options gen2

// Sandbox policy file for C++ integration tutorial 16.
//
// This .das_project is loaded by the host application and defines the
// security policy for user scripts.  The compiler invokes these [export]
// callbacks during compilation to decide what is allowed.
//
// Callbacks:
//   module_get             — resolve `require` paths to files (REQUIRED)
//   module_allowed         — whitelist which modules can be loaded
//   module_allowed_unsafe  — control whether unsafe blocks are permitted
//   option_allowed         — whitelist which `options` directives are accepted
//   annotation_allowed     — whitelist which annotations are accepted

require strings
require daslib/strings_boost

// Return type for module_get: (moduleName, fileName, importName)
typedef module_info = tuple<string; string; string> const

// Set by the runtime to the directory containing this .das_project file.
var DAS_PAK_ROOT = "./"

// ---------------------------------------------------------------------------
// module_get — module path resolution (REQUIRED)
// ---------------------------------------------------------------------------
[export]
def module_get(req, from : string) : module_info {
    let rs <- split_by_chars(req, "./")
    let mod_name = rs[length(rs) - 1]
    if (length(rs) == 2 && rs[0] == "daslib") {
        return (mod_name, "{get_das_root()}/daslib/{mod_name}.das", "")
    }
    // Relative module: resolve from the requiring file's directory
    var fr <- split_by_chars(from, "/")
    if (length(fr) > 0) {
        pop(fr)
    }
    for (se in rs) {
        push(fr, se)
    }
    let path_name = join(fr, "/") + ".das"
    return (mod_name, path_name, "")
}

// ---------------------------------------------------------------------------
// module_allowed — module whitelist
// ---------------------------------------------------------------------------
[export]
def module_allowed(mod, filename : string) : bool {
    if (mod == "$") {
        return true         // built-in core (always needed)
    }
    if (mod == "math" || mod == "strings") {
        return true         // safe native modules
    }
    if (mod == "strings_boost") {
        return true         // safe daslib module
    }
    return false            // block fio, network, ast, json, etc.
}

// ---------------------------------------------------------------------------
// module_allowed_unsafe — no module may use unsafe blocks
// ---------------------------------------------------------------------------
[export]
def module_allowed_unsafe(mod, filename : string) : bool {
    return false
}

// ---------------------------------------------------------------------------
// option_allowed — only safe, cosmetic options
// ---------------------------------------------------------------------------
[export]
def option_allowed(opt, from : string) : bool {
    if (opt == "gen2" || opt == "indenting") {
        return true
    }
    if (opt == "no_unused_function_arguments" || opt == "no_unused_block_arguments") {
        return true
    }
    return false
}

// ---------------------------------------------------------------------------
// annotation_allowed — only common safe annotations
// ---------------------------------------------------------------------------
[export]
def annotation_allowed(ann, from : string) : bool {
    if (ann == "export" || ann == "private") {
        return true
    }
    return false
}