1"""Format a paragraph, comment block, or selection to a max width. 2 3Does basic, standard text formatting, and also understands Python 4comment blocks. Thus, for editing Python source code, this 5extension is really only suitable for reformatting these comment 6blocks or triple-quoted strings. 7 8Known problems with comment reformatting: 9* If there is a selection marked, and the first line of the 10 selection is not complete, the block will probably not be detected 11 as comments, and will have the normal "text formatting" rules 12 applied. 13* If a comment block has leading whitespace that mixes tabs and 14 spaces, they will not be considered part of the same block. 15* Fancy comments, like this bulleted list, aren't handled :-) 16""" 17import re 18 19from idlelib.config import idleConf 20 21 22class FormatParagraph: 23 24 def __init__(self, editwin): 25 self.editwin = editwin 26 27 @classmethod 28 def reload(cls): 29 cls.max_width = idleConf.GetOption('extensions', 'FormatParagraph', 30 'max-width', type='int', default=72) 31 32 def close(self): 33 self.editwin = None 34 35 def format_paragraph_event(self, event, limit=None): 36 """Formats paragraph to a max width specified in idleConf. 37 38 If text is selected, format_paragraph_event will start breaking lines 39 at the max width, starting from the beginning selection. 40 41 If no text is selected, format_paragraph_event uses the current 42 cursor location to determine the paragraph (lines of text surrounded 43 by blank lines) and formats it. 44 45 The length limit parameter is for testing with a known value. 46 """ 47 limit = self.max_width if limit is None else limit 48 text = self.editwin.text 49 first, last = self.editwin.get_selection_indices() 50 if first and last: 51 data = text.get(first, last) 52 comment_header = get_comment_header(data) 53 else: 54 first, last, comment_header, data = \ 55 find_paragraph(text, text.index("insert")) 56 if comment_header: 57 newdata = reformat_comment(data, limit, comment_header) 58 else: 59 newdata = reformat_paragraph(data, limit) 60 text.tag_remove("sel", "1.0", "end") 61 62 if newdata != data: 63 text.mark_set("insert", first) 64 text.undo_block_start() 65 text.delete(first, last) 66 text.insert(first, newdata) 67 text.undo_block_stop() 68 else: 69 text.mark_set("insert", last) 70 text.see("insert") 71 return "break" 72 73 74FormatParagraph.reload() 75 76def find_paragraph(text, mark): 77 """Returns the start/stop indices enclosing the paragraph that mark is in. 78 79 Also returns the comment format string, if any, and paragraph of text 80 between the start/stop indices. 81 """ 82 lineno, col = map(int, mark.split(".")) 83 line = text.get("%d.0" % lineno, "%d.end" % lineno) 84 85 # Look for start of next paragraph if the index passed in is a blank line 86 while text.compare("%d.0" % lineno, "<", "end") and is_all_white(line): 87 lineno = lineno + 1 88 line = text.get("%d.0" % lineno, "%d.end" % lineno) 89 first_lineno = lineno 90 comment_header = get_comment_header(line) 91 comment_header_len = len(comment_header) 92 93 # Once start line found, search for end of paragraph (a blank line) 94 while get_comment_header(line)==comment_header and \ 95 not is_all_white(line[comment_header_len:]): 96 lineno = lineno + 1 97 line = text.get("%d.0" % lineno, "%d.end" % lineno) 98 last = "%d.0" % lineno 99 100 # Search back to beginning of paragraph (first blank line before) 101 lineno = first_lineno - 1 102 line = text.get("%d.0" % lineno, "%d.end" % lineno) 103 while lineno > 0 and \ 104 get_comment_header(line)==comment_header and \ 105 not is_all_white(line[comment_header_len:]): 106 lineno = lineno - 1 107 line = text.get("%d.0" % lineno, "%d.end" % lineno) 108 first = "%d.0" % (lineno+1) 109 110 return first, last, comment_header, text.get(first, last) 111 112# This should perhaps be replaced with textwrap.wrap 113def reformat_paragraph(data, limit): 114 """Return data reformatted to specified width (limit).""" 115 lines = data.split("\n") 116 i = 0 117 n = len(lines) 118 while i < n and is_all_white(lines[i]): 119 i = i+1 120 if i >= n: 121 return data 122 indent1 = get_indent(lines[i]) 123 if i+1 < n and not is_all_white(lines[i+1]): 124 indent2 = get_indent(lines[i+1]) 125 else: 126 indent2 = indent1 127 new = lines[:i] 128 partial = indent1 129 while i < n and not is_all_white(lines[i]): 130 # XXX Should take double space after period (etc.) into account 131 words = re.split(r"(\s+)", lines[i]) 132 for j in range(0, len(words), 2): 133 word = words[j] 134 if not word: 135 continue # Can happen when line ends in whitespace 136 if len((partial + word).expandtabs()) > limit and \ 137 partial != indent1: 138 new.append(partial.rstrip()) 139 partial = indent2 140 partial = partial + word + " " 141 if j+1 < len(words) and words[j+1] != " ": 142 partial = partial + " " 143 i = i+1 144 new.append(partial.rstrip()) 145 # XXX Should reformat remaining paragraphs as well 146 new.extend(lines[i:]) 147 return "\n".join(new) 148 149def reformat_comment(data, limit, comment_header): 150 """Return data reformatted to specified width with comment header.""" 151 152 # Remove header from the comment lines 153 lc = len(comment_header) 154 data = "\n".join(line[lc:] for line in data.split("\n")) 155 # Reformat to maxformatwidth chars or a 20 char width, 156 # whichever is greater. 157 format_width = max(limit - len(comment_header), 20) 158 newdata = reformat_paragraph(data, format_width) 159 # re-split and re-insert the comment header. 160 newdata = newdata.split("\n") 161 # If the block ends in a \n, we don't want the comment prefix 162 # inserted after it. (Im not sure it makes sense to reformat a 163 # comment block that is not made of complete lines, but whatever!) 164 # Can't think of a clean solution, so we hack away 165 block_suffix = "" 166 if not newdata[-1]: 167 block_suffix = "\n" 168 newdata = newdata[:-1] 169 return '\n'.join(comment_header+line for line in newdata) + block_suffix 170 171def is_all_white(line): 172 """Return True if line is empty or all whitespace.""" 173 174 return re.match(r"^\s*$", line) is not None 175 176def get_indent(line): 177 """Return the initial space or tab indent of line.""" 178 return re.match(r"^([ \t]*)", line).group() 179 180def get_comment_header(line): 181 """Return string with leading whitespace and '#' from line or ''. 182 183 A null return indicates that the line is not a comment line. A non- 184 null return, such as ' #', will be used to find the other lines of 185 a comment block with the same indent. 186 """ 187 m = re.match(r"^([ \t]*#*)", line) 188 if m is None: return "" 189 return m.group(1) 190 191 192if __name__ == "__main__": 193 from unittest import main 194 main('idlelib.idle_test.test_paragraph', verbosity=2, exit=False) 195