Merge branch 'formula'

1 files changed, 1867 insertions, 0 deletions

diff --git a/calc.go b/calc.go
new file mode 100644
index 0000000..2ab3d61
--- /dev/null
+++ b/calc.go
@@ -0,0 +1,1867 @@
+// Copyright 2016 - 2020 The excelize Authors. All rights reserved. Use of
+// this source code is governed by a BSD-style license that can be found in
+// the LICENSE file.
+//
+// Package excelize providing a set of functions that allow you to write to
+// and read from XLSX / XLSM / XLTM files. Supports reading and writing
+// spreadsheet documents generated by Microsoft Exce™ 2007 and later. Supports
+// complex components by high compatibility, and provided streaming API for
+// generating or reading data from a worksheet with huge amounts of data. This
+// library needs Go version 1.10 or later.
+
+package excelize
+
+import (
+	"container/list"
+	"errors"
+	"fmt"
+	"math"
+	"reflect"
+	"strconv"
+	"strings"
+
+	"github.com/xuri/efp"
+)
+
+// Excel formula errors
+const (
+	formulaErrorDIV         = "#DIV/0!"
+	formulaErrorNAME        = "#NAME?"
+	formulaErrorNA          = "#N/A"
+	formulaErrorNUM         = "#NUM!"
+	formulaErrorVALUE       = "#VALUE!"
+	formulaErrorREF         = "#REF!"
+	formulaErrorNULL        = "#NULL"
+	formulaErrorSPILL       = "#SPILL!"
+	formulaErrorCALC        = "#CALC!"
+	formulaErrorGETTINGDATA = "#GETTING_DATA"
+)
+
+// cellRef defines the structure of a cell reference.
+type cellRef struct {
+	Col   int
+	Row   int
+	Sheet string
+}
+
+// cellRef defines the structure of a cell range.
+type cellRange struct {
+	From cellRef
+	To   cellRef
+}
+
+// formulaArg is the argument of a formula or function.
+type formulaArg struct {
+	Value  string
+	Matrix []string
+}
+
+// formulaFuncs is the type of the formula functions.
+type formulaFuncs struct{}
+
+// CalcCellValue provides a function to get calculated cell value. This
+// feature is currently in beta. Array formula, table formula and some other
+// formulas are not supported currently.
+func (f *File) CalcCellValue(sheet, cell string) (result string, err error) {
+	var (
+		formula string
+		token   efp.Token
+	)
+	if formula, err = f.GetCellFormula(sheet, cell); err != nil {
+		return
+	}
+	ps := efp.ExcelParser()
+	tokens := ps.Parse(formula)
+	if tokens == nil {
+		return
+	}
+	if token, err = f.evalInfixExp(sheet, tokens); err != nil {
+		return
+	}
+	result = token.TValue
+	return
+}
+
+// getPriority calculate arithmetic operator priority.
+func getPriority(token efp.Token) (pri int) {
+	var priority = map[string]int{
+		"*": 2,
+		"/": 2,
+		"+": 1,
+		"-": 1,
+	}
+	pri, _ = priority[token.TValue]
+	if token.TValue == "-" && token.TType == efp.TokenTypeOperatorPrefix {
+		pri = 3
+	}
+	if token.TSubType == efp.TokenSubTypeStart && token.TType == efp.TokenTypeSubexpression { // (
+		pri = 0
+	}
+	return
+}
+
+// evalInfixExp evaluate syntax analysis by given infix expression after
+// lexical analysis. Evaluate an infix expression containing formulas by
+// stacks:
+//
+//    opd  - Operand
+//    opt  - Operator
+//    opf  - Operation formula
+//    opfd - Operand of the operation formula
+//    opft - Operator of the operation formula
+//
+// Evaluate arguments of the operation formula by list:
+//
+//    args - Arguments of the operation formula
+//
+// TODO: handle subtypes: Nothing, Text, Logical, Error, Concatenation, Intersection, Union
+//
+func (f *File) evalInfixExp(sheet string, tokens []efp.Token) (efp.Token, error) {
+	var err error
+	opdStack, optStack, opfStack, opfdStack, opftStack := NewStack(), NewStack(), NewStack(), NewStack(), NewStack()
+	argsList := list.New()
+	for i := 0; i < len(tokens); i++ {
+		token := tokens[i]
+
+		// out of function stack
+		if opfStack.Len() == 0 {
+			if err = f.parseToken(sheet, token, opdStack, optStack); err != nil {
+				return efp.Token{}, err
+			}
+		}
+
+		// function start
+		if token.TType == efp.TokenTypeFunction && token.TSubType == efp.TokenSubTypeStart {
+			opfStack.Push(token)
+			continue
+		}
+
+		// in function stack, walk 2 token at once
+		if opfStack.Len() > 0 {
+			var nextToken efp.Token
+			if i+1 < len(tokens) {
+				nextToken = tokens[i+1]
+			}
+
+			// current token is args or range, skip next token, order required: parse reference first
+			if token.TSubType == efp.TokenSubTypeRange {
+				if !opftStack.Empty() {
+					// parse reference: must reference at here
+					result, _, err := f.parseReference(sheet, token.TValue)
+					if err != nil {
+						return efp.Token{TValue: formulaErrorNAME}, err
+					}
+					if len(result) != 1 {
+						return efp.Token{}, errors.New(formulaErrorVALUE)
+					}
+					opfdStack.Push(efp.Token{
+						TType:    efp.TokenTypeOperand,
+						TSubType: efp.TokenSubTypeNumber,
+						TValue:   result[0],
+					})
+					continue
+				}
+				if nextToken.TType == efp.TokenTypeArgument || nextToken.TType == efp.TokenTypeFunction {
+					// parse reference: reference or range at here
+					result, matrix, err := f.parseReference(sheet, token.TValue)
+					if err != nil {
+						return efp.Token{TValue: formulaErrorNAME}, err
+					}
+					for idx, val := range result {
+						arg := formulaArg{Value: val}
+						if idx < len(matrix) {
+							arg.Matrix = matrix[idx]
+						}
+						argsList.PushBack(arg)
+					}
+					if len(result) == 0 {
+						return efp.Token{}, errors.New(formulaErrorVALUE)
+					}
+					continue
+				}
+			}
+
+			// check current token is opft
+			if err = f.parseToken(sheet, token, opfdStack, opftStack); err != nil {
+				return efp.Token{}, err
+			}
+
+			// current token is arg
+			if token.TType == efp.TokenTypeArgument {
+				for !opftStack.Empty() {
+					// calculate trigger
+					topOpt := opftStack.Peek().(efp.Token)
+					if err := calculate(opfdStack, topOpt); err != nil {
+						return efp.Token{}, err
+					}
+					opftStack.Pop()
+				}
+				if !opfdStack.Empty() {
+					argsList.PushBack(formulaArg{
+						Value: opfdStack.Pop().(efp.Token).TValue,
+					})
+				}
+				continue
+			}
+
+			// current token is logical
+			if token.TType == efp.OperatorsInfix && token.TSubType == efp.TokenSubTypeLogical {
+			}
+
+			// current token is text
+			if token.TType == efp.TokenTypeOperand && token.TSubType == efp.TokenSubTypeText {
+				argsList.PushBack(formulaArg{
+					Value: token.TValue,
+				})
+			}
+
+			// current token is function stop
+			if token.TType == efp.TokenTypeFunction && token.TSubType == efp.TokenSubTypeStop {
+				for !opftStack.Empty() {
+					// calculate trigger
+					topOpt := opftStack.Peek().(efp.Token)
+					if err := calculate(opfdStack, topOpt); err != nil {
+						return efp.Token{}, err
+					}
+					opftStack.Pop()
+				}
+
+				// push opfd to args
+				if opfdStack.Len() > 0 {
+					argsList.PushBack(formulaArg{
+						Value: opfdStack.Pop().(efp.Token).TValue,
+					})
+				}
+				// call formula function to evaluate
+				result, err := callFuncByName(&formulaFuncs{}, strings.NewReplacer(
+					"_xlfn", "", ".", "").Replace(opfStack.Peek().(efp.Token).TValue),
+					[]reflect.Value{reflect.ValueOf(argsList)})
+				if err != nil {
+					return efp.Token{}, err
+				}
+				argsList.Init()
+				opfStack.Pop()
+				if opfStack.Len() > 0 { // still in function stack
+					opfdStack.Push(efp.Token{TValue: result, TType: efp.TokenTypeOperand, TSubType: efp.TokenSubTypeNumber})
+				} else {
+					opdStack.Push(efp.Token{TValue: result, TType: efp.TokenTypeOperand, TSubType: efp.TokenSubTypeNumber})
+				}
+			}
+		}
+	}
+	for optStack.Len() != 0 {
+		topOpt := optStack.Peek().(efp.Token)
+		if err = calculate(opdStack, topOpt); err != nil {
+			return efp.Token{}, err
+		}
+		optStack.Pop()
+	}
+	return opdStack.Peek().(efp.Token), err
+}
+
+// calculate evaluate basic arithmetic operations.
+func calculate(opdStack *Stack, opt efp.Token) error {
+	if opt.TValue == "-" && opt.TType == efp.TokenTypeOperatorPrefix {
+		opd := opdStack.Pop().(efp.Token)
+		opdVal, err := strconv.ParseFloat(opd.TValue, 64)
+		if err != nil {
+			return err
+		}
+		result := 0 - opdVal
+		opdStack.Push(efp.Token{TValue: fmt.Sprintf("%g", result), TType: efp.TokenTypeOperand, TSubType: efp.TokenSubTypeNumber})
+	}
+	if opt.TValue == "+" {
+		rOpd := opdStack.Pop().(efp.Token)
+		lOpd := opdStack.Pop().(efp.Token)
+		lOpdVal, err := strconv.ParseFloat(lOpd.TValue, 64)
+		if err != nil {
+			return err
+		}
+		rOpdVal, err := strconv.ParseFloat(rOpd.TValue, 64)
+		if err != nil {
+			return err
+		}
+		result := lOpdVal + rOpdVal
+		opdStack.Push(efp.Token{TValue: fmt.Sprintf("%g", result), TType: efp.TokenTypeOperand, TSubType: efp.TokenSubTypeNumber})
+	}
+	if opt.TValue == "-" && opt.TType == efp.TokenTypeOperatorInfix {
+		rOpd := opdStack.Pop().(efp.Token)
+		lOpd := opdStack.Pop().(efp.Token)
+		lOpdVal, err := strconv.ParseFloat(lOpd.TValue, 64)
+		if err != nil {
+			return err
+		}
+		rOpdVal, err := strconv.ParseFloat(rOpd.TValue, 64)
+		if err != nil {
+			return err
+		}
+		result := lOpdVal - rOpdVal
+		opdStack.Push(efp.Token{TValue: fmt.Sprintf("%g", result), TType: efp.TokenTypeOperand, TSubType: efp.TokenSubTypeNumber})
+	}
+	if opt.TValue == "*" {
+		rOpd := opdStack.Pop().(efp.Token)
+		lOpd := opdStack.Pop().(efp.Token)
+		lOpdVal, err := strconv.ParseFloat(lOpd.TValue, 64)
+		if err != nil {
+			return err
+		}
+		rOpdVal, err := strconv.ParseFloat(rOpd.TValue, 64)
+		if err != nil {
+			return err
+		}
+		result := lOpdVal * rOpdVal
+		opdStack.Push(efp.Token{TValue: fmt.Sprintf("%g", result), TType: efp.TokenTypeOperand, TSubType: efp.TokenSubTypeNumber})
+	}
+	if opt.TValue == "/" {
+		rOpd := opdStack.Pop().(efp.Token)
+		lOpd := opdStack.Pop().(efp.Token)
+		lOpdVal, err := strconv.ParseFloat(lOpd.TValue, 64)
+		if err != nil {
+			return err
+		}
+		rOpdVal, err := strconv.ParseFloat(rOpd.TValue, 64)
+		if err != nil {
+			return err
+		}
+		result := lOpdVal / rOpdVal
+		if rOpdVal == 0 {
+			return errors.New(formulaErrorDIV)
+		}
+		opdStack.Push(efp.Token{TValue: fmt.Sprintf("%g", result), TType: efp.TokenTypeOperand, TSubType: efp.TokenSubTypeNumber})
+	}
+	return nil
+}
+
+// parseToken parse basic arithmetic operator priority and evaluate based on
+// operators and operands.
+func (f *File) parseToken(sheet string, token efp.Token, opdStack, optStack *Stack) error {
+	// parse reference: must reference at here
+	if token.TSubType == efp.TokenSubTypeRange {
+		result, _, err := f.parseReference(sheet, token.TValue)
+		if err != nil {
+			return errors.New(formulaErrorNAME)
+		}
+		if len(result) != 1 {
+			return errors.New(formulaErrorVALUE)
+		}
+		token.TValue = result[0]
+		token.TType = efp.TokenTypeOperand
+		token.TSubType = efp.TokenSubTypeNumber
+	}
+	if (token.TValue == "-" && token.TType == efp.TokenTypeOperatorPrefix) || token.TValue == "+" || token.TValue == "-" || token.TValue == "*" || token.TValue == "/" {
+		if optStack.Len() == 0 {
+			optStack.Push(token)
+		} else {
+			tokenPriority := getPriority(token)
+			topOpt := optStack.Peek().(efp.Token)
+			topOptPriority := getPriority(topOpt)
+			if tokenPriority > topOptPriority {
+				optStack.Push(token)
+			} else {
+				for tokenPriority <= topOptPriority {
+					optStack.Pop()
+					if err := calculate(opdStack, topOpt); err != nil {
+						return err
+					}
+					if optStack.Len() > 0 {
+						topOpt = optStack.Peek().(efp.Token)
+						topOptPriority = getPriority(topOpt)
+						continue
+					}
+					break
+				}
+				optStack.Push(token)
+			}
+		}
+	}
+	if token.TType == efp.TokenTypeSubexpression && token.TSubType == efp.TokenSubTypeStart { // (
+		optStack.Push(token)
+	}
+	if token.TType == efp.TokenTypeSubexpression && token.TSubType == efp.TokenSubTypeStop { // )
+		for optStack.Peek().(efp.Token).TSubType != efp.TokenSubTypeStart && optStack.Peek().(efp.Token).TType != efp.TokenTypeSubexpression { // != (
+			topOpt := optStack.Peek().(efp.Token)
+			if err := calculate(opdStack, topOpt); err != nil {
+				return err
+			}
+			optStack.Pop()
+		}
+		optStack.Pop()
+	}
+	// opd
+	if token.TType == efp.TokenTypeOperand && token.TSubType == efp.TokenSubTypeNumber {
+		opdStack.Push(token)
+	}
+	return nil
+}
+
+// parseReference parse reference and extract values by given reference
+// characters and default sheet name.
+func (f *File) parseReference(sheet, reference string) (result []string, matrix [][]string, err error) {
+	reference = strings.Replace(reference, "$", "", -1)
+	refs, cellRanges, cellRefs := list.New(), list.New(), list.New()
+	for _, ref := range strings.Split(reference, ":") {
+		tokens := strings.Split(ref, "!")
+		cr := cellRef{}
+		if len(tokens) == 2 { // have a worksheet name
+			cr.Sheet = tokens[0]
+			if cr.Col, cr.Row, err = CellNameToCoordinates(tokens[1]); err != nil {
+				return
+			}
+			if refs.Len() > 0 {
+				e := refs.Back()
+				cellRefs.PushBack(e.Value.(cellRef))
+				refs.Remove(e)
+			}
+			refs.PushBack(cr)
+			continue
+		}
+		if cr.Col, cr.Row, err = CellNameToCoordinates(tokens[0]); err != nil {
+			return
+		}
+		e := refs.Back()
+		if e == nil {
+			cr.Sheet = sheet
+			refs.PushBack(cr)
+			continue
+		}
+		cellRanges.PushBack(cellRange{
+			From: e.Value.(cellRef),
+			To:   cr,
+		})
+		refs.Remove(e)
+	}
+	if refs.Len() > 0 {
+		e := refs.Back()
+		cellRefs.PushBack(e.Value.(cellRef))
+		refs.Remove(e)
+	}
+
+	result, matrix, err = f.rangeResolver(cellRefs, cellRanges)
+	return
+}
+
+// rangeResolver extract value as string from given reference and range list.
+// This function will not ignore the empty cell. Note that the result of 3D
+// range references may be different from Excel in some cases, for example,
+// A1:A2:A2:B3 in Excel will include B1, but we wont.
+func (f *File) rangeResolver(cellRefs, cellRanges *list.List) (result []string, matrix [][]string, err error) {
+	filter := map[string]string{}
+	// extract value from ranges
+	for temp := cellRanges.Front(); temp != nil; temp = temp.Next() {
+		cr := temp.Value.(cellRange)
+		if cr.From.Sheet != cr.To.Sheet {
+			err = errors.New(formulaErrorVALUE)
+		}
+		rng := []int{cr.From.Col, cr.From.Row, cr.To.Col, cr.To.Row}
+		sortCoordinates(rng)
+		matrix = [][]string{}
+		for row := rng[1]; row <= rng[3]; row++ {
+			var matrixRow = []string{}
+			for col := rng[0]; col <= rng[2]; col++ {
+				var cell, value string
+				if cell, err = CoordinatesToCellName(col, row); err != nil {
+					return
+				}
+				if value, err = f.GetCellValue(cr.From.Sheet, cell); err != nil {
+					return
+				}
+				filter[cell] = value
+				matrixRow = append(matrixRow, value)
+			}
+			matrix = append(matrix, matrixRow)
+		}
+	}
+	// extract value from references
+	for temp := cellRefs.Front(); temp != nil; temp = temp.Next() {
+		cr := temp.Value.(cellRef)
+		var cell string
+		if cell, err = CoordinatesToCellName(cr.Col, cr.Row); err != nil {
+			return
+		}
+		if filter[cell], err = f.GetCellValue(cr.Sheet, cell); err != nil {
+			return
+		}
+	}
+
+	for _, val := range filter {
+		result = append(result, val)
+	}
+	return
+}
+
+// callFuncByName calls the no error or only error return function with
+// reflect by given receiver, name and parameters.
+func callFuncByName(receiver interface{}, name string, params []reflect.Value) (result string, err error) {
+	function := reflect.ValueOf(receiver).MethodByName(name)
+	if function.IsValid() {
+		rt := function.Call(params)
+		if len(rt) == 0 {
+			return
+		}
+		if !rt[1].IsNil() {
+			err = rt[1].Interface().(error)
+			return
+		}
+		result = rt[0].Interface().(string)
+		return
+	}
+	err = fmt.Errorf("not support %s function", name)
+	return
+}
+
+// Math and Trigonometric functions
+
+// ABS function returns the absolute value of any supplied number. The syntax
+// of the function is:
+//
+//   ABS(number)
+//
+func (fn *formulaFuncs) ABS(argsList *list.List) (result string, err error) {
+	if argsList.Len() != 1 {
+		err = errors.New("ABS requires 1 numeric argument")
+		return
+	}
+	var val float64
+	if val, err = strconv.ParseFloat(argsList.Front().Value.(formulaArg).Value, 64); err != nil {
+		return
+	}
+	result = fmt.Sprintf("%g", math.Abs(val))
+	return
+}
+
+// ACOS function calculates the arccosine (i.e. the inverse cosine) of a given
+// number, and returns an angle, in radians, between 0 and π. The syntax of
+// the function is:
+//
+//   ACOS(number)
+//
+func (fn *formulaFuncs) ACOS(argsList *list.List) (result string, err error) {
+	if argsList.Len() != 1 {
+		err = errors.New("ACOS requires 1 numeric argument")
+		return
+	}
+	var val float64
+	if val, err = strconv.ParseFloat(argsList.Front().Value.(formulaArg).Value, 64); err != nil {
+		return
+	}
+	result = fmt.Sprintf("%g", math.Acos(val))
+	return
+}
+
+// ACOSH function calculates the inverse hyperbolic cosine of a supplied number.
+// of the function is:
+//
+//   ACOSH(number)
+//
+func (fn *formulaFuncs) ACOSH(argsList *list.List) (result string, err error) {
+	if argsList.Len() != 1 {
+		err = errors.New("ACOSH requires 1 numeric argument")
+		return
+	}
+	var val float64
+	if val, err = strconv.ParseFloat(argsList.Front().Value.(formulaArg).Value, 64); err != nil {
+		return
+	}
+	result = fmt.Sprintf("%g", math.Acosh(val))
+	return
+}
+
+// ACOT function calculates the arccotangent (i.e. the inverse cotangent) of a
+// given number, and returns an angle, in radians, between 0 and π. The syntax
+// of the function is:
+//
+//   ACOT(number)
+//
+func (fn *formulaFuncs) ACOT(argsList *list.List) (result string, err error) {
+	if argsList.Len() != 1 {
+		err = errors.New("ACOT requires 1 numeric argument")
+		return
+	}
+	var val float64
+	if val, err = strconv.ParseFloat(argsList.Front().Value.(formulaArg).Value, 64); err != nil {
+		return
+	}
+	result = fmt.Sprintf("%g", math.Pi/2-math.Atan(val))
+	return
+}
+
+// ACOTH function calculates the hyperbolic arccotangent (coth) of a supplied
+// value. The syntax of the function is:
+//
+//   ACOTH(number)
+//
+func (fn *formulaFuncs) ACOTH(argsList *list.List) (result string, err error) {
+	if argsList.Len() != 1 {
+		err = errors.New("ACOTH requires 1 numeric argument")
+		return
+	}
+	var val float64
+	if val, err = strconv.ParseFloat(argsList.Front().Value.(formulaArg).Value, 64); err != nil {
+		return
+	}
+	result = fmt.Sprintf("%g", math.Atanh(1/val))
+	return
+}
+
+// ARABIC function converts a Roman numeral into an Arabic numeral. The syntax
+// of the function is:
+//
+//   ARABIC(text)
+//
+func (fn *formulaFuncs) ARABIC(argsList *list.List) (result string, err error) {
+	if argsList.Len() != 1 {
+		err = errors.New("ARABIC requires 1 numeric argument")
+		return
+	}
+	val, last, prefix := 0.0, 0.0, 1.0
+	for _, char := range argsList.Front().Value.(formulaArg).Value {
+		digit := 0.0
+		switch char {
+		case '-':
+			prefix = -1
+			continue
+		case 'I':
+			digit = 1
+		case 'V':
+			digit = 5
+		case 'X':
+			digit = 10
+		case 'L':
+			digit = 50
+		case 'C':
+			digit = 100
+		case 'D':
+			digit = 500
+		case 'M':
+			digit = 1000
+		}
+		val += digit
+		switch {
+		case last == digit && (last == 5 || last == 50 || last == 500):
+			result = formulaErrorVALUE
+			return
+		case 2*last == digit:
+			result = formulaErrorVALUE
+			return
+		}
+		if last < digit {
+			val -= 2 * last
+		}
+		last = digit
+	}
+	result = fmt.Sprintf("%g", prefix*val)
+	return
+}
+
+// ASIN function calculates the arcsine (i.e. the inverse sine) of a given
+// number, and returns an angle, in radians, between -π/2 and π/2. The syntax
+// of the function is:
+//
+//   ASIN(number)
+//
+func (fn *formulaFuncs) ASIN(argsList *list.List) (result string, err error) {
+	if argsList.Len() != 1 {
+		err = errors.New("ASIN requires 1 numeric argument")
+		return
+	}
+	var val float64
+	if val, err = strconv.ParseFloat(argsList.Front().Value.(formulaArg).Value, 64); err != nil {
+		return
+	}
+	result = fmt.Sprintf("%g", math.Asin(val))
+	return
+}
+
+// ASINH function calculates the inverse hyperbolic sine of a supplied number.
+// The syntax of the function is:
+//
+//   ASINH(number)
+//
+func (fn *formulaFuncs) ASINH(argsList *list.List) (result string, err error) {
+	if argsList.Len() != 1 {
+		err = errors.New("ASINH requires 1 numeric argument")
+		return
+	}
+	var val float64
+	if val, err = strconv.ParseFloat(argsList.Front().Value.(formulaArg).Value, 64); err != nil {
+		return
+	}
+	result = fmt.Sprintf("%g", math.Asinh(val))
+	return
+}
+
+// ATAN function calculates the arctangent (i.e. the inverse tangent) of a
+// given number, and returns an angle, in radians, between -π/2 and +π/2. The
+// syntax of the function is:
+//
+//   ATAN(number)
+//
+func (fn *formulaFuncs) ATAN(argsList *list.List) (result string, err error) {
+	if argsList.Len() != 1 {
+		err = errors.New("ATAN requires 1 numeric argument")
+		return
+	}
+	var val float64
+	if val, err = strconv.ParseFloat(argsList.Front().Value.(formulaArg).Value, 64); err != nil {
+		return
+	}
+	result = fmt.Sprintf("%g", math.Atan(val))
+	return
+}
+
+// ATANH function calculates the inverse hyperbolic tangent of a supplied
+// number. The syntax of the function is:
+//
+//   ATANH(number)
+//
+func (fn *formulaFuncs) ATANH(argsList *list.List) (result string, err error) {
+	if argsList.Len() != 1 {
+		err = errors.New("ATANH requires 1 numeric argument")
+		return
+	}
+	var val float64
+	if val, err = strconv.ParseFloat(argsList.Front().Value.(formulaArg).Value, 64); err != nil {
+		return
+	}
+	result = fmt.Sprintf("%g", math.Atanh(val))
+	return
+}
+
+// ATAN2 function calculates the arctangent (i.e. the inverse tangent) of a
+// 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)
+//
+func (fn *formulaFuncs) ATAN2(argsList *list.List) (result string, err error) {
+	if argsList.Len() != 2 {
+		err = errors.New("ATAN2 requires 2 numeric arguments")
+		return
+	}
+	var x, y float64
+	if x, err = strconv.ParseFloat(argsList.Back().Value.(formulaArg).Value, 64); err != nil {
+		return
+	}
+	if y, err = strconv.ParseFloat(argsList.Front().Value.(formulaArg).Value, 64); err != nil {
+		return
+	}
+	result = fmt.Sprintf("%g", math.Atan2(x, y))
+	return
+}
+
+// gcd returns the greatest common divisor of two supplied integers.
+func gcd(x, y float64) float64 {
+	x, y = math.Trunc(x), math.Trunc(y)
+	if x == 0 {
+		return y
+	}
+	if y == 0 {
+		return x
+	}
+	for x != y {
+		if x > y {
+			x = x - y
+		} else {
+			y = y - x
+		}
+	}
+	return x
+}
+
+// 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])
+//
+func (fn *formulaFuncs) BASE(argsList *list.List) (result string, err error) {
+	if argsList.Len() < 2 {
+		err = errors.New("BASE requires at least 2 arguments")
+		return
+	}
+	if argsList.Len() > 3 {
+		err = errors.New("BASE allows at most 3 arguments")
+		return
+	}
+	var number float64
+	var radix, minLength int
+	if number, err = strconv.ParseFloat(argsList.Front().Value.(formulaArg).Value, 64); err != nil {
+		return
+	}
+	if radix, err = strconv.Atoi(argsList.Front().Next().Value.(formulaArg).Value); err != nil {
+		return
+	}
+	if radix < 2 || radix > 36 {
+		err = errors.New("radix must be an integer ≥ 2 and ≤ 36")
+		return
+	}
+	if argsList.Len() > 2 {
+		if minLength, err = strconv.Atoi(argsList.Back().Value.(formulaArg).Value); err != nil {
+			return
+		}
+	}
+	result = strconv.FormatInt(int64(number), radix)
+	if len(result) < minLength {
+		result = strings.Repeat("0", minLength-len(result)) + result
+	}
+	result = strings.ToUpper(result)
+	return
+}
+
+// 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)
+//
+func (fn *formulaFuncs) CEILING(argsList *list.List) (result string, err error) {
+	if argsList.Len() == 0 {
+		err = errors.New("CEILING requires at least 1 argument")
+		return
+	}
+	if argsList.Len() > 2 {
+		err = errors.New("CEILING allows at most 2 arguments")
+		return
+	}
+	var number, significance float64 = 0, 1
+	if number, err = strconv.ParseFloat(argsList.Front().Value.(formulaArg).Value, 64); err != nil {
+		return
+	}
+	if number < 0 {
+		significance = -1
+	}
+	if argsList.Len() > 1 {
+		if significance, err = strconv.ParseFloat(argsList.Back().Value.(formulaArg).Value, 64); err != nil {
+			return
+		}
+	}
+	if significance < 0 && number > 0 {
+		err = errors.New("negative sig to CEILING invalid")
+		return
+	}
+	if argsList.Len() == 1 {
+		result = fmt.Sprintf("%g", math.Ceil(number))
+		return
+	}
+	number, res := math.Modf(number / significance)
+	if res > 0 {
+		number++
+	}
+	result = fmt.Sprintf("%g", number*significance)
+	return
+}
+
+// CEILINGMATH function rounds a supplied number up to a supplied multiple of
+// significance. The syntax of the function is:
+//
+//   CEILING.MATH(number,[significance],[mode])
+//
+func (fn *formulaFuncs) CEILINGMATH(argsList *list.List) (result string, err error) {
+	if argsList.Len() == 0 {
+		err = errors.New("CEILING.MATH requires at least 1 argument")
+		return
+	}
+	if argsList.Len() > 3 {
+		err = errors.New("CEILING.MATH allows at most 3 arguments")
+		return
+	}
+	var number, significance, mode float64 = 0, 1, 1
+	if number, err = strconv.ParseFloat(argsList.Front().Value.(formulaArg).Value, 64); err != nil {
+		return
+	}
+	if number < 0 {
+		significance = -1
+	}
+	if argsList.Len() > 1 {
+		if significance, err = strconv.ParseFloat(argsList.Front().Next().Value.(formulaArg).Value, 64); err != nil {
+			return
+		}
+	}
+	if argsList.Len() == 1 {
+		result = fmt.Sprintf("%g", math.Ceil(number))
+		return
+	}
+	if argsList.Len() > 2 {
+		if mode, err = strconv.ParseFloat(argsList.Back().Value.(formulaArg).Value, 64); err != nil {
+			return
+		}
+	}
+	val, res := math.Modf(number / significance)
+	if res != 0 {
+		if number > 0 {
+			val++
+		} else if mode < 0 {
+			val--
+		}
+	}
+	result = fmt.Sprintf("%g", val*significance)
+	return
+}
+
+// CEILINGPRECISE function rounds a supplied number up (regardless of the
+// number's sign), to the nearest multiple of a given number. The syntax of
+// the function is:
+//
+//   CEILING.PRECISE(number,[significance])
+//
+func (fn *formulaFuncs) CEILINGPRECISE(argsList *list.List) (result string, err error) {
+	if argsList.Len() == 0 {
+		err = errors.New("CEILING.PRECISE requires at least 1 argument")
+		return
+	}
+	if argsList.Len() > 2 {
+		err = errors.New("CEILING.PRECISE allows at most 2 arguments")
+		return
+	}
+	var number, significance float64 = 0, 1
+	if number, err = strconv.ParseFloat(argsList.Front().Value.(formulaArg).Value, 64); err != nil {
+		return
+	}
+	if number < 0 {
+		significance = -1
+	}
+	if argsList.Len() == 1 {
+		result = fmt.Sprintf("%g", math.Ceil(number))
+		return
+	}
+	if argsList.Len() > 1 {
+		if significance, err = strconv.ParseFloat(argsList.Back().Value.(formulaArg).Value, 64); err != nil {
+			return
+		}
+		significance = math.Abs(significance)
+		if significance == 0 {
+			result = "0"
+			return
+		}
+	}
+	val, res := math.Modf(number / significance)
+	if res != 0 {
+		if number > 0 {
+			val++
+		}
+	}
+	result = fmt.Sprintf("%g", val*significance)
+	return
+}
+
+// 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)
+//
+func (fn *formulaFuncs) COMBIN(argsList *list.List) (result string, err error) {
+	if argsList.Len() != 2 {
+		err = errors.New("COMBIN requires 2 argument")
+		return
+	}
+	var number, chosen, val float64 = 0, 0, 1
+	if number, err = strconv.ParseFloat(argsList.Front().Value.(formulaArg).Value, 64); err != nil {
+		return
+	}
+	if chosen, err = strconv.ParseFloat(argsList.Back().Value.(formulaArg).Value, 64); err != nil {
+		return
+	}
+	number, chosen = math.Trunc(number), math.Trunc(chosen)
+	if chosen > number {
+		err = errors.New("COMBIN requires number >= number_chosen")
+		return
+	}
+	if chosen == number || chosen == 0 {
+		result = "1"
+		return
+	}
+	for c := float64(1); c <= chosen; c++ {
+		val *= (number + 1 - c) / c
+	}
+	result = fmt.Sprintf("%g", math.Ceil(val))
+	return
+}
+
+// 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)
+//
+func (fn *formulaFuncs) COMBINA(argsList *list.List) (result string, err error) {
+	if argsList.Len() != 2 {
+		err = errors.New("COMBINA requires 2 argument")
+		return
+	}
+	var number, chosen float64
+	if number, err = strconv.ParseFloat(argsList.Front().Value.(formulaArg).Value, 64); err != nil {
+		return
+	}
+	if chosen, err = strconv.ParseFloat(argsList.Back().Value.(formulaArg).Value, 64); err != nil {
+		return
+	}
+	number, chosen = math.Trunc(number), math.Trunc(chosen)
+	if number < chosen {
+		err = errors.New("COMBINA requires number > number_chosen")
+		return
+	}
+	if number == 0 {
+		result = "0"
+		return
+	}
+	args := list.New()
+	args.PushBack(formulaArg{
+		Value: fmt.Sprintf("%g", number+chosen-1),
+	})
+	args.PushBack(formulaArg{
+		Value: fmt.Sprintf("%g", number-1),
+	})
+	return fn.COMBIN(args)
+}
+
+// COS function calculates the cosine of a given angle. The syntax of the
+// function is:
+//
+//   COS(number)
+//
+func (fn *formulaFuncs) COS(argsList *list.List) (result string, err error) {
+	if argsList.Len() != 1 {
+		err = errors.New("COS requires 1 numeric argument")
+		return
+	}
+	var val float64
+	if val, err = strconv.ParseFloat(argsList.Front().Value.(formulaArg).Value, 64); err != nil {
+		return
+	}
+	result = fmt.Sprintf("%g", math.Cos(val))
+	return
+}
+
+// COSH function calculates the hyperbolic cosine (cosh) of a supplied number.
+// The syntax of the function is:
+//
+//   COSH(number)
+//
+func (fn *formulaFuncs) COSH(argsList *list.List) (result string, err error) {
+	if argsList.Len() != 1 {
+		err = errors.New("COSH requires 1 numeric argument")
+		return
+	}
+	var val float64
+	if val, err = strconv.ParseFloat(argsList.Front().Value.(formulaArg).Value, 64); err != nil {
+		return
+	}
+	result = fmt.Sprintf("%g", math.Cosh(val))
+	return
+}
+
+// COT function calculates the cotangent of a given angle. The syntax of the
+// function is:
+//
+//   COT(number)
+//
+func (fn *formulaFuncs) COT(argsList *list.List) (result string, err error) {
+	if argsList.Len() != 1 {
+		err = errors.New("COT requires 1 numeric argument")
+		return
+	}
+	var val float64
+	if val, err = strconv.ParseFloat(argsList.Front().Value.(formulaArg).Value, 64); err != nil {
+		return
+	}
+	if val == 0 {
+		err = errors.New(formulaErrorNAME)
+		return
+	}
+	result = fmt.Sprintf("%g", math.Tan(val))
+	return
+}
+
+// COTH function calculates the hyperbolic cotangent (coth) of a supplied
+// angle. The syntax of the function is:
+//
+//   COTH(number)
+//
+func (fn *formulaFuncs) COTH(argsList *list.List) (result string, err error) {
+	if argsList.Len() != 1 {
+		err = errors.New("COTH requires 1 numeric argument")
+		return
+	}
+	var val float64
+	if val, err = strconv.ParseFloat(argsList.Front().Value.(formulaArg).Value, 64); err != nil {
+		return
+	}
+	if val == 0 {
+		err = errors.New(formulaErrorNAME)
+		return
+	}
+	result = fmt.Sprintf("%g", math.Tanh(val))
+	return
+}
+
+// CSC function calculates the cosecant of a given angle. The syntax of the
+// function is:
+//
+//   CSC(number)
+//
+func (fn *formulaFuncs) CSC(argsList *list.List) (result string, err error) {
+	if argsList.Len() != 1 {
+		err = errors.New("CSC requires 1 numeric argument")
+		return
+	}
+	var val float64
+	if val, err = strconv.ParseFloat(argsList.Front().Value.(formulaArg).Value, 64); err != nil {
+		return
+	}
+	if val == 0 {
+		err = errors.New(formulaErrorNAME)
+		return
+	}
+	result = fmt.Sprintf("%g", 1/math.Sin(val))
+	return
+}
+
+// CSCH function calculates the hyperbolic cosecant (csch) of a supplied
+// angle. The syntax of the function is:
+//
+//   CSCH(number)
+//
+func (fn *formulaFuncs) CSCH(argsList *list.List) (result string, err error) {
+	if argsList.Len() != 1 {
+		err = errors.New("CSCH requires 1 numeric argument")
+		return
+	}
+	var val float64
+	if val, err = strconv.ParseFloat(argsList.Front().Value.(formulaArg).Value, 64); err != nil {
+		return
+	}
+	if val == 0 {
+		err = errors.New(formulaErrorNAME)
+		return
+	}
+	result = fmt.Sprintf("%g", 1/math.Sinh(val))
+	return
+}
+
+// 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)
+//
+func (fn *formulaFuncs) DECIMAL(argsList *list.List) (result string, err error) {
+	if argsList.Len() != 2 {
+		err = errors.New("DECIMAL requires 2 numeric arguments")
+		return
+	}
+	var text = argsList.Front().Value.(formulaArg).Value
+	var radix int
+	if radix, err = strconv.Atoi(argsList.Back().Value.(formulaArg).Value); err != nil {
+		return
+	}
+	if len(text) > 2 && (strings.HasPrefix(text, "0x") || strings.HasPrefix(text, "0X")) {
+		text = text[2:]
+	}
+	val, err := strconv.ParseInt(text, radix, 64)
+	if err != nil {
+		err = errors.New(formulaErrorNUM)
+		return
+	}
+	result = fmt.Sprintf("%g", float64(val))
+	return
+}
+
+// DEGREES function converts radians into degrees. The syntax of the function
+// is:
+//
+//   DEGREES(angle)
+//
+func (fn *formulaFuncs) DEGREES(argsList *list.List) (result string, err error) {
+	if argsList.Len() != 1 {
+		err = errors.New("DEGREES requires 1 numeric argument")
+		return
+	}
+	var val float64
+	if val, err = strconv.ParseFloat(argsList.Front().Value.(formulaArg).Value, 64); err != nil {
+		return
+	}
+	if val == 0 {
+		err = errors.New(formulaErrorNAME)
+		return
+	}
+	result = fmt.Sprintf("%g", 180.0/math.Pi*val)
+	return
+}
+
+// EVEN function rounds a supplied number away from zero (i.e. rounds a
+// positive number up and a negative number down), to the next even number.
+// The syntax of the function is:
+//
+//   EVEN(number)
+//
+func (fn *formulaFuncs) EVEN(argsList *list.List) (result string, err error) {
+	if argsList.Len() != 1 {
+		err = errors.New("EVEN requires 1 numeric argument")
+		return
+	}
+	var number float64
+	if number, err = strconv.ParseFloat(argsList.Front().Value.(formulaArg).Value, 64); err != nil {
+		return
+	}
+	sign := math.Signbit(number)
+	m, frac := math.Modf(number / 2)
+	val := m * 2
+	if frac != 0 {
+		if !sign {
+			val += 2
+		} else {
+			val -= 2
+		}
+	}
+	result = fmt.Sprintf("%g", val)
+	return
+}
+
+// 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)
+//
+func (fn *formulaFuncs) EXP(argsList *list.List) (result string, err error) {
+	if argsList.Len() != 1 {
+		err = errors.New("EXP requires 1 numeric argument")
+		return
+	}
+	var number float64
+	if number, err = strconv.ParseFloat(argsList.Front().Value.(formulaArg).Value, 64); err != nil {
+		return
+	}
+	result = strings.ToUpper(fmt.Sprintf("%g", math.Exp(number)))
+	return
+}
+
+// fact returns the factorial of a supplied number.
+func fact(number float64) float64 {
+	val := float64(1)
+	for i := float64(2); i <= number; i++ {
+		val *= i
+	}
+	return val
+}
+
+// FACT function returns the factorial of a supplied number. The syntax of the
+// function is:
+//
+//   FACT(number)
+//
+func (fn *formulaFuncs) FACT(argsList *list.List) (result string, err error) {
+	if argsList.Len() != 1 {
+		err = errors.New("FACT requires 1 numeric argument")
+		return
+	}
+	var number float64
+	if number, err = strconv.ParseFloat(argsList.Front().Value.(formulaArg).Value, 64); err != nil {
+		return
+	}
+	if number < 0 {
+		err = errors.New(formulaErrorNUM)
+	}
+	result = strings.ToUpper(fmt.Sprintf("%g", fact(number)))
+	return
+}
+
+// FACTDOUBLE function returns the double factorial of a supplied number. The
+// syntax of the function is:
+//
+//   FACTDOUBLE(number)
+//
+func (fn *formulaFuncs) FACTDOUBLE(argsList *list.List) (result string, err error) {
+	if argsList.Len() != 1 {
+		err = errors.New("FACTDOUBLE requires 1 numeric argument")
+		return
+	}
+	var number, val float64 = 0, 1
+	if number, err = strconv.ParseFloat(argsList.Front().Value.(formulaArg).Value, 64); err != nil {
+		return
+	}
+	if number < 0 {
+		err = errors.New(formulaErrorNUM)
+	}
+	for i := math.Trunc(number); i > 1; i -= 2 {
+		val *= i
+	}
+	result = strings.ToUpper(fmt.Sprintf("%g", val))
+	return
+}
+
+// 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)
+//
+func (fn *formulaFuncs) FLOOR(argsList *list.List) (result string, err error) {
+	if argsList.Len() != 2 {
+		err = errors.New("FLOOR requires 2 numeric arguments")
+		return
+	}
+	var number, significance float64 = 0, 1
+	if number, err = strconv.ParseFloat(argsList.Front().Value.(formulaArg).Value, 64); err != nil {
+		return
+	}
+	if significance, err = strconv.ParseFloat(argsList.Back().Value.(formulaArg).Value, 64); err != nil {
+		return
+	}
+	if significance < 0 && number >= 0 {
+		err = errors.New(formulaErrorNUM)
+	}
+	val := number
+	val, res := math.Modf(val / significance)
+	if res != 0 {
+		if number < 0 && res < 0 {
+			val--
+		}
+	}
+	result = strings.ToUpper(fmt.Sprintf("%g", val*significance))
+	return
+}
+
+// FLOORMATH function rounds a supplied number down to a supplied multiple of
+// significance. The syntax of the function is:
+//
+//   FLOOR.MATH(number,[significance],[mode])
+//
+func (fn *formulaFuncs) FLOORMATH(argsList *list.List) (result string, err error) {
+	if argsList.Len() == 0 {
+		err = errors.New("FLOOR.MATH requires at least 1 argument")
+		return
+	}
+	if argsList.Len() > 3 {
+		err = errors.New("FLOOR.MATH allows at most 3 arguments")
+		return
+	}
+	var number, significance, mode float64 = 0, 1, 1
+	if number, err = strconv.ParseFloat(argsList.Front().Value.(formulaArg).Value, 64); err != nil {
+		return
+	}
+	if number < 0 {
+		significance = -1
+	}
+	if argsList.Len() > 1 {
+		if significance, err = strconv.ParseFloat(argsList.Front().Next().Value.(formulaArg).Value, 64); err != nil {
+			return
+		}
+	}
+	if argsList.Len() == 1 {
+		result = fmt.Sprintf("%g", math.Floor(number))
+		return
+	}
+	if argsList.Len() > 2 {
+		if mode, err = strconv.ParseFloat(argsList.Back().Value.(formulaArg).Value, 64); err != nil {
+			return
+		}
+	}
+	val, res := math.Modf(number / significance)
+	if res != 0 && number < 0 && mode > 0 {
+		val--
+	}
+	result = fmt.Sprintf("%g", val*significance)
+	return
+}
+
+// FLOORPRECISE function rounds a supplied number down to a supplied multiple
+// of significance. The syntax of the function is:
+//
+//   FLOOR.PRECISE(number,[significance])
+//
+func (fn *formulaFuncs) FLOORPRECISE(argsList *list.List) (result string, err error) {
+	if argsList.Len() == 0 {
+		err = errors.New("FLOOR.PRECISE requires at least 1 argument")
+		return
+	}
+	if argsList.Len() > 2 {
+		err = errors.New("FLOOR.PRECISE allows at most 2 arguments")
+		return
+	}
+	var number, significance float64 = 0, 1
+	if number, err = strconv.ParseFloat(argsList.Front().Value.(formulaArg).Value, 64); err != nil {
+		return
+	}
+	if number < 0 {
+		significance = -1
+	}
+	if argsList.Len() == 1 {
+		result = fmt.Sprintf("%g", math.Floor(number))
+		return
+	}
+	if argsList.Len() > 1 {
+		if significance, err = strconv.ParseFloat(argsList.Back().Value.(formulaArg).Value, 64); err != nil {
+			return
+		}
+		significance = math.Abs(significance)
+		if significance == 0 {
+			result = "0"
+			return
+		}
+	}
+	val, res := math.Modf(number / significance)
+	if res != 0 {
+		if number < 0 {
+			val--
+		}
+	}
+	result = fmt.Sprintf("%g", val*significance)
+	return
+}
+
+// GCD function returns the greatest common divisor of two or more supplied
+// integers. The syntax of the function is:
+//
+//   GCD(number1,[number2],...)
+//
+func (fn *formulaFuncs) GCD(argsList *list.List) (result string, err error) {
+	if argsList.Len() == 0 {
+		err = errors.New("GCD requires at least 1 argument")
+		return
+	}
+	var (
+		val  float64
+		nums = []float64{}
+	)
+	for arg := argsList.Front(); arg != nil; arg = arg.Next() {
+		token := arg.Value.(formulaArg).Value
+		if token == "" {
+			continue
+		}
+		if val, err = strconv.ParseFloat(token, 64); err != nil {
+			return
+		}
+		nums = append(nums, val)
+	}
+	if nums[0] < 0 {
+		err = errors.New("GCD only accepts positive arguments")
+		return
+	}
+	if len(nums) == 1 {
+		result = fmt.Sprintf("%g", nums[0])
+		return
+	}
+	cd := nums[0]
+	for i := 1; i < len(nums); i++ {
+		if nums[i] < 0 {
+			err = errors.New("GCD only accepts positive arguments")
+			return
+		}
+		cd = gcd(cd, nums[i])
+	}
+	result = fmt.Sprintf("%g", cd)
+	return
+}
+
+// INT function truncates a supplied number down to the closest integer. The
+// syntax of the function is:
+//
+//   INT(number)
+//
+func (fn *formulaFuncs) INT(argsList *list.List) (result string, err error) {
+	if argsList.Len() != 1 {
+		err = errors.New("INT requires 1 numeric argument")
+		return
+	}
+	var number float64
+	if number, err = strconv.ParseFloat(argsList.Front().Value.(formulaArg).Value, 64); err != nil {
+		return
+	}
+	val, frac := math.Modf(number)
+	if frac < 0 {
+		val--
+	}
+	result = fmt.Sprintf("%g", val)
+	return
+}
+
+// ISOCEILING function rounds a supplied number up (regardless of the number's
+// sign), to the nearest multiple of a supplied significance. The syntax of
+// the function is:
+//
+//   ISO.CEILING(number,[significance])
+//
+func (fn *formulaFuncs) ISOCEILING(argsList *list.List) (result string, err error) {
+	if argsList.Len() == 0 {
+		err = errors.New("ISO.CEILING requires at least 1 argument")
+		return
+	}
+	if argsList.Len() > 2 {
+		err = errors.New("ISO.CEILING allows at most 2 arguments")
+		return
+	}
+	var number, significance float64 = 0, 1
+	if number, err = strconv.ParseFloat(argsList.Front().Value.(formulaArg).Value, 64); err != nil {
+		return
+	}
+	if number < 0 {
+		significance = -1
+	}
+	if argsList.Len() == 1 {
+		result = fmt.Sprintf("%g", math.Ceil(number))
+		return
+	}
+	if argsList.Len() > 1 {
+		if significance, err = strconv.ParseFloat(argsList.Back().Value.(formulaArg).Value, 64); err != nil {
+			return
+		}
+		significance = math.Abs(significance)
+		if significance == 0 {
+			result = "0"
+			return
+		}
+	}
+	val, res := math.Modf(number / significance)
+	if res != 0 {
+		if number > 0 {
+			val++
+		}
+	}
+	result = fmt.Sprintf("%g", val*significance)
+	return
+}
+
+// lcm returns the least common multiple of two supplied integers.
+func lcm(a, b float64) float64 {
+	a = math.Trunc(a)
+	b = math.Trunc(b)
+	if a == 0 && b == 0 {
+		return 0
+	}
+	return a * b / gcd(a, b)
+}
+
+// LCM function returns the least common multiple of two or more supplied
+// integers. The syntax of the function is:
+//
+//   LCM(number1,[number2],...)
+//
+func (fn *formulaFuncs) LCM(argsList *list.List) (result string, err error) {
+	if argsList.Len() == 0 {
+		err = errors.New("LCM requires at least 1 argument")
+		return
+	}
+	var (
+		val  float64
+		nums = []float64{}
+	)
+	for arg := argsList.Front(); arg != nil; arg = arg.Next() {
+		token := arg.Value.(formulaArg).Value
+		if token == "" {
+			continue
+		}
+		if val, err = strconv.ParseFloat(token, 64); err != nil {
+			return
+		}
+		nums = append(nums, val)
+	}
+	if nums[0] < 0 {
+		err = errors.New("LCM only accepts positive arguments")
+		return
+	}
+	if len(nums) == 1 {
+		result = fmt.Sprintf("%g", nums[0])
+		return
+	}
+	cm := nums[0]
+	for i := 1; i < len(nums); i++ {
+		if nums[i] < 0 {
+			err = errors.New("LCM only accepts positive arguments")
+			return
+		}
+		cm = lcm(cm, nums[i])
+	}
+	result = fmt.Sprintf("%g", cm)
+	return
+}
+
+// LN function calculates the natural logarithm of a given number. The syntax
+// of the function is:
+//
+//   LN(number)
+//
+func (fn *formulaFuncs) LN(argsList *list.List) (result string, err error) {
+	if argsList.Len() != 1 {
+		err = errors.New("LN requires 1 numeric argument")
+		return
+	}
+	var number float64
+	if number, err = strconv.ParseFloat(argsList.Front().Value.(formulaArg).Value, 64); err != nil {
+		return
+	}
+	result = fmt.Sprintf("%g", math.Log(number))
+	return
+}
+
+// LOG function calculates the logarithm of a given number, to a supplied
+// base. The syntax of the function is:
+//
+//   LOG(number,[base])
+//
+func (fn *formulaFuncs) LOG(argsList *list.List) (result string, err error) {
+	if argsList.Len() == 0 {
+		err = errors.New("LOG requires at least 1 argument")
+		return
+	}
+	if argsList.Len() > 2 {
+		err = errors.New("LOG allows at most 2 arguments")
+		return
+	}
+	var number, base float64 = 0, 10
+	if number, err = strconv.ParseFloat(argsList.Front().Value.(formulaArg).Value, 64); err != nil {
+		return
+	}
+	if argsList.Len() > 1 {
+		if base, err = strconv.ParseFloat(argsList.Back().Value.(formulaArg).Value, 64); err != nil {
+			return
+		}
+	}
+	if number == 0 {
+		err = errors.New(formulaErrorNUM)
+		return
+	}
+	if base == 0 {
+		err = errors.New(formulaErrorNUM)
+		return
+	}
+	if base == 1 {
+		err = errors.New(formulaErrorDIV)
+		return
+	}
+	result = fmt.Sprintf("%g", math.Log(number)/math.Log(base))
+	return
+}
+
+// LOG10 function calculates the base 10 logarithm of a given number. The
+// syntax of the function is:
+//
+//   LOG10(number)
+//
+func (fn *formulaFuncs) LOG10(argsList *list.List) (result string, err error) {
+	if argsList.Len() != 1 {
+		err = errors.New("LOG10 requires 1 numeric argument")
+		return
+	}
+	var number float64
+	if number, err = strconv.ParseFloat(argsList.Front().Value.(formulaArg).Value, 64); err != nil {
+		return
+	}
+	result = fmt.Sprintf("%g", math.Log10(number))
+	return
+}
+
+func minor(sqMtx [][]float64, idx int) [][]float64 {
+	ret := [][]float64{}
+	for i := range sqMtx {
+		if i == 0 {
+			continue
+		}
+		row := []float64{}
+		for j := range sqMtx {
+			if j == idx {
+				continue
+			}
+			row = append(row, sqMtx[i][j])
+		}
+		ret = append(ret, row)
+	}
+	return ret
+}
+
+// det determinant of the 2x2 matrix.
+func det(sqMtx [][]float64) float64 {
+	if len(sqMtx) == 2 {
+		m00 := sqMtx[0][0]
+		m01 := sqMtx[0][1]
+		m10 := sqMtx[1][0]
+		m11 := sqMtx[1][1]
+		return m00*m11 - m10*m01
+	}
+	var res, sgn float64 = 0, 1
+	for j := range sqMtx {
+		res += sgn * sqMtx[0][j] * det(minor(sqMtx, j))
+		sgn *= -1
+	}
+	return res
+}
+
+// MDETERM calculates the determinant of a square matrix. The
+// syntax of the function is:
+//
+//   MDETERM(array)
+//
+func (fn *formulaFuncs) MDETERM(argsList *list.List) (result string, err error) {
+	var num float64
+	var rows int
+	var numMtx = [][]float64{}
+	var strMtx = [][]string{}
+	for arg := argsList.Front(); arg != nil; arg = arg.Next() {
+		if len(arg.Value.(formulaArg).Matrix) == 0 {
+			break
+		}
+		strMtx = append(strMtx, arg.Value.(formulaArg).Matrix)
+		rows++
+	}
+	for _, row := range strMtx {
+		if len(row) != rows {
+			err = errors.New(formulaErrorVALUE)
+			return
+		}
+		numRow := []float64{}
+		for _, ele := range row {
+			if num, err = strconv.ParseFloat(ele, 64); err != nil {
+				return
+			}
+			numRow = append(numRow, num)
+		}
+		numMtx = append(numMtx, numRow)
+	}
+	result = fmt.Sprintf("%g", det(numMtx))
+	return
+}
+
+// POWER function calculates a given number, raised to a supplied power.
+// The syntax of the function is:
+//
+//    POWER(number,power)
+//
+func (fn *formulaFuncs) POWER(argsList *list.List) (result string, err error) {
+	if argsList.Len() != 2 {
+		err = errors.New("POWER requires 2 numeric arguments")
+		return
+	}
+	var x, y float64
+	if x, err = strconv.ParseFloat(argsList.Front().Value.(formulaArg).Value, 64); err != nil {
+		return
+	}
+	if y, err = strconv.ParseFloat(argsList.Back().Value.(formulaArg).Value, 64); err != nil {
+		return
+	}
+	if x == 0 && y == 0 {
+		err = errors.New(formulaErrorNUM)
+		return
+	}
+	if x == 0 && y < 0 {
+		err = errors.New(formulaErrorDIV)
+		return
+	}
+	result = fmt.Sprintf("%g", math.Pow(x, y))
+	return
+}
+
+// PRODUCT function returns the product (multiplication) of a supplied set of
+// numerical values. The syntax of the function is:
+//
+//    PRODUCT(number1,[number2],...)
+//
+func (fn *formulaFuncs) PRODUCT(argsList *list.List) (result string, err error) {
+	var val, product float64 = 0, 1
+	for arg := argsList.Front(); arg != nil; arg = arg.Next() {
+		token := arg.Value.(formulaArg)
+		if token.Value == "" {
+			continue
+		}
+		if val, err = strconv.ParseFloat(token.Value, 64); err != nil {
+			return
+		}
+		product = product * val
+	}
+	result = fmt.Sprintf("%g", product)
+	return
+}
+
+// SIGN function returns the arithmetic sign (+1, -1 or 0) of a supplied
+// number. I.e. if the number is positive, the Sign function returns +1, if
+// the number is negative, the function returns -1 and if the number is 0
+// (zero), the function returns 0. The syntax of the function is:
+//
+//   SIGN(number)
+//
+func (fn *formulaFuncs) SIGN(argsList *list.List) (result string, err error) {
+	if argsList.Len() != 1 {
+		err = errors.New("SIGN requires 1 numeric argument")
+		return
+	}
+	var val float64
+	if val, err = strconv.ParseFloat(argsList.Front().Value.(formulaArg).Value, 64); err != nil {
+		return
+	}
+	if val < 0 {
+		result = "-1"
+		return
+	}
+	if val > 0 {
+		result = "1"
+		return
+	}
+	result = "0"
+	return
+}
+
+// SQRT function calculates the positive square root of a supplied number. The
+// syntax of the function is:
+//
+//    SQRT(number)
+//
+func (fn *formulaFuncs) SQRT(argsList *list.List) (result string, err error) {
+	if argsList.Len() != 1 {
+		err = errors.New("SQRT requires 1 numeric argument")
+		return
+	}
+	var res float64
+	var value = argsList.Front().Value.(formulaArg).Value
+	if value == "" {
+		result = "0"
+		return
+	}
+	if res, err = strconv.ParseFloat(value, 64); err != nil {
+		return
+	}
+	if res < 0 {
+		err = errors.New(formulaErrorNUM)
+		return
+	}
+	result = fmt.Sprintf("%g", math.Sqrt(res))
+	return
+}
+
+// SUM function adds together a supplied set of numbers and returns the sum of
+// these values. The syntax of the function is:
+//
+//    SUM(number1,[number2],...)
+//
+func (fn *formulaFuncs) SUM(argsList *list.List) (result string, err error) {
+	var val, sum float64
+	for arg := argsList.Front(); arg != nil; arg = arg.Next() {
+		token := arg.Value.(formulaArg)
+		if token.Value == "" {
+			continue
+		}
+		if val, err = strconv.ParseFloat(token.Value, 64); err != nil {
+			return
+		}
+		sum += val
+	}
+	result = fmt.Sprintf("%g", sum)
+	return
+}
+
+// QUOTIENT function returns the integer portion of a division between two
+// supplied numbers. The syntax of the function is:
+//
+//   QUOTIENT(numerator,denominator)
+//
+func (fn *formulaFuncs) QUOTIENT(argsList *list.List) (result string, err error) {
+	if argsList.Len() != 2 {
+		err = errors.New("QUOTIENT requires 2 numeric arguments")
+		return
+	}
+	var x, y float64
+	if x, err = strconv.ParseFloat(argsList.Front().Value.(formulaArg).Value, 64); err != nil {
+		return
+	}
+	if y, err = strconv.ParseFloat(argsList.Back().Value.(formulaArg).Value, 64); err != nil {
+		return
+	}
+	if y == 0 {
+		err = errors.New(formulaErrorDIV)
+		return
+	}
+	result = fmt.Sprintf("%g", math.Trunc(x/y))
+	return
+}