Snapman多人協作電子表格是一個即時工作系統。

Snapman中嵌入了Exprtk指令碼進行公式資料運算。Exprtk是一種高效能的指令碼，經測試它的資料運算效能只比C#和java底20%。

一、Exprtk的型別和變數定義

　　Exprtk的資料型別只有三種：Scalar（數字）, Vector(數字陣列）, String（字串）；特別說明：Exprtk沒有字串陣列

　　基本的運算子有：+, -, *, /, %, ^

　　賦值運算子有：:=, +=, -=, *=, /=, %=

　　判斷運算子有：=, ==, <>, !=, <, <=, >, >=

　　邏輯運算子有：and, mand, mor, nand, nor, not, or, shl, shr,xnor, xor, true, false

　　字串運算子有：in, like, ilike, concatenation

　　Exprtk的變數定義為:

var iData := 100;    　　　　　　//數字變數定義
var sData := 'Hello word.';    //字串變數定義
var vData[4] := {1,2,3,4};     //陣列變數定義

 　　Snapman中Exprtk定義了四種特殊變數：

　　1、單元格數字變數，列字母+行號數字，如：A1

　　2、單元格字串變數，列字母+行號數字+下劃線，如：A1_，H234_

　　3、選擇集陣列，列字母+行號數字+冒號+列字母+行號數字，這是一個數字陣列元素次序是按單元格從左往右從上往下，如：F2:G5

　　4、列陣列，列字母+冒號+列字母，這是一個數字陣列元素次序是按單元格從左往右從上往下，如：F:H

　　所以Snapman中Exprtk的變數定義都不要使用數字結尾或數字加下劃線結尾

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

　　1、if語句的型別

　　　　A、if表示式：if (x, y, z) ;如果x為真返回y否則返回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語句塊

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語句的型別

　　　 switch語句會逐句判斷case的條件，成立就執行程式碼表達式，如果case條件都不成立就執行default的程式碼表達式，最後將程式碼表達式的結果返回，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的條件和語句只允許有一條語句

　　3、for語句

　　for語句和C語言類似，但是它是一個表示式所以記住大括號後面需要有分號，如：

for (var x := 0; (x < n) and (x != y); x += 1)
{
  y := y + x / 2 - z;
  w := u + y;
};

　　4、while語句

　　while語句和C語言類似，但它是一個表示式所以記住大括號後面需要有分號，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[]語句

　　continue、break和其C語言類似，break[]的意思是for和while語句是一條有返回值的表示式，break返回的是NaN，而break[]卻是返回中括號中表達式的值，如上一個樣例。

三、Exprtk的陣列運算

　　Exprtk有一個非常強大的陣列運算，可以對陣列變數進行批量運算和賦值

　　1、賦值運算子都支援陣列變數，如下面樣例陣列中每個變數都增加了13：

var vData[5] := {1, 2, 3, 4, 5};
vData += 13;

　　2、其他支援陣列的運算子：+, -, *, /, %, ^

　　3、支援的函式：avg, max, min, mul, sum, count

　　4、當存在2個數組變數的時候，運算以個數少的為運算次數；當運算子為單維運算子或者單維函式，陣列變數會取第一個元素進行運算

四、Exprtk的Snapman函式介面

　　1、tolower(str)，將字串str轉換成小寫字母並返回，例如：e2_:=tolower('AHFGHJHKJDewiuri73972389HHJGJG中華人民共和國')
　　2、toupper(str)，將字串str轉換成大寫字母並返回，例如：e3_:=toupper('AHFGHJHKJDewiuri73972389HHJGJG中華人民共和國')
　　3、tostring(double)，將數字轉換成字串並返回，例如：e4_:=tostring(0.4444488)
　　4、tonumber(str)，將字串轉換成數字並返回，例如：e5:=tonumber('5643786587')
　　5、get(row,col)，獲取第row行、col列的單元格的數字，例如：e6:=get(7,1)
　　6、set(row,col,double)，設定第row行、col列的單元格的數字，例如：set(7,5,98766)
　　7、get_(row,col)，獲取第row行、col列的單元格的字串，例如：e8_:=get_(8,2)
　　8、set_(row,col,str)，設定第row行、col列的單元格的字串，例如：set_(9,5,'大不了的給開發商')
　　9、set_progress(n)，設定進度條，n必須大於等於0，例如：set_progress(10)
　　10、set_total_progress(t)，設定進度條的最大值，t必須大於0，例如：set_total_progress(100)
　　11、sleep(n)，讓執行緒睡眠n毫秒，例如：sleep(1000)
　　12、get_tick_count()，獲取從作業系統啟動所經過的毫秒數，例如：E12:=get_tick_count()
　　13、save()，儲存當前電子表格，例如：save()
　　14、count(vec)，獲取陣列vec的個數，例如：E14:=count(C4:C11)
　　15、print(str)，列印str的內容，例如：print('Hello world.')
　　16、set_background(row,col,str_lafer)，設定第row行、col列的單元格背景的lafer，例如：set_background(16,5,'[[18,#9845f2,8,8,8],[18,#F865f2,16,55,8]]')
　　17、E17或者e17，表格資料變數：字母表示列，數字表示行，例如：E17 := 100000.567;
　　18、E18_或者e18_，表格字串變數：字母表示列，數字表示行，例如：E18_ := '我是中國人。'
　　19、E19:E21或者A:B，表格資料變數陣列，先從左到右然後從上到下，沒有數字代表從某列到某列，例如：E19:E21 := A17:A19

五、Exprtk自帶的函式

    +----------+---------------------------------------------------------+
    | 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樣例

//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的具體語法，請參考：Exprtk語言語法說明

七、Snapman的下載地址

　　Snapman下載的官網地址：http://www.snapman.xyz

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