Add options for include directive

pdoc/__init__.py

@@ -283,7 +283,16 @@ class GoldenRetriever(Dog):
 """
 ```
 
-Since version 11, pdoc processes such reStructuredText elements by default.
+You can also include only parts of a file with the
+[`start-line`, `end-line`, `start-after`, and `end-after` options](https://docutils.sourceforge.io/docs/ref/rst/directives.html#including-an-external-document-fragment):
+
+```python
+"""
+.. include:: ../README.md
+ :start-line: 1
+ :end-before: Changelog
+"""
+```
 
 
 ## ...add a title page?

pdoc/docstrings.py

@@ -360,6 +360,38 @@ def replace_link(m: re.Match[str]) -> str:
  return contents
 
 
+def _rst_extract_options(contents: str) -> tuple[str, dict[str, str]]:
+ """
+ Extract options from the beginning of reStructuredText directives.
+
+ Return the trimmed content and a dict of options.
+ """
+ options = {}
+ while match := re.match(r"^\s*:(.+?):(.*)([\s\S]*)", contents):
+ key, value, contents = match.groups()
+ options[key] = value.strip()
+
+ return contents, options
+
+
+def _rst_include_trim(contents: str, options: dict[str, str]) -> str:
+ """
+ <https://docutils.sourceforge.io/docs/ref/rst/directives.html#include-options>
+ """
+ if "end-line" in options or "start-line" in options:
+ lines = contents.splitlines()
+ if i := options.get("end-line"):
+ lines = lines[: int(i)]
+ if i := options.get("start-line"):
+ lines = lines[int(i) :]
+ contents = "\n".join(lines)
+ if x := options.get("end-before"):
+ contents = contents[: contents.index(x)]
+ if x := options.get("start-after"):
+ contents = contents[contents.index(x) + len(x) :]
+ return contents
+
+
 def _rst_admonitions(contents: str, source_file: Path | None) -> str:
  """
  Convert reStructuredText admonitions - a bit tricky because they may already be indented themselves.
@@ -371,6 +403,7 @@ def _rst_admonition(m: re.Match[str]) -> str:
  type = m.group("type")
  val = m.group("val").strip()
  contents = dedent(m.group("contents")).strip()
+ contents, options = _rst_extract_options(contents)
 
  if type == "include":
  loc = source_file or Path(".")
@@ -379,6 +412,10 @@ def _rst_admonition(m: re.Match[str]) -> str:
  except OSError as e:
  warnings.warn(f"Cannot include {val!r}: {e}")
  included = "\n"
+ try:
+ included = _rst_include_trim(included, options) + "\n"
+ except ValueError as e:
+ warnings.warn(f"Failed to process include options for {val!r}: {e}")
  included = _rst_admonitions(included, loc.parent / val)
  return indent(included, ind)
  if type == "math":

test/test_docstrings.py

@@ -1,3 +1,4 @@
+from hypothesis import assume
 from hypothesis import given
 from hypothesis.strategies import text
 import pytest
@@ -26,6 +27,59 @@ def test_rst(s):
  assert not s or ret
 
 
+@given(text())
+def test_rst_extract_options_fuzz(s):
+ assume(not s.startswith(":"))
+ content, options = docstrings._rst_extract_options(s)
+ assert not options
+ assert content == s
+
+
+def test_rst_extract_options():
+ content = (
+ ":alpha: beta\n"
+ ":charlie:delta:foxtrot\n"
+ "rest of content\n"
+ ":option ignored: as follows content\n"
+ )
+ content, options = docstrings._rst_extract_options(content)
+ assert options == {
+ "alpha": "beta",
+ "charlie": "delta:foxtrot",
+ }
+ assert content == ("\nrest of content\n" ":option ignored: as follows content\n")
+
+
+@given(text())
+def test_rst_include_trim_fuzz(s):
+ content = docstrings._rst_include_trim(s, {})
+ assert content == s
+
+
+def test_rst_include_trim_lines():
+ content = "alpha\nbeta\ncharlie\ndelta\necho"
+ trimmed = docstrings._rst_include_trim(
+ content, {"start-line": "2", "end-line": "4"}
+ )
+ assert trimmed == "charlie\ndelta"
+
+
+def test_rst_include_trim_pattern():
+ content = "alpha\nbeta\ncharlie\ndelta\necho"
+ trimmed = docstrings._rst_include_trim(
+ content, {"start-after": "beta", "end-before": "echo"}
+ )
+ assert trimmed == "\ncharlie\ndelta\n"
+
+
+def test_rst_include_trim_mixture():
+ content = "alpha\nbeta\ncharlie\ndelta\necho"
+ trimmed = docstrings._rst_include_trim(
+ content, {"start-after": "beta", "end-line": "4"}
+ )
+ assert trimmed == "\ncharlie\ndelta"
+
+
 def test_rst_include_nonexistent():
  with pytest.warns(UserWarning, match="Cannot include 'nonexistent.txt'"):
  docstrings.rst(".. include:: nonexistent.txt", None)