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 := 100; //数字变量定义 var sData := 'Hello word.'; //字符串变量定义 var vData[4] := {1,2,3,4}; //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 := 100; var y := 300; var z := 500; var w := 58.7; var v := 32; var data := if ((x + 1) > 2y, z + 1, w / v) ; print(tostring(data));
B、if语句块
if (x < y or (x + z) > y) { z := x + 3; y := x - z; } else if (abs(2y - z) >= 3) 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 := 100; var y := 300; var z := 500; var a := switch { case x > (y + z) : 2 * x / abs(y - z); case x < 3 : sin(x + y); default : 1 + 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 := 0; (x < n) and (x != y); x += 1) { y := y + x / 2 - 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 += 1) < 10) { if (i < 5) j -= i + 2; else if (i % 2 == 0) break; else break[2i + 3]; };
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[5] := {1, 2, 3, 4, 5}; vData += 13;
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) / 6) |
+----------+---------------------------------------------------------+
| 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 1, 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 10 logarithm of x. (eg: log10(x)) |
+----------+---------------------------------------------------------+
| log1p | Natural logarithm of 1 + x, where x is very small. |
| | (eg: log1p(x)) |
+----------+---------------------------------------------------------+
| log2 | Base 2 logarithm of x. (eg: log2(x)) |
+----------+---------------------------------------------------------+
| logn | Base N logarithm of x. where n is a positive integer. |
| | (eg: logn(x,8)) |
+----------+---------------------------------------------------------+
| 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,3) == x^(1/3)) |
+----------+---------------------------------------------------------+
| round | Round x to the nearest integer. (eg: round(x)) |
+----------+---------------------------------------------------------+
| roundn | Round x to n decimal places (eg: roundn(x,3)) |
| | where n > 0 and is an integer. |
| | (eg: roundn(1.2345678,4) == 1.2346) |
+----------+---------------------------------------------------------+
| sgn | Sign of x, -1 where x < 0, +1 where x > 0, else zero. |
| | (eg: sgn(x)) |
+----------+---------------------------------------------------------+
| sqrt | Square root of x, where x >= 0. (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 [-1,+1] |
| | (eg: acos(x)) |
+----------+---------------------------------------------------------+
| acosh | Inverse hyperbolic cosine of x expressed in radians. |
| | (eg: acosh(x)) |
+----------+---------------------------------------------------------+
| asin | Arc sine of x expressed in radians. Interval [-1,+1] |
| | (eg: asin(x)) |
+----------+---------------------------------------------------------+
| asinh | Inverse hyperbolic sine of x expressed in radians. |
| | (eg: asinh(x)) |
+----------+---------------------------------------------------------+
| atan | Arc tangent of x expressed in radians. Interval [-1,+1] |
| | (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() - 3; row > 1; row := row - 1) { var isum := 0; for(var col := get_col_count() - 2; col >= 1; col := col - 1) { isum += get(row,col); } set(row,get_col_count() - 1,isum); }; //2、各列求和 for(var col := get_col_count() - 1; col >= 1; col := col - 1) { var isum := 0; for(var row := get_row_count() - 3; row > 1; row := row - 1) { isum += get(row,col); } set(get_row_count() - 2,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
