PHPOffice · MarkBaker · Jan 30, 2022 · Jan 30, 2022 · Jan 30, 2022 · Jan 30, 2022
diff --git a/docs/topics/accessing-cells.md b/docs/topics/accessing-cells.md
@@ -131,10 +131,10 @@ Formats handled by the advanced value binder include:
 - TRUE or FALSE (dependent on locale settings) are converted to booleans.
 - Numeric strings identified as scientific (exponential) format are
   converted to numbers.
-- Fractions and vulgar fractions are converted to numbers, and
+- Fractions and "vulgar" fractions are converted to numbers, and
   an appropriate number format mask applied.
-- Percentages are converted
-  to numbers, divided by 100, and an appropriate number format mask
+- Percentages are converted to numbers, divided by 100, and an
+  appropriate number format mask
   applied.
 - Dates and times are converted to Excel timestamp values
   (numbers), and an appropriate number format mask applied.

diff --git a/docs/topics/calculation-engine.md b/docs/topics/calculation-engine.md
@@ -10,6 +10,8 @@ formula calculation capabilities. A cell can be of a value type
 which can be evaluated). For example, the formula `=SUM(A1:A10)`
 evaluates to the sum of values in A1, A2, ..., A10.
 
+Calling `getValue()` on a cell that contains a formula will return the formula itself.
+
 To calculate a formula, you can call the cell containing the formula’s
 method `getCalculatedValue()`, for example:
 
@@ -22,6 +24,30 @@ with PhpSpreadsheet, it evaluates to the value "64":
 
 ![09-command-line-calculation.png](./images/09-command-line-calculation.png)
 
+Calling `getCalculatedValue()` on a cell that doesn't contain a formula will simply return the value of that cell; but if the cell does contain a formula, then PhpSpreadsheet will evaluate that formula to calculate the result.
+
+There are a few useful mehods to help identify whether a cell contains a formula or a simple value; and if a formula, to provide further information about it:
+
+```php
+$spreadsheet->getActiveSheet()->getCell('E11')->isFormula();
+```
+will return a boolean true/false, telling you whether that cell contains a formula or not, so you can determine if a call to `getCalculatedVaue()` will need to perform an evaluation. 
+
+A formula can be either a simple formula, or an array formula; and another method will identify which it is:
+```php
+$spreadsheet->getActiveSheet()->getCell('E11')->isArrayFormula();
+```
+Finally, an array formula might result in a single cell result, or a result that can spill over into a range of cells; so for array formulae the following method also exists:
+```php
+$spreadsheet->getActiveSheet()->getCell('E11')->arrayFormulaRange();
+```
+which returns a string containing a cell reference (e.g. `E11`) or a cell range reference (e.g. `E11:G13`).
+
+
+For more details on working with array formulae, see the [the recipes documentationn](./recipes.md/#array-formulae). 
+
+### Adjustments to formulae when Inserting/Deleting Columns/Rows
+
 When writing a formula to a cell, formulae should always be set as they would appear in an English version of Microsoft Office Excel, and PhpSpreadsheet handles all formulae internally in this format. This means that the following rules hold:
 
  - Decimal separator is `.` (period)
@@ -91,6 +117,11 @@ formula calculation is subject to PHP's language characteristics.
 Not all functions are supported, for a comprehensive list, read the
 [function list by name](../references/function-list-by-name.md).
 
+#### Array arguments for Function Calls in Formulae
+
+While most of the Excel function implementations now support array arguments, there are a few that should accept arrays as arguments but don't do so.
+In these cases, the result may be a single value rather than an array; or it may be a `#VALUE!` error.
+
 #### Operator precedence
 
 In Excel `+` wins over `&`, just like `*` wins over `+` in ordinary
@@ -112,7 +143,7 @@ content.
 
 - [Reference for this behaviour in PHP](https://php.net/manual/en/language.types.string.php#language.types.string.conversion)
 
-#### Formulas don’t seem to be calculated in Excel2003 using compatibility pack?
+#### Formulae don’t seem to be calculated in Excel2003 using compatibility pack?
 
 This is normal behaviour of the compatibility pack, Xlsx displays this
 correctly. Use `\PhpOffice\PhpSpreadsheet\Writer\Xls` if you really need
@@ -161,8 +192,7 @@ number of seconds from the PHP/Unix base date. The PHP/Unix base date
 (0) is 00:00 UST on 1st January 1970. This value can be positive or
 negative: so a value of -3600 would be 23:00 hrs on 31st December 1969;
 while a value of +3600 would be 01:00 hrs on 1st January 1970. This
-gives PHP a date range of between 14th December 1901 and 19th January
-2038.
+gives 32-bit PHP a date range of between 14th December 1901 and 19th January 2038.
 
 #### PHP `DateTime` Objects
 

diff --git a/docs/topics/images/12-CalculationEngine-Array-Formula-2.png b/docs/topics/images/12-CalculationEngine-Array-Formula-2.png
diff --git a/docs/topics/images/12-CalculationEngine-Array-Formula-3.png b/docs/topics/images/12-CalculationEngine-Array-Formula-3.png
diff --git a/docs/topics/images/12-CalculationEngine-Array-Formula.png b/docs/topics/images/12-CalculationEngine-Array-Formula.png
diff --git a/docs/topics/images/12-CalculationEngine-Basic-Formula-2.png b/docs/topics/images/12-CalculationEngine-Basic-Formula-2.png
diff --git a/docs/topics/images/12-CalculationEngine-Basic-Formula.png b/docs/topics/images/12-CalculationEngine-Basic-Formula.png
diff --git a/docs/topics/images/12-CalculationEngine-Spillage-Formula-2.png b/docs/topics/images/12-CalculationEngine-Spillage-Formula-2.png
diff --git a/docs/topics/images/12-CalculationEngine-Spillage-Formula.png b/docs/topics/images/12-CalculationEngine-Spillage-Formula.png
diff --git a/docs/topics/images/12-CalculationEngine-Spillage-Operator.png b/docs/topics/images/12-CalculationEngine-Spillage-Operator.png
diff --git a/docs/topics/reading-files.md b/docs/topics/reading-files.md
@@ -168,6 +168,68 @@ Once you have created a reader object for the workbook that you want to
 load, you have the opportunity to set additional options before
 executing the `load()` method.
 
+All of these options can be set by calling the appropriate methods against the Reader (as described below), but some options (those with only two possible values) can also be set through flags, either by calling the Reader's `setFlags()` method, or passing the flags as an argument in the call to `load()`.
+Those options that can be set through flags are:
+
+Option             | Flag                         | Default
+-------------------|------------------------------|---
+Ignore Empty Cells | IReader::IGNORE_EMPTY_CELLS  | Load empty cells
+Read Data Only     | IReader::READ_DATA_ONLY      | Read data, structure and style
+Include Charts     | IReader::LOAD_WITH_CHARTS    | Don't read charts
+
+Several flags can be combined in a single call:
+```php
+$inputFileType = 'Xlsx';
+$inputFileName = './sampleData/example1.xlsx';
+
+/**  Create a new Reader of the type defined in $inputFileType  **/
+$reader = \PhpOffice\PhpSpreadsheet\IOFactory::createReader($inputFileType);
+/** Set additional flags before the call to load() */
+$reader->setFlags(IReader::IGNORE_EMPTY_CELLS | IReader::LOAD_WITH_CHARTS);
+$reader->load($inputFileName);
+```
+or
+```php
+$inputFileType = 'Xlsx';
+$inputFileName = './sampleData/example1.xlsx';
+
+/**  Create a new Reader of the type defined in $inputFileType  **/
+$reader = \PhpOffice\PhpSpreadsheet\IOFactory::createReader($inputFileType);
+/** Set additional flags in the call to load() */
+$reader->load($inputFileName, IReader::IGNORE_EMPTY_CELLS | IReader::LOAD_WITH_CHARTS);
+```
+
+### Ignoring Empty Cells
+
+Many Excel files have empty rows or columns at the end of a worksheet, which can't easily be seen when looking at the file in Excel (Try using Ctrl-End to see the last cell in a worksheet).
+By default, PhpSpreadsheet will load these cells, because they are valid Excel values; but you may find that an apparently small spreadsheet requires a lot of memory for all those empty cells.
+If you are running into memory issues with seemingly small files, you can tell PhpSpreadsheet not to load those empty cells using the `setReadEmptyCells()` method. 
+
+```php
+$inputFileType = 'Xls';
+$inputFileName = './sampleData/example1.xls';
+
+/**  Create a new Reader of the type defined in $inputFileType  **/
+$reader = \PhpOffice\PhpSpreadsheet\IOFactory::createReader($inputFileType);
+/**  Advise the Reader that we only want to load cell's that contain actual content  **/
+$reader->setReadEmptyCells(false);
+/**  Load $inputFileName to a Spreadsheet Object  **/
+$spreadsheet = $reader->load($inputFileName);
+```
+
+Note that cells containing formulae will still be loaded, even if that formula evaluates to a NULL or an empty string.
+Similarly, Conditional Styling might also hide the value of a cell; but cells that contain Conditional Styling or Data Validation will always be loaded regardless of their value.
+
+This option is available for the following formats:
+
+Reader    | Y/N |Reader  | Y/N |Reader        | Y/N |
+----------|:---:|--------|:---:|--------------|:---:|
+Xlsx      | YES | Xls    | YES | Xml          | NO  |
+Ods       | NO  | SYLK   | NO  | Gnumeric     | NO  |
+CSV       | NO  | HTML   | NO
+
+This option is also available through flags.
+
 ### Reading Only Data from a Spreadsheet File
 
 If you're only interested in the cell values in a workbook, but don't
@@ -210,6 +272,8 @@ Xlsx      | YES | Xls    | YES | Xml          | YES |
 Ods       | YES | SYLK   | NO  | Gnumeric     | YES |
 CSV       | NO  | HTML   | NO
 
+This option is also available through flags.
+
 ### Reading Only Named WorkSheets from a File
 
 If your workbook contains a number of worksheets, but you are only
@@ -642,7 +706,7 @@ Xlsx      | NO  | Xls    | NO  | Xml          | NO  |
 Ods       | NO  | SYLK   | NO  | Gnumeric     | NO  |
 CSV       | YES | HTML   | NO
 
-### A Brief Word about the Advanced Value Binder
+## A Brief Word about the Advanced Value Binder
 
 When loading data from a file that contains no formatting information,
 such as a CSV file, then data is read either as strings or numbers
@@ -694,6 +758,9 @@ Xlsx      | NO  | Xls    | NO  | Xml          | NO
 Ods       | NO  | SYLK   | NO  | Gnumeric     | NO
 CSV       | YES | HTML   | YES
 
+Note that you can also use the Binder to determine how PhpSpreadsheet identified datatypes for values when you set a cell value without explicitly setting a datatype.
+Value Binders can also be used to set formatting for a cell appropriate to the value.
+
 ## Error Handling
 
 Of course, you should always apply some error handling to your scripts