Add platform and board validation to target workflow

README.md

@@ -90,10 +90,12 @@ pip install platformio  # required for automatic uploads
 
 Place `target()` **at the very top of your script**, immediately after imports. This is the entry point that tells Reduino to parse your entire file, transpile it to Arduino C++, and (optionally) upload it.
 
-| Parameter |  Type  | Default | Description                                                             |
-| --------: | :----: | :-----: | ----------------------------------------------------------------------- |
-|    `port` |  `str` |    —    | Serial port, e.g. `"COM3"` or `"/dev/ttyACM0"`.                         |
-|  `upload` | `bool` |  `True` | If `True`, compile & upload via PlatformIO. If `False`, only transpile. |
+| Parameter  |  Type  |   Default    | Description                                                                 |
+| ---------: | :----: | :----------: | --------------------------------------------------------------------------- |
+|     `port` |  `str` |      —       | Serial port, e.g. `"COM3"` or `"/dev/ttyACM0"`.                             |
+|   `upload` | `bool` |    `True`    | If `True`, compile & upload via PlatformIO. If `False`, only transpile.     |
+| `platform` |  `str` | `"atmelavr"` | PlatformIO platform ID. Reduino currently supports `atmelavr` and `atmelmegaavr`. |
+|    `board` |  `str` |   `"uno"`    | PlatformIO board ID. Must be compatible with `platform`. |
 
 **Returns:** `str` of the generated Arduino C++ source.
 
@@ -145,6 +147,31 @@ print(cpp)
 # Your Reduino code below...
 ```
 
+### Targeting different platforms & boards
+
+Reduino validates that the requested PlatformIO platform/board pair is supported.
+At the moment two PlatformIO platforms are available:
+
+* `atmelavr` – classic AVR-based boards (Uno, Nano, Leonardo, etc.).
+* `atmelmegaavr` – newer megaAVR devices (Nano Every, Uno WiFi Rev2, Curiosity Nano kits, ...).
+
+Every board listed in the [PlatformIO board registry for all platforms](https://docs.platformio.org/en/latest/boards/index.html) can be targeted. If you choose an unsupported board, or one that does not belong to the selected platform, `target()` raises a `ValueError` with a helpful message.
+
+```python
+from Reduino import target
+
+# Build for an Arduino Nano Every without uploading automatically.
+target(
+    "COM9",
+    upload=False,
+    platform="atmelmegaavr",
+    board="nano_every",
+)
+
+# Build for a classic Arduino Uno and upload immediately.
+target("/dev/ttyUSB0", platform="atmelavr", board="uno")
+```
+
 > [!IMPORTANT]
 > `target()` reads the whole file text and generates code for everything below it.
 > If `upload=True`, it also builds and flashes using a temporary PlatformIO project.

src/Reduino/__init__.py

@@ -10,7 +10,12 @@
 import tempfile
 from typing import List, Type
 
-from Reduino.toolchain.pio import compile_upload, ensure_pio, write_project
+from Reduino.toolchain.pio import (
+    compile_upload,
+    ensure_pio,
+    validate_platform_board,
+    write_project,
+)
 from Reduino.transpile.ast import LCDDecl, Program, ServoDecl
 from Reduino.transpile.emitter import emit
 from Reduino.transpile.parser import parse
@@ -83,7 +88,13 @@ def _visit(value: object) -> None:
     return requirements
 
 
-def target(port: str, *, upload: bool = True) -> None:
+def target(
+    port: str,
+    *,
+    upload: bool = True,
+    platform: str = "atmelavr",
+    board: str = "uno",
+) -> None:
     """Transpile the invoking script and prepare a PlatformIO project.
 
     Parameters
@@ -95,8 +106,20 @@ def target(port: str, *, upload: bool = True) -> None:
         after generating the temporary project directory.  Uploading is
         disabled by default so that unit tests can exercise the helper without
         requiring an Arduino board to be connected.
+    platform:
+        PlatformIO platform identifier.  Defaults to ``"atmelavr"`` for Arduino
+        AVR boards.
+    board:
+        PlatformIO board identifier.  Defaults to ``"uno"``.
+
+    Raises
+    ------
+    ValueError
+        If the requested platform or board is not supported or if the
+        combination is incompatible.
     """
 
+    validate_platform_board(platform, board)
     ensure_pio()
 
     main_file = pathlib.Path(sys.modules["__main__"].__file__)
@@ -112,8 +135,15 @@ def target(port: str, *, upload: bool = True) -> None:
     cpp = emit(program)
 
     tmp = pathlib.Path(tempfile.mkdtemp(prefix="reduino-pio-"))
-    write_project(tmp, cpp, port=port, lib_deps=required_libs)
+    write_project(
+        tmp,
+        cpp,
+        port=port,
+        platform=platform,
+        board=board,
+        lib_deps=required_libs,
+    )
     if upload:
         compile_upload(tmp)
 
-    return cpp
+    return cpp