fix(calc): strip quotes from sheet names

Excel wraps sheet names containing spaces or special characters in
single quotes. The calculation engine previously failed to resolve
these references because it included literal quotes in the sheet
lookup.

Strip surrounding quotes during parsing to ensure formulas correctly
resolve data across sheets with spaces, hyphens, or other special
characters.

Author: jpoz

calc.go

@@ -1534,6 +1534,11 @@ func parseRef(ref string) (cellRef, bool, bool, error) {
 	)
 	if len(tokens) == 2 { // have a worksheet
 		cr.Sheet, cell = tokens[0], tokens[1]
+		// Strip surrounding single quotes from sheet name if present
+		// Excel requires quotes around sheet names with spaces/special chars: 'Sheet Name'!A1
+		if len(cr.Sheet) >= 2 && cr.Sheet[0] == '\'' && cr.Sheet[len(cr.Sheet)-1] == '\'' {
+			cr.Sheet = cr.Sheet[1 : len(cr.Sheet)-1]
+		}
 	}
 	if cr.Col, cr.Row, err = CellNameToCoordinates(cell); err != nil {
 		if cr.Col, colErr = ColumnNameToNumber(cell); colErr == nil { // cast to column

calc_test.go

@@ -6821,3 +6821,175 @@ func TestCalcTrendGrowthRegression(t *testing.T) {
 	mtx := [][]float64{}
 	calcTrendGrowthRegression(false, false, 0, 0, 0, 0, 0, mtx, mtx, mtx, mtx)
 }
+
+func TestCalcCellValueWithNamedRangesInFormula(t *testing.T) {
+	f := NewFile()
+	defer func() {
+		assert.NoError(t, f.Close())
+	}()
+
+	sheetName := "Test - Sheet"
+	idx, err := f.NewSheet(sheetName)
+	assert.NoError(t, err)
+	f.SetActiveSheet(idx)
+
+	// Create cells with values
+	assert.NoError(t, f.SetCellValue(sheetName, "A1", 100))
+	assert.NoError(t, f.SetCellValue(sheetName, "A2", 20))
+	assert.NoError(t, f.SetCellValue(sheetName, "A3", 30))
+	assert.NoError(t, f.SetCellValue(sheetName, "A4", 5))
+
+	// Define named ranges with periods in names to test dot notation support
+	assert.NoError(t, f.SetDefinedName(&DefinedName{
+		Name:     "value.first",
+		RefersTo: "'Test - Sheet'!$A$1",
+		Scope:    "Workbook",
+	}))
+	assert.NoError(t, f.SetDefinedName(&DefinedName{
+		Name:     "value_second",
+		RefersTo: "'Test - Sheet'!$A$2",
+		Scope:    "Workbook",
+	}))
+	assert.NoError(t, f.SetDefinedName(&DefinedName{
+		Name:     "value_third",
+		RefersTo: "'Test - Sheet'!$A$3",
+		Scope:    "Workbook",
+	}))
+	assert.NoError(t, f.SetDefinedName(&DefinedName{
+		Name:     "value_fourth",
+		RefersTo: "'Test - Sheet'!$A$4",
+		Scope:    "Workbook",
+	}))
+
+	// Set formula that references multiple named ranges in arithmetic operations
+	assert.NoError(t, f.SetCellFormula(sheetName, "B1", "=value.first-value_second-value_third-value_fourth"))
+
+	// Define a named range for the result cell
+	assert.NoError(t, f.SetDefinedName(&DefinedName{
+		Name:     "result",
+		RefersTo: "'Test - Sheet'!$B$1",
+		Scope:    "Workbook",
+	}))
+
+	// This should calculate to 100 - 20 - 30 - 5 = 45
+	result, err := f.CalcCellValue(sheetName, "B1")
+	assert.NoError(t, err)
+	assert.NotEmpty(t, result, "Formula with named ranges should return a calculated value")
+	assert.Equal(t, "45", result, "Formula should calculate correctly: 100 - 20 - 30 - 5")
+}
+
+func TestCalcWithNamedRangesVariousScenarios(t *testing.T) {
+	// Test 1: Named ranges on sheet without special chars
+	t.Run("SimpleSheetName", func(t *testing.T) {
+		f := NewFile()
+		defer func() {
+			assert.NoError(t, f.Close())
+		}()
+
+		assert.NoError(t, f.SetCellValue("Sheet1", "A1", 100))
+		assert.NoError(t, f.SetCellValue("Sheet1", "A2", 50))
+
+		assert.NoError(t, f.SetDefinedName(&DefinedName{
+			Name:     "Value1",
+			RefersTo: "Sheet1!$A$1",
+			Scope:    "Workbook",
+		}))
+		assert.NoError(t, f.SetDefinedName(&DefinedName{
+			Name:     "Value2",
+			RefersTo: "Sheet1!$A$2",
+			Scope:    "Workbook",
+		}))
+
+		assert.NoError(t, f.SetCellFormula("Sheet1", "B1", "=Value1+Value2"))
+		result, err := f.CalcCellValue("Sheet1", "B1")
+		assert.NoError(t, err)
+		assert.Equal(t, "150", result)
+	})
+
+	// Test 2: Named ranges in functions
+	t.Run("NamedRangesInFunctions", func(t *testing.T) {
+		f := NewFile()
+		defer func() {
+			assert.NoError(t, f.Close())
+		}()
+
+		assert.NoError(t, f.SetCellValue("Sheet1", "A1", 10))
+		assert.NoError(t, f.SetCellValue("Sheet1", "A2", 20))
+		assert.NoError(t, f.SetCellValue("Sheet1", "A3", 30))
+
+		assert.NoError(t, f.SetDefinedName(&DefinedName{
+			Name:     "DataRange",
+			RefersTo: "Sheet1!$A$1:$A$3",
+			Scope:    "Workbook",
+		}))
+
+		assert.NoError(t, f.SetCellFormula("Sheet1", "B1", "=SUM(DataRange)"))
+		result, err := f.CalcCellValue("Sheet1", "B1")
+		assert.NoError(t, err)
+		assert.Equal(t, "60", result)
+	})
+
+	// Test 3: Named ranges with sheet names containing various special chars
+	t.Run("SheetWithHyphens", func(t *testing.T) {
+		f := NewFile()
+		defer func() {
+			assert.NoError(t, f.Close())
+		}()
+
+		sheetName := "Data-Sheet-2025"
+		idx, err := f.NewSheet(sheetName)
+		assert.NoError(t, err)
+		f.SetActiveSheet(idx)
+
+		assert.NoError(t, f.SetCellValue(sheetName, "C5", 42))
+
+		assert.NoError(t, f.SetDefinedName(&DefinedName{
+			Name:     "SpecialValue",
+			RefersTo: "'Data-Sheet-2025'!$C$5",
+			Scope:    "Workbook",
+		}))
+
+		assert.NoError(t, f.SetCellFormula(sheetName, "D5", "=SpecialValue*2"))
+		result, err := f.CalcCellValue(sheetName, "D5")
+		assert.NoError(t, err)
+		assert.Equal(t, "84", result)
+	})
+
+	// Test 4: Multiple arithmetic operations with named ranges
+	t.Run("ComplexArithmetic", func(t *testing.T) {
+		f := NewFile()
+		defer func() {
+			assert.NoError(t, f.Close())
+		}()
+
+		sheetName := "My Sheet"
+		idx, err := f.NewSheet(sheetName)
+		assert.NoError(t, err)
+		f.SetActiveSheet(idx)
+
+		assert.NoError(t, f.SetCellValue(sheetName, "A1", 1000))
+		assert.NoError(t, f.SetCellValue(sheetName, "A2", 200))
+		assert.NoError(t, f.SetCellValue(sheetName, "A3", 50))
+
+		assert.NoError(t, f.SetDefinedName(&DefinedName{
+			Name:     "Total",
+			RefersTo: "'My Sheet'!$A$1",
+			Scope:    "Workbook",
+		}))
+		assert.NoError(t, f.SetDefinedName(&DefinedName{
+			Name:     "Cost",
+			RefersTo: "'My Sheet'!$A$2",
+			Scope:    "Workbook",
+		}))
+		assert.NoError(t, f.SetDefinedName(&DefinedName{
+			Name:     "Tax",
+			RefersTo: "'My Sheet'!$A$3",
+			Scope:    "Workbook",
+		}))
+
+		assert.NoError(t, f.SetCellFormula(sheetName, "B1", "=(Total-Cost)*Tax/100"))
+		result, err := f.CalcCellValue(sheetName, "B1")
+		assert.NoError(t, err)
+		assert.Equal(t, "400", result)
+	})
+}