Patch up long lines in choices

Author: masaccio

README.md

@@ -40,10 +40,12 @@ usage: fractured-json [-h] [-V] [--output OUTPUT]
                       [--max-total-line-length N]
                       [--min-compact-array-row-items N]
                       [--nested-bracket-padding]
-                      [--number-list-alignment {LEFT,RIGHT,DECIMAL,NORMALIZE}]
+                      [--number-list-alignment {LEFT,RIGHT,DECIMAL,
+                                                NORMALIZE}]
                       [--prefix-string PREFIX_STRING]
                       [--preserve-blank-lines] [--simple-bracket-padding]
-                      [--table-comma-placement {BEFORE_PADDING,AFTER_PADDING,BEFORE_PADDING_EXCEPT_NUMBERS}]
+                      [--table-comma-placement {BEFORE_PADDING,AFTER_PADDING,
+                                                BEFORE_PADDING_EXCEPT_NUMBERS}]
                       [--use-tab-to-indent] [--east-asian-chars]
                       [json ...]
 
@@ -149,7 +151,8 @@ options:
                         array/object has a complexity of 1. That is, if it
                         only contains primitive elements and/or empty
                         arrays/objects. (default=False)
-  --table-comma-placement {BEFORE_PADDING,AFTER_PADDING,BEFORE_PADDING_EXCEPT_NUMBERS}
+  --table-comma-placement {BEFORE_PADDING,AFTER_PADDING,
+                           BEFORE_PADDING_EXCEPT_NUMBERS}
                         Where to place commas in table-formatted elements.
                         (default=BEFORE_PADDING_EXCEPT_NUMBERS)
   --use-tab-to-indent   If true, a single tab character is used per

src/build/generate_readme.py

@@ -5,20 +5,39 @@
 from pathlib import Path
 from typing import Final
 
+MAX_COLUMNS = 76
+
+
+def last_comma_after_pos(s: str, start: int) -> int:
+    """Find index of last comma in s after a start position."""
+    return s.rfind(",", start)
+
 
 def main() -> None:
     docs_readme: Final[Path] = Path("docs/README.md")
     out_readme: Final[Path] = Path("README.md")
 
-    environ["COLUMNS"] = "76"
+    environ["COLUMNS"] = str(MAX_COLUMNS)
     result = subprocess.run(
         ["fractured-json", "--help"],  # noqa: S607
         check=True,
         capture_output=True,
         text=True,
-        env={**subprocess.os.environ, "COLUMNS": "76"},
     )
-    help_text = result.stdout
+
+    help_text = ""
+    for line in result.stdout.splitlines():
+        if len(line) > MAX_COLUMNS and "{" in line:
+            # argparse doesn't break choices across lines so
+            # find the last fitting choice and insert a bread
+            # padding the next line to line up to the brace position
+            choice_start = line.find("{") + 1
+            choice_break = line.rfind(",", choice_start, MAX_COLUMNS + 1) + 1
+            help_text += line[:choice_break] + "\n"
+            help_text += " " * choice_start
+            help_text += line[choice_break:] + "\n"
+        else:
+            help_text += line + "\n"
 
     text = docs_readme.read_text(encoding="utf-8")