Re: [fpc-pascal] Adding Javascript to Pascal

[Mattias Gaertner via fpc-pascal]

On 2/21/25 12:04, Anthony Walter via fpc-pascal wrote:
[...]
Javascript:

let data = { name: "James", age: 25 };

function update(name) {
   data.name = name;
}

function verify(note) {
   console.log("received note " + note);
   console.log("data name is " + data.name);
   hello(data, " message from javascript");
   console.log("table size is " + table.size[0] + " by " + table.size[1]);
}

Pascal:

function JavascriptCallback(Script: IScript; Args: TScriptValues):
TScriptValue;
begin
   WriteLn(Args[0].age, Args[1]);



   // writes 25 message from javascript
   Result := Nothing;
end;

var
   TestScript: IJavascript;

procedure LoadScript;
begin
    Script := NewScript(MyScriptText);
    Script.Global.table.size := [15, 6];
    // { table: { size: [15, 6] } } is now available to javascript

Here I see one big problem.
Pascal needs specific types at compile-time.
JS at compile time can only check some basic syntax. An IDE can use some 
heuristic to guess, what an identifier is referring to, but how should 
that work with a compiler?



    Script.Global.hello := Script.DefineCallback(JavascriptCallback);
end;

procedure CallScript;
begin
   // Call the javascript verify method passing it a note
   Script.Global.verify("a note from pascal");
   // verify will call back out JavascriptCallback function
   Script.Global.update("Ralph");
end;

Mattias

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