四、Snapman多人协作电子表格之——Exprtk脚本

Snapman多人协作电子表格是一个即时工作系统。

Snapman中嵌入了Exprtk脚本进行公式数据运算。Exprtk是一种高性能的脚本，经测试它的数据运算性能只比C#和java底20%。

一、Exprtk的类型和变量定义

　　Exprtk的数据类型只有三种：Scalar（数字）, Vector(数字数组）, String（字符串）；特别说明：Exprtk没有字符串数组

　　基本的运算符有：+, -, *, /, %, ^

　　赋值运算符有：:=, +=, -=, *=, /=, %=

　　判断运算符有：=, ==, <>, !=, <, <=, >, >=

　　逻辑运算符有：and, mand, mor, nand, nor, not, or, shl, shr,xnor, xor, true, false

　　字符串运算符有：in, like, ilike, concatenation

　　Exprtk的变量定义为:

var iData := ;    　　　　　　//数字变量定义
var sData := 'Hello word.';    //字符串变量定义
var vData[] := {,,,};     //数组变量定义

　　Snapman中Exprtk定义了四种特殊变量：

　　1、单元格数字变量，列字母+行号数字，如：A1，H234

　　2、单元格字符串变量，列字母+行号数字+下划线，如：A1_，H234_

　　3、选择集数组，列字母+行号数字+冒号+列字母+行号数字，这是一个数字数组元素次序是按单元格从左往右从上往下，如：F2:G5

　　4、列数组，列字母+冒号+列字母，这是一个数字数组元素次序是按单元格从左往右从上往下，如：F:H

　　所以Snapman中Exprtk的变量定义都不要使用数字结尾或数字加下划线结尾

二、Exprtk的if、switch、for、while、continue、break语句

　　1、if语句的类型

　　　　A、if表达式：if (x, y, z) ;如果x为真返回y否则返回z；例如：

var x := ;
var y := ;
var z := ;
var w := 58.7;
var v := ;
var data := if ((x + ) > 2y, z + , w / v) ;
print(tostring(data));

　　　　B、if语句块

if (x < y or (x + z) > y)
{
    z := x + ;
    y := x - z;
}
else if (abs(2y - z) >= )
    y := x - z;
else
{
    z := abs(x * x);
    x * y * z;
};

　　2、switch语句的类型

　　　 switch语句会逐句判断case的条件，成立就执行代码表达式，如果case条件都不成立就执行default的代码表达式，最后将代码表达式的结果返回，如：

var x := ;
var y := ;
var z := ;
var a := switch
{
case x > (y + z) :  * x / abs(y - z);
case x <        : sin(x + y);
default          :  + x;
};
print(tostring(a));

　　　　注意：case的条件和语句只允许有一条语句

　　3、for语句

　　for语句和C语言类似，但是它是一个表达式所以记住大括号后面需要有分号，如：

for (var x := ; (x < n) and (x != y); x += )
{
  y := y + x /  - z;
  w := u + y;
};

　　4、while语句

　　while语句和C语言类似，但它是一个表达式所以记住大括号后面需要有分号，如：

while ((i += ) < )
{
  if (i < )
    j -= i + ;
  else if (i %  == )
    break;
  else
    break[2i + ];
};

　　5、continue、break、break[]语句

　　continue、break和其C语言类似，break[]的意思是for和while语句是一条有返回值的表达式，break返回的是NaN，而break[]却是返回中括号中表达式的值，如上一个样例。

三、Exprtk的数组运算

　　Exprtk有一个非常强大的数组运算，可以对数组变量进行批量运算和赋值

　　1、赋值运算符都支持数组变量，如下面样例数组中每个变量都增加了13：

var vData[] := {, , , , };
vData += ;

　　2、其他支持数组的运算符：+, -, *, /, %, ^

　　3、支持的函数：avg, max, min, mul, sum, count

　　4、当存在2个数组变量的时候，运算以个数少的为运算次数；当运算符为单维运算符或者单维函数，数组变量会取第一个元素进行运算

四、Exprtk的Snapman函数接口

　　1、tolower(str)，将字符串str转换成小写字母并返回，例如：e2_:=tolower('AHFGHJHKJDewiuri73972389HHJGJG中华人民共和国')
　　2、toupper(str)，将字符串str转换成大写字母并返回，例如：e3_:=toupper('AHFGHJHKJDewiuri73972389HHJGJG中华人民共和国')
　　3、tostring(double)，将数字转换成字符串并返回，例如：e4_:=tostring(0.4444488)
　　4、tonumber(str)，将字符串转换成数字并返回，例如：e5:=tonumber('5643786587')
　　5、get(row,col)，获取第row行、col列的单元格的数字，例如：e6:=get(7,1)
　　6、set(row,col,double)，设置第row行、col列的单元格的数字，例如：set(7,5,98766)
　　7、get_(row,col)，获取第row行、col列的单元格的字符串，例如：e8_:=get_(8,2)
　　8、set_(row,col,str)，设置第row行、col列的单元格的字符串，例如：set_(9,5,'大不了的给开发商')
　　9、set_progress(n)，设置进度条，n必须大于等于0，例如：set_progress(10)
　　10、set_total_progress(t)，设置进度条的最大值，t必须大于0，例如：set_total_progress(100)
　　11、sleep(n)，让线程睡眠n毫秒，例如：sleep(1000)
　　12、get_tick_count()，获取从操作系统启动所经过的毫秒数，例如：E12:=get_tick_count()
　　13、save()，保存当前电子表格，例如：save()
　　14、count(vec)，获取数组vec的个数，例如：E14:=count(C4:C11)
　　15、print(str)，打印str的内容，例如：print('Hello world.')
　　16、set_background(row,col,str_lafer)，设置第row行、col列的单元格背景的lafer，例如：set_background(16,5,'[[18,#9845f2,8,8,8],[18,#F865f2,16,55,8]]')

　　17，get_row_count()，获取当前表格有内容的单元格行数，例如：set(18,5,get_row_count())
　　18，get_col_count()，获取当前表格有内容的单元格列数，例如：set(19,5,get_col_count())

　　19、E17或者e17，表格数据变量：字母表示列，数字表示行，例如：E17 := 100000.567;
　　20、E18_或者e18_，表格字符串变量：字母表示列，数字表示行，例如：E18_ := '我是中国人。'
　　21、E19:E21或者A:B，表格数据变量数组，先从左到右然后从上到下，没有数字代表从某列到某列，例如：E19:E21 := A17:A19

五、Exprtk自带的函数

    +----------+---------------------------------------------------------+
    | FUNCTION | DEFINITION                                              |
    +----------+---------------------------------------------------------+
    | abs      | Absolute value of x.  (eg: abs(x))                      |
    +----------+---------------------------------------------------------+
    | avg      | Average of all the inputs.                              |
    |          | (eg: avg(x,y,z,w,u,v) == (x + y + z + w + u + v) / )   |
    +----------+---------------------------------------------------------+
    | ceil     | Smallest integer that is greater than or equal to x.    |
    +----------+---------------------------------------------------------+
    | clamp    | Clamp x in range between r0 and r1, where r0 < r1.      |
    |          | (eg: clamp(r0,x,r1))                                    |
    +----------+---------------------------------------------------------+
    | equal    | Equality test between x and y using normalised epsilon  |
    +----------+---------------------------------------------------------+
    | erf      | Error function of x.  (eg: erf(x))                      |
    +----------+---------------------------------------------------------+
    | erfc     | Complimentary error function of x.  (eg: erfc(x))       |
    +----------+---------------------------------------------------------+
    | exp      | e to the power of x.  (eg: exp(x))                      |
    +----------+---------------------------------------------------------+
    | expm1    | e to the power of x minus , where x is very small.     |
    |          | (eg: expm1(x))                                          |
    +----------+---------------------------------------------------------+
    | floor    | Largest integer that is less than or equal to x.        |
    |          | (eg: floor(x))                                          |
    +----------+---------------------------------------------------------+
    | frac     | Fractional portion of x.  (eg: frac(x))                 |
    +----------+---------------------------------------------------------+
    | hypot    | Hypotenuse of x and y (eg: hypot(x,y) = sqrt(x*x + y*y))|
    +----------+---------------------------------------------------------+
    | iclamp   | Inverse-clamp x outside of the range r0 and r1. Where   |
    |          | r0 < r1. If x is within the range it will snap to the   |
    |          | closest bound. (eg: iclamp(r0,x,r1)                     |
    +----------+---------------------------------------------------------+
    | inrange  | In-range returns 'true' when x is within the range r0   |
    |          | and r1. Where r0 < r1.  (eg: inrange(r0,x,r1)           |
    +----------+---------------------------------------------------------+
    | log      | Natural logarithm of x.  (eg: log(x))                   |
    +----------+---------------------------------------------------------+
    | log10    | Base  logarithm of x.  (eg: log10(x))                 |
    +----------+---------------------------------------------------------+
    | log1p    | Natural logarithm of  + x, where x is very small.      |
    |          | (eg: log1p(x))                                          |
    +----------+---------------------------------------------------------+
    | log2     | Base  logarithm of x.  (eg: log2(x))                   |
    +----------+---------------------------------------------------------+
    | logn     | Base N logarithm of x. where n is a positive integer.   |
    |          | (eg: logn(x,))                                         |
    +----------+---------------------------------------------------------+
    | max      | Largest value of all the inputs. (eg: max(x,y,z,w,u,v)) |
    +----------+---------------------------------------------------------+
    | min      | Smallest value of all the inputs. (eg: min(x,y,z,w,u))  |
    +----------+---------------------------------------------------------+
    | mul      | Product of all the inputs.                              |
    |          | (eg: mul(x,y,z,w,u,v,t) == (x * y * z * w * u * v * t)) |
    +----------+---------------------------------------------------------+
    | ncdf     | Normal cumulative distribution function.  (eg: ncdf(x)) |
    +----------+---------------------------------------------------------+
    | nequal   | Not-equal test between x and y using normalised epsilon |
    +----------+---------------------------------------------------------+
    | pow      | x to the power of y.  (eg: pow(x,y) == x ^ y)           |
    +----------+---------------------------------------------------------+
    | root     | Nth-Root of x. where n is a positive integer.           |
    |          | (eg: root(x,) == x^(/))                              |
    +----------+---------------------------------------------------------+
    | round    | Round x to the nearest integer.  (eg: round(x))         |
    +----------+---------------------------------------------------------+
    | roundn   | Round x to n decimal places  (eg: roundn(x,))          |
    |          | where n >  and is an integer.                          |
    |          | (eg: roundn(1.2345678,) == 1.2346)                     |
    +----------+---------------------------------------------------------+
    | sgn      | Sign of x, - where x < , + where x > , else zero.   |
    |          | (eg: sgn(x))                                            |
    +----------+---------------------------------------------------------+
    | sqrt     | Square root of x, where x >= .  (eg: sqrt(x))          |
    +----------+---------------------------------------------------------+
    | sum      | Sum of all the inputs.                                  |
    |          | (eg: sum(x,y,z,w,u,v,t) == (x + y + z + w + u + v + t)) |
    +----------+---------------------------------------------------------+
    | swap     | Swap the values of the variables x and y and return the |
    | <=>      | current value of y.  (eg: swap(x,y) or x <=> y)         |
    +----------+---------------------------------------------------------+
    | trunc    | Integer portion of x.  (eg: trunc(x))                   |
    +----------+---------------------------------------------------------+
    | acos     | Arc cosine of x expressed in radians. Interval [-,+]  |
    |          | (eg: acos(x))                                           |
    +----------+---------------------------------------------------------+
    | acosh    | Inverse hyperbolic cosine of x expressed in radians.    |
    |          | (eg: acosh(x))                                          |
    +----------+---------------------------------------------------------+
    | asin     | Arc sine of x expressed in radians. Interval [-,+]    |
    |          | (eg: asin(x))                                           |
    +----------+---------------------------------------------------------+
    | asinh    | Inverse hyperbolic sine of x expressed in radians.      |
    |          | (eg: asinh(x))                                          |
    +----------+---------------------------------------------------------+
    | atan     | Arc tangent of x expressed in radians. Interval [-,+] |
    |          | (eg: atan(x))                                           |
    +----------+---------------------------------------------------------+
    | atan2    | Arc tangent of (x / y) expressed in radians. [-pi,+pi]  |
    |          | eg: atan2(x,y)                                          |
    +----------+---------------------------------------------------------+
    | atanh    | Inverse hyperbolic tangent of x expressed in radians.   |
    |          | (eg: atanh(x))                                          |
    +----------+---------------------------------------------------------+
    | cos      | Cosine of x.  (eg: cos(x))                              |
    +----------+---------------------------------------------------------+
    | cosh     | Hyperbolic cosine of x.  (eg: cosh(x))                  |
    +----------+---------------------------------------------------------+
    | cot      | Cotangent of x.  (eg: cot(x))                           |
    +----------+---------------------------------------------------------+
    | csc      | Cosecant of x.  (eg: csc(x))                            |
    +----------+---------------------------------------------------------+
    | sec      | Secant of x.  (eg: sec(x))                              |
    +----------+---------------------------------------------------------+
    | sin      | Sine of x.  (eg: sin(x))                                |
    +----------+---------------------------------------------------------+
    | sinc     | Sine cardinal of x.  (eg: sinc(x))                      |
    +----------+---------------------------------------------------------+
    | sinh     | Hyperbolic sine of x.  (eg: sinh(x))                    |
    +----------+---------------------------------------------------------+
    | tan      | Tangent of x.  (eg: tan(x))                             |
    +----------+---------------------------------------------------------+
    | tanh     | Hyperbolic tangent of x.  (eg: tanh(x))                 |
    +----------+---------------------------------------------------------+
    | deg2rad  | Convert x from degrees to radians.  (eg: deg2rad(x))    |
    +----------+---------------------------------------------------------+
    | deg2grad | Convert x from degrees to gradians.  (eg: deg2grad(x))  |
    +----------+---------------------------------------------------------+
    | rad2deg  | Convert x from radians to degrees.  (eg: rad2deg(x))    |
    +----------+---------------------------------------------------------+
    | grad2deg | Convert x from gradians to degrees.  (eg: grad2deg(x))  |
    +----------+---------------------------------------------------------+

六、Exprtk样例

//1、各行求和
for(var row := get_row_count() - ; row > ; row := row - )
{
    var isum := ;
    for(var col := get_col_count() - ; col >= ; col := col - )
    {
        isum += get(row,col);
    }
    set(row,get_col_count() - ,isum);
};
//2、各列求和
for(var col := get_col_count() - ; col >= ; col := col - )
{
    var isum := ;
    for(var row := get_row_count() - ; row > ; row := row - )
    {
        isum += get(row,col);
    }
    set(get_row_count() - ,col,isum);
};

　　Exprtk的具体语法，请参考：Exprtk语言语法说明

七、Snapman的下载地址

　　Snapman下载的官网地址：http://www.snapman.xyz

　　Snapman技术支持QQ群：596654328