v1.3.1

modules.cpp v1.3.1

Something to connect and store with. v1.3.0 gave the project a language of its
own with sketches and a native shell; v1.3.1 gives programs standard USB
connectivity and mass storage: the USB subsystem (mm.usb) introduces device
and host abstractions, CDC ACM console communication for mm.stdio, and SCSI
Mass Storage Class (mm.usb.msc) for block storage; sketches gain secondary
peripheral buses (Wire1, Wire2, Serial1, Serial2), interrupts, SD card
redirection, and a legacy profile (sketch --legacy) for seamless third-party
Arduino library compatibility; native USB port ownership is unlocked on
Raspberry Pi Pico; Linux adds emulated ST7789 and ILI9341 display support over
SDL2; and fenced code blocks arrive in mm.mdy.

out/bin/sketch apps/ino/blink && ./build.sh apps/ino/blink/
./scripts/build-pico.sh --board pico_usb_device --app apps/shell-smoke --dry-run
./scripts/build-linux.sh --board lcd --app apps/gfx-demo --dry-run
./test.sh

The USB subsystem introduces standard USB vocabularies and platform interfaces.
mm.usb defines status, speed, transfer types, endpoint addresses, and setup
packets. mm.usb.device provides nonblocking asynchronous transfers, device
descriptors, and setup request dispatching. mm.usb.host handles device
enumeration, pipe allocation, and interface claiming. On top of these,
mm.usb.cdc supplies CDC ACM device functions and a CdcConsole provider for
mm.stdio, mm.usb.msc implements Bulk-Only Transport (BOT) backing block
storage via transparent SCSI commands, and mm.usb.vendor provides echo
devices and hosts for loopback qualification.

Sketches expand their hardware reach and library compatibility. Wire1 and
Wire2 add second and third I2C buses with independent buffers, pins, and clock
configuration. Serial1 and Serial2 expose hardware UART streams with pin
assignment, timeouts, and nonblocking reads. The legacy profile
(sketch --legacy) enables seamless compilation of third-party Arduino
libraries by providing using namespace mm::sketch::legacy, defining
ARDUINO=10819, redirecting SD.h to SdFat, exporting standard SPI pin names
(SS, MOSI, MISO, SCK), providing flash helper macros, and adding
interrupts() and noInterrupts() control.

On hardware and platforms, Raspberry Pi Pico gains native USB port ownership
options (console vs application) with dedicated pico_usb_device and
pico2_usb_device boards, while pico_usb_host and pico2_usb_host support
mass storage drives via Pico-PIO-USB. On Linux, platforms/linux/lcd provides
emulated ST7789 and ILI9341 displays rendered in SDL2 windows for desktop
graphics development, and platforms/linux/libusb provides the Linux USB host
provider.

mm.mdy now natively parses multi-line fenced code blocks with language tags,
preserving indentation and blank lines, and renders them into HTML <pre><code class="language-..."> tags. tools/flash adds --auto-flash for automatic
Pico device discovery and bootloader reset, configure adds --check to audit
manifest trees, and bootstrap.sh supports custom compiler overrides via
--compiler.

USB device and host hardware operations have been qualified on Raspberry Pi
Pico and Linux host. Emulated displays require SDL2 development libraries on
the host.

mm: 1.0, mm: 1.1, mm: 1.2, and mm: 1.3 manifests remain fully
supported.

Requires a C++20 compiler with module support (GCC 15 recommended, Clang 16+),
a POSIX shell, and libusb / SDL2 for hosted providers. See
CHANGELOG.md for the full change list,
docs/modules-usb.mdy for the USB subsystem, docs/modules-sketch.mdy and
docs/modules-ino.mdy for sketches, and docs/modules-platform-pico.mdy for
Pico platform details.