# Interactive prototyping workflows

**URL:** <https://discourse.julialang.org/t/interactive-prototyping-workflows/133265>\
**Category:** New to Julia\
**Tags:** question, workflow\
**Created:** [October 18, 2025, 5:42pm UTC](https://discourse.julialang.org/t/interactive-prototyping-workflows/133265 "2025-10-18T17:42:46Z")\
**Posts on this page:** 1\
**Showing post:** 36

<div class="post-metadata">

**Author:** ![kousu](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/kousu/32/219064_2.png) [@kousu](https://discourse.julialang.org/u/kousu)\
**Post date:** [October 24, 2025, 3:29am UTC](https://discourse.julialang.org/t/interactive-prototyping-workflows/133265/36 "2025-10-24T03:29:01Z")

</div>

> [@Benny](#):
>
> That looks like
> 
> ```julia-auto
> using REPL; let m = Module()
> Base.include(m, "my_script.jl") # not the module-specific include
> REPL.activate(m)
> end
> 
> ```

I followed this on a flight of fancy. In my startup.jl:

```julia-auto
if isinteractive()
# https://discourse.julialang.org/t/interactive-prototyping-workflows/133265/30
import REPL
struct InteractiveMode end
Interactive = InteractiveMode()
(::Base.IncludeInto)(script::String, ::Val{Interactive}) = begin
  let m = Module(Symbol(script))
    Base.include(m, script) # not the module-specific include
    REPL.activate(m)
  end
end
(::Base.IncludeInto)(script::String, interactive::InteractiveMode) = include(script, Val(interactive))
end

```

I tried to make `include(script; interactive=true)` work but I couldn’t get the magic of `Val()` to work with keyword arguments. I guess you don’t really need the type-based multiple dispatch, that was the flight of fancy part.

Demo:

```julia-auto

julia> run(`cat t.jl`);

A = 1
display(A)

julia> include("t.jl", Interactive)
1

(Main.var"t.jl") julia> A
1

(Main.var"t.jl") julia> A = 8
8

(Main.var"t.jl") julia> Main.REPL.activate(Main) # quit

julia> A # namespace was not polluted
ERROR: UndefVarError: `A` not defined in `Main`
Suggestion: check for spelling errors or missing imports.

```

I’m not sure if I’ll like it, yet. `REPL.activate` doesn’t nest; rather, it simply updates a global pointer to what module you’re interacting with, so to step out of it you have to explicitly step back to the previous module you were in; and also you need to call it `Main.REPL.activate` when you’re inside the other module. **I** wish I could Ctrl-D to get back to `Main`.

I’m not sure either how this interacts with garbage collection. It’s neat though!

I feel like this is worth branching into another thread if you want to continue developing this.

---

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