[Pretty printers] Can the name or type of a child value change?

Elmenthaler, Jens jens.elmenthaler@verigy.com
Fri Aug 13 06:41:00 GMT 2010


Consider the following code example:

  struct JAny {
    union {
      char *text;
      int number;
    } val;

    // 1 -> text, 2 -> number
    int type;
  };

And the following pretty printer:
class AnyPrinter:
    class _iterator:
        def __init__ (self, name, value):
            self.count = 0
            self.name = name
            self.value = value

        def __iter__(self):
            return self

        def next(self):
            if self.count != 0:
                raise StopIteration
            
            self.count = self.count + 1
            return (self.name, self.value)    

    def __init__(self, val):
        self.type = val['type']
        
        if self.type == 1:
            self.value = val['val']['text']
            self.name = "text"
            
        if self.type == 2:
            self.value = val['val']['number']
            self.name = "number"
            
    def children(self):
        return self._iterator(self.name, self.value)

    def to_string(self):
        return "JAny"

When stepping in the debugger over a line that changes JAny.type, the name and the type of the child value returned by the pretty printer change.

Are the MI variable objects meant to handle this?

Greetings, Jens.



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