191 lines
7 KiB
Python
191 lines
7 KiB
Python
"""Extension to format a paragraph or selection to a max width.
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Does basic, standard text formatting, and also understands Python
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comment blocks. Thus, for editing Python source code, this
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extension is really only suitable for reformatting these comment
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blocks or triple-quoted strings.
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Known problems with comment reformatting:
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* If there is a selection marked, and the first line of the
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selection is not complete, the block will probably not be detected
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as comments, and will have the normal "text formatting" rules
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applied.
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* If a comment block has leading whitespace that mixes tabs and
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spaces, they will not be considered part of the same block.
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* Fancy comments, like this bulleted list, aren't handled :-)
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"""
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import re
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from idlelib.configHandler import idleConf
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class FormatParagraph:
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menudefs = [
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('format', [ # /s/edit/format dscherer@cmu.edu
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('Format Paragraph', '<<format-paragraph>>'),
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])
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]
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def __init__(self, editwin):
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self.editwin = editwin
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def close(self):
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self.editwin = None
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def format_paragraph_event(self, event):
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"""Formats paragraph to a max width specified in idleConf.
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If text is selected, format_paragraph_event will start breaking lines
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at the max width, starting from the beginning selection.
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If no text is selected, format_paragraph_event uses the current
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cursor location to determine the paragraph (lines of text surrounded
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by blank lines) and formats it.
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"""
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maxformatwidth = idleConf.GetOption(
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'main', 'FormatParagraph', 'paragraph', type='int')
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text = self.editwin.text
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first, last = self.editwin.get_selection_indices()
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if first and last:
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data = text.get(first, last)
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comment_header = get_comment_header(data)
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else:
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first, last, comment_header, data = \
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find_paragraph(text, text.index("insert"))
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if comment_header:
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newdata = reformat_comment(data, maxformatwidth, comment_header)
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else:
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newdata = reformat_paragraph(data, maxformatwidth)
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text.tag_remove("sel", "1.0", "end")
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if newdata != data:
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text.mark_set("insert", first)
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text.undo_block_start()
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text.delete(first, last)
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text.insert(first, newdata)
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text.undo_block_stop()
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else:
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text.mark_set("insert", last)
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text.see("insert")
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return "break"
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def find_paragraph(text, mark):
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"""Returns the start/stop indices enclosing the paragraph that mark is in.
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Also returns the comment format string, if any, and paragraph of text
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between the start/stop indices.
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"""
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lineno, col = map(int, mark.split("."))
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line = text.get("%d.0" % lineno, "%d.end" % lineno)
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# Look for start of next paragraph if the index passed in is a blank line
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while text.compare("%d.0" % lineno, "<", "end") and is_all_white(line):
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lineno = lineno + 1
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line = text.get("%d.0" % lineno, "%d.end" % lineno)
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first_lineno = lineno
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comment_header = get_comment_header(line)
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comment_header_len = len(comment_header)
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# Once start line found, search for end of paragraph (a blank line)
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while get_comment_header(line)==comment_header and \
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not is_all_white(line[comment_header_len:]):
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lineno = lineno + 1
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line = text.get("%d.0" % lineno, "%d.end" % lineno)
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last = "%d.0" % lineno
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# Search back to beginning of paragraph (first blank line before)
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lineno = first_lineno - 1
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line = text.get("%d.0" % lineno, "%d.end" % lineno)
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while lineno > 0 and \
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get_comment_header(line)==comment_header and \
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not is_all_white(line[comment_header_len:]):
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lineno = lineno - 1
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line = text.get("%d.0" % lineno, "%d.end" % lineno)
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first = "%d.0" % (lineno+1)
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return first, last, comment_header, text.get(first, last)
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# This should perhaps be replaced with textwrap.wrap
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def reformat_paragraph(data, limit):
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"""Return data reformatted to specified width (limit)."""
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lines = data.split("\n")
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i = 0
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n = len(lines)
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while i < n and is_all_white(lines[i]):
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i = i+1
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if i >= n:
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return data
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indent1 = get_indent(lines[i])
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if i+1 < n and not is_all_white(lines[i+1]):
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indent2 = get_indent(lines[i+1])
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else:
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indent2 = indent1
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new = lines[:i]
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partial = indent1
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while i < n and not is_all_white(lines[i]):
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# XXX Should take double space after period (etc.) into account
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words = re.split("(\s+)", lines[i])
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for j in range(0, len(words), 2):
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word = words[j]
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if not word:
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continue # Can happen when line ends in whitespace
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if len((partial + word).expandtabs()) > limit and \
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partial != indent1:
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new.append(partial.rstrip())
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partial = indent2
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partial = partial + word + " "
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if j+1 < len(words) and words[j+1] != " ":
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partial = partial + " "
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i = i+1
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new.append(partial.rstrip())
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# XXX Should reformat remaining paragraphs as well
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new.extend(lines[i:])
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return "\n".join(new)
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def reformat_comment(data, limit, comment_header):
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"""Return data reformatted to specified width with comment header."""
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# Remove header from the comment lines
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lc = len(comment_header)
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data = "\n".join(line[lc:] for line in data.split("\n"))
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# Reformat to maxformatwidth chars or a 20 char width,
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# whichever is greater.
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format_width = max(limit - len(comment_header), 20)
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newdata = reformat_paragraph(data, format_width)
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# re-split and re-insert the comment header.
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newdata = newdata.split("\n")
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# If the block ends in a \n, we dont want the comment prefix
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# inserted after it. (Im not sure it makes sense to reformat a
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# comment block that is not made of complete lines, but whatever!)
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# Can't think of a clean solution, so we hack away
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block_suffix = ""
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if not newdata[-1]:
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block_suffix = "\n"
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newdata = newdata[:-1]
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return '\n'.join(comment_header+line for line in newdata) + block_suffix
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def is_all_white(line):
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"""Return True if line is empty or all whitespace."""
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return re.match(r"^\s*$", line) is not None
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def get_indent(line):
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"""Return the initial space or tab indent of line."""
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return re.match(r"^([ \t]*)", line).group()
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def get_comment_header(line):
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"""Return string with leading whitespace and '#' from line or ''.
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A null return indicates that the line is not a comment line. A non-
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null return, such as ' #', will be used to find the other lines of
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a comment block with the same indent.
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"""
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m = re.match(r"^([ \t]*#*)", line)
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if m is None: return ""
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return m.group(1)
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if __name__ == "__main__":
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from test import support; support.use_resources = ['gui']
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import unittest
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unittest.main('idlelib.idle_test.test_formatparagraph',
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verbosity=2, exit=False)
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