libcli for Arduino IDE

Support library to help implementing asynchronous command line interface.

Because Arduino API for serial console is mostly synchronous and blocking, it is not easy to write a sketch which accepts human interaction from serial console while controlling hardware etc. Of course we can use Serial.available() in loop() and carefully use Serial.read() not to block program flow.

So libcli library comes for help. This library offers a Cli instance as a command line interface which can

• read a letter, a word string, a line of string, decimal and hexadecimal number from serial console asynchronously.

• act as Stream and do any form of print() and println().

• print decimal number with left or right aligned in a specified width format, such as "%-6d" or "%6d" in printf().

• print hexadecimal number in specified fixed-width format, such as "%08X" in printf().

• print string with left or right aligned in a specified width, such as "%-8s" or "%8s" in printf().

Asynchronous read can be implemented with request and callback. For example, to read a 16-bit hexadecimal, call readHex() request with a callback function pointer, UINT16_MAX as a limit of input, and a context. When human finishes input with space or enter key, the callback function will be called with input value, the context passed in the request, and a input state.

You can find concrete examples at libasm and retro-bionic.

libcli::Cli cli;
using State = libcli::State;

/** NumberCallback function */
void handleHex16(uint32_t value, uintptr_t context, State state) {
    if (state == State::CLI_SPACE || state == State::CLI_ENTER) {
        cli.printHex(value, sizeof(uint16_t) * 2);
    }
}

void begin() {
    Serial.begin(9600);
    cli.begin(Serial);
    cli.print(F("16bit Hex? "));
    cli.readHex(handleHex16, context, UINT16_MAX);
}

void loop() {
    cli.loop();
    /* do other stuff */
}

The version 1.3 API has the following functions.

/** void (*LetterCallback)(char letter, uintptr_t context); */
using LetterCallback = libcli::LetterCallback;
void readLetter(LetterCallback callback, uintptr_t context);

/** void (*StringCallback)(char *string, uintptr_t context, State state); */
using StringCallback = libcli::StringCallback;
void readWord(StringCallback callback, uintptr_t context, char *buffer, size_t size, bool hasDefval = false);
void readLine(StringCallback callback, uintptr_t context, char *buffer, size_t size, bool hasDefval = false);

/** void (*NumberCallback)(uint32_t number, uintptr_t context, State state); */
using NumberCallback = libcli::NumberCallback;
void readHex(NumberCallback callback, uintptr_t context, uint32_t limit = UINT32_MAX);
void readHex(NumberCallback callback, uintptr_t context, uint32_t limit, uint32_t defVal);
void readDec(NumberCallback callback, uintptr_t context, uint23_t limit = UINt32_MAX);
void readDec(NumberCallback callback, uintptr_t context, uint23_t limit, uint32_t defVal);

void printStr(const char *text, int8_t width = 0);
void printStr(const __FlashStringHelper *text, int8_t width = 0);
void printStr_P(const /*PROGMEM*/ char *text_P, int8_t width = 0);
void printHex(uint32_t number, int8_t width = 0);
void printDec(uint32_t number, int8_t width = 0);
void printlnStr(const __FlashStringHelper *text, int8_t width = 0);
void printlnStr_P(const /*PROGMEM*/ char *text_P, int8_t width = 0);
void printlnHex(uint32_t number, int8_t width = 0);
void printlnDec(uint32_t number, int8_t width = 0);
void backspace(int8_t n = 1);

Note	More information about this library can be found at GitHub