VSCode extension for quick semantic info - visual-studio-code

Question

I am used to point the mouse and get information about certain references in Visual studio code.
Here one example, using Javascript, I point the mouse to a function reference and I get information about the function signature.
I would like to have something similar to other files.
e.g.
Take the following example, in a less popular language
module top #(
parameter NB=4
);
logic [NB /*I would like info here */ -1:0] b;
endmodule
How can I write an extension that when I point the mouse to the parameter it shows me the the declaration in a box, preferably with the same syntax highlight as it is shown in the editor.

Answer 1

Now there is a pull request with a sample to vscode-extension-samples.
Basically you have to write something like this
import * as vscode from 'vscode';
class SimpleHoverProvider implements vscode.HoverProvider {
public provideHover(
document: vscode.TextDocument,
position: vscode.Position,
token: vscode.CancellationToken
): vscode.Hover | null {
return new vscode.Hover(`${location.line}: ${location.character}`);
// return null; if there is no information to show
}
}
export function activate(context: vscode.ExtensionContext) {
// Use the console to output diagnostic information (console.log) and errors (console.error)
// This line of code will only be executed once when your extension is activated
console.log('Congratulations, hover-provider-sample extension is active!');
const hoverProvider = new SimpleHoverProvider();
vscode.languages.registerHoverProvider('text', hoverProvider);
}
And define languages and activation events on package.json
{
"activationEvents": [
"onLanguage:text",
"onLanguage:report"
],
"contributes": {
"languages": [
{
"id": "text",
"extensions": [
".txt"
]
},
{
"id": "report",
"extensions": [
".rpt"
]
}
]
},
}