How to keep Risor state between different Eval()

[gmelchett]

Hi,

I've been trying out Risor as an embedded language for a pet project. I'm happy with Risor so far and it seems to fit my needs. However I need to be able to keep the Risor state between different Eval() calls. Example:

func main() {
        ctx := context.Background()

        result, err := risor.Eval(ctx, "a := 5; b := 6")
        fmt.Printf("eval result: %v err: %v\n", result, err)

        result, err = risor.Eval(ctx, "print(a); print(b)")
        fmt.Printf("eval result: %v err: %v\n", result, err)
}

This fails, since the second Eval() has no knowledge of the previous Eval()s state. I can't seem to figure out how to, in this example, to keep what a and b is set to for the second Eval() call. In this example I guess I could add 'return [a, b]' and then use the result with 'WithGlobalsfor the secondEval()`, but I need something generic.
Can this be done? If then how? Thanks!

[gmelchett]

Had a look in: cmd/risor/repl/repl.go and got a short example working (error checks removed):

func main() {
        cfg := risor.NewConfig()
        ctx := context.Background()

        c, _ := compiler.New(cfg.CompilerOpts()...)

        ast, _ := parser.Parse(ctx, "a := 5; b := 6; c := 4; func value() { 77 }")
        code, _ := c.Compile(ast)

        vm := vm.New(code, cfg.VMOpts()...)

        vm.Run(ctx)

        ast, _ = parser.Parse(ctx, "print(b); print(value())")
        c.Compile(ast)

        vm.Run(ctx)
}

It seems to be working, but I have no idea how print(b); print(value()) gets loaded into the vm. Perhalps via ctx?

Well, I'm satisified, but IMHO Risor would benefit for a nicer API for this kind of usecase.
Anyway, thanks a lot for all the efforts put into Risor!