feat(forge): Add enum string representation support.

crates/weaver_forge/codegen_examples/templates/registry/rust/README.md

@@ -0,0 +1,20 @@
+# Semantic Conventions for Rust
+
+# Usage
+
+```rust
+fn main() {
+    // Display the KeyValue of the attribute CLIENT_ADDRESS initialized with the value "145.34.23.56"
+    println!("{:?}", semconv::client::CLIENT_ADDRESS.value("145.34.23.56".into()));
+    // Display the key of the attribute CLIENT_ADDRESS
+    println!("{:?}", semconv::client::CLIENT_ADDRESS.key());
+
+    // Display the KeyValue of the attribute CLIENT_PORT initialized with the value 8080
+    println!("{:?}", semconv::client::CLIENT_PORT.value(8080));
+    // Display the key of the attribute CLIENT_PORT
+    println!("{:?}", semconv::client::CLIENT_PORT.key());
+
+    // Display the string representation of the enum variant HttpRequestMethod::Connect
+    println!("{}", semconv::http::HttpRequestMethod::Connect);
+}
+```

crates/weaver_forge/codegen_examples/templates/registry/rust/semantic_attributes.rs.j2

@@ -36,6 +36,7 @@ use crate::AttributeKey;
 {% if attribute.type.allow_custom_values is defined %}pub const {{ attribute.name | screaming_snake_case }}: AttributeKey<{{ attribute.name | pascal_case }}> = AttributeKey::new("{{ attribute.name }}");
 {% elif attribute.type == "string" %}pub const {{ attribute.name | screaming_snake_case }}: AttributeKey<{{ attribute.type | type_mapping }}Value> = AttributeKey::new("{{ attribute.name }}");
 {% else %}pub const {{ attribute.name | screaming_snake_case }}: AttributeKey<{{ attribute.type | type_mapping }}> = AttributeKey::new("{{ attribute.name }}");{% endif %}
+
 {% if attribute.type.allow_custom_values is defined %}
 {%- if attribute.brief %}
 {{ attribute.brief | comment_with_prefix("/// ") }}
@@ -50,5 +51,29 @@ pub enum {{ attribute.name | pascal_case }} {
     {{ variant.id | pascal_case }},
 {% endfor %}
 }
+
+impl {{ attribute.name | pascal_case }} {
+    /// Returns the string representation of the [`{{ attribute.name | pascal_case }}`].
+    pub fn as_str(&self) -> &'static str {
+        match self {
+        {%- for variant in attribute.type.members %}
+            {%- if variant is experimental %}
+            #[cfg(feature = "semconv_experimental")] {% endif %}
+            {{ attribute.name | pascal_case }}::{{ variant.id | pascal_case }} => "{{ variant.value }}",
+        {%- endfor %}
+            /// Without this default case, the match expression would not
+            /// contain any variants if all variants are annotated with the
+            /// 'semconv_experimental' feature and the feature is not enabled.
+            _ => unreachable!(),
+        }
+    }
+}
+
+impl core::fmt::Display for {{ attribute.name | pascal_case }} {
+    /// Formats the value using the given formatter.
+    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
+        write!(f, "{}", self.as_str())
+    }
+}
 {% endif %}
 {% endfor %}

crates/weaver_forge/codegen_examples/templates/registry/rust/weaver.yaml

@@ -8,6 +8,9 @@ type_mapping:
   template[string[]]: Vec<String>   # Not yet properly handled in codegen
 
 templates:
+  - pattern: README.md
+    filter: .
+    application_mode: single
   - pattern: lib.rs.j2
     # The following JQ filter extracts the id, type, brief, and prefix of groups matching the following criteria:
     # - groups with an id starting with the prefix `registry.`