add an indent to a stream

[Dave Brueck]

On Mon, 10 Mar 2003, Manuel M Garcia wrote:

> I often need to add an indent to a stream, usually so the output of
> pprint or traceback is indented so I can tell debugging output from my
> program's actual output.
>
> Below is a class to help do this.  I think I got the details right.
> The 'print' statement, when used with commas, is more complicated than
> I thought.
>
> What is the exact rule for when the 'print' command inserts a space
> because of a comma?  I guess it has something to do with the attribute
> 'softspace'.

Does the stream indenter have to worry about this? It's external to the
indenter, I think.

> class IndentStream:
>     """Stream with indent at start of each line.
>
>     Indent can be a string or
>     the number of spaces you wish to indent.
>
>     """
>
>     def __init__(self, indent='    ', stream=None):
>         if stream is None:
>             self._stream = sys.stdout
>         else:
>             self._stream = stream
>         try:
>             indent = ' ' * indent
>         except TypeError:
>             pass
>         self._indent = indent
>         self._nl_indent = '\n' + indent
>         self._indent_size = len(indent)
>         self._comma = 0
>         self.softspace = 0
>
>     def write(self, s):
>         comma = not s.endswith('\n')
>         s = s.replace('\n', self._nl_indent)
>         if not self._comma: s = self._indent + s
>         if s.endswith(self._nl_indent): s = s[:-self._indent_size]
>         self._stream.write(s)
>         self._comma = comma

Doesn't the above behave the same as:

class IndentStream:
    def __init__(self, indent='    ', stream=sys.stdout):
        self.stream = stream
        stream.write(indent)
        self.indent = indent

    def write(self, s):
        self.stream.write(s.replace('\n', '\n' + self.indent))

??

-Dave