foo.v

module main

import vweb

struct App {
	vweb.Context
	alphabets []string
}

fn new_app(alphabets []string) &App {
	assert alphabets == ['a', 'b', 'c']

	return &App{
		alphabets: alphabets
	}
}

fn (mut app App) index() vweb.Result {
	return app.text('alphabets: ${app.alphabets}')
}

fn main() {
	vweb.run(new_app(['a', 'b', 'c']), 8080)
}

I found changing alphabets to shared works, while I'm not sure if it's the right approach.

module main

import vweb

struct App {
	vweb.Context
mut:
	alphabets shared []string
}

fn new_app(alphabets []string) &App {
	assert alphabets == ['a', 'b', 'c']

	mut app := &App{}

	lock app.alphabets {
		app.alphabets = alphabets
	}

	return app
}

fn (mut app App) index() vweb.Result {
	text := rlock app.alphabets {
		'alphabets: $app.alphabets'
	}
	return app.text(text)
}

fn main() {
	vweb.run(new_app(['a', 'b', 'c']), 8080)
}