Collect CLI arguments sent to basilisp run or Basilisp scripts (#781)

Fixes #779

Author: chrisrink10

CHANGELOG.md

@@ -7,11 +7,12 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ## [Unreleased]
 ### Added
  * Added support for passing through `:tag` metadata to the generated Python AST (#354)
+ * Added support for calling symbols as functions on maps and sets (#775)
+ * Added support for passing command line arguments to Basilisp (#779)
 
 ### Changed
  * Optimize calls to Python's `operator` module into their corresponding native operators (#754)
  * Allow vars to be callable to adhere to Clojure conventions (#767)
- * Support symbols as fns for sets and maps (#775)
 
 ### Fixed
  * Fix issue with `(count nil)` throwing an exception (#759)

src/basilisp/cli.py

@@ -13,6 +13,7 @@
 from basilisp.lang import reader as reader
 from basilisp.lang import runtime as runtime
 from basilisp.lang import symbol as sym
+from basilisp.lang import vector as vec
 from basilisp.prompt import get_prompter
 
 CLI_INPUT_FILE_PATH = "<CLI Input>"
@@ -417,6 +418,11 @@ def run(
     with runtime.ns_bindings(args.in_ns) as ns:
         ns.refer_all(core_ns)
 
+        if args.args:
+            cli_args_var = core_ns.find(sym.symbol(runtime.COMMAND_LINE_ARGS_VAR_NAME))
+            assert cli_args_var is not None
+            cli_args_var.bind_root(vec.vector(args.args))
+
         if args.code:
             eval_str(args.file_or_code, ctx, ns, eof)
         elif args.file_or_code == STDIN_FILE_NAME:
@@ -445,6 +451,11 @@ def _add_run_subcommand(parser: argparse.ArgumentParser):
     parser.add_argument(
         "--in-ns", default=runtime.REPL_DEFAULT_NS, help="namespace to use for the code"
     )
+    parser.add_argument(
+        "args",
+        nargs=argparse.REMAINDER,
+        help="command line args made accessible to the script as basilisp.core/*command-line-args*",
+    )
     _add_compiler_arg_group(parser)
     _add_debug_arg_group(parser)
 
@@ -490,7 +501,12 @@ def run_script():
     The current process is replaced as by `os.execlp`."""
     # os.exec* functions do not perform shell expansion, so we must do so manually.
     script_path = Path(sys.argv[1]).resolve()
-    os.execlp("basilisp", "basilisp", "run", script_path)
+    args = ["basilisp", "run", str(script_path)]
+    # Collect arguments sent to the script and pass them onto `basilisp run`
+    if rest := sys.argv[2:]:
+        args.append("--")
+        args.extend(rest)
+    os.execvp("basilisp", args)
 
 
 def invoke_cli(args: Optional[Sequence[str]] = None) -> None:

src/basilisp/lang/runtime.py

@@ -82,6 +82,7 @@
 
 # Public basilisp.core symbol names
 COMPILER_OPTIONS_VAR_NAME = "*compiler-options*"
+COMMAND_LINE_ARGS_VAR_NAME = "*command-line-args*"
 DEFAULT_READER_FEATURES_VAR_NAME = "*default-reader-features*"
 GENERATED_PYTHON_VAR_NAME = "*generated-python*"
 PRINT_GENERATED_PY_VAR_NAME = "*print-generated-python*"
@@ -2083,6 +2084,26 @@ def in_ns(s: sym.Symbol):
         dynamic=True,
     )
 
+    # Dynamic Var containing command line arguments passed via `basilisp run`
+    Var.intern(
+        CORE_NS_SYM,
+        sym.symbol(COMMAND_LINE_ARGS_VAR_NAME),
+        None,
+        dynamic=True,
+        meta=lmap.map(
+            {
+                _DOC_META_KEY: (
+                    "A vector of command line arguments if this process was started "
+                    "with command line arguments as by ``basilisp run {file_or_code}`` "
+                    "or ``nil`` otherwise.\n\n"
+                    "Note that this value will differ from ``sys.argv`` since it will "
+                    "not include the command line arguments consumed by Basilisp's "
+                    "own CLI."
+                )
+            }
+        ),
+    )
+
     # Dynamic Var for introspecting the default reader featureset
     Var.intern(
         CORE_NS_SYM,

tests/basilisp/cli_test.py

@@ -8,7 +8,7 @@
 import tempfile
 import time
 from threading import Thread
-from typing import Optional, Sequence
+from typing import List, Optional, Sequence
 from unittest.mock import patch
 
 import attr
@@ -164,20 +164,50 @@ def test_other_exception(self, run_cli):
 
 
 class TestRun:
+    cli_args_params = [
+        ([], "0\n"),
+        (["--"], "0\n"),
+        (["1", "2", "3"], "6\n"),
+        (["--", "1", "2", "3"], "6\n"),
+    ]
+    cli_args_code = "(println (apply + (map int *command-line-args*)))"
+
     def test_run_code(self, run_cli):
         result = run_cli(["run", "-c", "(println (+ 1 2))"])
         assert "3\n" == result.lisp_out
 
+    @pytest.mark.parametrize("args,ret", cli_args_params)
+    def test_run_code_with_args(self, run_cli, args: List[str], ret: str):
+        result = run_cli(["run", "-c", self.cli_args_code, *args])
+        assert ret == result.lisp_out
+
     def test_run_file(self, isolated_filesystem, run_cli):
         with open("test.lpy", mode="w") as f:
             f.write("(println (+ 1 2))")
         result = run_cli(["run", "test.lpy"])
         assert "3\n" == result.lisp_out
 
+    @pytest.mark.parametrize("args,ret", cli_args_params)
+    def test_run_file_with_args(
+        self, isolated_filesystem, run_cli, args: List[str], ret: str
+    ):
+        with open("test.lpy", mode="w") as f:
+            f.write(self.cli_args_code)
+        result = run_cli(["run", "test.lpy", *args])
+        assert ret == result.lisp_out
+
     def test_run_stdin(self, run_cli):
         result = run_cli(["run", "-"], input="(println (+ 1 2))")
         assert "3\n" == result.lisp_out
 
+    @pytest.mark.parametrize("args,ret", cli_args_params)
+    def test_run_stdin_with_args(self, run_cli, args: List[str], ret: str):
+        result = run_cli(
+            ["run", "-", *args],
+            input=self.cli_args_code,
+        )
+        assert ret == result.lisp_out
+
 
 def test_version(run_cli):
     result = run_cli(["version"])
@@ -191,7 +221,14 @@ def test_version(run_cli):
         "so this doesn't work natively on Windows"
     ),
 )
-def test_run_script(tmp_path: pathlib.Path):
+@pytest.mark.parametrize(
+    "args,ret",
+    [
+        ([], b"nil\n"),
+        (["1", "hi", "yes"], b"[1 hi yes]\n"),
+    ],
+)
+def test_run_script(tmp_path: pathlib.Path, args: List[str], ret: bytes):
     script_path = tmp_path / "script.lpy"
     script_path.write_text(
         "\n".join(
@@ -200,10 +237,12 @@ def test_run_script(tmp_path: pathlib.Path):
                 "(ns test-run-script-ns ",
                 "  (:import os))",
                 "",
-                '(println "Hello world from Basilisp!")',
+                "(println *command-line-args*)",
             ]
         )
     )
     script_path.chmod(script_path.stat().st_mode | stat.S_IEXEC)
-    res = subprocess.run([script_path.resolve()], check=True, capture_output=True)
-    assert res.stdout == b"Hello world from Basilisp!\n"
+    res = subprocess.run(
+        [script_path.resolve(), *args], check=True, capture_output=True
+    )
+    assert res.stdout == ret