Added a simple build script

src/build.py

@@ -0,0 +1,88 @@
+# Copyright 2020 Mattia Giambirtone
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# A minimalistic build script for JAPL
+
+import os
+import shlex
+import logging
+import argparse
+from time import time
+from typing import Dict
+from subprocess import Popen, PIPE, DEVNULL
+
+
+def build(path: str = os.getcwd(), flags: Dict[str, str] = {}):
+    """
+    Compiles the JAPL runtime, nim 1.2 or above is required to build it
+
+    :param path: The directory where JAPL's main.nim file
+    is located, defaults to the current directory
+    :type path: string, optional
+    :param flags: Any extra compiler flags that will
+    be passed to nim. Keys and values should be strings,
+    but any object with a proper __str__ or __repr__
+    method is probably fine as long as it's a valid
+    nim option for the compiler. Defaults to {} (no flags)
+    :type flags: dict, optional
+    """
+
+    logging.info("JAPL build script version 0.1")
+    if not os.path.exists(path):
+        logging.error(f"Input path '{path}' does not exist")
+        return
+    logging.debug(f"Compiling '{os.path.join(path, 'main.nim')}'")
+    nim_flags = " ".join(f"-{name}:{value}" if len(name) == 1 else f"--{name}:{value}" for name, value in flags.items())
+    command = "nim {flags} compile {path}"
+    command = command.format(flags=nim_flags, path=os.path.join(path, 'main.nim'))
+    logging.debug(f"Running '{command}'")
+    logging.info("Compiling JAPL")
+    start = time()
+    try:
+        process = Popen(shlex.split(command), stdout=DEVNULL, stderr=PIPE)
+        _, stderr = process.communicate()
+        stderr = stderr.decode()
+        assert process.returncode == 0, f"Command '{command}' exited with non-0 exit code {process.returncode}, output below:\n{stderr}"
+    except Exception as fatal:
+        logging.error(f"A fatal unhandled exception occurred -> {type(fatal).__name__}: {fatal}")
+    else:
+        logging.debug(f"Compilation completed in {time() - start:.2f} seconds")
+        logging.info("Build completed")
+
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser()
+    parser.add_argument("--path", help="The directory where JAPL's main.nim file is located, defaults to the current directory")
+    parser.add_argument("--verbose", help="Prints debug information to stdout", action="store_true")
+    parser.add_argument("--flags", help="Optional flags to be passed to the nim compiler. Must be a comma-separated list of name:value (without spaces)")
+    args = parser.parse_args()
+    flags = {}
+    if args.verbose:
+        level = logging.DEBUG
+    else:
+        level = logging.INFO
+    logging.basicConfig(format="[%(levelname)s - %(asctime)s] %(message)s",
+                        datefmt="%T",
+                        level=level
+                        )
+    if args.flags:
+        try:
+            for value in args.flags.split(","):
+                k, v = value.split(":", maxsplit=2)
+                flags[k] = v
+        except Exception:
+            logging.error("Invalid parameter for --flags")
+            exit()
+    build(args.path or os.getcwd(), flags)
+    logging.debug("Build tool exited")