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 2023 October 3 in Maple 2023.

:::

:::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 wb = XLSX.read(original_file_data, {type: "buffer"});
var new_file_data = XLSX.write(wb, {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 C extensions are shared libraries or DLLs that use special Maple methods for parsing arguments and returning values.

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"))
  1. Ensure "Windows Subsystem for Linux" (WSL) and Visual Studio are installed.

  2. 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
  1. Copy the headers and lib files from the Maple folder to the project folder. For example, using Maple 2023 on Windows x64:
copy "C:\Program Files\Maple 2023\extern\include\"*.h .
copy "c:\Program Files\Maple 2023\bin.x86_64_WINDOWS"\*.lib .
  1. Run bash to enter WSL

  2. 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} .
  1. 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}

  1. Still within WSL, download the extension C code
curl -LO https://docs.sheetjs.com/maple/sheetjs-maple.c
  1. Exit WSL by running exit. The window will return to the command prompt.

  2. Build the extension DLL:

cl -Gz sheetjs-maple.c duktape.c /EHsc -link -dll -out:sheetjs-maple.dll maplec.lib
  1. Close and re-open Maple, then create a new Maple Worksheet or Document

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

currentdir("c:\\sheetjs-maple");
  1. Load the SheetToXLSX method from the extension:
with(ExternalCalling):
dll:=ExternalLibraryName("sheetjs-maple"):
SheetToXLSX:=DefineExternal("SheetToXLSX",dll):
  1. Read the pres.numbers test file:
with(ExcelTools);
Import(SheetToXLSX("pres.numbers"))

The result will show the data from pres.numbers

Maple Screenshot