""" help.py: Implement the Idle help menu.

Contents are subject to revision at any time, without notice.

Help => About IDLE: display About Idle dialog

<to be moved here from help_about.py>

Help => IDLE Help: Display help.html with proper formatting.

Doc/library/idle.rst (Sphinx)=> Doc/build/html/library/idle.html

(help.copy_strip)=> Lib/idlelib/help.html

HelpParser - Parse help.html and render to tk Text.

HelpText - Display formatted help.html.

HelpFrame - Contain text, scrollbar, and table-of-contents.

(This will be needed for display in a future tabbed window.)

HelpWindow - Display HelpFrame in a standalone window.

copy_strip - Copy idle.html to help.html, rstripping each line.

show_idlehelp - Create HelpWindow. Called in EditorWindow.help_dialog.

"""

from html.parser import HTMLParser

from os.path import abspath, dirname, isfile, join

from platform import python_version

from tkinter import Toplevel, Frame, Text, Menu

from tkinter.ttk import Menubutton, Scrollbar

from tkinter import font as tkfont

from idlelib.config import idleConf

## About IDLE ##

## IDLE Help ##

class HelpParser(HTMLParser):

"""Render help.html into a text widget.

The overridden handle_xyz methods handle a subset of html tags.

The supplied text should have the needed tag configurations.

The behavior for unsupported tags, such as table, is undefined.

If the tags generated by Sphinx change, this class, especially

the handle_starttag and handle_endtags methods, might have to also.

"""

def __init__(self, text):

HTMLParser.__init__(self, convert_charrefs=True)

self.text = text # text widget we're rendering into

self.tags = '' # current block level text tags to apply

self.chartags = '' # current character level text tags

self.show = False # used so we exclude page navigation

self.hdrlink = False # used so we don't show header links

self.level = 0 # indentation level

self.pre = False # displaying preformatted text

self.hprefix = '' # prefix such as '25.5' to strip from headings

self.nested_dl = False # if we're in a nested <dl>

self.simplelist = False # simple list (no double spacing)

self.toc = [] # pair headers with text indexes for toc

self.header = '' # text within header tags for toc

def indent(self, amt=1):

self.level += amt

self.tags = '' if self.level == 0 else 'l'+str(self.level)

def handle_starttag(self, tag, attrs):

"Handle starttags in help.html."

class_ = ''

for a, v in attrs:

if a == 'class':

class_ = v

s = ''

if tag == 'div' and class_ == 'section':

self.show = True # start of main content

elif tag == 'div' and class_ == 'sphinxsidebar':

self.show = False # end of main content

elif tag == 'p' and class_ != 'first':

s = '\n\n'

elif tag == 'span' and class_ == 'pre':

self.chartags = 'pre'

elif tag == 'span' and class_ == 'versionmodified':

self.chartags = 'em'

elif tag == 'em':

self.chartags = 'em'

elif tag in ['ul', 'ol']:

if class_.find('simple') != -1:

s = '\n'

self.simplelist = True

else:

self.simplelist = False

self.indent()

elif tag == 'dl':

if self.level > 0:

self.nested_dl = True

elif tag == 'li':

s = '\n* ' if self.simplelist else '\n\n* '

elif tag == 'dt':

s = '\n\n' if not self.nested_dl else '\n' # avoid extra line

self.nested_dl = False

elif tag == 'dd':

self.indent()

s = '\n'

elif tag == 'pre':

self.pre = True

if self.show:

self.text.insert('end', '\n\n')

self.tags = 'preblock'

elif tag == 'a' and class_ == 'headerlink':

self.hdrlink = True

elif tag == 'h1':

self.tags = tag

elif tag in ['h2', 'h3']:

if self.show:

self.header = ''

self.text.insert('end', '\n\n')

self.tags = tag

if self.show:

self.text.insert('end', s, (self.tags, self.chartags))

def handle_endtag(self, tag):

"Handle endtags in help.html."

if tag in ['h1', 'h2', 'h3']:

self.indent(0) # clear tag, reset indent

if self.show:

indent = (' ' if tag == 'h3' else

' ' if tag == 'h2' else

'')

self.toc.append((indent+self.header, self.text.index('insert')))

elif tag in ['span', 'em']:

self.chartags = ''

elif tag == 'a':

self.hdrlink = False

elif tag == 'pre':

self.pre = False

self.tags = ''

elif tag in ['ul', 'dd', 'ol']:

self.indent(amt=-1)

def handle_data(self, data):

"Handle date segments in help.html."

if self.show and not self.hdrlink:

d = data if self.pre else data.replace('\n', ' ')

if self.tags == 'h1':

try:

self.hprefix = d[0:d.index(' ')]

except ValueError:

self.hprefix = ''

if self.tags in ['h1', 'h2', 'h3']:

if (self.hprefix != '' and

d[0:len(self.hprefix)] == self.hprefix):

d = d[len(self.hprefix):]

self.header += d.strip()

self.text.insert('end', d, (self.tags, self.chartags))

class HelpText(Text):

"Display help.html."

def __init__(self, parent, filename):

"Configure tags and feed file to parser."

uwide = idleConf.GetOption('main', 'EditorWindow', 'width', type='int')

uhigh = idleConf.GetOption('main', 'EditorWindow', 'height', type='int')

uhigh = 3 * uhigh // 4 # lines average 4/3 of editor line height

Text.__init__(self, parent, wrap='word', highlightthickness=0,

padx=5, borderwidth=0, width=uwide, height=uhigh)

normalfont = self.findfont(['TkDefaultFont', 'arial', 'helvetica'])

fixedfont = self.findfont(['TkFixedFont', 'monaco', 'courier'])

self['font'] = (normalfont, 12)

self.tag_configure('em', font=(normalfont, 12, 'italic'))

self.tag_configure('h1', font=(normalfont, 20, 'bold'))

self.tag_configure('h2', font=(normalfont, 18, 'bold'))

self.tag_configure('h3', font=(normalfont, 15, 'bold'))

self.tag_configure('pre', font=(fixedfont, 12), background='#f6f6ff')

self.tag_configure('preblock', font=(fixedfont, 10), lmargin1=25,

borderwidth=1, relief='solid', background='#eeffcc')

self.tag_configure('l1', lmargin1=25, lmargin2=25)

self.tag_configure('l2', lmargin1=50, lmargin2=50)

self.tag_configure('l3', lmargin1=75, lmargin2=75)

self.tag_configure('l4', lmargin1=100, lmargin2=100)

self.parser = HelpParser(self)

with open(filename, encoding='utf-8') as f:

contents = f.read()

self.parser.feed(contents)

self['state'] = 'disabled'

def findfont(self, names):

"Return name of first font family derived from names."

for name in names:

if name.lower() in (x.lower() for x in tkfont.names(root=self)):

font = tkfont.Font(name=name, exists=True, root=self)

return font.actual()['family']

elif name.lower() in (x.lower()

for x in tkfont.families(root=self)):

return name

class HelpFrame(Frame):

"Display html text, scrollbar, and toc."

def __init__(self, parent, filename):

Frame.__init__(self, parent)

# keep references to widgets for test access.

self.text = text = HelpText(self, filename)

self['background'] = text['background']

self.toc = toc = self.toc_menu(text)

self.scroll = scroll = Scrollbar(self, command=text.yview)

text['yscrollcommand'] = scroll.set

self.rowconfigure(0, weight=1)

self.columnconfigure(1, weight=1) # text

toc.grid(row=0, column=0, sticky='nw')

text.grid(row=0, column=1, sticky='nsew')

scroll.grid(row=0, column=2, sticky='ns')

def toc_menu(self, text):

"Create table of contents as drop-down menu."

toc = Menubutton(self, text='TOC')

drop = Menu(toc, tearoff=False)

for lbl, dex in text.parser.toc:

drop.add_command(label=lbl, command=lambda dex=dex:text.yview(dex))

toc['menu'] = drop

return toc

class HelpWindow(Toplevel):

"Display frame with rendered html."

def __init__(self, parent, filename, title):

Toplevel.__init__(self, parent)

self.wm_title(title)

self.protocol("WM_DELETE_WINDOW", self.destroy)

HelpFrame(self, filename).grid(column=0, row=0, sticky='nsew')

self.grid_columnconfigure(0, weight=1)

self.grid_rowconfigure(0, weight=1)

def copy_strip():

"""Copy idle.html to idlelib/help.html, stripping trailing whitespace.

Files with trailing whitespace cannot be pushed to the git cpython

repository. For 3.x (on Windows), help.html is generated, after

editing idle.rst on the master branch, with

sphinx-build -bhtml . build/html

python_d.exe -c "from idlelib.help import copy_strip; copy_strip()"

Check build/html/library/idle.html, the help.html diff, and the text

displayed by Help => IDLE Help. Add a blurb and create a PR.

It can be worthwhile to occasionally generate help.html without

touching idle.rst. Changes to the master version and to the doc

build system may result in changes that should not changed

the displayed text, but might break HelpParser.

As long as master and maintenance versions of idle.rst remain the

same, help.html can be backported. The internal Python version

number is not displayed. If maintenance idle.rst diverges from

the master version, then instead of backporting help.html from

master, repeat the proceedure above to generate a maintenance

version.

"""

src = join(abspath(dirname(dirname(dirname(__file__)))),

'Doc', 'build', 'html', 'library', 'idle.html')

dst = join(abspath(dirname(__file__)), 'help.html')

with open(src, 'rb') as inn,\

open(dst, 'wb') as out:

for line in inn:

out.write(line.rstrip() + b'\n')

print(f'{src} copied to {dst}')

def show_idlehelp(parent):

"Create HelpWindow; called from Idle Help event handler."

filename = join(abspath(dirname(__file__)), 'help.html')

if not isfile(filename):

# try copy_strip, present message

return

HelpWindow(parent, filename, 'IDLE Help (%s)' % python_version())

if __name__ == '__main__':

from unittest import main

main('idlelib.idle_test.test_help', verbosity=2, exit=False)

from idlelib.idle_test.htest import run

run(show_idlehelp)