The GNAT-LLVM project provides an opportunity to port Ada to new platforms, one of which is WebAssembly. We conducted an experiment to evaluate the porting of Ada and the development of bindings to use Web API provided by the browser directly from Ada applications.

Subtotals

As a result of the experiment, the standard language library and runtime library were partially ported. Together with a binding for the Web API, this allowed us to write a simple example showing the possibility of using Ada for developing applications compiled into WebAssembly and executed inside the browser. At the same time, there are some limitations both of WebAssembly and of the current GNAT-LLVM implementation:

the inability to use tasks and protected types

support for exceptions limited to local propagation and the last chance handler

the inability to use nested subprograms

Example

Here is small example of an Ada program that shows/hides the text when pressing the button by manipulating attributes of document nodes.