Skip to content

feat: implement spec-driven directive parser #196

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
rlippmann merged 3 commits into from
Jul 23, 2026
Merged

feat: implement spec-driven directive parser #196

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
3 commits
Select commit Hold shift + click to select a range
147fc8d
feat: implement spec-driven directive parser
rlippmann Jul 23, 2026
7da3578
test: restore engine coverage
rlippmann Jul 23, 2026
61467ab
test: complete grammar parser coverage
rlippmann Jul 23, 2026
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
82 changes: 24 additions & 58 deletions src/context_compiler/engine.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -16,6 +16,8 @@
STATE_PREMISE,
STATE_VERSION,
)
from .grammar import DirectiveKind
from .grammar import _parse_directive as _parse_canonical_directive

PolicyValue = Literal["use", "prohibit"]

Expand Down Expand Up @@ -332,67 +334,31 @@ def _apply_replacement_explicit(self, new_item: str, old_item: str) -> None:


def _parse_directive(user_input: str) -> Action | None:
if _contains_compound_directive(user_input):
return Action(kind="compound_directive_invalid")
parsed = _parse_canonical_directive(user_input)
if parsed is None:
return None

if user_input == _CLEAR_PREMISE:
if parsed.kind is DirectiveKind.SET_PREMISE:
return Action(kind="set_premise", value=parsed.operands["value"])
if parsed.kind is DirectiveKind.CHANGE_PREMISE:
return Action(kind="change_premise", value=parsed.operands["value"])
if parsed.kind is DirectiveKind.USE_ITEM:
return Action(kind="use_item", item=parsed.operands["item"])
if parsed.kind is DirectiveKind.PROHIBIT_ITEM:
return Action(kind="prohibit_item", item=parsed.operands["item"])
if parsed.kind is DirectiveKind.REMOVE_POLICY:
return Action(kind="remove_policy_item", item=parsed.operands["item"])
if parsed.kind is DirectiveKind.REPLACE_USE:
return Action(
kind="replace_use",
new_item=parsed.operands["new_item"],
old_item=parsed.operands["old_item"],
)
if parsed.kind is DirectiveKind.CLEAR_PREMISE:
return Action(kind="clear_premise")
if user_input == _RESET_POLICIES:
if parsed.kind is DirectiveKind.RESET_POLICIES:
return Action(kind="reset_policies")
if user_input == _CLEAR_STATE:
return Action(kind="clear_state")

if user_input == _REMOVE_POLICY_BASE:
return Action(kind="remove_policy_item", item="")
remove_policy_prefix = f"{_REMOVE_POLICY_BASE} "
if user_input.startswith(remove_policy_prefix):
return Action(kind="remove_policy_item", item=user_input[len(remove_policy_prefix) :])

if (
user_input.startswith(_CHANGE_PREMISE_PREFIX)
and not user_input.startswith(f"{_CHANGE_PREMISE_BASE} ")
and user_input != _CHANGE_PREMISE_BASE
):
return None

if user_input == _SET_PREMISE_BASE:
return Action(kind="set_premise", value="")
set_prefix = f"{_SET_PREMISE_BASE} "
if user_input.startswith(set_prefix):
value = user_input[len(set_prefix) :]
return Action(kind="set_premise", value=value)

if user_input == _CHANGE_PREMISE_BASE:
return Action(kind="change_premise", value="")
change_prefix = f"{_CHANGE_PREMISE_BASE} "
if user_input.startswith(change_prefix):
value = user_input[len(change_prefix) :]
return Action(kind="change_premise", value=value)

if user_input == "use":
return Action(kind="use_item", item="")

if user_input.startswith(_USE_PREFIX):
payload = user_input[len(_USE_PREFIX) :]
left, sep, right = payload.partition(" instead of ")
if sep:
if left.strip() != "" and right.strip() != "":
return Action(kind="replace_use", new_item=left, old_item=right)
return Action(kind="replace_use_incomplete")
if payload.strip() == "":
return Action(kind="use_item", item="")
if payload.startswith("instead of ") or payload.endswith(" instead of"):
return Action(kind="replace_use_incomplete")
return Action(kind="use_item", item=payload)

if user_input == _PROHIBIT_BASE:
return Action(kind="prohibit_item", item="")

if user_input.startswith(_PROHIBIT_PREFIX):
item = user_input[len(_PROHIBIT_PREFIX) :]
return Action(kind="prohibit_item", item=item)

return None
return Action(kind="clear_state")


def _contains_compound_directive(user_input: str) -> bool:
Expand Down
Loading