Cython/CodeWriter.py

   1 from Cython.Compiler.Visitor import TreeVisitor
   2 from Cython.Compiler.Nodes import *
   3
   4 """
   5 Serializes a Cython code tree to Cython code. This is primarily useful for
   6 debugging and testing purposes.
   7
   8 The output is in a strict format, no whitespace or comments from the input
   9 is preserved (and it could not be as it is not present in the code tree).
  10 """
  11
  12 class LinesResult(object):
  13     def __init__(self):
  14         self.lines = []
  15         self.s = u""
  16
  17     def put(self, s):
  18         self.s += s
  19
  20     def newline(self):
  21         self.lines.append(self.s)
  22         self.s = u""
  23
  24     def putline(self, s):
  25         self.put(s)
  26         self.newline()
  27
  28 class CodeWriter(TreeVisitor):
  29
  30     indent_string = u"    "
  31
  32     def __init__(self, result = None):
  33         super(CodeWriter, self).__init__()
  34         if result is None:
  35             result = LinesResult()
  36         self.result = result
  37         self.numindents = 0
  38
  39     def write(self, tree):
  40         self.visit(tree)
  41
  42     def indent(self):
  43         self.numindents += 1
  44
  45     def dedent(self):
  46         self.numindents -= 1
  47
  48     def startline(self, s = u""):
  49         self.result.put(self.indent_string * self.numindents + s)
  50
  51     def put(self, s):
  52         self.result.put(s)
  53
  54     def endline(self, s = u""):
  55         self.result.putline(s)
  56
  57     def line(self, s):
  58         self.startline(s)
  59         self.endline()
  60
  61     def comma_seperated_list(self, items, output_rhs=False):
  62         if len(items) > 0:
  63             for item in items[:-1]:
  64                 self.visit(item)
  65                 if output_rhs and item.rhs is not None:
  66                     self.put(u" = ")
  67                     self.visit(item.rhs)
  68                 self.put(u", ")
  69             self.visit(items[-1])
  70
  71     def visit_Node(self, node):
  72         raise AssertionError("Node not handled by serializer: %r" % node)
  73
  74     def visit_ModuleNode(self, node):
  75         self.visitchildren(node)
  76
  77     def visit_StatListNode(self, node):
  78         self.visitchildren(node)
  79
  80     def visit_FuncDefNode(self, node):
  81         self.startline(u"def %s(" % node.name)
  82         self.comma_seperated_list(node.args)
  83         self.endline(u"):")
  84         self.indent()
  85         self.visit(node.body)
  86         self.dedent()
  87
  88     def visit_CArgDeclNode(self, node):
  89         if node.base_type.name is not None:
  90             self.visit(node.base_type)
  91             self.put(u" ")
  92         self.visit(node.declarator)
  93         if node.default is not None:
  94             self.put(u" = ")
  95             self.visit(node.default)
  96
  97     def visit_CNameDeclaratorNode(self, node):
  98         self.put(node.name)
  99
 100     def visit_CSimpleBaseTypeNode(self, node):
 101         # See Parsing.p_sign_and_longness
 102         if node.is_basic_c_type:
 103             self.put(("unsigned ", "", "signed ")[node.signed])
 104             if node.longness < 0:
 105                 self.put("short " * -node.longness)
 106             elif node.longness > 0:
 107                 self.put("long " * node.longness)
 108
 109         self.put(node.name)
 110
 111     def visit_SingleAssignmentNode(self, node):
 112         self.startline()
 113         self.visit(node.lhs)
 114         self.put(u" = ")
 115         self.visit(node.rhs)
 116         self.endline()
 117
 118     def visit_NameNode(self, node):
 119         self.put(node.name)
 120
 121     def visit_IntNode(self, node):
 122         self.put(node.value)
 123
 124     def visit_IfStatNode(self, node):
 125         # The IfClauseNode is handled directly without a seperate match
 126         # for clariy.
 127         self.startline(u"if ")
 128         self.visit(node.if_clauses[0].condition)
 129         self.endline(":")
 130         self.indent()
 131         self.visit(node.if_clauses[0].body)
 132         self.dedent()
 133         for clause in node.if_clauses[1:]:
 134             self.startline("elif ")
 135             self.visit(clause.condition)
 136             self.endline(":")
 137             self.indent()
 138             self.visit(clause.body)
 139             self.dedent()
 140         if node.else_clause is not None:
 141             self.line("else:")
 142             self.indent()
 143             self.visit(node.else_clause)
 144             self.dedent()
 145
 146     def visit_PassStatNode(self, node):
 147         self.startline(u"pass")
 148         self.endline()
 149
 150     def visit_PrintStatNode(self, node):
 151         self.startline(u"print ")
 152         self.comma_seperated_list(node.arg_tuple.args)
 153         if not node.append_newline:
 154             self.put(u",")
 155         self.endline()
 156
 157     def visit_BinopNode(self, node):
 158         self.visit(node.operand1)
 159         self.put(u" %s " % node.operator)
 160         self.visit(node.operand2)
 161
 162     def visit_CVarDefNode(self, node):
 163         self.startline(u"cdef ")
 164         self.visit(node.base_type)
 165         self.put(u" ")
 166         self.comma_seperated_list(node.declarators, output_rhs=True)
 167         self.endline()
 168
 169     def visit_ForInStatNode(self, node):
 170         self.startline(u"for ")
 171         self.visit(node.target)
 172         self.put(u" in ")
 173         self.visit(node.iterator.sequence)
 174         self.endline(u":")
 175         self.indent()
 176         self.visit(node.body)
 177         self.dedent()
 178         if node.else_clause is not None:
 179             self.line(u"else:")
 180             self.indent()
 181             self.visit(node.else_clause)
 182             self.dedent()
 183
 184     def visit_SequenceNode(self, node):
 185         self.comma_seperated_list(node.args) # Might need to discover whether we need () around tuples...hmm...
 186
 187     def visit_SimpleCallNode(self, node):
 188         self.put(node.function.name + u"(")
 189         self.comma_seperated_list(node.args)
 190         self.put(")")
 191
 192     def visit_ExprStatNode(self, node):
 193         self.startline()
 194         self.visit(node.expr)
 195         self.endline()
 196
 197     def visit_InPlaceAssignmentNode(self, node):
 198         self.startline()
 199         self.visit(node.lhs)
 200         self.put(" %s= " % node.operator)
 201         self.visit(node.rhs)
 202         self.endline()
 203
 204
 205