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1""" help.py: Implement the Idle help menu.
2Contents are subject to revision at any time, without notice.
3
4
5Help => About IDLE: diplay About Idle dialog
6
7<to be moved here from help_about.py>
8
9
10Help => IDLE Help: Display help.html with proper formatting.
11Doc/library/idle.rst (Sphinx)=> Doc/build/html/library/idle.html
12(help.copy_strip)=> Lib/idlelib/help.html
13
14HelpParser - Parse help.html and render to tk Text.
15
16HelpText - Display formatted help.html.
17
18HelpFrame - Contain text, scrollbar, and table-of-contents.
19(This will be needed for display in a future tabbed window.)
20
21HelpWindow - Display HelpFrame in a standalone window.
22
23copy_strip - Copy idle.html to help.html, rstripping each line.
24
25show_idlehelp - Create HelpWindow.  Called in EditorWindow.help_dialog.
26"""
27from html.parser import HTMLParser
28from os.path import abspath, dirname, isfile, join
29from platform import python_version
30
31from tkinter import Toplevel, Frame, Text, Menu
32from tkinter.ttk import Menubutton, Scrollbar
33from tkinter import font as tkfont
34
35from idlelib.config import idleConf
36
37## About IDLE ##
38
39
40## IDLE Help ##
41
42class HelpParser(HTMLParser):
43    """Render help.html into a text widget.
44
45    The overridden handle_xyz methods handle a subset of html tags.
46    The supplied text should have the needed tag configurations.
47    The behavior for unsupported tags, such as table, is undefined.
48    If the tags generated by Sphinx change, this class, especially
49    the handle_starttag and handle_endtags methods, might have to also.
50    """
51    def __init__(self, text):
52        HTMLParser.__init__(self, convert_charrefs=True)
53        self.text = text         # text widget we're rendering into
54        self.tags = ''           # current block level text tags to apply
55        self.chartags = ''       # current character level text tags
56        self.show = False        # used so we exclude page navigation
57        self.hdrlink = False     # used so we don't show header links
58        self.level = 0           # indentation level
59        self.pre = False         # displaying preformatted text
60        self.hprefix = ''        # prefix such as '25.5' to strip from headings
61        self.nested_dl = False   # if we're in a nested <dl>
62        self.simplelist = False  # simple list (no double spacing)
63        self.toc = []            # pair headers with text indexes for toc
64        self.header = ''         # text within header tags for toc
65
66    def indent(self, amt=1):
67        self.level += amt
68        self.tags = '' if self.level == 0 else 'l'+str(self.level)
69
70    def handle_starttag(self, tag, attrs):
71        "Handle starttags in help.html."
72        class_ = ''
73        for a, v in attrs:
74            if a == 'class':
75                class_ = v
76        s = ''
77        if tag == 'div' and class_ == 'section':
78            self.show = True    # start of main content
79        elif tag == 'div' and class_ == 'sphinxsidebar':
80            self.show = False   # end of main content
81        elif tag == 'p' and class_ != 'first':
82            s = '\n\n'
83        elif tag == 'span' and class_ == 'pre':
84            self.chartags = 'pre'
85        elif tag == 'span' and class_ == 'versionmodified':
86            self.chartags = 'em'
87        elif tag == 'em':
88            self.chartags = 'em'
89        elif tag in ['ul', 'ol']:
90            if class_.find('simple') != -1:
91                s = '\n'
92                self.simplelist = True
93            else:
94                self.simplelist = False
95            self.indent()
96        elif tag == 'dl':
97            if self.level > 0:
98                self.nested_dl = True
99        elif tag == 'li':
100            s = '\n* ' if self.simplelist else '\n\n* '
101        elif tag == 'dt':
102            s = '\n\n' if not self.nested_dl else '\n'  # avoid extra line
103            self.nested_dl = False
104        elif tag == 'dd':
105            self.indent()
106            s = '\n'
107        elif tag == 'pre':
108            self.pre = True
109            if self.show:
110                self.text.insert('end', '\n\n')
111            self.tags = 'preblock'
112        elif tag == 'a' and class_ == 'headerlink':
113            self.hdrlink = True
114        elif tag == 'h1':
115            self.tags = tag
116        elif tag in ['h2', 'h3']:
117            if self.show:
118                self.header = ''
119                self.text.insert('end', '\n\n')
120            self.tags = tag
121        if self.show:
122            self.text.insert('end', s, (self.tags, self.chartags))
123
124    def handle_endtag(self, tag):
125        "Handle endtags in help.html."
126        if tag in ['h1', 'h2', 'h3']:
127            self.indent(0)  # clear tag, reset indent
128            if self.show:
129                self.toc.append((self.header, self.text.index('insert')))
130        elif tag in ['span', 'em']:
131            self.chartags = ''
132        elif tag == 'a':
133            self.hdrlink = False
134        elif tag == 'pre':
135            self.pre = False
136            self.tags = ''
137        elif tag in ['ul', 'dd', 'ol']:
138            self.indent(amt=-1)
139
140    def handle_data(self, data):
141        "Handle date segments in help.html."
142        if self.show and not self.hdrlink:
143            d = data if self.pre else data.replace('\n', ' ')
144            if self.tags == 'h1':
145                self.hprefix = d[0:d.index(' ')]
146            if self.tags in ['h1', 'h2', 'h3'] and self.hprefix != '':
147                if d[0:len(self.hprefix)] == self.hprefix:
148                    d = d[len(self.hprefix):].strip()
149                self.header += d
150            self.text.insert('end', d, (self.tags, self.chartags))
151
152
153class HelpText(Text):
154    "Display help.html."
155    def __init__(self, parent, filename):
156        "Configure tags and feed file to parser."
157        uwide = idleConf.GetOption('main', 'EditorWindow', 'width', type='int')
158        uhigh = idleConf.GetOption('main', 'EditorWindow', 'height', type='int')
159        uhigh = 3 * uhigh // 4  # lines average 4/3 of editor line height
160        Text.__init__(self, parent, wrap='word', highlightthickness=0,
161                      padx=5, borderwidth=0, width=uwide, height=uhigh)
162
163        normalfont = self.findfont(['TkDefaultFont', 'arial', 'helvetica'])
164        fixedfont = self.findfont(['TkFixedFont', 'monaco', 'courier'])
165        self['font'] = (normalfont, 12)
166        self.tag_configure('em', font=(normalfont, 12, 'italic'))
167        self.tag_configure('h1', font=(normalfont, 20, 'bold'))
168        self.tag_configure('h2', font=(normalfont, 18, 'bold'))
169        self.tag_configure('h3', font=(normalfont, 15, 'bold'))
170        self.tag_configure('pre', font=(fixedfont, 12), background='#f6f6ff')
171        self.tag_configure('preblock', font=(fixedfont, 10), lmargin1=25,
172                borderwidth=1, relief='solid', background='#eeffcc')
173        self.tag_configure('l1', lmargin1=25, lmargin2=25)
174        self.tag_configure('l2', lmargin1=50, lmargin2=50)
175        self.tag_configure('l3', lmargin1=75, lmargin2=75)
176        self.tag_configure('l4', lmargin1=100, lmargin2=100)
177
178        self.parser = HelpParser(self)
179        with open(filename, encoding='utf-8') as f:
180            contents = f.read()
181        self.parser.feed(contents)
182        self['state'] = 'disabled'
183
184    def findfont(self, names):
185        "Return name of first font family derived from names."
186        for name in names:
187            if name.lower() in (x.lower() for x in tkfont.names(root=self)):
188                font = tkfont.Font(name=name, exists=True, root=self)
189                return font.actual()['family']
190            elif name.lower() in (x.lower()
191                                  for x in tkfont.families(root=self)):
192                return name
193
194
195class HelpFrame(Frame):
196    "Display html text, scrollbar, and toc."
197    def __init__(self, parent, filename):
198        Frame.__init__(self, parent)
199        # keep references to widgets for test access.
200        self.text = text = HelpText(self, filename)
201        self['background'] = text['background']
202        self.toc = toc = self.toc_menu(text)
203        self.scroll = scroll = Scrollbar(self, command=text.yview)
204        text['yscrollcommand'] = scroll.set
205
206        self.rowconfigure(0, weight=1)
207        self.columnconfigure(1, weight=1)  # text
208        toc.grid(row=0, column=0, sticky='nw')
209        text.grid(row=0, column=1, sticky='nsew')
210        scroll.grid(row=0, column=2, sticky='ns')
211
212    def toc_menu(self, text):
213        "Create table of contents as drop-down menu."
214        toc = Menubutton(self, text='TOC')
215        drop = Menu(toc, tearoff=False)
216        for lbl, dex in text.parser.toc:
217            drop.add_command(label=lbl, command=lambda dex=dex:text.yview(dex))
218        toc['menu'] = drop
219        return toc
220
221
222class HelpWindow(Toplevel):
223    "Display frame with rendered html."
224    def __init__(self, parent, filename, title):
225        Toplevel.__init__(self, parent)
226        self.wm_title(title)
227        self.protocol("WM_DELETE_WINDOW", self.destroy)
228        HelpFrame(self, filename).grid(column=0, row=0, sticky='nsew')
229        self.grid_columnconfigure(0, weight=1)
230        self.grid_rowconfigure(0, weight=1)
231
232
233def copy_strip():
234    """Copy idle.html to idlelib/help.html, stripping trailing whitespace.
235
236    Files with trailing whitespace cannot be pushed to the hg cpython
237    repository.  For 3.x (on Windows), help.html is generated, after
238    editing idle.rst in the earliest maintenance version, with
239      sphinx-build -bhtml . build/html
240      python_d.exe -c "from idlelib.help import copy_strip; copy_strip()"
241    After refreshing TortoiseHG workshop to generate a diff,
242    check  both the diff and displayed text.  Push the diff along with
243    the idle.rst change and merge both into default (or an intermediate
244    maintenance version).
245
246    When the 'earlist' version gets its final maintenance release,
247    do an update as described above, without editing idle.rst, to
248    rebase help.html on the next version of idle.rst.  Do not worry
249    about version changes as version is not displayed.  Examine other
250    changes and the result of Help -> IDLE Help.
251
252    If maintenance and default versions of idle.rst diverge, and
253    merging does not go smoothly, then consider generating
254    separate help.html files from separate idle.htmls.
255    """
256    src = join(abspath(dirname(dirname(dirname(__file__)))),
257               'Doc', 'build', 'html', 'library', 'idle.html')
258    dst = join(abspath(dirname(__file__)), 'help.html')
259    with open(src, 'rb') as inn,\
260         open(dst, 'wb') as out:
261        for line in inn:
262            out.write(line.rstrip() + b'\n')
263    print('idle.html copied to help.html')
264
265def show_idlehelp(parent):
266    "Create HelpWindow; called from Idle Help event handler."
267    filename = join(abspath(dirname(__file__)), 'help.html')
268    if not isfile(filename):
269        # try copy_strip, present message
270        return
271    HelpWindow(parent, filename, 'IDLE Help (%s)' % python_version())
272
273if __name__ == '__main__':
274    from idlelib.idle_test.htest import run
275    run(show_idlehelp)
276