rust_xlsxwriter 0.96.0

/*!

# Working with VBA Macros

This section explains how to add a VBA file containing functions or macros to a
`rust_xlsxwriter` file.

<img src="https://rustxlsxwriter.github.io/images/app_macros.png">

# The Excel XLSM File Format

An Excel `xlsm` file is structurally the same as an `xlsx` file, except that it
contains an additional `vbaProject.bin` binary file containing VBA functions
and/or macros.

Excel `xlsm` files are subject to additional security checks and warnings when
loaded:

<img src="https://rustxlsxwriter.github.io/images/doc_macros_warning.png">


# How VBA macros are included in `rust_xlsxwriter`

The `vbaProject.bin` in a `xlsm` file is a binary OLE COM container. This was
the format used in older `xls` versions of Excel prior to Excel 2007. Unlike
other components of an `xlsx`/`xlsm` file, the data isn't stored in XML format.
Instead, the functions and macros are stored in a pre-parsed binary format. As
such, it wouldn't be feasible to programmatically define macros and create a
`vbaProject.bin` file from scratch (at least not in the remaining lifespan
and interest levels of the author).

Instead, as a workaround, a utility is used to extract `vbaProject.bin` files
from existing `xlsm` files, which you can then add to `rust_xlsxwriter` files.

# The `vba_extract` Utility

The Rust [`vba_extract`](https://crates.io/crates/vba_extract) utility is used
to extract the `vbaProject.bin` binary from an Excel `xlsm` file. The utility
can be installed via `cargo`:

```bash
$ cargo install vba_extract
```

Once `vba_extract` is installed, it can be used as follows:

```bash
$ vba_extract macro_file.xlsm

Extracted: vbaProject.bin
```

If the VBA project is signed, `vba_extract` also extracts the
`vbaProjectSignature.bin` file from the `xlsm` file (see below).

The syntax and options for `vba_extract` are:

```text
$ vba_extract --help

Utility to extract a `vbaProject.bin` binary from an Excel `xlsm` macro file
for insertion into a `rust_xlsxwriter` file. If the macros are digitally
signed, it also extracts a `vbaProjectSignature.bin` file.

Usage: vba_extract [OPTIONS] <FILENAME_XLSM>

Arguments:
  <FILENAME_XLSM>
          Input Excel xlsm filename

Options:
  -o, --output-macro-filename <OUTPUT_MACRO_FILENAME>
          Output vba macro filename

          [default: vbaProject.bin]

  -s, --output-sig-filename <OUTPUT_SIG_FILENAME>
          Output vba signature filename (if present in the parent file)

          [default: vbaProjectSignature.bin]

  -h, --help
          Print help (see a summary with '-h')

  -V, --version
          Print version
```

# Adding VBA Macros to a `rust_xlsxwriter` File

Once the `vbaProject.bin` file has been extracted, it can be added to the
`rust_xlsxwriter` workbook using the
[`Workbook::add_vba_project()`](crate::Workbook::add_vba_project()) method:

```
# // This code is available in examples/doc_macros_add.rs
# use rust_xlsxwriter::{Workbook, XlsxError};
#
# #[allow(unused_variables)]
# fn main() -> Result<(), XlsxError> {
#     let mut workbook = Workbook::new();
#
    workbook.add_vba_project("examples/vbaProject.bin")?;
#
#     Ok(())
# }
```

Here is a complete example which adds a macro file with a dialog. It also uses a
button, via [`Worksheet::insert_button()`](crate::Worksheet::insert_button), to
trigger the macro:

```
# // This code is available in examples/app_macros.rs
use rust_xlsxwriter::{Button, Workbook, XlsxError};

fn main() -> Result<(), XlsxError> {
    // Create a new Excel file object.
    let mut workbook = Workbook::new();

    // Add the VBA macro file.
    workbook.add_vba_project("examples/vbaProject.bin")?;

    // Add a worksheet and some text.
    let worksheet = workbook.add_worksheet();

    // Widen the first column for clarity.
    worksheet.set_column_width(0, 30)?;

    worksheet.write(2, 0, "Press the button to say hello:")?;

    // Add a button tied to a macro in the VBA project.
    let button = Button::new()
        .set_caption("Press Me")
        .set_macro("say_hello")
        .set_width(80)
        .set_height(30);

    worksheet.insert_button(2, 1, &button)?;

    // Save the file to disk. Note the `.xlsm` extension. This is required by
    // Excel or it will raise a warning.
    workbook.save("macros.xlsm")?;

    Ok(())
}
```
The macro in this example is the following VBA code:

```basic
Sub say_hello()
    MsgBox ("Hello from Rust!")
End Sub
```

Output file after running macro:

<img src="https://rustxlsxwriter.github.io/images/app_macros.png">

If the VBA file contains functions you can then refer to them in calculations
using [`Worksheet::write_formula()`](crate::Worksheet::write_formula()):

```
# // This code is available in examples/doc_macros_calc.rs
# use rust_xlsxwriter::{Workbook, XlsxError};
#
# fn main() -> Result<(), XlsxError> {
#     let mut workbook = Workbook::new();
#
#     workbook.add_vba_project("examples/vbaProject.bin")?;
#
#     let worksheet = workbook.add_worksheet();
#
    worksheet.write_formula(0, 0, "=MyMortgageCalc(200000, 25)")?;
#
#     // Note the `.xlsm` extension.
#     workbook.save("macros.xlsm")?;
#
#     Ok(())
# }
```

**Note**: Excel files that contain functions and macros must use an `.xlsm`
extension or else Excel will complain and possibly not open the file.

```
# // This code is available in examples/doc_macros_save.rs
# use rust_xlsxwriter::{Workbook, XlsxError};
#
# #[allow(unused_variables)]
# fn main() -> Result<(), XlsxError> {
#     let mut workbook = Workbook::new();
#
#     workbook.add_vba_project("examples/vbaProject.bin")?;
#
#     let worksheet = workbook.add_worksheet();
#
    // Note the `.xlsm` extension.
    workbook.save("macros.xlsm")?;
#
#     Ok(())
# }
```

Here is the dialog that appears when a valid `xlsm` file is incorrectly given a
`xlsx` extension:

<img src="https://rustxlsxwriter.github.io/images/doc_macros_wrong_extension.png">

# Setting the VBA Object Names

VBA macros generally refer to workbook and worksheet objects via names such as
`ThisWorkbook` and `Sheet1`, `Sheet2` etc.

If the imported macro uses other names, you can set them using the
[`Workbook::set_vba_name()`](crate::Workbook::set_vba_name()) and
[`Worksheet::set_vba_name()`](crate::Worksheet::set_vba_name()) methods as
follows.

```
# // This code is available in examples/doc_macros_name.rs
# use rust_xlsxwriter::{Workbook, XlsxError};
#
# fn main() -> Result<(), XlsxError> {
#     let mut workbook = Workbook::new();
#
#     workbook.add_vba_project("examples/vbaProject.bin")?;
    workbook.set_vba_name("MyWorkbook")?;
#
#     let worksheet = workbook.add_worksheet();
    worksheet.set_vba_name("MySheet1")?;
#
#     // Note the `.xlsm` extension.
#     workbook.save("macros.xlsm")?;
#
#     Ok(())
# }
```

**Note**: If you are using a non-English version of Excel you need to pay
particular attention to the workbook/worksheet naming that your version of Excel
uses and add the correct VBA names. You can find the names that are used in the
VBA editor:

<img src="https://rustxlsxwriter.github.io/images/doc_macros_editor.png">

You can also find them by unzipping the `xlsm` file and grepping the component
XML files. The following shows how to do that using system `unzip` and libxml's
[xmllint](http://xmlsoft.org/xmllint.html) to format the XML for clarity

```bash
$ unzip myfile.xlsm -d myfile
$ xmllint --format `find myfile -name "*.xml" | xargs` | grep "Pr.*codeName"

    <workbookPr codeName="MyWorkbook" defaultThemeVersion="124226"/>
    <sheetPr codeName="MySheet"/>
```

# Adding a VBA Macro Signature File to a `rust_xlsxwriter` File

VBA macros can be signed in Excel to allow for further control over execution.
The signature part is added to the `xlsm` file in another binary called `vbaProjectSignature.bin`.

The `vba_extract` utility will extract the `vbaProject.bin` and
`vbaProjectSignature.bin` files from an `xlsm` file with signed macros.

These files can be added to a `rust_xlsxwriter` file using the
[`Workbook::add_vba_project_with_signature()`](crate::Workbook::add_vba_project_with_signature())
method:

```
# // This code is available in examples/doc_macros_signed.rs
# use rust_xlsxwriter::{Workbook, XlsxError};
#
# #[allow(unused_variables)]
# fn main() -> Result<(), XlsxError> {
#     let mut workbook = Workbook::new();
#
    workbook.add_vba_project_with_signature(
        "examples/vbaProject.bin",
        "examples/vbaProjectSignature.bin",
    )?;
#
#     let worksheet = workbook.add_worksheet();
#
#     // Note the `.xlsm` extension.
#     workbook.save("macros.xlsm")?;
#
#     Ok(())
# }
```

# What to do if it doesn't work

The `rust_xlsxwriter` test suite contains several tests to ensure that this
feature works and there is a working example shown above. However, there is no
guarantee that it will work in all cases. Some trial and error may be required
and some knowledge of VBA will certainly help. If things don't work out here are
some things to try:

1. Start with a simple macro file, ensure that it works, and then add
   complexity.

2. Check the code names that macros use to refer to the workbook and worksheets
   (see above). In general VBA uses a code name of
   `ThisWorkbook` to refer to the current workbook and the sheet name (such as
   `Sheet1`) to refer to the worksheets. These are the defaults used by
   `rust_xlsxwriter`. If the macro uses other names, or the macro was extracted
   from an non-English language version of Excel, then you can specify these
   using the workbook and worksheet `set_vba_name` methods.
*/