文本计算器

# coding:utf-8
from __future__ import division
import sys
from math import *
import logging as log
python_version = sys.version_info.major
if python_version == 3:
    import tkinter as tk
elif python_version == 2:
    import Tkinter as tk

class StrCalc(tk.Frame):
    def __init__(self, parent, *args, **kwargs):
        tk.Frame.__init__(self, parent, *args, **kwargs)
        self.parent = parent
        scroll_bar = tk.Scrollbar(root)
        text_box = tk.Text(root, height=4)
        scroll_bar.pack(side=tk.RIGHT, fill=tk.Y)
        text_box.pack(side=tk.LEFT, fill=tk.Y)
        scroll_bar.config(command=text_box.yview)
        text_box.config(yscrollcommand=scroll_bar.set)
        self.MainText = text_box
        parent.bind("<Return>",self.calc)
        self.MainText.pack()

    def calc(self,event):
        current_line = self.MainText.index(tk.INSERT)
        line_text = self.MainText.get("{}".format(float(current_line) - 1), "{}".format(float(current_line)))
        # messagebox.showinfo("Say Hello", line_text)
        if line_text.strip() == "clean":
            self.MainText.delete('1.0', tk.END)
            return
        result = StrCalc.calc_str(line_text)
        try:
            result = "{:.4f}".format(result)
        except:
            pass
        log.debug("calc result is %s" % result)
        self.MainText.insert("{}".format(float(current_line)), "%s\n" % result)

    @staticmethod
    def calc_str(input_str):
        try:
            if input_str.strip() == "":
                return ""
            result = eval(input_str)
            log.debug("calc_str result {}".format(result))
            return result
        except Exception as errors:
            return "".join((input_str, str(errors)))


if __name__ == "__main__":
    root=tk.Tk()
    root.attributes('-topmost', True)
    root.title(u"文本计算器-yinzihao")
    root.geometry("600x400")
    main = StrCalc(root)
    main.pack(sid="top", fill="both", expand=True)
    root.mainloop()