[libgraphql-core-v1] Task 16: Schema struct, SchemaBuilder::build(), OperationKind

crates/libgraphql-core-v1/src/lib.rs

@@ -34,6 +34,7 @@ pub mod directive_annotation;
 pub mod error_note;
 pub mod located;
 pub mod names;
+pub mod operation_kind;
 pub mod schema;
 pub mod schema_source_map;
 pub mod span;
@@ -43,6 +44,7 @@ pub(crate) mod validators;
 pub mod value;
 
 pub use crate::located::Located;
+pub use crate::operation_kind::OperationKind;
 pub use crate::schema_source_map::LineCol;
 pub use crate::schema_source_map::SchemaSourceMap;
 pub use crate::span::Span;

crates/libgraphql-core-v1/src/operation_kind.rs

@@ -0,0 +1,30 @@
+/// The kind of GraphQL operation.
+///
+/// See [Operations](https://spec.graphql.org/September2025/#sec-Language.Operations).
+#[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
+#[derive(serde::Deserialize, serde::Serialize)]
+pub enum OperationKind {
+    Mutation,
+    Query,
+    Subscription,
+}
+
+impl From<libgraphql_parser::ast::OperationKind> for OperationKind {
+    fn from(kind: libgraphql_parser::ast::OperationKind) -> Self {
+        match kind {
+            libgraphql_parser::ast::OperationKind::Mutation => Self::Mutation,
+            libgraphql_parser::ast::OperationKind::Query => Self::Query,
+            libgraphql_parser::ast::OperationKind::Subscription => Self::Subscription,
+        }
+    }
+}
+
+impl std::fmt::Display for OperationKind {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.write_str(match self {
+            Self::Mutation => "mutation",
+            Self::Query => "query",
+            Self::Subscription => "subscription",
+        })
+    }
+}

crates/libgraphql-core-v1/src/schema/schema_build_error.rs

@@ -1,4 +1,5 @@
 use crate::error_note::ErrorNote;
+use crate::operation_kind::OperationKind;
 use crate::schema::type_validation_error::TypeValidationError;
 use crate::span::Span;
 
@@ -95,7 +96,7 @@ pub enum SchemaBuildErrorKind {
         (already bound to `{type_name}`)"
     )]
     DuplicateOperationDefinition {
-        operation: String,
+        operation: OperationKind,
         type_name: String,
     },
 
@@ -214,7 +215,7 @@ pub enum SchemaBuildErrorKind {
 
     #[error("root {operation} type `{type_name}` is not defined")]
     RootOperationTypeNotDefined {
-        operation: String,
+        operation: OperationKind,
         type_name: String,
     },
 
@@ -224,7 +225,7 @@ pub enum SchemaBuildErrorKind {
     )]
     RootOperationTypeNotObjectType {
         actual_kind: crate::types::GraphQLTypeKind,
-        operation: String,
+        operation: OperationKind,
         type_name: String,
     },