Generate docs using Python instead of Bash

The reason for this change is that Bash script has unexpected failures
during execution in Docker on Mac. Also, as Python is already used, it
won't introduce updates to the CI environment.

.workflows/ci-pipeline.bash

@@ -31,7 +31,7 @@ pipeline() {
         --exclude=docs/*.png \
         --verbose --file=/dev/null                    || fail "Unreadable todo is identified."
     (
-        .workflows/docs-generation.bash
+        python .workflows/docs.py
         git update-index --really-refresh
         git diff-index --quiet HEAD --
     ) || fail "The documentation is not up to date. Please run './.workflows/docs-generation.bash' and commit the changes"

.workflows/docs.py

@@ -0,0 +1,52 @@
+"""The script generates 'docs/commands.md' file."""
+import subprocess
+
+from typing import List, Sequence
+
+
+def output(raw) -> str:
+    return raw.decode("utf-8")
+
+
+def command_output(command) -> List[str]:
+    return output(subprocess.check_output(command)).splitlines()
+
+
+def header(command: str):
+    return f"# `{command}`\n"
+
+
+def normalize_command_line(line: str):
+    if line.startswith("usage:"):
+        return f"```bash\n{line}\n```\n"
+    return f"{line}\n"
+
+
+def body() -> Sequence[str]:
+    print("Generate documentation...")
+    data = []
+    print("Explain 'git-elegant'...")
+    data.append(header("git-elegant"))
+    data.append("```bash\n")
+    data.extend(map(lambda line: f"{line}\n", command_output("bin/git-elegant")))
+    data.append("```\n\n")
+    for command in command_output(["bin/git-elegant", "show-commands"]):
+        print(f"Explain 'git-elegant {command}'...")
+        data.append(header(command))
+        data.extend(
+            map(
+                normalize_command_line,
+                command_output(["bin/git-elegant", command, "--help"]),
+            )
+        )
+    return data[:-1]
+
+
+def save_text(documentation: Sequence[str], destination: str) -> None:
+    print("Write documentation to", destination)
+    with open(destination, "w") as doc:
+        doc.writelines(documentation)
+
+
+if __name__ == "__main__":
+    save_text(body(), "docs/commands.md")

workflows

@@ -10,7 +10,7 @@ testing() {
 }
 
 generate-docs() {
-    .workflows/docs-generation.bash
+    python .workflows/docs.py
 }
 
 preview-docs() {