diff --git a/lib/protoboeuf/codegen.rb b/lib/protoboeuf/codegen.rb
index 9f6492e..1713f11 100644
--- a/lib/protoboeuf/codegen.rb
+++ b/lib/protoboeuf/codegen.rb
@@ -26,31 +26,53 @@ def initialize(enum, generate_types:, options: {})
       end
 
       def result
-        "module #{enum.name}\n" + class_body + "; end\n"
+        <<~RESULT
+          module #{enum.name}
+            #{values}
+
+            #{lookup}
+
+            #{resolve}
+          end
+        RESULT
       end
 
       private
 
-      def class_body
-        enum.value.map { |const|
-          "#{const.name} = #{const.number}"
-        }.join("\n") + "\n\n" + lookup + "\n\n" + resolve
+      VALUES = ERB.new(<<~VALUES, trim_mode: "-")
+        <%- enum.value.each do |const| -%>
+          <%= const.name %> = <%= const.number %>
+        <%- end -%>
+      VALUES
+
+      def values
+        VALUES.result(binding)
       end
 
+      LOOKUP = ERB.new(<<~LOOKUP, trim_mode: "-")
+        <%= type_signature(params: { val: "Integer" }, returns: "Symbol", newline: true) %>
+        def self.lookup(val)
+          <%- enum.value.each do |const| -%>
+            return :<%= const.name %> if val == <%= const.number %>
+          <%- end -%>
+        end
+      LOOKUP
+
       def lookup
-        type_signature(params: { val: "Integer" }, returns: "Symbol", newline: true) +
-          "def self.lookup(val)\n" \
-            "if " + enum.value.map { |const|
-                      "val == #{const.number} then :#{const.name}"
-                    }.join(" elsif ") + " end; end"
+        LOOKUP.result(binding)
       end
 
+      RESOLVE = ERB.new(<<~RESOLVE, trim_mode: "-")
+        <%= type_signature(params: { val: "Symbol" }, returns: "Integer", newline: true) %>
+        def self.resolve(val)
+          <%- enum.value.each do |const| -%>
+            return <%= const.number %> if val == :<%= const.name %>
+          <%- end -%>
+        end
+      RESOLVE
+
       def resolve
-        type_signature(params: { val: "Symbol" }, returns: "Integer", newline: true) +
-          "def self.resolve(val)\n" \
-            "if " + enum.value.map { |const|
-                      "val == :#{const.name} then #{const.number}"
-                    }.join(" elsif ") + " end; end"
+        RESOLVE.result(binding)
       end
     end
 
@@ -699,9 +721,9 @@ def enum_writers
         return "" if fields.empty?
 
         "# enum writers\n" +
-          fields.map { |field|
+          fields.map do |field|
             "def #{field.name}=(v); #{iv_name(field)} = #{enum_name(field)}.resolve(v) || v; end"
-          }.join("\n") + "\n\n"
+          end.join("\n") + "\n\n"
       end
 
       def required_writers
@@ -709,7 +731,7 @@ def required_writers
 
         return "" if fields.empty?
 
-        fields.map { |field|
+        fields.map do |field|
           <<~RUBY
             #{type_signature(params: { v: convert_field_type(field) })}
             def #{field.name}=(v)
@@ -717,7 +739,7 @@ def #{field.name}=(v)
               #{iv_name(field)} = v
             end
           RUBY
-        }.join("\n") + "\n"
+        end.join("\n") + "\n"
       end
 
       def optional_writers
@@ -741,11 +763,11 @@ def oneof_writers
         return "" if oneof_fields.empty?
 
         "# BEGIN writers for oneof fields\n" +
-          oneof_fields.map.with_index { |sub_fields, i|
+          oneof_fields.map.with_index do |sub_fields, i|
             next unless sub_fields
 
             oneof = message.oneof_decl[i]
-            sub_fields.map { |field|
+            sub_fields.map do |field|
               <<~RUBY
                 def #{field.name}=(v)
                   #{bounds_check(field, "v")}
@@ -753,8 +775,8 @@ def #{field.name}=(v)
                   #{iv_name(field)} = v
                 end
               RUBY
-            }.join("\n")
-          }.join("\n") +
+            end.join("\n")
+          end.join("\n") +
           "# END writers for oneof fields\n\n"
       end
 
@@ -915,14 +937,14 @@ def to_proto(_options = {})
       def optional_predicates
         return "" if optional_fields.empty?
 
-        optional_fields.map { |field|
+        optional_fields.map do |field|
           <<~RUBY
             #{type_signature(returns: "T::Boolean")}
             def has_#{field.name}?
               #{test_bitmask(field)}
             end
           RUBY
-        }.join("\n") + "\n"
+        end.join("\n") + "\n"
       end
 
       def decode
diff --git a/lib/protoboeuf/google/api/field_behavior.rb b/lib/protoboeuf/google/api/field_behavior.rb
index 0860143..9b9cdf3 100644
--- a/lib/protoboeuf/google/api/field_behavior.rb
+++ b/lib/protoboeuf/google/api/field_behavior.rb
@@ -17,47 +17,27 @@ module FieldBehavior
         IDENTIFIER = 8
 
         def self.lookup(val)
-          if val == 0
-            :FIELD_BEHAVIOR_UNSPECIFIED
-          elsif val == 1
-            :OPTIONAL
-          elsif val == 2
-            :REQUIRED
-          elsif val == 3
-            :OUTPUT_ONLY
-          elsif val == 4
-            :INPUT_ONLY
-          elsif val == 5
-            :IMMUTABLE
-          elsif val == 6
-            :UNORDERED_LIST
-          elsif val == 7
-            :NON_EMPTY_DEFAULT
-          elsif val == 8
-            :IDENTIFIER
-          end
+          return :FIELD_BEHAVIOR_UNSPECIFIED if val == 0
+          return :OPTIONAL if val == 1
+          return :REQUIRED if val == 2
+          return :OUTPUT_ONLY if val == 3
+          return :INPUT_ONLY if val == 4
+          return :IMMUTABLE if val == 5
+          return :UNORDERED_LIST if val == 6
+          return :NON_EMPTY_DEFAULT if val == 7
+          return :IDENTIFIER if val == 8
         end
 
         def self.resolve(val)
-          if val == :FIELD_BEHAVIOR_UNSPECIFIED
-            0
-          elsif val == :OPTIONAL
-            1
-          elsif val == :REQUIRED
-            2
-          elsif val == :OUTPUT_ONLY
-            3
-          elsif val == :INPUT_ONLY
-            4
-          elsif val == :IMMUTABLE
-            5
-          elsif val == :UNORDERED_LIST
-            6
-          elsif val == :NON_EMPTY_DEFAULT
-            7
-          elsif val == :IDENTIFIER
-            8
-          end
+          return 0 if val == :FIELD_BEHAVIOR_UNSPECIFIED
+          return 1 if val == :OPTIONAL
+          return 2 if val == :REQUIRED
+          return 3 if val == :OUTPUT_ONLY
+          return 4 if val == :INPUT_ONLY
+          return 5 if val == :IMMUTABLE
+          return 6 if val == :UNORDERED_LIST
+          return 7 if val == :NON_EMPTY_DEFAULT
+          return 8 if val == :IDENTIFIER
         end
       end
     end
diff --git a/lib/protoboeuf/google/protobuf/descriptor.rb b/lib/protoboeuf/google/protobuf/descriptor.rb
index 500d905..af152fe 100644
--- a/lib/protoboeuf/google/protobuf/descriptor.rb
+++ b/lib/protoboeuf/google/protobuf/descriptor.rb
@@ -20,59 +20,33 @@ module Edition
         EDITION_MAX = 2_147_483_647
 
         def self.lookup(val)
-          if val == 0
-            :EDITION_UNKNOWN
-          elsif val == 900
-            :EDITION_LEGACY
-          elsif val == 998
-            :EDITION_PROTO2
-          elsif val == 999
-            :EDITION_PROTO3
-          elsif val == 1000
-            :EDITION_2023
-          elsif val == 1001
-            :EDITION_2024
-          elsif val == 1
-            :EDITION_1_TEST_ONLY
-          elsif val == 2
-            :EDITION_2_TEST_ONLY
-          elsif val == 99_997
-            :EDITION_99997_TEST_ONLY
-          elsif val == 99_998
-            :EDITION_99998_TEST_ONLY
-          elsif val == 99_999
-            :EDITION_99999_TEST_ONLY
-          elsif val == 2_147_483_647
-            :EDITION_MAX
-          end
+          return :EDITION_UNKNOWN if val == 0
+          return :EDITION_LEGACY if val == 900
+          return :EDITION_PROTO2 if val == 998
+          return :EDITION_PROTO3 if val == 999
+          return :EDITION_2023 if val == 1000
+          return :EDITION_2024 if val == 1001
+          return :EDITION_1_TEST_ONLY if val == 1
+          return :EDITION_2_TEST_ONLY if val == 2
+          return :EDITION_99997_TEST_ONLY if val == 99_997
+          return :EDITION_99998_TEST_ONLY if val == 99_998
+          return :EDITION_99999_TEST_ONLY if val == 99_999
+          return :EDITION_MAX if val == 2_147_483_647
         end
 
         def self.resolve(val)
-          if val == :EDITION_UNKNOWN
-            0
-          elsif val == :EDITION_LEGACY
-            900
-          elsif val == :EDITION_PROTO2
-            998
-          elsif val == :EDITION_PROTO3
-            999
-          elsif val == :EDITION_2023
-            1000
-          elsif val == :EDITION_2024
-            1001
-          elsif val == :EDITION_1_TEST_ONLY
-            1
-          elsif val == :EDITION_2_TEST_ONLY
-            2
-          elsif val == :EDITION_99997_TEST_ONLY
-            99_997
-          elsif val == :EDITION_99998_TEST_ONLY
-            99_998
-          elsif val == :EDITION_99999_TEST_ONLY
-            99_999
-          elsif val == :EDITION_MAX
-            2_147_483_647
-          end
+          return 0 if val == :EDITION_UNKNOWN
+          return 900 if val == :EDITION_LEGACY
+          return 998 if val == :EDITION_PROTO2
+          return 999 if val == :EDITION_PROTO3
+          return 1000 if val == :EDITION_2023
+          return 1001 if val == :EDITION_2024
+          return 1 if val == :EDITION_1_TEST_ONLY
+          return 2 if val == :EDITION_2_TEST_ONLY
+          return 99_997 if val == :EDITION_99997_TEST_ONLY
+          return 99_998 if val == :EDITION_99998_TEST_ONLY
+          return 99_999 if val == :EDITION_99999_TEST_ONLY
+          return 2_147_483_647 if val == :EDITION_MAX
         end
       end
 
@@ -8077,19 +8051,13 @@ module VerificationState
           UNVERIFIED = 1
 
           def self.lookup(val)
-            if val == 0
-              :DECLARATION
-            elsif val == 1
-              :UNVERIFIED
-            end
+            return :DECLARATION if val == 0
+            return :UNVERIFIED if val == 1
           end
 
           def self.resolve(val)
-            if val == :DECLARATION
-              0
-            elsif val == :UNVERIFIED
-              1
-            end
+            return 0 if val == :DECLARATION
+            return 1 if val == :UNVERIFIED
           end
         end
         # required field readers
@@ -9172,83 +9140,45 @@ module Type
           TYPE_SINT64 = 18
 
           def self.lookup(val)
-            if val == 1
-              :TYPE_DOUBLE
-            elsif val == 2
-              :TYPE_FLOAT
-            elsif val == 3
-              :TYPE_INT64
-            elsif val == 4
-              :TYPE_UINT64
-            elsif val == 5
-              :TYPE_INT32
-            elsif val == 6
-              :TYPE_FIXED64
-            elsif val == 7
-              :TYPE_FIXED32
-            elsif val == 8
-              :TYPE_BOOL
-            elsif val == 9
-              :TYPE_STRING
-            elsif val == 10
-              :TYPE_GROUP
-            elsif val == 11
-              :TYPE_MESSAGE
-            elsif val == 12
-              :TYPE_BYTES
-            elsif val == 13
-              :TYPE_UINT32
-            elsif val == 14
-              :TYPE_ENUM
-            elsif val == 15
-              :TYPE_SFIXED32
-            elsif val == 16
-              :TYPE_SFIXED64
-            elsif val == 17
-              :TYPE_SINT32
-            elsif val == 18
-              :TYPE_SINT64
-            end
+            return :TYPE_DOUBLE if val == 1
+            return :TYPE_FLOAT if val == 2
+            return :TYPE_INT64 if val == 3
+            return :TYPE_UINT64 if val == 4
+            return :TYPE_INT32 if val == 5
+            return :TYPE_FIXED64 if val == 6
+            return :TYPE_FIXED32 if val == 7
+            return :TYPE_BOOL if val == 8
+            return :TYPE_STRING if val == 9
+            return :TYPE_GROUP if val == 10
+            return :TYPE_MESSAGE if val == 11
+            return :TYPE_BYTES if val == 12
+            return :TYPE_UINT32 if val == 13
+            return :TYPE_ENUM if val == 14
+            return :TYPE_SFIXED32 if val == 15
+            return :TYPE_SFIXED64 if val == 16
+            return :TYPE_SINT32 if val == 17
+            return :TYPE_SINT64 if val == 18
           end
 
           def self.resolve(val)
-            if val == :TYPE_DOUBLE
-              1
-            elsif val == :TYPE_FLOAT
-              2
-            elsif val == :TYPE_INT64
-              3
-            elsif val == :TYPE_UINT64
-              4
-            elsif val == :TYPE_INT32
-              5
-            elsif val == :TYPE_FIXED64
-              6
-            elsif val == :TYPE_FIXED32
-              7
-            elsif val == :TYPE_BOOL
-              8
-            elsif val == :TYPE_STRING
-              9
-            elsif val == :TYPE_GROUP
-              10
-            elsif val == :TYPE_MESSAGE
-              11
-            elsif val == :TYPE_BYTES
-              12
-            elsif val == :TYPE_UINT32
-              13
-            elsif val == :TYPE_ENUM
-              14
-            elsif val == :TYPE_SFIXED32
-              15
-            elsif val == :TYPE_SFIXED64
-              16
-            elsif val == :TYPE_SINT32
-              17
-            elsif val == :TYPE_SINT64
-              18
-            end
+            return 1 if val == :TYPE_DOUBLE
+            return 2 if val == :TYPE_FLOAT
+            return 3 if val == :TYPE_INT64
+            return 4 if val == :TYPE_UINT64
+            return 5 if val == :TYPE_INT32
+            return 6 if val == :TYPE_FIXED64
+            return 7 if val == :TYPE_FIXED32
+            return 8 if val == :TYPE_BOOL
+            return 9 if val == :TYPE_STRING
+            return 10 if val == :TYPE_GROUP
+            return 11 if val == :TYPE_MESSAGE
+            return 12 if val == :TYPE_BYTES
+            return 13 if val == :TYPE_UINT32
+            return 14 if val == :TYPE_ENUM
+            return 15 if val == :TYPE_SFIXED32
+            return 16 if val == :TYPE_SFIXED64
+            return 17 if val == :TYPE_SINT32
+            return 18 if val == :TYPE_SINT64
           end
         end
 
@@ -9258,23 +9188,15 @@ module Label
           LABEL_REQUIRED = 2
 
           def self.lookup(val)
-            if val == 1
-              :LABEL_OPTIONAL
-            elsif val == 3
-              :LABEL_REPEATED
-            elsif val == 2
-              :LABEL_REQUIRED
-            end
+            return :LABEL_OPTIONAL if val == 1
+            return :LABEL_REPEATED if val == 3
+            return :LABEL_REQUIRED if val == 2
           end
 
           def self.resolve(val)
-            if val == :LABEL_OPTIONAL
-              1
-            elsif val == :LABEL_REPEATED
-              3
-            elsif val == :LABEL_REQUIRED
-              2
-            end
+            return 1 if val == :LABEL_OPTIONAL
+            return 3 if val == :LABEL_REPEATED
+            return 2 if val == :LABEL_REQUIRED
           end
         end
         # required field readers
@@ -16579,23 +16501,15 @@ module OptimizeMode
           LITE_RUNTIME = 3
 
           def self.lookup(val)
-            if val == 1
-              :SPEED
-            elsif val == 2
-              :CODE_SIZE
-            elsif val == 3
-              :LITE_RUNTIME
-            end
+            return :SPEED if val == 1
+            return :CODE_SIZE if val == 2
+            return :LITE_RUNTIME if val == 3
           end
 
           def self.resolve(val)
-            if val == :SPEED
-              1
-            elsif val == :CODE_SIZE
-              2
-            elsif val == :LITE_RUNTIME
-              3
-            end
+            return 1 if val == :SPEED
+            return 2 if val == :CODE_SIZE
+            return 3 if val == :LITE_RUNTIME
           end
         end
         # required field readers
@@ -22575,23 +22489,15 @@ module CType
           STRING_PIECE = 2
 
           def self.lookup(val)
-            if val == 0
-              :STRING
-            elsif val == 1
-              :CORD
-            elsif val == 2
-              :STRING_PIECE
-            end
+            return :STRING if val == 0
+            return :CORD if val == 1
+            return :STRING_PIECE if val == 2
           end
 
           def self.resolve(val)
-            if val == :STRING
-              0
-            elsif val == :CORD
-              1
-            elsif val == :STRING_PIECE
-              2
-            end
+            return 0 if val == :STRING
+            return 1 if val == :CORD
+            return 2 if val == :STRING_PIECE
           end
         end
 
@@ -22601,23 +22507,15 @@ module JSType
           JS_NUMBER = 2
 
           def self.lookup(val)
-            if val == 0
-              :JS_NORMAL
-            elsif val == 1
-              :JS_STRING
-            elsif val == 2
-              :JS_NUMBER
-            end
+            return :JS_NORMAL if val == 0
+            return :JS_STRING if val == 1
+            return :JS_NUMBER if val == 2
           end
 
           def self.resolve(val)
-            if val == :JS_NORMAL
-              0
-            elsif val == :JS_STRING
-              1
-            elsif val == :JS_NUMBER
-              2
-            end
+            return 0 if val == :JS_NORMAL
+            return 1 if val == :JS_STRING
+            return 2 if val == :JS_NUMBER
           end
         end
 
@@ -22627,23 +22525,15 @@ module OptionRetention
           RETENTION_SOURCE = 2
 
           def self.lookup(val)
-            if val == 0
-              :RETENTION_UNKNOWN
-            elsif val == 1
-              :RETENTION_RUNTIME
-            elsif val == 2
-              :RETENTION_SOURCE
-            end
+            return :RETENTION_UNKNOWN if val == 0
+            return :RETENTION_RUNTIME if val == 1
+            return :RETENTION_SOURCE if val == 2
           end
 
           def self.resolve(val)
-            if val == :RETENTION_UNKNOWN
-              0
-            elsif val == :RETENTION_RUNTIME
-              1
-            elsif val == :RETENTION_SOURCE
-              2
-            end
+            return 0 if val == :RETENTION_UNKNOWN
+            return 1 if val == :RETENTION_RUNTIME
+            return 2 if val == :RETENTION_SOURCE
           end
         end
 
@@ -22660,51 +22550,29 @@ module OptionTargetType
           TARGET_TYPE_METHOD = 9
 
           def self.lookup(val)
-            if val == 0
-              :TARGET_TYPE_UNKNOWN
-            elsif val == 1
-              :TARGET_TYPE_FILE
-            elsif val == 2
-              :TARGET_TYPE_EXTENSION_RANGE
-            elsif val == 3
-              :TARGET_TYPE_MESSAGE
-            elsif val == 4
-              :TARGET_TYPE_FIELD
-            elsif val == 5
-              :TARGET_TYPE_ONEOF
-            elsif val == 6
-              :TARGET_TYPE_ENUM
-            elsif val == 7
-              :TARGET_TYPE_ENUM_ENTRY
-            elsif val == 8
-              :TARGET_TYPE_SERVICE
-            elsif val == 9
-              :TARGET_TYPE_METHOD
-            end
+            return :TARGET_TYPE_UNKNOWN if val == 0
+            return :TARGET_TYPE_FILE if val == 1
+            return :TARGET_TYPE_EXTENSION_RANGE if val == 2
+            return :TARGET_TYPE_MESSAGE if val == 3
+            return :TARGET_TYPE_FIELD if val == 4
+            return :TARGET_TYPE_ONEOF if val == 5
+            return :TARGET_TYPE_ENUM if val == 6
+            return :TARGET_TYPE_ENUM_ENTRY if val == 7
+            return :TARGET_TYPE_SERVICE if val == 8
+            return :TARGET_TYPE_METHOD if val == 9
           end
 
           def self.resolve(val)
-            if val == :TARGET_TYPE_UNKNOWN
-              0
-            elsif val == :TARGET_TYPE_FILE
-              1
-            elsif val == :TARGET_TYPE_EXTENSION_RANGE
-              2
-            elsif val == :TARGET_TYPE_MESSAGE
-              3
-            elsif val == :TARGET_TYPE_FIELD
-              4
-            elsif val == :TARGET_TYPE_ONEOF
-              5
-            elsif val == :TARGET_TYPE_ENUM
-              6
-            elsif val == :TARGET_TYPE_ENUM_ENTRY
-              7
-            elsif val == :TARGET_TYPE_SERVICE
-              8
-            elsif val == :TARGET_TYPE_METHOD
-              9
-            end
+            return 0 if val == :TARGET_TYPE_UNKNOWN
+            return 1 if val == :TARGET_TYPE_FILE
+            return 2 if val == :TARGET_TYPE_EXTENSION_RANGE
+            return 3 if val == :TARGET_TYPE_MESSAGE
+            return 4 if val == :TARGET_TYPE_FIELD
+            return 5 if val == :TARGET_TYPE_ONEOF
+            return 6 if val == :TARGET_TYPE_ENUM
+            return 7 if val == :TARGET_TYPE_ENUM_ENTRY
+            return 8 if val == :TARGET_TYPE_SERVICE
+            return 9 if val == :TARGET_TYPE_METHOD
           end
         end
         # required field readers
@@ -28585,23 +28453,15 @@ module IdempotencyLevel
           IDEMPOTENT = 2
 
           def self.lookup(val)
-            if val == 0
-              :IDEMPOTENCY_UNKNOWN
-            elsif val == 1
-              :NO_SIDE_EFFECTS
-            elsif val == 2
-              :IDEMPOTENT
-            end
+            return :IDEMPOTENCY_UNKNOWN if val == 0
+            return :NO_SIDE_EFFECTS if val == 1
+            return :IDEMPOTENT if val == 2
           end
 
           def self.resolve(val)
-            if val == :IDEMPOTENCY_UNKNOWN
-              0
-            elsif val == :NO_SIDE_EFFECTS
-              1
-            elsif val == :IDEMPOTENT
-              2
-            end
+            return 0 if val == :IDEMPOTENCY_UNKNOWN
+            return 1 if val == :NO_SIDE_EFFECTS
+            return 2 if val == :IDEMPOTENT
           end
         end
         # required field readers
@@ -31452,27 +31312,17 @@ module FieldPresence
           LEGACY_REQUIRED = 3
 
           def self.lookup(val)
-            if val == 0
-              :FIELD_PRESENCE_UNKNOWN
-            elsif val == 1
-              :EXPLICIT
-            elsif val == 2
-              :IMPLICIT
-            elsif val == 3
-              :LEGACY_REQUIRED
-            end
+            return :FIELD_PRESENCE_UNKNOWN if val == 0
+            return :EXPLICIT if val == 1
+            return :IMPLICIT if val == 2
+            return :LEGACY_REQUIRED if val == 3
           end
 
           def self.resolve(val)
-            if val == :FIELD_PRESENCE_UNKNOWN
-              0
-            elsif val == :EXPLICIT
-              1
-            elsif val == :IMPLICIT
-              2
-            elsif val == :LEGACY_REQUIRED
-              3
-            end
+            return 0 if val == :FIELD_PRESENCE_UNKNOWN
+            return 1 if val == :EXPLICIT
+            return 2 if val == :IMPLICIT
+            return 3 if val == :LEGACY_REQUIRED
           end
         end
 
@@ -31482,23 +31332,15 @@ module EnumType
           CLOSED = 2
 
           def self.lookup(val)
-            if val == 0
-              :ENUM_TYPE_UNKNOWN
-            elsif val == 1
-              :OPEN
-            elsif val == 2
-              :CLOSED
-            end
+            return :ENUM_TYPE_UNKNOWN if val == 0
+            return :OPEN if val == 1
+            return :CLOSED if val == 2
           end
 
           def self.resolve(val)
-            if val == :ENUM_TYPE_UNKNOWN
-              0
-            elsif val == :OPEN
-              1
-            elsif val == :CLOSED
-              2
-            end
+            return 0 if val == :ENUM_TYPE_UNKNOWN
+            return 1 if val == :OPEN
+            return 2 if val == :CLOSED
           end
         end
 
@@ -31508,23 +31350,15 @@ module RepeatedFieldEncoding
           EXPANDED = 2
 
           def self.lookup(val)
-            if val == 0
-              :REPEATED_FIELD_ENCODING_UNKNOWN
-            elsif val == 1
-              :PACKED
-            elsif val == 2
-              :EXPANDED
-            end
+            return :REPEATED_FIELD_ENCODING_UNKNOWN if val == 0
+            return :PACKED if val == 1
+            return :EXPANDED if val == 2
           end
 
           def self.resolve(val)
-            if val == :REPEATED_FIELD_ENCODING_UNKNOWN
-              0
-            elsif val == :PACKED
-              1
-            elsif val == :EXPANDED
-              2
-            end
+            return 0 if val == :REPEATED_FIELD_ENCODING_UNKNOWN
+            return 1 if val == :PACKED
+            return 2 if val == :EXPANDED
           end
         end
 
@@ -31534,23 +31368,15 @@ module Utf8Validation
           NONE = 3
 
           def self.lookup(val)
-            if val == 0
-              :UTF8_VALIDATION_UNKNOWN
-            elsif val == 2
-              :VERIFY
-            elsif val == 3
-              :NONE
-            end
+            return :UTF8_VALIDATION_UNKNOWN if val == 0
+            return :VERIFY if val == 2
+            return :NONE if val == 3
           end
 
           def self.resolve(val)
-            if val == :UTF8_VALIDATION_UNKNOWN
-              0
-            elsif val == :VERIFY
-              2
-            elsif val == :NONE
-              3
-            end
+            return 0 if val == :UTF8_VALIDATION_UNKNOWN
+            return 2 if val == :VERIFY
+            return 3 if val == :NONE
           end
         end
 
@@ -31560,23 +31386,15 @@ module MessageEncoding
           DELIMITED = 2
 
           def self.lookup(val)
-            if val == 0
-              :MESSAGE_ENCODING_UNKNOWN
-            elsif val == 1
-              :LENGTH_PREFIXED
-            elsif val == 2
-              :DELIMITED
-            end
+            return :MESSAGE_ENCODING_UNKNOWN if val == 0
+            return :LENGTH_PREFIXED if val == 1
+            return :DELIMITED if val == 2
           end
 
           def self.resolve(val)
-            if val == :MESSAGE_ENCODING_UNKNOWN
-              0
-            elsif val == :LENGTH_PREFIXED
-              1
-            elsif val == :DELIMITED
-              2
-            end
+            return 0 if val == :MESSAGE_ENCODING_UNKNOWN
+            return 1 if val == :LENGTH_PREFIXED
+            return 2 if val == :DELIMITED
           end
         end
 
@@ -31586,23 +31404,15 @@ module JsonFormat
           LEGACY_BEST_EFFORT = 2
 
           def self.lookup(val)
-            if val == 0
-              :JSON_FORMAT_UNKNOWN
-            elsif val == 1
-              :ALLOW
-            elsif val == 2
-              :LEGACY_BEST_EFFORT
-            end
+            return :JSON_FORMAT_UNKNOWN if val == 0
+            return :ALLOW if val == 1
+            return :LEGACY_BEST_EFFORT if val == 2
           end
 
           def self.resolve(val)
-            if val == :JSON_FORMAT_UNKNOWN
-              0
-            elsif val == :ALLOW
-              1
-            elsif val == :LEGACY_BEST_EFFORT
-              2
-            end
+            return 0 if val == :JSON_FORMAT_UNKNOWN
+            return 1 if val == :ALLOW
+            return 2 if val == :LEGACY_BEST_EFFORT
           end
         end
         # required field readers
@@ -36353,23 +36163,15 @@ module Semantic
             ALIAS = 2
 
             def self.lookup(val)
-              if val == 0
-                :NONE
-              elsif val == 1
-                :SET
-              elsif val == 2
-                :ALIAS
-              end
+              return :NONE if val == 0
+              return :SET if val == 1
+              return :ALIAS if val == 2
             end
 
             def self.resolve(val)
-              if val == :NONE
-                0
-              elsif val == :SET
-                1
-              elsif val == :ALIAS
-                2
-              end
+              return 0 if val == :NONE
+              return 1 if val == :SET
+              return 2 if val == :ALIAS
             end
           end
           # required field readers
diff --git a/lib/protoboeuf/google/protobuf/struct.rb b/lib/protoboeuf/google/protobuf/struct.rb
index 79b39f3..0228456 100644
--- a/lib/protoboeuf/google/protobuf/struct.rb
+++ b/lib/protoboeuf/google/protobuf/struct.rb
@@ -9,11 +9,11 @@ module NullValue
         NULL_VALUE = 0
 
         def self.lookup(val)
-          :NULL_VALUE if val == 0
+          return :NULL_VALUE if val == 0
         end
 
         def self.resolve(val)
-          0 if val == :NULL_VALUE
+          return 0 if val == :NULL_VALUE
         end
       end
 
diff --git a/test/codegen_test.rb b/test/codegen_test.rb
index f84ab95..3f2dfc1 100644
--- a/test/codegen_test.rb
+++ b/test/codegen_test.rb
@@ -816,5 +816,36 @@ def test_bounds_checks
         obj.u64s = [0, 18_446_744_073_709_551_615, 18_446_744_073_709_551_616]
       end
     end
+
+    def test_big_enum
+      # Test that we don't see the following exception encountered when working with an enum with many values:
+      # 1) Error:
+      # ProtoBoeuf::CodeGenTest#test_big_enum:
+      # SyntaxTree::Parser::ParseError: nesting too deep
+      #     /Users/dave/.gem/ruby/3.3.4/gems/syntax_tree-6.2.0/lib/syntax_tree/parser.rb:2864:in `on_parse_error'
+      #     /Users/dave/.gem/ruby/3.3.4/gems/syntax_tree-6.2.0/lib/syntax_tree.rb:124:in `parse'
+      #     /Users/dave/.gem/ruby/3.3.4/gems/syntax_tree-6.2.0/lib/syntax_tree.rb:124:in `parse'
+      #     /Users/dave/.gem/ruby/3.3.4/gems/syntax_tree-6.2.0/lib/syntax_tree.rb:68:in `format'
+      #     lib/protoboeuf/codegen.rb:1723:in `block in to_ruby'
+      #     lib/protoboeuf/codegen.rb:1703:in `each'
+      #     lib/protoboeuf/codegen.rb:1703:in `to_ruby'
+      #     test/codegen_test.rb:12:in `to_ruby'
+      #     test/codegen_test.rb:834:in `test_big_enum'
+
+      unit = parse_proto_string(ERB.new(<<~EOPROTO, trim_mode: "-").result(binding))
+        syntax = "proto3";
+
+        enum BigEnum {
+          UNKNOWN = 0;
+          <%- (1..5000).each do |i| -%>
+          VALUE_<%= i %> = <%= i %>;
+          <%- end -%>
+        }
+      EOPROTO
+
+      gen = CodeGen.new(unit)
+
+      gen.to_ruby
+    end
   end
 end
diff --git a/test/fixtures/typed_test.correct.rb b/test/fixtures/typed_test.correct.rb
index 5676e52..9f73016 100644
--- a/test/fixtures/typed_test.correct.rb
+++ b/test/fixtures/typed_test.correct.rb
@@ -9,25 +9,19 @@ module TestEnum
   BAZ = 2
 
   sig { params(val: Integer).returns(Symbol) }
+
   def self.lookup(val)
-    if val == 0
-      :FOO
-    elsif val == 1
-      :BAR
-    elsif val == 2
-      :BAZ
-    end
+    return :FOO if val == 0
+    return :BAR if val == 1
+    return :BAZ if val == 2
   end
 
   sig { params(val: Symbol).returns(Integer) }
+
   def self.resolve(val)
-    if val == :FOO
-      0
-    elsif val == :BAR
-      1
-    elsif val == :BAZ
-      2
-    end
+    return 0 if val == :FOO
+    return 1 if val == :BAR
+    return 2 if val == :BAZ
   end
 end
 module TestEnum2
@@ -36,25 +30,19 @@ module TestEnum2
   FOOFOO = 2
 
   sig { params(val: Integer).returns(Symbol) }
+
   def self.lookup(val)
-    if val == 0
-      :BAZBAZ
-    elsif val == 1
-      :BARBAR
-    elsif val == 2
-      :FOOFOO
-    end
+    return :BAZBAZ if val == 0
+    return :BARBAR if val == 1
+    return :FOOFOO if val == 2
   end
 
   sig { params(val: Symbol).returns(Integer) }
+
   def self.resolve(val)
-    if val == :BAZBAZ
-      0
-    elsif val == :BARBAR
-      1
-    elsif val == :FOOFOO
-      2
-    end
+    return 0 if val == :BAZBAZ
+    return 1 if val == :BARBAR
+    return 2 if val == :FOOFOO
   end
 end