formula: compatibility & bug fixes

- Make UNICODE with no arguments behave like Excel
- Fix OFFSET/INDEX for named ranges

spreadsheet/formula/fnindex.go

@@ -7,7 +7,10 @@
 
 package formula
 
-import "fmt"
+import (
+	"fmt"
+	"strings"
+)
 
 func init() {
 	RegisterFunction("INDEX", Index)
@@ -51,7 +54,12 @@ func Index(args []Result) Result {
 		return MakeErrorResult("INDEX has col out of range")
 	}
 
-	return rowVal[col]
+	rv := rowVal[col]
+	// empty cell returns a zero
+	if rv.Type == ResultTypeEmpty {
+		return MakeNumberResult(0)
+	}
+	return rv
 }
 
 // Indirect is an implementation of the Excel INDIRECT function that returns the
@@ -72,12 +80,20 @@ func Offset(ctx Context, ev Evaluator, args []Result) Result {
 		return MakeErrorResult("OFFSET requires one or two arguments")
 	}
 	ref := args[0].Ref
-	origin := "A1"
+	// resolve a named range
+	for ref.Type == ReferenceTypeNamedRange {
+		ref = ctx.NamedRange(ref.Value)
+	}
+
+	origin := ""
 	switch ref.Type {
 	case ReferenceTypeCell:
 		origin = ref.Value
 	case ReferenceTypeRange:
-	case ReferenceTypeNamedRange:
+		sp := strings.Split(ref.Value, ":")
+		if len(sp) == 2 {
+			origin = sp[0]
+		}
 	default:
 		return MakeErrorResult(fmt.Sprintf("Invalid range in OFFSET(): %s", ref.Type))
 	}
@@ -91,27 +107,26 @@ func Offset(ctx Context, ev Evaluator, args []Result) Result {
 	if rOff.Type != ResultTypeNumber {
 		return MakeErrorResult("OFFSET requires numeric row offset")
 	}
-	cOff := args[1].AsNumber()
+	cOff := args[2].AsNumber()
 	if cOff.Type != ResultTypeNumber {
 		return MakeErrorResult("OFFSET requires numeric col offset")
 	}
 
-	height := args[1].AsNumber()
+	height := args[3].AsNumber()
 	if height.Type != ResultTypeNumber {
 		return MakeErrorResult("OFFSET requires numeric height")
 	}
-	width := args[1].AsNumber()
+	width := args[4].AsNumber()
 	if width.Type != ResultTypeNumber {
 		return MakeErrorResult("OFFSET requires numeric width")
 	}
 	colIdx := ColumnToIndex(col)
 	origRow := rowIdx + uint32(rOff.ValueNumber)
 	origCol := colIdx + uint32(cOff.ValueNumber)
-	endRow := origRow + uint32(height.ValueNumber)
-	endCol := origCol + uint32(width.ValueNumber)
+	endRow := origRow + uint32(height.ValueNumber) - 1
+	endCol := origCol + uint32(width.ValueNumber) - 1
 
 	beg := fmt.Sprintf("%s%d", IndexToColumn(origCol), origRow)
 	end := fmt.Sprintf("%s%d", IndexToColumn(endCol), endRow)
 	return resultFromCellRange(ctx, ev, beg, end)
-
 }

spreadsheet/formula/fnlogical.go

@@ -106,6 +106,10 @@ func IfError(args []Result) Result {
 	}
 
 	if args[0].Type != ResultTypeError {
+		// empty cell returns a zero
+		if args[0].Type == ResultTypeEmpty {
+			return MakeNumberResult(0)
+		}
 		return args[0]
 	}
 

spreadsheet/formula/fntext.go

@@ -50,7 +50,7 @@ func init() {
 	//RegisterFunction("TEXTJOIN")
 	RegisterFunction("TRIM", Trim)
 	RegisterFunction("_xlfn.UNICHAR", Char) // for now
-	RegisterFunction("_xlfn.UNICODE", Code) // for now
+	RegisterFunction("_xlfn.UNICODE", Unicode)
 	RegisterFunction("UPPER", Upper)
 	//RegisterFunction("VALUE", )
 }
@@ -109,6 +109,22 @@ func Code(args []Result) Result {
 	return MakeNumberResult(float64(s.ValueString[0]))
 }
 
+func Unicode(args []Result) Result {
+	if len(args) != 1 {
+		return MakeErrorResult("UNICODE requires a single string argument")
+	}
+	s := args[0].AsString()
+	if s.Type != ResultTypeString {
+		return MakeErrorResult("UNICODE requires a single string argument")
+	}
+	// Zero length string returns an error
+	if len(s.ValueString) == 0 {
+		return MakeErrorResult("UNICODE requires a non-zero length argument")
+	}
+
+	return MakeNumberResult(float64(s.ValueString[0]))
+}
+
 // Concatenate is an implementation of the Excel CONCATENATE() function.
 func Concatenate(args []Result) Result {
 	buf := bytes.Buffer{}

spreadsheet/formula/range.go

@@ -44,6 +44,7 @@ func (r Range) Reference(ctx Context, ev Evaluator) Reference {
 
 // TODO: move these somewhere to remove duplication
 func ParseCellReference(s string) (col string, row uint32, err error) {
+	s = strings.Replace(s, "$", "", -1)
 	split := -1
 lfor:
 	for i := 0; i < len(s); i++ {
@@ -108,7 +109,8 @@ func resultFromCellRange(ctx Context, ev Evaluator, from, to string) Result {
 	for r := fr; r <= tr; r++ {
 		args := []Result{}
 		for c := bc; c <= ec; c++ {
-			args = append(args, ctx.Cell(fmt.Sprintf("%s%d", IndexToColumn(c), r), ev))
+			res := ctx.Cell(fmt.Sprintf("%s%d", IndexToColumn(c), r), ev)
+			args = append(args, res)
 		}
 		arr = append(arr, args)
 	}

spreadsheet/parse.go

@@ -16,6 +16,7 @@ import (
 // ParseCellReference parses a cell reference of the form 'A10' and splits it
 // into column/row segments.
 func ParseCellReference(s string) (col string, row uint32, err error) {
+	s = strings.Replace(s, "$", "", -1)
 	split := -1
 lfor:
 	for i := 0; i < len(s); i++ {