This is a good point. We do have an article about compiling over from C : https://developer.mozilla.org/en-US/docs/WebAssembly/C_to_wasm

But there is nowhere where we show direct comparisons between source (e.g. C ) and equivalent WA, along with compilation to wasm and usage in the JS.

Early next year I am intending to add a bunch of information on Rust and it's advantages over C in being the source of WAT/WASM. I will make this part of that initiative for sure.

I actually am putting together an outline for a tutorial with a realistic example: passing a Unicode string from JS to C -compiled WASM, and passing it back in chunks.

The inspiration is a need I have for a XML parser. I was thinking of compiling Expat in WebAssembly. Before I can do that, I need someone to fill in some gaps on bridging C and JS.

So, I want to provide a baseline demo project with very specific questions and a tutorial document outline. I also want to find a colleague who understands WebAssembly well enough to answer those questions and complete writing the tutorial. The tutorial will assume general familiarity with JavaScript and C .

I would provide:

• Test code in C which passes
• Test code in JS which passes (without calling the C code)
• A not-insignificant Unicode string to pass around.
  • I'm thinking a MathML fragment for the definition of a limit from calculus.
• A Makefile to build the C project and to run the test code in C and JS
• A partial tutorial document, with complete outline.

The questions I want answered:

• JS code to import the module
• JS code to create an instance of the module's desired WASM class
• Passing a JS callback function into the instance for the C code to invoke, with the first argument being an Unicode string
• JS code calling a C method of the WASM instance, with an Unicode string
• Excluding void main() from the generated WASM code
• Makefile changes needed to compile the C code by em
• How to migrate comments from C to WASM module, if possible
• A configure script to check for a minimal version of em (and probably nodejs as well)

Is there anyone out there who could be an effective partner in this?

There's also a lot of work on ergonomics and integrating into existing ESM/node workflows over in https://rust-lang-nursery.github.io/rust-wasm/. In particular, you can see mentioned in the README.md that one of the goals of that project is a small book documenting the whole workflow and I see a lot of active work on that in my GH notifications.

I actually am putting together an outline for a tutorial with a realistic example: passing a Unicode string from JS to C -compiled WASM, and passing it back in chunks.

The inspiration is a need I have for a XML parser. I was thinking of compiling Expat in WebAssembly. Before I can do that, I need someone to fill in some gaps on bridging C and JS.

So, I want to provide a baseline demo project with very specific questions and a tutorial document outline. I also want to find a colleague who understands WebAssembly well enough to answer those questions and complete writing the tutorial. The tutorial will assume general familiarity with JavaScript and C .

I would provide:

• Test code in C which passes

• Test code in JS which passes (without calling the C code)

• A not-insignificant Unicode string to pass around.

  • I'm thinking a MathML fragment for the definition of a limit from calculus.

• A Makefile to build the C project and to run the test code in C and JS

• A partial tutorial document, with complete outline.

The questions I want answered:

• JS code to import the module
• JS code to create an instance of the module's desired WASM class
• Passing a JS callback function into the instance for the C code to invoke, with the first argument being an Unicode string
• JS code calling a C method of the WASM instance, with an Unicode string
• Excluding void main() from the generated WASM code
• Makefile changes needed to compile the C code by em
• How to migrate comments from C to WASM module, if possible
• A configure script to check for a minimal version of em (and probably nodejs as well)

Is there anyone out there who could be an effective partner in this?

Hi, I was wondering if there was any follow-up?

No, sorry, life got in the way of my ambitions. Again.

No, sorry, life got in the way of my ambitions. Again.

May I ask you a question?
I want to know how to receive functions and variables imported from JS in C language. From the tutorial, I can only see how to import functions and variables in wat format, but can not find how to operate in C language

You'll have to ask someone else. I really haven't done any WebAssembly work at all. This ticket was supposed to be a way into that for me.

May I ask you a question? I want to know how to receive functions and variables imported from JS in C language. From the tutorial, I can only see how to import functions and variables in wat format, but can not find how to operate in C language

Hey, @HackerWand. if you're still interested in an answer to that: you would use C's extern keyword before the function, and in emscripten you might need to use their macro before that, EMSCRIPTEN_KEEPALIVE. But you can always ask for how to do the same of dedicated programming assistance websites, such as stackoverflow.com.