feat: adds ape vyper flatten command

ape_vyper/_cli.py

@@ -0,0 +1,25 @@
+from pathlib import Path
+
+import ape
+import click
+from ape.cli import ape_cli_context
+
+
+@click.group
+def cli():
+    """`vyper` command group"""
+
+
+@cli.command(short_help="Flatten select contract source files")
+@ape_cli_context()
+@click.argument("CONTRACT", type=click.Path(exists=True, resolve_path=True))
+@click.argument("OUTFILE", type=click.Path(exists=False, resolve_path=True, writable=True))
+def flatten(cli_ctx, contract: Path, outfile: Path):
+    """
+    Flatten a contract into a single file.
+    """
+    with Path(outfile).open("w") as fout:
+        content = ape.compilers.flatten_contract(
+            Path(contract), base_path=ape.project.contracts_folder
+        )
+        fout.write(str(content))

setup.py

@@ -67,6 +67,11 @@
     python_requires=">=3.8,<4",
     extras_require=extras_require,
     py_modules=["ape_vyper"],
+    entry_points={
+        "ape_cli_subcommands": [
+            "ape_vyper=ape_vyper._cli:cli",
+        ],
+    },
     license="Apache-2.0",
     zip_safe=False,
     keywords="ethereum",