Implement the legalizer

experimental/ast/syntax/doc.go

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+// Copyright 2020-2025 Buf Technologies, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// package syntax specifies all of the syntax pragmas (including editions)
+// that Protocompile understands.
+package syntax
+
+//go:generate go run github.com/bufbuild/protocompile/internal/enum syntax.yaml

experimental/ast/syntax/is_edition.go

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+// Copyright 2020-2025 Buf Technologies, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package syntax
+
+// IsEdition returns whether this represents an edition.
+func (s Syntax) IsEdition() bool {
+	return s != Proto2 && s != Proto3
+}

experimental/ast/syntax/syntax.yaml

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+# Copyright 2020-2024 Buf Technologies, Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http:#www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+- name: Syntax
+  type: int
+  docs: |
+    Syntax is a known syntax pragma.
+
+    Not only does this include "proto2" and "proto3", but also all of the
+    editions.
+  methods:
+  - kind: string
+  - kind: go-string
+  - kind: from-string
+    name: Lookup
+    docs: |
+      Lookup looks up a syntax pragma by name.
+
+      If name does not name a known pragma, returns [Unknown].
+    skip: [Unknown]
+  - kind: all
+    name: All
+    docs: |
+      All returns an iterator over all known [Syntax] values.
+    skip: [Unknown]
+  values:
+    - {name: Unknown, string: "<unknown>"}
+    - {name: Proto2, string: proto2}
+    - {name: Proto3, string: proto3}
+    - {name: Edition2023, string: "2023"}
+