bp_cmd Interactive Prompting

Developer reference for driving interactive prompts via bp_cmd_prompt() and the dual-path (CLI / interactive) pattern.

bp_cmd_prompt() API 

bp_cmd_status_t bp_cmd_prompt(const bp_val_constraint_t *con, void *out);

bp_cmd_prompt() drives an interactive prompt loop from a constraint descriptor:

Constraint typeBehaviour
BP_VAL_UINT32Shows range display (min–max), validates input, retries on error
BP_VAL_CHOICEShows numbered menu, accepts name / alias / number

Return values

ValueMeaning
BP_CMD_OKUser provided a valid value
BP_CMD_EXITUser cancelled the prompt

Dual-Path Pattern

Check the “primary” argument first. If it is missing, fall back to interactive prompts. This lets every command work both from the command line and as a guided wizard.

Mode Setup — src/mode/hwuart.c 

bp_cmd_status_t st = bp_cmd_flag(&uart_setup_def, 'b', &mode_config.baudrate);
if (st == BP_CMD_INVALID) return 0;
bool interactive = (st == BP_CMD_MISSING);

if (interactive) {
    // Try loading saved settings first
    if (storage_load_mode(config_file, config_t, count_of(config_t))) {
        printf("\r\n\r\n%s%s%s\r\n", ui_term_color_info(),
               GET_T(T_USE_PREVIOUS_SETTINGS), ui_term_color_reset());
        hwuart_settings();
        prompt_result result;
        bool user_value;
        if (!ui_prompt_bool(&result, true, true, true, &user_value)) {
            return 0;
        }
        if (user_value) {
            return 1; // User accepted saved settings
        }
    }

    // Full interactive wizard
    if (bp_cmd_prompt(&uart_baud_range, &mode_config.baudrate) != BP_CMD_OK) return 0;
    if (bp_cmd_prompt(&uart_databits_range, &temp) != BP_CMD_OK) return 0;
    mode_config.data_bits = (uint8_t)temp;
    if (bp_cmd_prompt(&uart_parity_choice, &temp) != BP_CMD_OK) return 0;
    mode_config.parity = (uint8_t)temp;
    // ... remaining prompts ...
} else {
    // CLI mode — remaining flags use defaults if absent
    st = bp_cmd_flag(&uart_setup_def, 'd', &temp);
    if (st == BP_CMD_INVALID) return 0;
    mode_config.data_bits = (uint8_t)temp;
    // ... remaining flags ...
}
storage_save_mode(config_file, config_t, count_of(config_t));

Command with Positionals — src/commands/global/w_psu.c 

// Get voltage from command line
s = bp_cmd_positional(&psucmd_enable_def, 1, &volts);
if (s == BP_CMD_MISSING || s == BP_CMD_INVALID) {
    // Not on command line — prompt interactively
    if (bp_cmd_prompt(&voltage_range, &volts) != BP_CMD_OK) {
        res->error = true;
        return;
    }
    if (bp_cmd_prompt(&current_range, &current) != BP_CMD_OK) {
        res->error = true;
        return;
    }
} else {
    // Voltage on command line — try current too
    if (bp_cmd_positional(&psucmd_enable_def, 2, &current) == BP_CMD_INVALID) {
        res->error = true;
        return;
    }
}

BP_VAL_UINT32 Prompts

Define a numeric range constraint and pass it to bp_cmd_prompt():

static const bp_val_constraint_t uart_baud_range = {
    .type = BP_VAL_UINT32,
    .u = { .min = 1, .max = 7372800, .def = 115200 },
    .prompt = T_UART_SPEED_MENU,
    .hint = T_UART_SPEED_MENU_1,
};

Prompt flow: prompt text → range (min–max) → default → validate input → loop on error.

BP_VAL_CHOICE Prompts

Define a choice array and a constraint that references it:

static const bp_val_choice_t parity_choices[] = {
    { "none", "n", T_UART_PARITY_MENU_1, 0 },
    { "even", "e", T_UART_PARITY_MENU_2, 1 },
    { "odd",  "o", T_UART_PARITY_MENU_3, 2 },
};
static const bp_val_constraint_t uart_parity_choice = {
    .type = BP_VAL_CHOICE,
    .choice = { .choices = parity_choices, .count = 3, .def = 0 },
    .prompt = T_UART_PARITY_MENU,
};

Prompt flow: numbered menu with labels → accepts name / alias / number → validate.

Saved Configuration Integration

Modes combine bp_cmd_prompt() with the storage subsystem so users can reuse previous settings:

  1. storage_load_mode() — read config from flash.
  2. Display the loaded values to the user.
  3. ui_prompt_bool() — ask “Use previous settings?”
  4. If yes → skip the wizard and return immediately.
  5. If no → run the full prompt sequence.
  6. storage_save_mode() — persist the new settings after setup completes.