fix: some cli issues resolved (#1091)

Noticed these issues, and adding a table of contents like feature. If we
expand this in the future, the default should still print out help, so
it's forward compatible.

Signed-off-by: Henry Schreiner <[email protected]>

Author: henryiii

docs/reference/cli.md

@@ -4,6 +4,10 @@ Scikit-build-core has a few integrated CLI tools. These are not guaranteed to be
 stable between releases yet, but can still be useful to investigate your
 environment.
 
+```{program-output} python -m scikit_build_core
+
+```
+
 ## Build utilities
 
 ```{program-output} python -m scikit_build_core.build --help
@@ -36,7 +40,7 @@ Example:
 
 ```
 
-## Wheel tag
+## Building environment info
 
 ```{program-output} python -m scikit_build_core.builder.wheel_tag --help
 

src/scikit_build_core/__main__.py

@@ -0,0 +1,40 @@
+from __future__ import annotations
+
+from ._logging import rich_print
+
+__all__ = ["main"]
+
+
+def __dir__() -> list[str]:
+    return __all__
+
+
+def main() -> None:
+    rich_print("{blue}A top level CLI is not currently provided for scikit-build-core.")
+    rich_print("{blue}However, the following modules have CLI utilities:")
+    rich_print(
+        "  python -m scikit_build_core.build requires       {green}Get the build requirements"
+    )
+    rich_print(
+        "  python -m scikit_build_core.build project-table  {green}Get the project table (with dynamic metadata)"
+    )
+    rich_print(
+        "  python -m scikit_build_core.builder              {green}Info about the system"
+    )
+    rich_print(
+        "  python -m scikit_build_core.builder.wheel_tag    {green}Info about the computed wheel tag"
+    )
+    rich_print(
+        "  python -m scikit_build_core.builder.sysconfig    {green}Info from sysconfig"
+    )
+    rich_print(
+        "  python -m scikit_build_core.file_api.query       {green}Request CMake file API"
+    )
+    rich_print(
+        "  python -m scikit_build_core.file_api.reply       {green}Process CMake file API"
+    )
+    rich_print()
+
+
+if __name__ == "__main__":
+    main()

src/scikit_build_core/_logging.py

@@ -305,8 +305,7 @@ def rich_print(
     ``color=`` argument will set a default color to apply to every argument, and
     is available to arguments as ``{color}``.
     """
-    if color:
-        kwargs["color"] = _style[color]
+    kwargs["color"] = _style[color] if color else ""
 
     args_1 = tuple(str(arg) for arg in args)
     args_1_gen = (

src/scikit_build_core/build/__main__.py

@@ -55,7 +55,7 @@ def main() -> None:
         description="Build backend utilities.",
     )
 
-    subparsers = parser.add_subparsers(help="Commands")
+    subparsers = parser.add_subparsers(required=True, help="Commands")
     requires = subparsers.add_parser(
         "requires",
         help="Get the build requirements",