计算器(Calculator)——speedcrunch

功能很强大

Overview:

• history and results on a scrollable display
• up to 50 decimal precisions
• unlimited variable storage
• intelligent automatic completion
• fully usable from the keyboard
• more than 50 built-in math functions
• optional virtual keypad to be used with a mouse
• on-the-fly and selection calculation
• customizable appearance
• syntax highlighting and parentheses matching

路径：http://code.google.com/p/speedcrunch/

描述：

SpeedCrunch is a simple but powerful calculator.

Among its features are:
- high precision, up to 50 decimal digits
- to be enjoyed using keyboard
- result shown in scrollable window
- history of last expressions (use up and down arrow)
- built-in functions: abs, sqrt, pi, log, exp, ln, sin, cos, tan, sinh,
  cosh, tanh, asin, acos, atan, arsinh, arcosh, artanh
- postfix operator ! lets you compute factorials
- support for variables, e.g try x=pi/3 and then sin(x)
- special variable ans holds the last calculation result
- percent operator, try e.g. 45%*75 or price/80%
- angle mode: Alt+D for degrees, Alt+R for radians
- automatic parentheses closing, e.g. cos(pi/4 becomes cos(pi/4)

SpeedCrunch is easy to use, just type the expression that you want to calculate
and press Enter. Result is shown in the scrollable display. And, you can quickly
copy the last calculation result to the clipboard using Ctrl+R.

If you want to reuse again the expression which you typed before, then press up
and down arrow to access the expression history.

Beside standard algebraic operators like + (addition), - (substraction),
* (multiplication), * (division), ^ or ** (power), there is support for some
functions, for example sin, log, abs, and many more. You do not need to memorize
function names, use Ctrl+F to pop up a dialog where you can choose the function
that you need. Or take advantage of auto-completion feature, for example type s
only and in less than a second you will be automagically given with choices of
sin, sinh, and sqrt.

Advanced calculation sometimes needs memory feature. SpeedCrunch allows a
variable to hold calculation result. Using assignment, such as x=0.3 means that
variable named x has the value of 0.3, which you can always later on, for
example sin(x). You can define as many variables as you want. When you want to
use a variable but you can not recall its exact name, use Ctrl+I to show a list
of variables that you can pick easily.

There is a special variable, ans, which always holds the last calculation
result. Another variable pi holds one of the most important constant in
math world.

Your expression history (maximum last 100 expressions), as well as variables
you have defined, are saved between sessions. This means, you can still recall
those calculations you have done yesterday or last week.

Often, SpeedCrunch can still understand an incomplete expression. For example,
just typing sin followed by Enter - likely means taking the sine of last value
- is automatically translated as sin(ans). Also, for such function you may skip
the parentheses if you pass simple number or variable, sin 0.1 is as valid as
sin(0.1). Speaking about parentheses, closing them can be left to SpeedCrunch,
e.g. cos(pi/4 is automatically corrected to cos(pi/4).

Keyboard Shortcuts:

    Up/Down   recall last expression
    Ctrl+I    insert variable
    Ctrl+F    insert function
    Ctrl+R    copy last result to clipboard
    Ctrl+S    save current session to text file
    Alt+D     degrees mode for trigonometric functions
    Alt+R     radians mode for trigonometric functions

路径：https://github.com/speedcrunch/SpeedCrunch