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- """CodeContext - Display the block context of code at top of edit window
-
- Once code has scrolled off the top of the screen, it can be difficult
- to determine which block you are in. This extension implements a pane
- at the top of each IDLE edit window which provides block structure
- hints. These hints are the lines which contain the block opening
- keywords, e.g. 'if', for the enclosing block. The number of hint lines
- is determined by the numlines variable in the CodeContext section of
- config-extensions.def. Lines which do not open blocks are not shown in
- the context hints pane.
-
- """
- import Tkinter
- from configHandler import idleConf
- from sets import Set
- import re
-
- BLOCKOPENERS = Set(["class", "def", "elif", "else", "except", "finally", "for",
- "if", "try", "while"])
- INFINITY = 1 << 30
- UPDATEINTERVAL = 100 # millisec
- FONTUPDATEINTERVAL = 1000 # millisec
-
- getspacesfirstword = lambda s, c=re.compile(r"^(\s*)(\w*)"): c.match(s).groups()
-
- class CodeContext:
- menudefs = [('options', [('!Code Conte_xt', '<<toggle-code-context>>')])]
-
- numlines = idleConf.GetOption("extensions", "CodeContext",
- "numlines", type="int", default=3)
- bgcolor = idleConf.GetOption("extensions", "CodeContext",
- "bgcolor", type="str", default="LightGray")
- fgcolor = idleConf.GetOption("extensions", "CodeContext",
- "fgcolor", type="str", default="Black")
- def __init__(self, editwin):
- self.editwin = editwin
- self.text = editwin.text
- self.textfont = self.text["font"]
- self.label = None
- # Dummy line, which starts the "block" of the whole document:
- self.info = list(self.interesting_lines(1))
- self.lastfirstline = 1
- visible = idleConf.GetOption("extensions", "CodeContext",
- "visible", type="bool", default=False)
- if visible:
- self.toggle_code_context_event()
- self.editwin.setvar('<<toggle-code-context>>', True)
- # Start two update cycles, one for context lines, one for font changes.
- self.text.after(UPDATEINTERVAL, self.timer_event)
- self.text.after(FONTUPDATEINTERVAL, self.font_timer_event)
-
- def toggle_code_context_event(self, event=None):
- if not self.label:
- self.label = Tkinter.Label(self.editwin.top,
- text="\n" * (self.numlines - 1),
- anchor="w", justify="left",
- font=self.textfont,
- bg=self.bgcolor, fg=self.fgcolor,
- relief="sunken",
- width=1, # Don't request more than we get
- )
- self.label.pack(side="top", fill="x", expand=0,
- after=self.editwin.status_bar)
- else:
- self.label.destroy()
- self.label = None
- idleConf.SetOption("extensions", "CodeContext", "visible",
- str(self.label is not None))
- idleConf.SaveUserCfgFiles()
-
- def get_line_info(self, linenum):
- """Get the line indent value, text, and any block start keyword
-
- If the line does not start a block, the keyword value is False.
- The indentation of empty lines (or comment lines) is INFINITY.
- There is a dummy block start, with indentation -1 and text "".
-
- Return the indent level, text (including leading whitespace),
- and the block opening keyword.
-
- """
- if linenum == 0:
- return -1, "", True
- text = self.text.get("%d.0" % linenum, "%d.end" % linenum)
- spaces, firstword = getspacesfirstword(text)
- opener = firstword in BLOCKOPENERS and firstword
- if len(text) == len(spaces) or text[len(spaces)] == '#':
- indent = INFINITY
- else:
- indent = len(spaces)
- return indent, text, opener
-
- def interesting_lines(self, firstline):
- """Generator which yields context lines, starting at firstline."""
- # The indentation level we are currently in:
- lastindent = INFINITY
- # For a line to be interesting, it must begin with a block opening
- # keyword, and have less indentation than lastindent.
- for line_index in xrange(firstline, -1, -1):
- indent, text, opener = self.get_line_info(line_index)
- if indent < lastindent:
- lastindent = indent
- if opener in ("else", "elif"):
- # We also show the if statement
- lastindent += 1
- if opener and line_index < firstline:
- yield line_index, text
-
- def update_label(self):
- firstline = int(self.text.index("@0,0").split('.')[0])
- if self.lastfirstline == firstline:
- return
- self.lastfirstline = firstline
- tmpstack = []
- for line_index, text in self.interesting_lines(firstline):
- # Remove irrelevant self.info items, and when we reach a relevant
- # item (which must happen because of the dummy element), break.
- while self.info[-1][0] > line_index:
- del self.info[-1]
- if self.info[-1][0] == line_index:
- break
- tmpstack.append((line_index, text))
- while tmpstack:
- self.info.append(tmpstack.pop())
- lines = [""] * max(0, self.numlines - len(self.info)) + \
- [x[1] for x in self.info[-self.numlines:]]
- self.label["text"] = '\n'.join(lines)
-
- def timer_event(self):
- if self.label:
- self.update_label()
- self.text.after(UPDATEINTERVAL, self.timer_event)
-
- def font_timer_event(self):
- newtextfont = self.text["font"]
- if self.label and newtextfont != self.textfont:
- self.textfont = newtextfont
- self.label["font"] = self.textfont
- self.text.after(FONTUPDATEINTERVAL, self.font_timer_event)
-