From da847a34a0c23353d862339f9d8c772315e56b5b Mon Sep 17 00:00:00 2001
From: wpbonelli <wbonelli@ucar.edu>
Date: Sat, 10 Feb 2024 18:00:53 -0500
Subject: [PATCH] feat: fortran style transform script

* proof of concept for rewriting fortran files per style conventions
* rules currently implemented: just one variable per line
* todo: no return statements / add return statements
* todo: no empty comments / add empty comments
---
 .github/common/update_fortran_style.py | 158 +++++++++++++++++++++++++
 1 file changed, 158 insertions(+)
 create mode 100644 .github/common/update_fortran_style.py

diff --git a/.github/common/update_fortran_style.py b/.github/common/update_fortran_style.py
new file mode 100644
index 00000000000..c8bd15c500f
--- /dev/null
+++ b/.github/common/update_fortran_style.py
@@ -0,0 +1,158 @@
+import argparse
+import re
+from contextlib import nullcontext
+from itertools import repeat
+from pathlib import Path
+from typing import Iterator, Optional
+from warnings import warn
+
+from fprettify.fparse_utils import InputStream
+
+INTENT_PATTERN = re.compile(r".*(intent\(.+\)).*")
+
+
+def get_intent(s) -> Optional[str]:
+    result = INTENT_PATTERN.match(s)
+    return result.group(1) if result else None
+
+
+def get_param(s) -> bool:
+    return "parameter" in s
+
+
+def get_comments(comments) -> Iterator[str]:
+    for comment in comments:
+        if not any(comment):
+            continue
+        yield comment.rstrip()
+
+
+class Transforms:
+    @staticmethod
+    def separate_lines(path, overwrite=False):
+        """Variables defined on separate lines"""
+
+        flines = []
+        with open(path, "r") as f:
+            stream = InputStream(f)
+            while 1:
+                line, comments, lines = stream.next_fortran_line()
+                if not lines:
+                    break
+                line = line.rstrip()
+                parts = line.rpartition("::")
+                comments = " " + "".join(get_comments(comments))
+                if not parts[1] or "procedure" in parts[0]:
+                    for l in lines:
+                        flines.append(l.rstrip())
+                    continue
+
+                nspaces = len(lines[0]) - len(lines[0].lstrip())
+                prefix = "".join(repeat(" ", nspaces))
+                vtype = parts[0].split(",")[0].strip()
+                split = parts[2].split(",")
+                intent = get_intent(parts[0])
+                param = get_param(parts[0])
+
+                if not line:
+                    continue
+                if (len(parts[0]) == 0 and len(parts[1]) == 0) or (
+                    "(" in parts[2] or ")" in parts[2]
+                ):
+                    flines.append(prefix + line + comments)
+                elif len(split) == 1:
+                    flines.append(prefix + line + comments)
+                elif param:
+                    flines.append(prefix + line + comments)
+                else:
+                    for s in split:
+                        if s.strip() == "&":
+                            continue
+                        l = prefix + vtype
+                        if intent:
+                            l += f", {intent}"
+                        l += f" :: {s.strip()}"
+                        flines.append(l + comments)
+
+        with open(path, "w") if overwrite else nullcontext() as f:
+            def write(line):
+                if overwrite:
+                    f.write(line + "\n")
+                else:
+                    print(line)
+
+            for line in flines:
+                write(line)
+
+    @staticmethod
+    def no_return_statements(path, overwrite=False):
+        """Remove return statements at the end of routines"""
+        # todo
+        pass
+
+    @staticmethod
+    def no_empty_comments(path, overwrite=False):
+        """Remove comments on lines with only whitespace"""
+        # todo
+        pass
+
+
+def reformat(path, overwrite, separate_lines, no_return_statements, no_empty_comments):
+    if separate_lines:
+        Transforms.separate_lines(path, overwrite=overwrite)
+    if no_return_statements:
+        Transforms.no_return_statements(path, overwrite=overwrite)
+        warn("--no-return not implemented yet")
+    if no_empty_comments:
+        Transforms.no_empty_comments(path, overwrite=overwrite)
+        warn("--no-empty-comments not implemented yet")
+
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser(
+        """
+        Modify MODFLOW 6 Fortran source code, either writing to stdout or
+        overwriting the input file. Options are provided for several code
+        styles.
+        """
+    )
+    parser.add_argument(
+        "-i", "--input", help="path to input file"  # todo: or directory
+    )
+    parser.add_argument(
+        "-f",
+        "--force",
+        action="store_true",
+        default=False,
+        required=False,
+        help="overwrite/reformat files",
+    )
+    parser.add_argument(
+        "--separate-lines",
+        action="store_true",
+        default=True,
+        required=False,
+        help="define variables on separate lines",
+    )
+    parser.add_argument(
+        "--no-return_statements",
+        action="store_true",
+        default=False,
+        required=False,
+        help="no return statements at the end of routines",
+    )
+    parser.add_argument(
+        "--no-empty-comments",
+        action="store_true",
+        default=False,
+        required=False,
+        help="no empty comments",
+    )
+    args = parser.parse_args()
+    reformat(
+        path=Path(args.input).expanduser().absolute(),
+        overwrite=args.force,
+        separate_lines=args.separate_lines,
+        no_return_statements=args.no_return_statements,
+        no_empty_comments=args.no_empty_comments,
+    )