Demo/tkinter/guido/regexdemo.py

   1 """Basic regular expression demostration facility.
   2
   3 This displays a window with two type-in boxes.  In the top box, you enter a
   4 regular expression.  In the bottom box, you enter a string.  The first
   5 match in the string of the regular expression is highlighted with a yellow
   6 background (or red if the match is empty -- then the character at the match
   7 is highlighted).  The highlighting is continuously updated.  At the bottom
   8 are a number of checkboxes which control the regular expression syntax used
   9 (see the regex_syntax module for descriptions).  When there's no match, or
  10 when the regular expression is syntactically incorrect, an error message is
  11 displayed.
  12
  13 """
  14
  15 from Tkinter import *
  16 import regex
  17 import regex_syntax
  18
  19 class RegexDemo:
  20
  21         def __init__(self, master):
  22                 self.master = master
  23                 self.topframe = Frame(self.master)
  24                 self.topframe.pack(fill=X)
  25                 self.promptdisplay = Label(self.topframe, text="Enter a regex:")
  26                 self.promptdisplay.pack(side=LEFT)
  27                 self.statusdisplay = Label(self.topframe, text="", anchor=W)
  28                 self.statusdisplay.pack(side=LEFT, fill=X)
  29                 self.regexdisplay = Entry(self.master)
  30                 self.regexdisplay.pack(fill=X)
  31                 self.regexdisplay.focus_set()
  32                 self.labeldisplay = Label(self.master, anchor=W,
  33                         text="Enter a string:")
  34                 self.labeldisplay.pack(fill=X)
  35                 self.labeldisplay.pack(fill=X)
  36                 self.stringdisplay = Text(self.master, width=60, height=4)
  37                 self.stringdisplay.pack(fill=BOTH, expand=1)
  38                 self.stringdisplay.tag_configure("hit", background="yellow")
  39                 self.addoptions()
  40                 self.regexdisplay.bind('<Key>', self.recompile)
  41                 self.stringdisplay.bind('<Key>', self.reevaluate)
  42                 self.compiled = None
  43                 self.recompile()
  44                 btags = self.regexdisplay.bindtags()
  45                 self.regexdisplay.bindtags(btags[1:] + btags[:1])
  46                 btags = self.stringdisplay.bindtags()
  47                 self.stringdisplay.bindtags(btags[1:] + btags[:1])
  48
  49         def addoptions(self):
  50                 self.frames = []
  51                 self.boxes = []
  52                 self.vars = []
  53                 for name in (   'RE_NO_BK_PARENS',
  54                                 'RE_NO_BK_VBAR',
  55                                 'RE_BK_PLUS_QM',
  56                                 'RE_TIGHT_VBAR',
  57                                 'RE_NEWLINE_OR',
  58                                 'RE_CONTEXT_INDEP_OPS'):
  59                         if len(self.boxes) % 3 == 0:
  60                                 frame = Frame(self.master)
  61                                 frame.pack(fill=X)
  62                                 self.frames.append(frame)
  63                         val = getattr(regex_syntax, name)
  64                         var = IntVar()
  65                         box = Checkbutton(frame,
  66                                 variable=var, text=name,
  67                                 offvalue=0, onvalue=val,
  68                                 command=self.newsyntax)
  69                         box.pack(side=LEFT)
  70                         self.boxes.append(box)
  71                         self.vars.append(var)
  72
  73         def newsyntax(self):
  74                 syntax = 0
  75                 for var in self.vars:
  76                         syntax = syntax | var.get()
  77                 regex.set_syntax(syntax)
  78                 self.recompile()
  79
  80         def recompile(self, event=None):
  81                 try:
  82                         self.compiled = regex.compile(self.regexdisplay.get())
  83                         self.statusdisplay.config(text="")
  84                 except regex.error, msg:
  85                         self.compiled = None
  86                         self.statusdisplay.config(text="regex.error: %s" % str(msg))
  87                 self.reevaluate()
  88
  89         def reevaluate(self, event=None):
  90                 try:
  91                         self.stringdisplay.tag_remove("hit", "1.0", END)
  92                 except TclError:
  93                         pass
  94                 if not self.compiled:
  95                         return
  96                 text = self.stringdisplay.get("1.0", END)
  97                 i = self.compiled.search(text)
  98                 if i < 0:
  99                         self.statusdisplay.config(text="(no match)")
 100                 else:
 101                         self.statusdisplay.config(text="")
 102                         regs = self.compiled.regs
 103                         first, last = regs[0]
 104                         if last == first:
 105                                 last = first+1
 106                                 self.stringdisplay.tag_configure("hit",
 107                                         background="red")
 108                         else:
 109                                 self.stringdisplay.tag_configure("hit",
 110                                         background="yellow")
 111                         pfirst = "1.0 + %d chars" % first
 112                         plast = "1.0 + %d chars" % last
 113                         self.stringdisplay.tag_add("hit", pfirst, plast)
 114                         self.stringdisplay.yview_pickplace(pfirst)
 115
 116
 117
 118 # Main function, run when invoked as a stand-alone Python program.
 119
 120 def main():
 121     root = Tk()
 122     demo = RegexDemo(root)
 123     root.protocol('WM_DELETE_WINDOW', root.quit)
 124     root.mainloop()
 125
 126 if __name__ == '__main__':
 127     main()