Cut down memory footprint

gersemi/builtin_commands.py

@@ -1,5 +1,6 @@
 # pylint: disable=too-many-lines
 from typing import Iterable, List, Mapping
+from gersemi.immutable import make_immutable
 from gersemi.specializations.add_custom_target import add_custom_target
 from gersemi.specializations.condition_syntax_command_invocation_dumper import (
     condition_syntax_commands,
@@ -3140,10 +3141,12 @@ def add_canonical_name(value, canonical_name):
 
 
 def preprocess_definitions(definitions):
-    return {
-        key.lower(): add_canonical_name(value, key)
-        for key, value in definitions.items()
-    }
+    return make_immutable(
+        {
+            key.lower(): add_canonical_name(value, key)
+            for key, value in definitions.items()
+        }
+    )
 
 
 builtin_commands = preprocess_definitions(builtin_commands_impl)

gersemi/command_invocation_dumper.py

@@ -1,3 +1,4 @@
+import collections.abc
 from contextlib import contextmanager
 from functools import lru_cache
 from lark import Tree
@@ -36,7 +37,7 @@ def _get_patch(self, raw_command_name):
         command_name = raw_command_name.lower()
         if command_name in builtin_commands:
             command = builtin_commands[command_name]
-            if isinstance(command, dict):
+            if isinstance(command, collections.abc.Mapping):
                 return create_standard_dumper(command)
 
             return command

gersemi/custom_command_definition_finder.py

@@ -2,6 +2,7 @@
 from lark import Discard
 from lark.visitors import Interpreter, Transformer
 from gersemi.ast_helpers import is_keyword
+from gersemi.immutable import make_immutable
 from gersemi.keywords import Hint, Keywords
 
 
@@ -208,4 +209,4 @@ def get_just_definitions(definitions):
         sorted_info = list(sorted(info, key=lambda item: item[1]))
         (canonical_name, (positional_arguments, keywords)), _ = sorted_info[0]
         result[name] = create_command(canonical_name, positional_arguments, keywords)
-    return result
+    return make_immutable(result)

gersemi/immutable.py

@@ -0,0 +1,36 @@
+from collections import abc
+
+
+class ImmutableDict(abc.Mapping):
+    def __init__(self, d):
+        self._d = d
+
+    def __getitem__(self, key):
+        return self._d[key]
+
+    def __iter__(self):
+        return iter(self._d)
+
+    def __len__(self):
+        return len(self._d)
+
+    def __contains__(self, item):
+        return item in self._d
+
+    def __hash__(self):
+        return hash(frozenset(self._d.items()))
+
+
+def make_immutable(thing):
+    if isinstance(thing, abc.Mapping):
+        return ImmutableDict(
+            {key: make_immutable(value) for key, value in thing.items()}
+        )
+
+    if isinstance(thing, str):
+        return thing
+
+    if isinstance(thing, abc.Collection):
+        return tuple(map(make_immutable, thing))
+
+    return thing

gersemi/specializations/standard_command_dumper.py

@@ -1,3 +1,4 @@
+from functools import lru_cache
 from lark import Tree
 from gersemi.command_line_formatter import CommandLineFormatter
 from gersemi.keyword_with_pairs_formatter import KeywordWithPairsFormatter
@@ -17,6 +18,7 @@ def custom_command(self, tree):
         return self.visit(Tree("command_invocation", [command_name, arguments]))
 
 
+@lru_cache(maxsize=None)
 def create_standard_dumper(data, custom_command=False):
     bases = [
         SectionAwareCommandInvocationDumper,