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- """Generic output formatting.
- Formatter objects transform an abstract flow of formatting events into
- specific output events on writer objects. Formatters manage several stack
- structures to allow various properties of a writer object to be changed and
- restored; writers need not be able to handle relative changes nor any sort
- of ``change back'' operation. Specific writer properties which may be
- controlled via formatter objects are horizontal alignment, font, and left
- margin indentations. A mechanism is provided which supports providing
- arbitrary, non-exclusive style settings to a writer as well. Additional
- interfaces facilitate formatting events which are not reversible, such as
- paragraph separation.
- Writer objects encapsulate device interfaces. Abstract devices, such as
- file formats, are supported as well as physical devices. The provided
- implementations all work with abstract devices. The interface makes
- available mechanisms for setting the properties which formatter objects
- manage and inserting data into the output.
- """
- import sys
- import warnings
- warnings.warn('the formatter module is deprecated', DeprecationWarning,
- stacklevel=2)
- AS_IS = None
- class NullFormatter:
- """A formatter which does nothing.
- If the writer parameter is omitted, a NullWriter instance is created.
- No methods of the writer are called by NullFormatter instances.
- Implementations should inherit from this class if implementing a writer
- interface but don't need to inherit any implementation.
- """
- def __init__(self, writer=None):
- if writer is None:
- writer = NullWriter()
- self.writer = writer
- def end_paragraph(self, blankline): pass
- def add_line_break(self): pass
- def add_hor_rule(self, *args, **kw): pass
- def add_label_data(self, format, counter, blankline=None): pass
- def add_flowing_data(self, data): pass
- def add_literal_data(self, data): pass
- def flush_softspace(self): pass
- def push_alignment(self, align): pass
- def pop_alignment(self): pass
- def push_font(self, x): pass
- def pop_font(self): pass
- def push_margin(self, margin): pass
- def pop_margin(self): pass
- def set_spacing(self, spacing): pass
- def push_style(self, *styles): pass
- def pop_style(self, n=1): pass
- def assert_line_data(self, flag=1): pass
- class AbstractFormatter:
- """The standard formatter.
- This implementation has demonstrated wide applicability to many writers,
- and may be used directly in most circumstances. It has been used to
- implement a full-featured World Wide Web browser.
- """
- # Space handling policy: blank spaces at the boundary between elements
- # are handled by the outermost context. "Literal" data is not checked
- # to determine context, so spaces in literal data are handled directly
- # in all circumstances.
- def __init__(self, writer):
- self.writer = writer # Output device
- self.align = None # Current alignment
- self.align_stack = [] # Alignment stack
- self.font_stack = [] # Font state
- self.margin_stack = [] # Margin state
- self.spacing = None # Vertical spacing state
- self.style_stack = [] # Other state, e.g. color
- self.nospace = 1 # Should leading space be suppressed
- self.softspace = 0 # Should a space be inserted
- self.para_end = 1 # Just ended a paragraph
- self.parskip = 0 # Skipped space between paragraphs?
- self.hard_break = 1 # Have a hard break
- self.have_label = 0
- def end_paragraph(self, blankline):
- if not self.hard_break:
- self.writer.send_line_break()
- self.have_label = 0
- if self.parskip < blankline and not self.have_label:
- self.writer.send_paragraph(blankline - self.parskip)
- self.parskip = blankline
- self.have_label = 0
- self.hard_break = self.nospace = self.para_end = 1
- self.softspace = 0
- def add_line_break(self):
- if not (self.hard_break or self.para_end):
- self.writer.send_line_break()
- self.have_label = self.parskip = 0
- self.hard_break = self.nospace = 1
- self.softspace = 0
- def add_hor_rule(self, *args, **kw):
- if not self.hard_break:
- self.writer.send_line_break()
- self.writer.send_hor_rule(*args, **kw)
- self.hard_break = self.nospace = 1
- self.have_label = self.para_end = self.softspace = self.parskip = 0
- def add_label_data(self, format, counter, blankline = None):
- if self.have_label or not self.hard_break:
- self.writer.send_line_break()
- if not self.para_end:
- self.writer.send_paragraph((blankline and 1) or 0)
- if isinstance(format, str):
- self.writer.send_label_data(self.format_counter(format, counter))
- else:
- self.writer.send_label_data(format)
- self.nospace = self.have_label = self.hard_break = self.para_end = 1
- self.softspace = self.parskip = 0
- def format_counter(self, format, counter):
- label = ''
- for c in format:
- if c == '1':
- label = label + ('%d' % counter)
- elif c in 'aA':
- if counter > 0:
- label = label + self.format_letter(c, counter)
- elif c in 'iI':
- if counter > 0:
- label = label + self.format_roman(c, counter)
- else:
- label = label + c
- return label
- def format_letter(self, case, counter):
- label = ''
- while counter > 0:
- counter, x = divmod(counter-1, 26)
- # This makes a strong assumption that lowercase letters
- # and uppercase letters form two contiguous blocks, with
- # letters in order!
- s = chr(ord(case) + x)
- label = s + label
- return label
- def format_roman(self, case, counter):
- ones = ['i', 'x', 'c', 'm']
- fives = ['v', 'l', 'd']
- label, index = '', 0
- # This will die of IndexError when counter is too big
- while counter > 0:
- counter, x = divmod(counter, 10)
- if x == 9:
- label = ones[index] + ones[index+1] + label
- elif x == 4:
- label = ones[index] + fives[index] + label
- else:
- if x >= 5:
- s = fives[index]
- x = x-5
- else:
- s = ''
- s = s + ones[index]*x
- label = s + label
- index = index + 1
- if case == 'I':
- return label.upper()
- return label
- def add_flowing_data(self, data):
- if not data: return
- prespace = data[:1].isspace()
- postspace = data[-1:].isspace()
- data = " ".join(data.split())
- if self.nospace and not data:
- return
- elif prespace or self.softspace:
- if not data:
- if not self.nospace:
- self.softspace = 1
- self.parskip = 0
- return
- if not self.nospace:
- data = ' ' + data
- self.hard_break = self.nospace = self.para_end = \
- self.parskip = self.have_label = 0
- self.softspace = postspace
- self.writer.send_flowing_data(data)
- def add_literal_data(self, data):
- if not data: return
- if self.softspace:
- self.writer.send_flowing_data(" ")
- self.hard_break = data[-1:] == '\n'
- self.nospace = self.para_end = self.softspace = \
- self.parskip = self.have_label = 0
- self.writer.send_literal_data(data)
- def flush_softspace(self):
- if self.softspace:
- self.hard_break = self.para_end = self.parskip = \
- self.have_label = self.softspace = 0
- self.nospace = 1
- self.writer.send_flowing_data(' ')
- def push_alignment(self, align):
- if align and align != self.align:
- self.writer.new_alignment(align)
- self.align = align
- self.align_stack.append(align)
- else:
- self.align_stack.append(self.align)
- def pop_alignment(self):
- if self.align_stack:
- del self.align_stack[-1]
- if self.align_stack:
- self.align = align = self.align_stack[-1]
- self.writer.new_alignment(align)
- else:
- self.align = None
- self.writer.new_alignment(None)
- def push_font(self, font):
- size, i, b, tt = font
- if self.softspace:
- self.hard_break = self.para_end = self.softspace = 0
- self.nospace = 1
- self.writer.send_flowing_data(' ')
- if self.font_stack:
- csize, ci, cb, ctt = self.font_stack[-1]
- if size is AS_IS: size = csize
- if i is AS_IS: i = ci
- if b is AS_IS: b = cb
- if tt is AS_IS: tt = ctt
- font = (size, i, b, tt)
- self.font_stack.append(font)
- self.writer.new_font(font)
- def pop_font(self):
- if self.font_stack:
- del self.font_stack[-1]
- if self.font_stack:
- font = self.font_stack[-1]
- else:
- font = None
- self.writer.new_font(font)
- def push_margin(self, margin):
- self.margin_stack.append(margin)
- fstack = [m for m in self.margin_stack if m]
- if not margin and fstack:
- margin = fstack[-1]
- self.writer.new_margin(margin, len(fstack))
- def pop_margin(self):
- if self.margin_stack:
- del self.margin_stack[-1]
- fstack = [m for m in self.margin_stack if m]
- if fstack:
- margin = fstack[-1]
- else:
- margin = None
- self.writer.new_margin(margin, len(fstack))
- def set_spacing(self, spacing):
- self.spacing = spacing
- self.writer.new_spacing(spacing)
- def push_style(self, *styles):
- if self.softspace:
- self.hard_break = self.para_end = self.softspace = 0
- self.nospace = 1
- self.writer.send_flowing_data(' ')
- for style in styles:
- self.style_stack.append(style)
- self.writer.new_styles(tuple(self.style_stack))
- def pop_style(self, n=1):
- del self.style_stack[-n:]
- self.writer.new_styles(tuple(self.style_stack))
- def assert_line_data(self, flag=1):
- self.nospace = self.hard_break = not flag
- self.para_end = self.parskip = self.have_label = 0
- class NullWriter:
- """Minimal writer interface to use in testing & inheritance.
- A writer which only provides the interface definition; no actions are
- taken on any methods. This should be the base class for all writers
- which do not need to inherit any implementation methods.
- """
- def __init__(self): pass
- def flush(self): pass
- def new_alignment(self, align): pass
- def new_font(self, font): pass
- def new_margin(self, margin, level): pass
- def new_spacing(self, spacing): pass
- def new_styles(self, styles): pass
- def send_paragraph(self, blankline): pass
- def send_line_break(self): pass
- def send_hor_rule(self, *args, **kw): pass
- def send_label_data(self, data): pass
- def send_flowing_data(self, data): pass
- def send_literal_data(self, data): pass
- class AbstractWriter(NullWriter):
- """A writer which can be used in debugging formatters, but not much else.
- Each method simply announces itself by printing its name and
- arguments on standard output.
- """
- def new_alignment(self, align):
- print("new_alignment(%r)" % (align,))
- def new_font(self, font):
- print("new_font(%r)" % (font,))
- def new_margin(self, margin, level):
- print("new_margin(%r, %d)" % (margin, level))
- def new_spacing(self, spacing):
- print("new_spacing(%r)" % (spacing,))
- def new_styles(self, styles):
- print("new_styles(%r)" % (styles,))
- def send_paragraph(self, blankline):
- print("send_paragraph(%r)" % (blankline,))
- def send_line_break(self):
- print("send_line_break()")
- def send_hor_rule(self, *args, **kw):
- print("send_hor_rule()")
- def send_label_data(self, data):
- print("send_label_data(%r)" % (data,))
- def send_flowing_data(self, data):
- print("send_flowing_data(%r)" % (data,))
- def send_literal_data(self, data):
- print("send_literal_data(%r)" % (data,))
- class DumbWriter(NullWriter):
- """Simple writer class which writes output on the file object passed in
- as the file parameter or, if file is omitted, on standard output. The
- output is simply word-wrapped to the number of columns specified by
- the maxcol parameter. This class is suitable for reflowing a sequence
- of paragraphs.
- """
- def __init__(self, file=None, maxcol=72):
- self.file = file or sys.stdout
- self.maxcol = maxcol
- NullWriter.__init__(self)
- self.reset()
- def reset(self):
- self.col = 0
- self.atbreak = 0
- def send_paragraph(self, blankline):
- self.file.write('\n'*blankline)
- self.col = 0
- self.atbreak = 0
- def send_line_break(self):
- self.file.write('\n')
- self.col = 0
- self.atbreak = 0
- def send_hor_rule(self, *args, **kw):
- self.file.write('\n')
- self.file.write('-'*self.maxcol)
- self.file.write('\n')
- self.col = 0
- self.atbreak = 0
- def send_literal_data(self, data):
- self.file.write(data)
- i = data.rfind('\n')
- if i >= 0:
- self.col = 0
- data = data[i+1:]
- data = data.expandtabs()
- self.col = self.col + len(data)
- self.atbreak = 0
- def send_flowing_data(self, data):
- if not data: return
- atbreak = self.atbreak or data[0].isspace()
- col = self.col
- maxcol = self.maxcol
- write = self.file.write
- for word in data.split():
- if atbreak:
- if col + len(word) >= maxcol:
- write('\n')
- col = 0
- else:
- write(' ')
- col = col + 1
- write(word)
- col = col + len(word)
- atbreak = 1
- self.col = col
- self.atbreak = data[-1].isspace()
- def test(file = None):
- w = DumbWriter()
- f = AbstractFormatter(w)
- if file is not None:
- fp = open(file)
- elif sys.argv[1:]:
- fp = open(sys.argv[1])
- else:
- fp = sys.stdin
- try:
- for line in fp:
- if line == '\n':
- f.end_paragraph(1)
- else:
- f.add_flowing_data(line)
- finally:
- if fp is not sys.stdin:
- fp.close()
- f.end_paragraph(0)
- if __name__ == '__main__':
- test()
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