beancount_types: Add types related to loading the books.

These will help support loading methods in the books module.

conservancy_beancount/beancount_types.py

@@ -20,17 +20,23 @@ import datetime
 import beancount.core.data as bc_data
 
 from typing import (
+    TYPE_CHECKING,
     Any,
     FrozenSet,
     Iterable,
     List,
+    Mapping,
     NamedTuple,
     Optional,
     Set,
     Tuple,
     Type,
+    Union,
 )
 
+if TYPE_CHECKING:
+    from . import errors as errormod
+
 Account = bc_data.Account
 MetaKey = str
 MetaValue = Any
@@ -42,6 +48,12 @@ class Directive(NamedTuple):
     date: datetime.date
 
 
+class Error(NamedTuple):
+    source: Optional[bc_data.Meta]
+    message: str
+    entry: Optional[Directive]
+
+
 class Transaction(Directive):
     flag: bc_data.Flag
     payee: Optional[str]
@@ -54,3 +66,8 @@ class Transaction(Directive):
 ALL_DIRECTIVES: FrozenSet[Type[Directive]] = frozenset([
     Transaction,
 ])
+
+Entries = List[Directive]
+Errors = List[Union[Error, 'errormod.Error']]
+OptionsMap = Mapping[str, Any]
+LoadResult = Tuple[Entries, Errors, OptionsMap]

conservancy_beancount/plugin/__init__.py

@@ -32,6 +32,9 @@ from typing import (
 from ..beancount_types import (
     ALL_DIRECTIVES,
     Directive,
+    Entries,
+    Errors,
+    OptionsMap,
 )
 from .. import config as configmod
 from .core import (
@@ -117,15 +120,15 @@ class HookRegistry:
 
 
 def run(
-        entries: List[Directive],
-        options_map: Dict[str, Any],
+        entries: Entries,
+        options_map: OptionsMap,
         config: str='',
         hook_registry: Optional[HookRegistry]=None,
-) -> Tuple[List[Directive], List[Error]]:
+) -> Tuple[Entries, Errors]:
     if hook_registry is None:
         hook_registry = HookRegistry()
         hook_registry.load_included_hooks()
-    errors: List[Error] = []
+    errors: Errors = []
     hooks: Dict[HookName, List[Hook]] = {
         # mypy thinks NamedTuples don't have __name__ but they do at runtime.
         t.__name__: [] for t in bc_data.ALL_DIRECTIVES  # type:ignore[attr-defined]