docs.sheetjs.com/docz/docs/03-demos/32-extensions/12-maple.md

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Maple is a numeric computing platform. It offers a robust C-based extension system.

SheetJS is a JavaScript library for reading and writing data from spreadsheets.

This demo uses SheetJS to pull data from a spreadsheet for further analysis within Maple. We'll create a Maple native extension that loads the Duktape JavaScript engine and uses the SheetJS library to read data from spreadsheets and converts to a Maple-friendly format.

flowchart LR
  ofile[(workbook\nXLSB file)]
  nfile[(clean file\nXLSX)]
  data[[Maple\nTable]]
  ofile --> |Maple Extension\nSheetJS + Duktape| nfile
  nfile --> |ExcelTools\nImport|data

:::note Tested Deployments

This demo was last tested by SheetJS users on 2024 March 31 in Maple 2024.

:::

:::info pass

Maple has limited support for processing spreadsheets through the ExcelTools package¹. At the time of writing, it lacked support for XLSB, NUMBERS, and other common spreadsheet formats.

SheetJS libraries help fill the gap by normalizing spreadsheets to a form that Maple can understand.

:::

Integration Details

The current recommendation involves a native plugin that reads arbitrary files and generates clean XLSX files that Maple can import.

The extension function ultimately pairs the SheetJS read² and write³ methods to read data from the old file and write a new file:

var workbook = XLSX.read(original_file_data, { type: "buffer" });
var new_file_data = XLSX.write(workbook, { type: "array", bookType: "xlsx" });

The extension function will receive a file name and perform the following steps:

flowchart LR
  ofile{{File\nName}}
  subgraph JS Operations
    ojbuf[(Buffer\nFile Bytes)]
    wb(((SheetJS\nWorkbook)))
    njbuf[(Buffer\nXLSX bytes)]
  end
  obuf[(File\nbytes)]
  nbuf[(New file\nbytes)]
  nfile[(XLSX\nFile)]
  ofile --> |C\nRead File| obuf
  obuf --> |Duktape\nBuffer Ops| ojbuf
  ojbuf --> |SheetJS\n`read`| wb
  wb --> |SheetJS\n`write`| njbuf
  njbuf --> |Duktape\nBuffer Ops| nbuf
  nbuf --> |C\nWrite File| nfile

C Extensions

Maple extensions are shared libraries or DLLs that use special Maple methods for parsing arguments and returning values. They are typically written in the C programming language.

To simplify the flow, the new function will take one argument (the original file name) and return one value (the new file name).

The official documentation has a comprehensive list⁴ of methods. For this demo, the following methods are used:

• MapleNumArgs and IsMapleString are used in argument validation. The demo function will raise a Maple exception if no file name is specified.

• MapleRaiseError and MapleRaiseError2 programmatically raise errors.

• MapleToString and ToMapleString convert between Maple and C strings.

Duktape JS Engine

This demo uses the Duktape JavaScript engine. The SheetJS + Duktape demo covers engine integration details in more detail.

The SheetJS Standalone scripts can be loaded in Duktape by reading the source from the filesystem.

Complete Demo

:::info pass

This demo was tested in Windows x64. The path names and build commands will differ in other platforms and operating systems.

:::

The sheetjs-maple.c extension exports the SheetToXLSX Maple method. It takes a file name argument, parses the specified file, exports data to sheetjsw.xlsx and returns the string "sheetjsw.xlsx".

This can be chained with Import from ExcelTools:

with(ExcelTools);
Import(SheetToXLSX("pres.numbers"))

0. Install "Windows Subsystem for Linux" (WSL)⁵ and Visual Studio⁶.

1. Open a new "x64 Native Tools Command Prompt" window and create a project folder c:\sheetjs-maple:

cd c:\
mkdir sheetjs-maple
cd sheetjs-maple

2. Copy the headers and lib files from the Maple folder to the project folder. For example, using Maple 2024 on Windows x64:

copy "C:\Program Files\Maple 2024\extern\include\"*.h .
copy "c:\Program Files\Maple 2024\bin.x86_64_WINDOWS"\*.lib .

3. Run bash to enter WSL

4. Within WSL, install Duktape:

curl -LO https://duktape.org/duktape-2.7.0.tar.xz
tar -xJf duktape-2.7.0.tar.xz
mv duktape-2.7.0/src/*.{c,h} .

5. Still within WSL, download SheetJS scripts and the test file.

{\ curl -LO https://cdn.sheetjs.com/xlsx-${current}/package/dist/shim.min.js curl -LO https://cdn.sheetjs.com/xlsx-${current}/package/dist/xlsx.full.min.js curl -LO https://sheetjs.com/pres.numbers}

6. Still within WSL, download the extension C code

curl -LO https://docs.sheetjs.com/maple/sheetjs-maple.c

7. Exit WSL by running exit. The window will return to the command prompt.

8. Build the extension DLL:

cl -Gz sheetjs-maple.c duktape.c /EHsc -link -dll -out:sheetjs-maple.dll maplec.lib

9. Close and re-open Maple, then create a new Maple Worksheet or Document

10. Run the following command in Maple to change the working directory:

currentdir("c:\\sheetjs-maple");

11. Load the SheetToXLSX method from the extension:

with(ExternalCalling):
dll:=ExternalLibraryName("sheetjs-maple"):
SheetToXLSX:=DefineExternal("SheetToXLSX",dll):

12. Read the pres.numbers test file:

with(ExcelTools);
Import(SheetToXLSX("pres.numbers"))

The result will show the data from pres.numbers

---

1. See "ExcelTools" in the Maple documentation. ↩︎

2. See read in "Reading Files" ↩︎

3. See write in "Writing Files" ↩︎

4. See "C OpenMaple and ExternalCalling Application Program Interface (API)" in the Maple documentation. ↩︎

5. In a PowerShell terminal window, run wsl --install Ubuntu ↩︎

6. See the Visual Studio website for download links. In the Visual Studio Installer, install the "Desktop development with C++" workflow. ↩︎