6 files changed, 254 insertions, 94 deletions
diff --git a/README.md b/README.md
index 4dbf532..7c67092 100644
--- a/README.md
+++ b/README.md
@@ -97,7 +97,7 @@ func main() {
 
 ### Add chart to spreadsheet file
 
-With Excelize chart generation and management is as easy as a few lines of code. You can build charts based off data in your worksheet or generate charts without any data in your worksheet at all.
+With Excelize chart generation and management is as easy as a few lines of code. You can build charts based on data in your worksheet or generate charts without any data in your worksheet at all.
 
 <p align="center"><img width="650" src="./test/images/chart.png" alt="Excelize"></p>
 
@@ -111,8 +111,10 @@ import (
 )
 
 func main() {
-    categories := map[string]string{"A2": "Small", "A3": "Normal", "A4": "Large", "B1": "Apple", "C1": "Orange", "D1": "Pear"}
-    values := map[string]int{"B2": 2, "C2": 3, "D2": 3, "B3": 5, "C3": 2, "D3": 4, "B4": 6, "C4": 7, "D4": 8}
+    categories := map[string]string{
+        "A2": "Small", "A3": "Normal", "A4": "Large", "B1": "Apple", "C1": "Orange", "D1": "Pear"}
+    values := map[string]int{
+        "B2": 2, "C2": 3, "D2": 3, "B3": 5, "C3": 2, "D3": 4, "B4": 6, "C4": 7, "D4": 8}
     f := excelize.NewFile()
     for k, v := range categories {
         f.SetCellValue("Sheet1", k, v)
@@ -120,7 +122,29 @@ func main() {
     for k, v := range values {
         f.SetCellValue("Sheet1", k, v)
     }
-    if err := f.AddChart("Sheet1", "E1", `{"type":"col3DClustered","series":[{"name":"Sheet1!$A$2","categories":"Sheet1!$B$1:$D$1","values":"Sheet1!$B$2:$D$2"},{"name":"Sheet1!$A$3","categories":"Sheet1!$B$1:$D$1","values":"Sheet1!$B$3:$D$3"},{"name":"Sheet1!$A$4","categories":"Sheet1!$B$1:$D$1","values":"Sheet1!$B$4:$D$4"}],"title":{"name":"Fruit 3D Clustered Column Chart"}}`); err != nil {
+    if err := f.AddChart("Sheet1", "E1", `{
+        "type": "col3DClustered",
+        "series": [
+        {
+            "name": "Sheet1!$A$2",
+            "categories": "Sheet1!$B$1:$D$1",
+            "values": "Sheet1!$B$2:$D$2"
+        },
+        {
+            "name": "Sheet1!$A$3",
+            "categories": "Sheet1!$B$1:$D$1",
+            "values": "Sheet1!$B$3:$D$3"
+        },
+        {
+            "name": "Sheet1!$A$4",
+            "categories": "Sheet1!$B$1:$D$1",
+            "values": "Sheet1!$B$4:$D$4"
+        }],
+        "title":
+        {
+            "name": "Fruit 3D Clustered Column Chart"
+        }
+    }`); err != nil {
         fmt.Println(err)
         return
     }
@@ -156,11 +180,18 @@ func main() {
         fmt.Println(err)
     }
     // Insert a picture to worksheet with scaling.
-    if err := f.AddPicture("Sheet1", "D2", "image.jpg", `{"x_scale": 0.5, "y_scale": 0.5}`); err != nil {
+    if err := f.AddPicture("Sheet1", "D2", "image.jpg",
+        `{"x_scale": 0.5, "y_scale": 0.5}`); err != nil {
         fmt.Println(err)
     }
     // Insert a picture offset in the cell with printing support.
-    if err := f.AddPicture("Sheet1", "H2", "image.gif", `{"x_offset": 15, "y_offset": 10, "print_obj": true, "lock_aspect_ratio": false, "locked": false}`); err != nil {
+    if err := f.AddPicture("Sheet1", "H2", "image.gif", `{
+        "x_offset": 15,
+        "y_offset": 10,
+        "print_obj": true,
+        "lock_aspect_ratio": false,
+        "locked": false
+    }`); err != nil {
         fmt.Println(err)
     }
     // Save the spreadsheet with the origin path.
diff --git a/README_zh.md b/README_zh.md
index 25b2fbf..daafd1d 100644
--- a/README_zh.md
+++ b/README_zh.md
@@ -99,7 +99,7 @@ func main() {
 
 使用 Excelize 生成图表十分简单，仅需几行代码。您可以根据工作表中的已有数据构建图表，或向工作表中添加数据并创建图表。
 
-<p align="center"><img width="650" src="./test/images/chart.png" alt="Excelize"></p>
+<p align="center"><img width="650" src="./test/images/chart.png" alt="使用 Excelize 在 Excel 电子表格文档中创建图表"></p>
 
 ```go
 package main
@@ -111,8 +111,10 @@ import (
 )
 
 func main() {
-    categories := map[string]string{"A2": "Small", "A3": "Normal", "A4": "Large", "B1": "Apple", "C1": "Orange", "D1": "Pear"}
-    values := map[string]int{"B2": 2, "C2": 3, "D2": 3, "B3": 5, "C3": 2, "D3": 4, "B4": 6, "C4": 7, "D4": 8}
+    categories := map[string]string{
+        "A2": "Small", "A3": "Normal", "A4": "Large", "B1": "Apple", "C1": "Orange", "D1": "Pear"}
+    values := map[string]int{
+        "B2": 2, "C2": 3, "D2": 3, "B3": 5, "C3": 2, "D3": 4, "B4": 6, "C4": 7, "D4": 8}
     f := excelize.NewFile()
     for k, v := range categories {
         f.SetCellValue("Sheet1", k, v)
@@ -120,7 +122,29 @@ func main() {
     for k, v := range values {
         f.SetCellValue("Sheet1", k, v)
     }
-    if err := f.AddChart("Sheet1", "E1", `{"type":"col3DClustered","series":[{"name":"Sheet1!$A$2","categories":"Sheet1!$B$1:$D$1","values":"Sheet1!$B$2:$D$2"},{"name":"Sheet1!$A$3","categories":"Sheet1!$B$1:$D$1","values":"Sheet1!$B$3:$D$3"},{"name":"Sheet1!$A$4","categories":"Sheet1!$B$1:$D$1","values":"Sheet1!$B$4:$D$4"}],"title":{"name":"Fruit 3D Clustered Column Chart"}}`); err != nil {
+    if err := f.AddChart("Sheet1", "E1", `{
+        "type": "col3DClustered",
+        "series": [
+        {
+            "name": "Sheet1!$A$2",
+            "categories": "Sheet1!$B$1:$D$1",
+            "values": "Sheet1!$B$2:$D$2"
+        },
+        {
+            "name": "Sheet1!$A$3",
+            "categories": "Sheet1!$B$1:$D$1",
+            "values": "Sheet1!$B$3:$D$3"
+        },
+        {
+            "name": "Sheet1!$A$4",
+            "categories": "Sheet1!$B$1:$D$1",
+            "values": "Sheet1!$B$4:$D$4"
+        }],
+        "title":
+        {
+            "name": "Fruit 3D Clustered Column Chart"
+        }
+    }`); err != nil {
         fmt.Println(err)
         return
     }
@@ -156,11 +180,18 @@ func main() {
         fmt.Println(err)
     }
     // 在工作表中插入图片，并设置图片的缩放比例
-    if err := f.AddPicture("Sheet1", "D2", "image.jpg", `{"x_scale": 0.5, "y_scale": 0.5}`); err != nil {
+    if err := f.AddPicture("Sheet1", "D2", "image.jpg",
+        `{"x_scale": 0.5, "y_scale": 0.5}`); err != nil {
         fmt.Println(err)
     }
     // 在工作表中插入图片，并设置图片的打印属性
-    if err := f.AddPicture("Sheet1", "H2", "image.gif", `{"x_offset": 15, "y_offset": 10, "print_obj": true, "lock_aspect_ratio": false, "locked": false}`); err != nil {
+    if err := f.AddPicture("Sheet1", "H2", "image.gif", `{
+        "x_offset": 15,
+        "y_offset": 10,
+        "print_obj": true,
+        "lock_aspect_ratio": false,
+        "locked": false
+    }`); err != nil {
         fmt.Println(err)
     }
     // 保存文件
diff --git a/calc.go b/calc.go
index 7da2493..d2bab1d 100644
--- a/calc.go
+++ b/calc.go
@@ -24,6 +24,7 @@ import (
 	"strconv"
 	"strings"
 	"time"
+	"unicode"
 
 	"github.com/xuri/efp"
 )
@@ -123,14 +124,15 @@ var tokenPriority = map[string]int{
 // Supported formulas:
 //
 //    ABS, ACOS, ACOSH, ACOT, ACOTH, AND, ARABIC, ASIN, ASINH, ATAN2, ATANH,
-//    BASE, CEILING, CEILING.MATH, CEILING.PRECISE, COMBIN, COMBINA, COS,
-//    COSH, COT, COTH, COUNTA, CSC, CSCH, DATE, DECIMAL, DEGREES, EVEN, EXP,
-//    FACT, FACTDOUBLE, FLOOR, FLOOR.MATH, FLOOR.PRECISE, GCD, INT, ISBLANK,
-//    ISERR, ISERROR, ISEVEN, ISNA, ISNONTEXT, ISNUMBER, ISO.CEILING, ISODD,
-//    LCM, LN, LOG, LOG10, MDETERM, MEDIAN, MOD, MROUND, MULTINOMIAL, MUNIT,
-//    NA, ODD, OR, PI, POWER, PRODUCT, QUOTIENT, RADIANS, RAND, RANDBETWEEN,
-//    ROUND, ROUNDDOWN, ROUNDUP, SEC, SECH, SIGN, SIN, SINH, SQRT, SQRTPI,
-//    SUM, SUMIF, SUMSQ, TAN, TANH, TRUNC
+//    BASE, CEILING, CEILING.MATH, CEILING.PRECISE, CLEAN, COMBIN, COMBINA,
+//    COS, COSH, COT, COTH, COUNTA, CSC, CSCH, DATE, DECIMAL, DEGREES, EVEN,
+//    EXP, FACT, FACTDOUBLE, FLOOR, FLOOR.MATH, FLOOR.PRECISE, GCD, INT,
+//    ISBLANK, ISERR, ISERROR, ISEVEN, ISNA, ISNONTEXT, ISNUMBER, ISO.CEILING,
+//    ISODD, LCM, LN, LOG, LOG10, LOWER, MDETERM, MEDIAN, MOD, MROUND,
+//    MULTINOMIAL, MUNIT, NA, ODD, OR, PI, POWER, PRODUCT, PROPER, QUOTIENT,
+//    RADIANS, RAND, RANDBETWEEN, ROUND, ROUNDDOWN, ROUNDUP, SEC, SECH, SIGN,
+//    SIN, SINH, SQRT, SQRTPI, SUM, SUMIF, SUMSQ, TAN, TANH, TRIM, TRUNC,
+//    UPPER
 //
 func (f *File) CalcCellValue(sheet, cell string) (result string, err error) {
 	var (
@@ -869,7 +871,7 @@ func formulaCriteriaEval(val string, criteria *formulaCriteria) (result bool, er
 // ABS function returns the absolute value of any supplied number. The syntax
 // of the function is:
 //
-//   ABS(number)
+//    ABS(number)
 //
 func (fn *formulaFuncs) ABS(argsList *list.List) (result string, err error) {
 	if argsList.Len() != 1 {
@@ -889,7 +891,7 @@ func (fn *formulaFuncs) ABS(argsList *list.List) (result string, err error) {
 // number, and returns an angle, in radians, between 0 and π. The syntax of
 // the function is:
 //
-//   ACOS(number)
+//    ACOS(number)
 //
 func (fn *formulaFuncs) ACOS(argsList *list.List) (result string, err error) {
 	if argsList.Len() != 1 {
@@ -908,7 +910,7 @@ func (fn *formulaFuncs) ACOS(argsList *list.List) (result string, err error) {
 // ACOSH function calculates the inverse hyperbolic cosine of a supplied number.
 // of the function is:
 //
-//   ACOSH(number)
+//    ACOSH(number)
 //
 func (fn *formulaFuncs) ACOSH(argsList *list.List) (result string, err error) {
 	if argsList.Len() != 1 {
@@ -928,7 +930,7 @@ func (fn *formulaFuncs) ACOSH(argsList *list.List) (result string, err error) {
 // given number, and returns an angle, in radians, between 0 and π. The syntax
 // of the function is:
 //
-//   ACOT(number)
+//    ACOT(number)
 //
 func (fn *formulaFuncs) ACOT(argsList *list.List) (result string, err error) {
 	if argsList.Len() != 1 {
@@ -947,7 +949,7 @@ func (fn *formulaFuncs) ACOT(argsList *list.List) (result string, err error) {
 // ACOTH function calculates the hyperbolic arccotangent (coth) of a supplied
 // value. The syntax of the function is:
 //
-//   ACOTH(number)
+//    ACOTH(number)
 //
 func (fn *formulaFuncs) ACOTH(argsList *list.List) (result string, err error) {
 	if argsList.Len() != 1 {
@@ -966,7 +968,7 @@ func (fn *formulaFuncs) ACOTH(argsList *list.List) (result string, err error) {
 // ARABIC function converts a Roman numeral into an Arabic numeral. The syntax
 // of the function is:
 //
-//   ARABIC(text)
+//    ARABIC(text)
 //
 func (fn *formulaFuncs) ARABIC(argsList *list.List) (result string, err error) {
 	if argsList.Len() != 1 {
@@ -1004,7 +1006,7 @@ func (fn *formulaFuncs) ARABIC(argsList *list.List) (result string, err error) {
 // number, and returns an angle, in radians, between -π/2 and π/2. The syntax
 // of the function is:
 //
-//   ASIN(number)
+//    ASIN(number)
 //
 func (fn *formulaFuncs) ASIN(argsList *list.List) (result string, err error) {
 	if argsList.Len() != 1 {
@@ -1023,7 +1025,7 @@ func (fn *formulaFuncs) ASIN(argsList *list.List) (result string, err error) {
 // ASINH function calculates the inverse hyperbolic sine of a supplied number.
 // The syntax of the function is:
 //
-//   ASINH(number)
+//    ASINH(number)
 //
 func (fn *formulaFuncs) ASINH(argsList *list.List) (result string, err error) {
 	if argsList.Len() != 1 {
@@ -1043,7 +1045,7 @@ func (fn *formulaFuncs) ASINH(argsList *list.List) (result string, err error) {
 // given number, and returns an angle, in radians, between -π/2 and +π/2. The
 // syntax of the function is:
 //
-//   ATAN(number)
+//    ATAN(number)
 //
 func (fn *formulaFuncs) ATAN(argsList *list.List) (result string, err error) {
 	if argsList.Len() != 1 {
@@ -1062,7 +1064,7 @@ func (fn *formulaFuncs) ATAN(argsList *list.List) (result string, err error) {
 // ATANH function calculates the inverse hyperbolic tangent of a supplied
 // number. The syntax of the function is:
 //
-//   ATANH(number)
+//    ATANH(number)
 //
 func (fn *formulaFuncs) ATANH(argsList *list.List) (result string, err error) {
 	if argsList.Len() != 1 {
@@ -1082,7 +1084,7 @@ func (fn *formulaFuncs) ATANH(argsList *list.List) (result string, err error) {
 // given set of x and y coordinates, and returns an angle, in radians, between
 // -π/2 and +π/2. The syntax of the function is:
 //
-//   ATAN2(x_num,y_num)
+//    ATAN2(x_num,y_num)
 //
 func (fn *formulaFuncs) ATAN2(argsList *list.List) (result string, err error) {
 	if argsList.Len() != 2 {
@@ -1105,7 +1107,7 @@ func (fn *formulaFuncs) ATAN2(argsList *list.List) (result string, err error) {
 // BASE function converts a number into a supplied base (radix), and returns a
 // text representation of the calculated value. The syntax of the function is:
 //
-//   BASE(number,radix,[min_length])
+//    BASE(number,radix,[min_length])
 //
 func (fn *formulaFuncs) BASE(argsList *list.List) (result string, err error) {
 	if argsList.Len() < 2 {
@@ -1147,7 +1149,7 @@ func (fn *formulaFuncs) BASE(argsList *list.List) (result string, err error) {
 // CEILING function rounds a supplied number away from zero, to the nearest
 // multiple of a given number. The syntax of the function is:
 //
-//   CEILING(number,significance)
+//    CEILING(number,significance)
 //
 func (fn *formulaFuncs) CEILING(argsList *list.List) (result string, err error) {
 	if argsList.Len() == 0 {
@@ -1191,7 +1193,7 @@ func (fn *formulaFuncs) CEILING(argsList *list.List) (result string, err error)
 // CEILINGMATH function rounds a supplied number up to a supplied multiple of
 // significance. The syntax of the function is:
 //
-//   CEILING.MATH(number,[significance],[mode])
+//    CEILING.MATH(number,[significance],[mode])
 //
 func (fn *formulaFuncs) CEILINGMATH(argsList *list.List) (result string, err error) {
 	if argsList.Len() == 0 {
@@ -1242,7 +1244,7 @@ func (fn *formulaFuncs) CEILINGMATH(argsList *list.List) (result string, err err
 // number's sign), to the nearest multiple of a given number. The syntax of
 // the function is:
 //
-//   CEILING.PRECISE(number,[significance])
+//    CEILING.PRECISE(number,[significance])
 //
 func (fn *formulaFuncs) CEILINGPRECISE(argsList *list.List) (result string, err error) {
 	if argsList.Len() == 0 {
@@ -1289,7 +1291,7 @@ func (fn *formulaFuncs) CEILINGPRECISE(argsList *list.List) (result string, err
 // COMBIN function calculates the number of combinations (in any order) of a
 // given number objects from a set. The syntax of the function is:
 //
-//   COMBIN(number,number_chosen)
+//    COMBIN(number,number_chosen)
 //
 func (fn *formulaFuncs) COMBIN(argsList *list.List) (result string, err error) {
 	if argsList.Len() != 2 {
@@ -1324,7 +1326,7 @@ func (fn *formulaFuncs) COMBIN(argsList *list.List) (result string, err error) {
 // COMBINA function calculates the number of combinations, with repetitions,
 // of a given number objects from a set. The syntax of the function is:
 //
-//   COMBINA(number,number_chosen)
+//    COMBINA(number,number_chosen)
 //
 func (fn *formulaFuncs) COMBINA(argsList *list.List) (result string, err error) {
 	if argsList.Len() != 2 {
@@ -1364,7 +1366,7 @@ func (fn *formulaFuncs) COMBINA(argsList *list.List) (result string, err error)
 // COS function calculates the cosine of a given angle. The syntax of the
 // function is:
 //
-//   COS(number)
+//    COS(number)
 //
 func (fn *formulaFuncs) COS(argsList *list.List) (result string, err error) {
 	if argsList.Len() != 1 {
@@ -1383,7 +1385,7 @@ func (fn *formulaFuncs) COS(argsList *list.List) (result string, err error) {
 // COSH function calculates the hyperbolic cosine (cosh) of a supplied number.
 // The syntax of the function is:
 //
-//   COSH(number)
+//    COSH(number)
 //
 func (fn *formulaFuncs) COSH(argsList *list.List) (result string, err error) {
 	if argsList.Len() != 1 {
@@ -1402,7 +1404,7 @@ func (fn *formulaFuncs) COSH(argsList *list.List) (result string, err error) {
 // COT function calculates the cotangent of a given angle. The syntax of the
 // function is:
 //
-//   COT(number)
+//    COT(number)
 //
 func (fn *formulaFuncs) COT(argsList *list.List) (result string, err error) {
 	if argsList.Len() != 1 {
@@ -1425,7 +1427,7 @@ func (fn *formulaFuncs) COT(argsList *list.List) (result string, err error) {
 // COTH function calculates the hyperbolic cotangent (coth) of a supplied
 // angle. The syntax of the function is:
 //
-//   COTH(number)
+//    COTH(number)
 //
 func (fn *formulaFuncs) COTH(argsList *list.List) (result string, err error) {
 	if argsList.Len() != 1 {
@@ -1448,7 +1450,7 @@ func (fn *formulaFuncs) COTH(argsList *list.List) (result string, err error) {
 // CSC function calculates the cosecant of a given angle. The syntax of the
 // function is:
 //
-//   CSC(number)
+//    CSC(number)
 //
 func (fn *formulaFuncs) CSC(argsList *list.List) (result string, err error) {
 	if argsList.Len() != 1 {
@@ -1471,7 +1473,7 @@ func (fn *formulaFuncs) CSC(argsList *list.List) (result string, err error) {
 // CSCH function calculates the hyperbolic cosecant (csch) of a supplied
 // angle. The syntax of the function is:
 //
-//   CSCH(number)
+//    CSCH(number)
 //
 func (fn *formulaFuncs) CSCH(argsList *list.List) (result string, err error) {
 	if argsList.Len() != 1 {
@@ -1494,7 +1496,7 @@ func (fn *formulaFuncs) CSCH(argsList *list.List) (result string, err error) {
 // DECIMAL function converts a text representation of a number in a specified
 // base, into a decimal value. The syntax of the function is:
 //
-//   DECIMAL(text,radix)
+//    DECIMAL(text,radix)
 //
 func (fn *formulaFuncs) DECIMAL(argsList *list.List) (result string, err error) {
 	if argsList.Len() != 2 {
@@ -1522,7 +1524,7 @@ func (fn *formulaFuncs) DECIMAL(argsList *list.List) (result string, err error)
 // DEGREES function converts radians into degrees. The syntax of the function
 // is:
 //
-//   DEGREES(angle)
+//    DEGREES(angle)
 //
 func (fn *formulaFuncs) DEGREES(argsList *list.List) (result string, err error) {
 	if argsList.Len() != 1 {
@@ -1546,7 +1548,7 @@ func (fn *formulaFuncs) DEGREES(argsList *list.List) (result string, err error)
 // positive number up and a negative number down), to the next even number.
 // The syntax of the function is:
 //
-//   EVEN(number)
+//    EVEN(number)
 //
 func (fn *formulaFuncs) EVEN(argsList *list.List) (result string, err error) {
 	if argsList.Len() != 1 {
@@ -1575,7 +1577,7 @@ func (fn *formulaFuncs) EVEN(argsList *list.List) (result string, err error) {
 // EXP function calculates the value of the mathematical constant e, raised to
 // the power of a given number. The syntax of the function is:
 //
-//   EXP(number)
+//    EXP(number)
 //
 func (fn *formulaFuncs) EXP(argsList *list.List) (result string, err error) {
 	if argsList.Len() != 1 {
@@ -1603,7 +1605,7 @@ func fact(number float64) float64 {
 // FACT function returns the factorial of a supplied number. The syntax of the
 // function is:
 //
-//   FACT(number)
+//    FACT(number)
 //
 func (fn *formulaFuncs) FACT(argsList *list.List) (result string, err error) {
 	if argsList.Len() != 1 {
@@ -1625,7 +1627,7 @@ func (fn *formulaFuncs) FACT(argsList *list.List) (result string, err error) {
 // FACTDOUBLE function returns the double factorial of a supplied number. The
 // syntax of the function is:
 //
-//   FACTDOUBLE(number)
+//    FACTDOUBLE(number)
 //
 func (fn *formulaFuncs) FACTDOUBLE(argsList *list.List) (result string, err error) {
 	if argsList.Len() != 1 {
@@ -1651,7 +1653,7 @@ func (fn *formulaFuncs) FACTDOUBLE(argsList *list.List) (result string, err erro
 // FLOOR function rounds a supplied number towards zero to the nearest
 // multiple of a specified significance. The syntax of the function is:
 //
-//   FLOOR(number,significance)
+//    FLOOR(number,significance)
 //
 func (fn *formulaFuncs) FLOOR(argsList *list.List) (result string, err error) {
 	if argsList.Len() != 2 {
@@ -1685,7 +1687,7 @@ func (fn *formulaFuncs) FLOOR(argsList *list.List) (result string, err error) {
 // FLOORMATH function rounds a supplied number down to a supplied multiple of
 // significance. The syntax of the function is:
 //
-//   FLOOR.MATH(number,[significance],[mode])
+//    FLOOR.MATH(number,[significance],[mode])
 //
 func (fn *formulaFuncs) FLOORMATH(argsList *list.List) (result string, err error) {
 	if argsList.Len() == 0 {
@@ -1731,7 +1733,7 @@ func (fn *formulaFuncs) FLOORMATH(argsList *list.List) (result string, err error
 // FLOORPRECISE function rounds a supplied number down to a supplied multiple
 // of significance. The syntax of the function is:
 //
-//   FLOOR.PRECISE(number,[significance])
+//    FLOOR.PRECISE(number,[significance])
 //
 func (fn *formulaFuncs) FLOORPRECISE(argsList *list.List) (result string, err error) {
 	if argsList.Len() == 0 {
@@ -1797,7 +1799,7 @@ func gcd(x, y float64) float64 {
 // GCD function returns the greatest common divisor of two or more supplied
 // integers. The syntax of the function is:
 //
-//   GCD(number1,[number2],...)
+//    GCD(number1,[number2],...)
 //
 func (fn *formulaFuncs) GCD(argsList *list.List) (result string, err error) {
 	if argsList.Len() == 0 {
@@ -1842,7 +1844,7 @@ func (fn *formulaFuncs) GCD(argsList *list.List) (result string, err error) {
 // INT function truncates a supplied number down to the closest integer. The
 // syntax of the function is:
 //
-//   INT(number)
+//    INT(number)
 //
 func (fn *formulaFuncs) INT(argsList *list.List) (result string, err error) {
 	if argsList.Len() != 1 {
@@ -1866,7 +1868,7 @@ func (fn *formulaFuncs) INT(argsList *list.List) (result string, err error) {
 // sign), to the nearest multiple of a supplied significance. The syntax of
 // the function is:
 //
-//   ISO.CEILING(number,[significance])
+//    ISO.CEILING(number,[significance])
 //
 func (fn *formulaFuncs) ISOCEILING(argsList *list.List) (result string, err error) {
 	if argsList.Len() == 0 {
@@ -1923,7 +1925,7 @@ func lcm(a, b float64) float64 {
 // LCM function returns the least common multiple of two or more supplied
 // integers. The syntax of the function is:
 //
-//   LCM(number1,[number2],...)
+//    LCM(number1,[number2],...)
 //
 func (fn *formulaFuncs) LCM(argsList *list.List) (result string, err error) {
 	if argsList.Len() == 0 {
@@ -1968,7 +1970,7 @@ func (fn *formulaFuncs) LCM(argsList *list.List) (result string, err error) {
 // LN function calculates the natural logarithm of a given number. The syntax
 // of the function is:
 //
-//   LN(number)
+//    LN(number)
 //
 func (fn *formulaFuncs) LN(argsList *list.List) (result string, err error) {
 	if argsList.Len() != 1 {
@@ -1987,7 +1989,7 @@ func (fn *formulaFuncs) LN(argsList *list.List) (result string, err error) {
 // LOG function calculates the logarithm of a given number, to a supplied
 // base. The syntax of the function is:
 //
-//   LOG(number,[base])
+//    LOG(number,[base])
 //
 func (fn *formulaFuncs) LOG(argsList *list.List) (result string, err error) {
 	if argsList.Len() == 0 {
@@ -2028,7 +2030,7 @@ func (fn *formulaFuncs) LOG(argsList *list.List) (result string, err error) {
 // LOG10 function calculates the base 10 logarithm of a given number. The
 // syntax of the function is:
 //
-//   LOG10(number)
+//    LOG10(number)
 //
 func (fn *formulaFuncs) LOG10(argsList *list.List) (result string, err error) {
 	if argsList.Len() != 1 {
@@ -2082,7 +2084,7 @@ func det(sqMtx [][]float64) float64 {
 // MDETERM calculates the determinant of a square matrix. The
 // syntax of the function is:
 //
-//   MDETERM(array)
+//    MDETERM(array)
 //
 func (fn *formulaFuncs) MDETERM(argsList *list.List) (result string, err error) {
 	var num float64
@@ -2113,7 +2115,7 @@ func (fn *formulaFuncs) MDETERM(argsList *list.List) (result string, err error)
 // MOD function returns the remainder of a division between two supplied
 // numbers. The syntax of the function is:
 //
-//   MOD(number,divisor)
+//    MOD(number,divisor)
 //
 func (fn *formulaFuncs) MOD(argsList *list.List) (result string, err error) {
 	if argsList.Len() != 2 {
@@ -2144,7 +2146,7 @@ func (fn *formulaFuncs) MOD(argsList *list.List) (result string, err error) {
 // MROUND function rounds a supplied number up or down to the nearest multiple
 // of a given number. The syntax of the function is:
 //
-//   MOD(number,multiple)
+//    MROUND(number,multiple)
 //
 func (fn *formulaFuncs) MROUND(argsList *list.List) (result string, err error) {
 	if argsList.Len() != 2 {
@@ -2852,7 +2854,7 @@ func (fn *formulaFuncs) SUMIF(argsList *list.List) (result string, err error) {
 // SUMSQ function returns the sum of squares of a supplied set of values. The
 // syntax of the function is:
 //
-//   SUMSQ(number1,[number2],...)
+//    SUMSQ(number1,[number2],...)
 //
 func (fn *formulaFuncs) SUMSQ(argsList *list.List) (result string, err error) {
 	var val, sq float64
@@ -2928,7 +2930,7 @@ func (fn *formulaFuncs) TANH(argsList *list.List) (result string, err error) {
 // TRUNC function truncates a supplied number to a specified number of decimal
 // places. The syntax of the function is:
 //
-//   TRUNC(number,[number_digits])
+//    TRUNC(number,[number_digits])
 //
 func (fn *formulaFuncs) TRUNC(argsList *list.List) (result string, err error) {
 	if argsList.Len() == 0 {
@@ -2967,7 +2969,7 @@ func (fn *formulaFuncs) TRUNC(argsList *list.List) (result string, err error) {
 // COUNTA function returns the number of non-blanks within a supplied set of
 // cells or values. The syntax of the function is:
 //
-//   COUNTA(value1,[value2],...)
+//    COUNTA(value1,[value2],...)
 //
 func (fn *formulaFuncs) COUNTA(argsList *list.List) (result string, err error) {
 	var count int
@@ -2995,7 +2997,7 @@ func (fn *formulaFuncs) COUNTA(argsList *list.List) (result string, err error) {
 // MEDIAN function returns the statistical median (the middle value) of a list
 // of supplied numbers. The syntax of the function is:
 //
-//   MEDIAN(number1,[number2],...)
+//    MEDIAN(number1,[number2],...)
 //
 func (fn *formulaFuncs) MEDIAN(argsList *list.List) (result string, err error) {
 	if argsList.Len() == 0 {
@@ -3044,7 +3046,7 @@ func (fn *formulaFuncs) MEDIAN(argsList *list.List) (result string, err error) {
 // returns TRUE; Otherwise the function returns FALSE. The syntax of the
 // function is:
 //
-//   ISBLANK(value)
+//    ISBLANK(value)
 //
 func (fn *formulaFuncs) ISBLANK(argsList *list.List) (result string, err error) {
 	if argsList.Len() != 1 {
@@ -3069,7 +3071,7 @@ func (fn *formulaFuncs) ISBLANK(argsList *list.List) (result string, err error)
 // logical value TRUE; If the supplied value is not an error or is the #N/A
 // error, the ISERR function returns FALSE. The syntax of the function is:
 //
-//   ISERR(value)
+//    ISERR(value)
 //
 func (fn *formulaFuncs) ISERR(argsList *list.List) (result string, err error) {
 	if argsList.Len() != 1 {
@@ -3092,7 +3094,7 @@ func (fn *formulaFuncs) ISERR(argsList *list.List) (result string, err error) {
 // an Excel Error, and if so, returns the logical value TRUE; Otherwise the
 // function returns FALSE. The syntax of the function is:
 //
-//   ISERROR(value)
+//    ISERROR(value)
 //
 func (fn *formulaFuncs) ISERROR(argsList *list.List) (result string, err error) {
 	if argsList.Len() != 1 {
@@ -3115,7 +3117,7 @@ func (fn *formulaFuncs) ISERROR(argsList *list.List) (result string, err error)
 // evaluates to an even number, and if so, returns TRUE; Otherwise, the
 // function returns FALSE. The syntax of the function is:
 //
-//   ISEVEN(value)
+//    ISEVEN(value)
 //
 func (fn *formulaFuncs) ISEVEN(argsList *list.List) (result string, err error) {
 	if argsList.Len() != 1 {
@@ -3142,7 +3144,7 @@ func (fn *formulaFuncs) ISEVEN(argsList *list.List) (result string, err error) {
 // the Excel #N/A Error, and if so, returns TRUE; Otherwise the function
 // returns FALSE. The syntax of the function is:
 //
-//   ISNA(value)
+//    ISNA(value)
 //
 func (fn *formulaFuncs) ISNA(argsList *list.List) (result string, err error) {
 	if argsList.Len() != 1 {
@@ -3161,7 +3163,7 @@ func (fn *formulaFuncs) ISNA(argsList *list.List) (result string, err error) {
 // function returns TRUE; If the supplied value is text, the function returns
 // FALSE. The syntax of the function is:
 //
-//   ISNONTEXT(value)
+//    ISNONTEXT(value)
 //
 func (fn *formulaFuncs) ISNONTEXT(argsList *list.List) (result string, err error) {
 	if argsList.Len() != 1 {
@@ -3180,7 +3182,7 @@ func (fn *formulaFuncs) ISNONTEXT(argsList *list.List) (result string, err error
 // the function returns TRUE; Otherwise it returns FALSE. The syntax of the
 // function is:
 //
-//   ISNUMBER(value)
+//    ISNUMBER(value)
 //
 func (fn *formulaFuncs) ISNUMBER(argsList *list.List) (result string, err error) {
 	if argsList.Len() != 1 {
@@ -3202,7 +3204,7 @@ func (fn *formulaFuncs) ISNUMBER(argsList *list.List) (result string, err error)
 // to an odd number, and if so, returns TRUE; Otherwise, the function returns
 // FALSE. The syntax of the function is:
 //
-//   ISODD(value)
+//    ISODD(value)
 //
 func (fn *formulaFuncs) ISODD(argsList *list.List) (result string, err error) {
 	if argsList.Len() != 1 {
@@ -3229,7 +3231,7 @@ func (fn *formulaFuncs) ISODD(argsList *list.List) (result string, err error) {
 // meaning 'value not available' and is produced when an Excel Formula is
 // unable to find a value that it needs. The syntax of the function is:
 //
-//   NA()
+//    NA()
 //
 func (fn *formulaFuncs) NA(argsList *list.List) (result string, err error) {
 	if argsList.Len() != 0 {
@@ -3243,7 +3245,10 @@ func (fn *formulaFuncs) NA(argsList *list.List) (result string, err error) {
 // Logical Functions
 
 // AND function tests a number of supplied conditions and returns TRUE or
-// FALSE.
+// FALSE. The syntax of the function is:
+//
+//    AND(logical_test1,[logical_test2],...)
+//
 func (fn *formulaFuncs) AND(argsList *list.List) (result string, err error) {
 	if argsList.Len() == 0 {
 		err = errors.New("AND requires at least 1 argument")
@@ -3284,7 +3289,10 @@ func (fn *formulaFuncs) AND(argsList *list.List) (result string, err error) {
 }
 
 // OR function tests a number of supplied conditions and returns either TRUE
-// or FALSE.
+// or FALSE. The syntax of the function is:
+//
+//    OR(logical_test1,[logical_test2],...)
+//
 func (fn *formulaFuncs) OR(argsList *list.List) (result string, err error) {
 	if argsList.Len() == 0 {
 		err = errors.New("OR requires at least 1 argument")
@@ -3326,7 +3334,11 @@ func (fn *formulaFuncs) OR(argsList *list.List) (result string, err error) {
 
 // Date and Time Functions
 
-// DATE returns a date, from a user-supplied year, month and day.
+// DATE returns a date, from a user-supplied year, month and day. The syntax
+// of the function is:
+//
+//    DATE(year,month,day)
+//
 func (fn *formulaFuncs) DATE(argsList *list.List) (result string, err error) {
 	if argsList.Len() != 3 {
 		err = errors.New("DATE requires 3 number arguments")
@@ -3368,7 +3380,11 @@ func daysBetween(startDate, endDate int64) float64 {
 
 // Text Functions
 
-// CLEAN removes all non-printable characters from a supplied text string.
+// CLEAN removes all non-printable characters from a supplied text string. The
+// syntax of the function is:
+//
+//    CLEAN(text)
+//
 func (fn *formulaFuncs) CLEAN(argsList *list.List) (result string, err error) {
 	if argsList.Len() != 1 {
 		err = errors.New("CLEAN requires 1 argument")
@@ -3385,7 +3401,11 @@ func (fn *formulaFuncs) CLEAN(argsList *list.List) (result string, err error) {
 }
 
 // TRIM removes extra spaces (i.e. all spaces except for single spaces between
-// words or characters) from a supplied text string.
+// words or characters) from a supplied text string. The syntax of the
+// function is:
+//
+//    TRIM(text)
+//
 func (fn *formulaFuncs) TRIM(argsList *list.List) (result string, err error) {
 	if argsList.Len() != 1 {
 		err = errors.New("TRIM requires 1 argument")
@@ -3394,3 +3414,58 @@ func (fn *formulaFuncs) TRIM(argsList *list.List) (result string, err error) {
 	result = strings.TrimSpace(argsList.Front().Value.(formulaArg).String)
 	return
 }
+
+// LOWER converts all characters in a supplied text string to lower case. The
+// syntax of the function is:
+//
+//    LOWER(text)
+//
+func (fn *formulaFuncs) LOWER(argsList *list.List) (result string, err error) {
+	if argsList.Len() != 1 {
+		err = errors.New("LOWER requires 1 argument")
+		return
+	}
+	result = strings.ToLower(argsList.Front().Value.(formulaArg).String)
+	return
+}
+
+// PROPER converts all characters in a supplied text string to proper case
+// (i.e. all letters that do not immediately follow another letter are set to
+// upper case and all other characters are lower case). The syntax of the
+// function is:
+//
+//    PROPER(text)
+//
+func (fn *formulaFuncs) PROPER(argsList *list.List) (result string, err error) {
+	if argsList.Len() != 1 {
+		err = errors.New("PROPER requires 1 argument")
+		return
+	}
+	buf := bytes.Buffer{}
+	isLetter := false
+	for _, char := range argsList.Front().Value.(formulaArg).String {
+		if !isLetter && unicode.IsLetter(char) {
+			buf.WriteRune(unicode.ToUpper(char))
+		} else {
+			buf.WriteRune(unicode.ToLower(char))
+		}
+		isLetter = unicode.IsLetter(char)
+	}
+
+	result = buf.String()
+	return
+}
+
+// UPPER converts all characters in a supplied text string to upper case. The
+// syntax of the function is:
+//
+//    UPPER(text)
+//
+func (fn *formulaFuncs) UPPER(argsList *list.List) (result string, err error) {
+	if argsList.Len() != 1 {
+		err = errors.New("UPPER requires 1 argument")
+		return
+	}
+	result = strings.ToUpper(argsList.Front().Value.(formulaArg).String)
+	return
+}
diff --git a/calc_test.go b/calc_test.go
index f928797..ea60a50 100644
--- a/calc_test.go
+++ b/calc_test.go
@@ -470,6 +470,21 @@ func TestCalcCellValue(t *testing.T) {
 		// TRIM
 		"=TRIM(\" trim text \")": "trim text",
 		"=TRIM(0)":               "0",
+		// LOWER
+		"=LOWER(\"test\")":     "test",
+		"=LOWER(\"TEST\")":     "test",
+		"=LOWER(\"Test\")":     "test",
+		"=LOWER(\"TEST 123\")": "test 123",
+		// PROPER
+		"=PROPER(\"this is a test sentence\")": "This Is A Test Sentence",
+		"=PROPER(\"THIS IS A TEST SENTENCE\")": "This Is A Test Sentence",
+		"=PROPER(\"123tEST teXT\")":            "123Test Text",
+		"=PROPER(\"Mr. SMITH's address\")":     "Mr. Smith'S Address",
+		// UPPER
+		"=UPPER(\"test\")":     "TEST",
+		"=UPPER(\"TEST\")":     "TEST",
+		"=UPPER(\"Test\")":     "TEST",
+		"=UPPER(\"TEST 123\")": "TEST 123",
 	}
 	for formula, expected := range mathCalc {
 		f := prepareData()
@@ -793,6 +808,15 @@ func TestCalcCellValue(t *testing.T) {
 		// TRIM
 		"=TRIM()":    "TRIM requires 1 argument",
 		"=TRIM(1,2)": "TRIM requires 1 argument",
+		// LOWER
+		"=LOWER()":    "LOWER requires 1 argument",
+		"=LOWER(1,2)": "LOWER requires 1 argument",
+		// UPPER
+		"=UPPER()":    "UPPER requires 1 argument",
+		"=UPPER(1,2)": "UPPER requires 1 argument",
+		// PROPER
+		"=PROPER()":    "PROPER requires 1 argument",
+		"=PROPER(1,2)": "PROPER requires 1 argument",
 	}
 	for formula, expected := range mathCalcError {
 		f := prepareData()
diff --git a/rows.go b/rows.go
index 591d7e9..1e29d8f 100644
--- a/rows.go
+++ b/rows.go
@@ -602,7 +602,6 @@ func (f *File) duplicateMergeCells(sheet string, ws *xlsxWorksheet, row, row2 in
 			if err := f.MergeCell(sheet, from, to); err != nil {
 				return err
 			}
-			i++
 		}
 	}
 	return nil
diff --git a/rows_test.go b/rows_test.go
index e49b28a..02b00da 100644
--- a/rows_test.go
+++ b/rows_test.go
@@ -323,7 +323,7 @@ func TestDuplicateRowFromSingleRow(t *testing.T) {
 		assert.NoError(t, f.SetCellStr(sheet, "B1", cells["B1"]))
 
 		assert.NoError(t, f.DuplicateRow(sheet, 1))
-		if !assert.NoError(t, f.SaveAs(fmt.Sprintf(outFile, "TestDuplicateRow.FromSingleRow_1"))) {
+		if !assert.NoError(t, f.SaveAs(fmt.Sprintf(outFile, "FromSingleRow_1"))) {
 			t.FailNow()
 		}
 		expect := map[string]string{
@@ -339,7 +339,7 @@ func TestDuplicateRowFromSingleRow(t *testing.T) {
 		}
 
 		assert.NoError(t, f.DuplicateRow(sheet, 2))
-		if !assert.NoError(t, f.SaveAs(fmt.Sprintf(outFile, "TestDuplicateRow.FromSingleRow_2"))) {
+		if !assert.NoError(t, f.SaveAs(fmt.Sprintf(outFile, "FromSingleRow_2"))) {
 			t.FailNow()
 		}
 		expect = map[string]string{
@@ -380,7 +380,7 @@ func TestDuplicateRowUpdateDuplicatedRows(t *testing.T) {
 		assert.NoError(t, f.SetCellStr(sheet, "A2", cells["A2"]))
 		assert.NoError(t, f.SetCellStr(sheet, "B2", cells["B2"]))
 
-		if !assert.NoError(t, f.SaveAs(fmt.Sprintf(outFile, "TestDuplicateRow.UpdateDuplicatedRows"))) {
+		if !assert.NoError(t, f.SaveAs(fmt.Sprintf(outFile, "UpdateDuplicatedRows"))) {
 			t.FailNow()
 		}
 		expect := map[string]string{
@@ -423,7 +423,7 @@ func TestDuplicateRowFirstOfMultipleRows(t *testing.T) {
 
 		assert.NoError(t, f.DuplicateRow(sheet, 1))
 
-		if !assert.NoError(t, f.SaveAs(fmt.Sprintf(outFile, "TestDuplicateRow.FirstOfMultipleRows"))) {
+		if !assert.NoError(t, f.SaveAs(fmt.Sprintf(outFile, "FirstOfMultipleRows"))) {
 			t.FailNow()
 		}
 		expect := map[string]string{
@@ -451,7 +451,7 @@ func TestDuplicateRowZeroWithNoRows(t *testing.T) {
 
 		assert.EqualError(t, f.DuplicateRow(sheet, 0), "invalid row number 0")
 
-		if !assert.NoError(t, f.SaveAs(fmt.Sprintf(outFile, "TestDuplicateRow.ZeroWithNoRows"))) {
+		if !assert.NoError(t, f.SaveAs(fmt.Sprintf(outFile, "ZeroWithNoRows"))) {
 			t.FailNow()
 		}
 
@@ -493,7 +493,7 @@ func TestDuplicateRowMiddleRowOfEmptyFile(t *testing.T) {
 
 		assert.NoError(t, f.DuplicateRow(sheet, 99))
 
-		if !assert.NoError(t, f.SaveAs(fmt.Sprintf(outFile, "TestDuplicateRow.MiddleRowOfEmptyFile"))) {
+		if !assert.NoError(t, f.SaveAs(fmt.Sprintf(outFile, "MiddleRowOfEmptyFile"))) {
 			t.FailNow()
 		}
 		expect := map[string]string{
@@ -537,7 +537,7 @@ func TestDuplicateRowWithLargeOffsetToMiddleOfData(t *testing.T) {
 
 		assert.NoError(t, f.DuplicateRowTo(sheet, 1, 3))
 
-		if !assert.NoError(t, f.SaveAs(fmt.Sprintf(outFile, "TestDuplicateRow.WithLargeOffsetToMiddleOfData"))) {
+		if !assert.NoError(t, f.SaveAs(fmt.Sprintf(outFile, "WithLargeOffsetToMiddleOfData"))) {
 			t.FailNow()
 		}
 		expect := map[string]string{
@@ -582,7 +582,7 @@ func TestDuplicateRowWithLargeOffsetToEmptyRows(t *testing.T) {
 
 		assert.NoError(t, f.DuplicateRowTo(sheet, 1, 7))
 
-		if !assert.NoError(t, f.SaveAs(fmt.Sprintf(outFile, "TestDuplicateRow.WithLargeOffsetToEmptyRows"))) {
+		if !assert.NoError(t, f.SaveAs(fmt.Sprintf(outFile, "WithLargeOffsetToEmptyRows"))) {
 			t.FailNow()
 		}
 		expect := map[string]string{
@@ -627,7 +627,7 @@ func TestDuplicateRowInsertBefore(t *testing.T) {
 
 		assert.NoError(t, f.DuplicateRowTo(sheet, 2, 1))
 
-		if !assert.NoError(t, f.SaveAs(fmt.Sprintf(outFile, "TestDuplicateRow.InsertBefore"))) {
+		if !assert.NoError(t, f.SaveAs(fmt.Sprintf(outFile, "InsertBefore"))) {
 			t.FailNow()
 		}
 
@@ -673,7 +673,7 @@ func TestDuplicateRowInsertBeforeWithLargeOffset(t *testing.T) {
 
 		assert.NoError(t, f.DuplicateRowTo(sheet, 3, 1))
 
-		if !assert.NoError(t, f.SaveAs(fmt.Sprintf(outFile, "TestDuplicateRow.InsertBeforeWithLargeOffset"))) {
+		if !assert.NoError(t, f.SaveAs(fmt.Sprintf(outFile, "InsertBeforeWithLargeOffset"))) {
 			t.FailNow()
 		}
 
@@ -722,7 +722,7 @@ func TestDuplicateRowInsertBeforeWithMergeCells(t *testing.T) {
 		assert.NoError(t, f.DuplicateRowTo(sheet, 2, 1))
 		assert.NoError(t, f.DuplicateRowTo(sheet, 1, 8))
 
-		if !assert.NoError(t, f.SaveAs(fmt.Sprintf(outFile, "TestDuplicateRow.InsertBeforeWithMergeCells"))) {
+		if !assert.NoError(t, f.SaveAs(fmt.Sprintf(outFile, "InsertBeforeWithMergeCells"))) {
 			t.FailNow()
 		}
 
@@ -742,9 +742,9 @@ func TestDuplicateRowInsertBeforeWithMergeCells(t *testing.T) {
 	})
 }
 
-func TestDuplicateRowInvalidRownum(t *testing.T) {
+func TestDuplicateRowInvalidRowNum(t *testing.T) {
 	const sheet = "Sheet1"
-	outFile := filepath.Join("test", "TestDuplicateRowInvalidRownum.%s.xlsx")
+	outFile := filepath.Join("test", "TestDuplicateRow.InvalidRowNum.%s.xlsx")
 
 	cells := map[string]string{
 		"A1": "A1 Value",