-        for expr in n.exprs:
-            if isinstance(expr, c_ast.ExprList):
-                visited_subexprs.append('{' + self.visit(expr) + '}')
-            else:
-                visited_subexprs.append(self.visit(expr))
-        return ', '.join(visited_subexprs)
-    
-    def visit_Enum(self, n):
-        s = 'enum'
-        if n.name: s += ' ' + n.name
-        if n.values:
-            s += ' {'
-            for i, enumerator in enumerate(n.values.enumerators):
-                s += enumerator.name
-                if enumerator.value: 
-                    s += ' = ' + self.visit(enumerator.value)
-                if i != len(n.values.enumerators) - 1: 
-                    s += ', '
-            s += '}'
-        return s
-        
-    def visit_FuncDef(self, n):
-        decl = self.visit(n.decl)
-        self.indent_level = 0
-        # The body is a Compound node
-        body = self.visit(n.body)
-        return decl + '\n' + body + '\n'
-
-    def visit_FileAST(self, n):
-        s = ''
-        for ext in n.ext:
-            if isinstance(ext, c_ast.FuncDef):
-                s += self.visit(ext)
-            else:
-                s += self.visit(ext) + ';\n'
-        return s
-
-    def visit_Compound(self, n):
-        s = self._make_indent() + '{\n'
-        self.indent_level += 2
-        if n.block_items:
-            s += ''.join(self._generate_stmt(stmt) for stmt in n.block_items)
-        self.indent_level -= 2
-        s += self._make_indent() + '}\n'
-        return s
-    
-    def visit_EmptyStatement(self, n):
-        return ';'
-    
-    def visit_ParamList(self, n):
-        return ', '.join(self.visit(param) for param in n.params)
-
-    def visit_Return(self, n):
-        s = 'return'
-        if n.expr: s += ' ' + self.visit(n.expr)
-        return s + ';'
-
-    def visit_Break(self, n):
-        return 'break;'
-        
-    def visit_Continue(self, n):
-        return 'continue;'
-    
-    def visit_TernaryOp(self, n):
-        s = self.visit(n.cond) + ' ? '
-        s += self.visit(n.iftrue) + ' : '
-        s += self.visit(n.iffalse)
-        return s
-    
-    def visit_If(self, n):
-        s = 'if ('
-        if n.cond: s += self.visit(n.cond)
-        s += ')\n'
-        s += self._generate_stmt(n.iftrue, add_indent=True)
-        if n.iffalse: 
-            s += self._make_indent() + 'else\n'
-            s += self._generate_stmt(n.iffalse, add_indent=True)
-        return s
-    
-    def visit_For(self, n):
-        s = 'for ('
-        if n.init: s += self.visit(n.init)
-        s += ';'
-        if n.cond: s += ' ' + self.visit(n.cond)
-        s += ';'
-        if n.next: s += ' ' + self.visit(n.next)
-        s += ')\n'
-        s += self._generate_stmt(n.stmt, add_indent=True)
-        return s
-
-    def visit_While(self, n):
-        s = 'while ('
-        if n.cond: s += self.visit(n.cond)
-        s += ')\n'
-        s += self._generate_stmt(n.stmt, add_indent=True)
-        return s
-
-    def visit_DoWhile(self, n):
-        s = 'do\n'
-        s += self._generate_stmt(n.stmt, add_indent=True)
-        s += self._make_indent() + 'while ('
-        if n.cond: s += self.visit(n.cond)
-        s += ');'
-        return s
-
-    def visit_Switch(self, n):
-        s = 'switch (' + self.visit(n.cond) + ')\n'
-        s += self._generate_stmt(n.stmt, add_indent=True)
-        return s
-    
-    def visit_Case(self, n):
-        s = 'case ' + self.visit(n.expr) + ':\n'
-        s += self._generate_stmt(n.stmt, add_indent=True)
-        return s
-    
-    def visit_Default(self, n):
-        return 'default:\n' + self._generate_stmt(n.stmt, add_indent=True)
-
-    def visit_Label(self, n):
-        return n.name + ':\n' + self._generate_stmt(n.stmt)
-
-    def visit_Goto(self, n):
-        return 'goto ' + n.name + ';'
-
-    def visit_EllipsisParam(self, n):
-        return '...'
-
-    def visit_Struct(self, n):
-        return self._generate_struct_union(n, 'struct')
-
-    def visit_Typename(self, n):
-        return self._generate_type(n.type)
-        
-    def visit_Union(self, n):
-        return self._generate_struct_union(n, 'union')
-
-    def visit_NamedInitializer(self, n):
-        s = ''
-        for name in n.name:
-            if isinstance(name, c_ast.ID):
-                s += '.' + name.name
-            elif isinstance(name, c_ast.Constant):
-                s += '[' + name.value + ']'
-        s += ' = ' + self.visit(n.expr)
-        return s
-
-    def _generate_struct_union(self, n, name):
-        """ Generates code for structs and unions. name should be either 
-            'struct' or union.
-        """
-        s = name + ' ' + (n.name or '')
-        if n.decls:
-            s += '\n'
-            s += self._make_indent() 
-            self.indent_level += 2
-            s += '{\n'
-            for decl in n.decls:
-                s += self._generate_stmt(decl)
-            self.indent_level -= 2
-            s += self._make_indent() + '}'
-        return s
-
-    def _generate_stmt(self, n, add_indent=False):
-        """ Generation from a statement node. This method exists as a wrapper
-            for individual visit_* methods to handle different treatment of 
-            some statements in this context.
-        """
-        typ = type(n)
-        if add_indent: self.indent_level += 2
-        indent = self._make_indent()
-        if add_indent: self.indent_level -= 2
-        
-        if typ in ( 
-                c_ast.Decl, c_ast.Assignment, c_ast.Cast, c_ast.UnaryOp,
-                c_ast.BinaryOp, c_ast.TernaryOp, c_ast.FuncCall, c_ast.ArrayRef,
-                c_ast.StructRef):
-            # These can also appear in an expression context so no semicolon
-            # is added to them automatically
-            #
-            return indent + self.visit(n) + ';\n'
-        elif typ in (c_ast.Compound,):
-            # No extra indentation required before the opening brace of a 
-            # compound - because it consists of multiple lines it has to 
-            # compute its own indentation.
-            #
-            return self.visit(n)
-        else:
-            return indent + self.visit(n) + '\n'
-
-    def _generate_decl(self, n):
-        """ Generation from a Decl node.
-        """
-        s = ''
-        if n.funcspec: s = ' '.join(n.funcspec) + ' '
-        if n.storage: s += ' '.join(n.storage) + ' '
-        s += self._generate_type(n.type)
-        return s
-    
-    def _generate_type(self, n, modifiers=[]):
-        """ Recursive generation from a type node. n is the type node. 
-            modifiers collects the PtrDecl, ArrayDecl and FuncDecl modifiers 
-            encountered on the way down to a TypeDecl, to allow proper
-            generation from it.
-        """
-        typ = type(n)
-        #~ print(n, modifiers)
-        
-        if typ == c_ast.TypeDecl:
-            s = ''
-            if n.quals: s += ' '.join(n.quals) + ' '
-            s += self.visit(n.type)
-            
-            nstr = n.declname if n.declname else ''
-            # Resolve modifiers.
-            # Wrap in parens to distinguish pointer to array and pointer to
-            # function syntax.
-            #
-            for i, modifier in enumerate(modifiers):
-                if isinstance(modifier, c_ast.ArrayDecl):
-                    if (i != 0 and isinstance(modifiers[i - 1], c_ast.PtrDecl)):
-                        nstr = '(' + nstr + ')'
-                    nstr += '[' + self.visit(modifier.dim) + ']'
-                elif isinstance(modifier, c_ast.FuncDecl):
-                    if (i != 0 and isinstance(modifiers[i - 1], c_ast.PtrDecl)):
-                        nstr = '(' + nstr + ')'
-                    nstr += '(' + self.visit(modifier.args) + ')'
-                elif isinstance(modifier, c_ast.PtrDecl):
-                    nstr = '*' + nstr
-            if nstr: s += ' ' + nstr
-            return s
-        elif typ == c_ast.Decl:
-            return self._generate_decl(n.type)
-        elif typ == c_ast.Typename:
-            return self._generate_type(n.type)
-        elif typ == c_ast.IdentifierType:
-            return ' '.join(n.names) + ' '
-        elif typ in (c_ast.ArrayDecl, c_ast.PtrDecl, c_ast.FuncDecl):
-            return self._generate_type(n.type, modifiers + [n])
-        else:
-            return self.visit(n)
-
-    def _parenthesize_if(self, n, condition):
-        """ Visits 'n' and returns its string representation, parenthesized
-            if the condition function applied to the node returns True.
-        """
-        s = self.visit(n)
-        if condition(n):
-            return '(' + s + ')'
-        else:
-            return s
-
-    def _parenthesize_unless_simple(self, n):
-        """ Common use case for _parenthesize_if
-        """
-        return self._parenthesize_if(n, lambda d: not self._is_simple_node(d))
-
-    def _is_simple_node(self, n):
-        """ Returns True for nodes that are "simple" - i.e. nodes that always
-            have higher precedence than operators.
-        """
-        return isinstance(n,(   c_ast.Constant, c_ast.ID, c_ast.ArrayRef, 
-                                c_ast.StructRef, c_ast.FuncCall))
+from pycparser import parse_file, c_parser, c_generator
 
 
 def translate_to_c(filename):
     ast = parse_file(filename, use_cpp=True)
-    generator = CGenerator()
+    generator = c_generator.CGenerator()
     print(generator.visit(ast))
 
 
@@ -412,7 +39,7 @@ int main(void)
     parser = c_parser.CParser()
     ast = parser.parse(src)
     ast.show()
-    generator = CGenerator()
+    generator = c_generator.CGenerator()
     
     print(generator.visit(ast))
     
@@ -425,7 +52,7 @@ int main(void)
 
 #------------------------------------------------------------------------------
 if __name__ == "__main__":
-    zz_test_translate()
+    #zz_test_translate()
     if len(sys.argv) > 1:
         translate_to_c(sys.argv[1])
     else: