"""Basic regular expression demostration facility. This displays a window with two type-in boxes. In the top box, you enter a regular expression. In the bottom box, you enter a string. The first match in the string of the regular expression is highlighted with a yellow background (or red if the match is empty -- then the character at the match is highlighted). The highlighting is continuously updated. At the bottom are a number of checkboxes which control the regular expression syntax used (see the regex_syntax module for descriptions). When there's no match, or when the regular expression is syntactically incorrect, an error message is displayed. """ from Tkinter import * import regex import regex_syntax class RegexDemo: def __init__(self, master): self.master = master self.topframe = Frame(self.master) self.topframe.pack(fill=X) self.promptdisplay = Label(self.topframe, text="Enter a regex:") self.promptdisplay.pack(side=LEFT) self.statusdisplay = Label(self.topframe, text="", anchor=W) self.statusdisplay.pack(side=LEFT, fill=X) self.regexdisplay = Entry(self.master) self.regexdisplay.pack(fill=X) self.regexdisplay.focus_set() self.labeldisplay = Label(self.master, anchor=W, text="Enter a string:") self.labeldisplay.pack(fill=X) self.labeldisplay.pack(fill=X) self.stringdisplay = Text(self.master, width=60, height=4) self.stringdisplay.pack(fill=BOTH, expand=1) self.stringdisplay.tag_configure("hit", background="yellow") self.addoptions() self.regexdisplay.bind('<Key>', self.recompile) self.stringdisplay.bind('<Key>', self.reevaluate) self.compiled = None self.recompile() btags = self.regexdisplay.bindtags() self.regexdisplay.bindtags(btags[1:] + btags[:1]) btags = self.stringdisplay.bindtags() self.stringdisplay.bindtags(btags[1:] + btags[:1]) def addoptions(self): self.frames = [] self.boxes = [] self.vars = [] for name in ( 'RE_NO_BK_PARENS', 'RE_NO_BK_VBAR', 'RE_BK_PLUS_QM', 'RE_TIGHT_VBAR', 'RE_NEWLINE_OR', 'RE_CONTEXT_INDEP_OPS'): if len(self.boxes) % 3 == 0: frame = Frame(self.master) frame.pack(fill=X) self.frames.append(frame) val = getattr(regex_syntax, name) var = IntVar() box = Checkbutton(frame, variable=var, text=name, offvalue=0, onvalue=val, command=self.newsyntax) box.pack(side=LEFT) self.boxes.append(box) self.vars.append(var) def newsyntax(self): syntax = 0 for var in self.vars: syntax = syntax | var.get() regex.set_syntax(syntax) self.recompile() def recompile(self, event=None): try: self.compiled = regex.compile(self.regexdisplay.get()) self.statusdisplay.config(text="") except regex.error, msg: self.compiled = None self.statusdisplay.config(text="regex.error: %s" % str(msg)) self.reevaluate() def reevaluate(self, event=None): try: self.stringdisplay.tag_remove("hit", "1.0", END) except TclError: pass if not self.compiled: return text = self.stringdisplay.get("1.0", END) i = self.compiled.search(text) if i < 0: self.statusdisplay.config(text="(no match)") else: self.statusdisplay.config(text="") regs = self.compiled.regs first, last = regs[0] if last == first: last = first+1 self.stringdisplay.tag_configure("hit", background="red") else: self.stringdisplay.tag_configure("hit", background="yellow") pfirst = "1.0 + %d chars" % first plast = "1.0 + %d chars" % last self.stringdisplay.tag_add("hit", pfirst, plast) self.stringdisplay.yview_pickplace(pfirst) # Main function, run when invoked as a stand-alone Python program. def main(): root = Tk() demo = RegexDemo(root) root.protocol('WM_DELETE_WINDOW', root.quit) root.mainloop() if __name__ == '__main__': main()