From 5f148aa29533e5ece27a07e3b751226674e94525 Mon Sep 17 00:00:00 2001
From: Graeme Coupar <graeme@turbofish.tech>
Date: Sun, 7 Jan 2024 16:34:02 +0000
Subject: [PATCH] parse `implements` on object

---
 cynic-parser/src/ast.rs          |  1 +
 cynic-parser/src/ast/reader.rs   |  8 ++++++++
 cynic-parser/src/lexer/tokens.rs |  4 ++++
 cynic-parser/src/lib.rs          |  4 ++--
 cynic-parser/src/printer.rs      | 16 ++++++++++++++--
 cynic-parser/src/schema.lalrpop  | 21 ++++++++++++++++++++-
 6 files changed, 49 insertions(+), 5 deletions(-)

diff --git a/cynic-parser/src/ast.rs b/cynic-parser/src/ast.rs
index 2505321c..6ef907bf 100644
--- a/cynic-parser/src/ast.rs
+++ b/cynic-parser/src/ast.rs
@@ -58,6 +58,7 @@ pub struct ObjectDefinition {
     pub name: StringId,
     pub fields: Vec<NodeId>,
     pub directives: Vec<DirectiveId>,
+    pub implements: Vec<StringId>,
 }
 
 pub struct FieldDefinition {
diff --git a/cynic-parser/src/ast/reader.rs b/cynic-parser/src/ast/reader.rs
index 82663948..4d90efac 100644
--- a/cynic-parser/src/ast/reader.rs
+++ b/cynic-parser/src/ast/reader.rs
@@ -67,6 +67,14 @@ impl<'a> AstReader<'a, ObjectDefinitionId> {
         self.ast.lookup(self.ast.lookup(self.id).name)
     }
 
+    pub fn implements_interfaces(&self) -> impl Iterator<Item = &'a str> + 'a {
+        self.ast
+            .lookup(self.id)
+            .implements
+            .iter()
+            .map(|id| self.ast.lookup(*id))
+    }
+
     pub fn fields(&self) -> impl Iterator<Item = AstReader<'a, FieldDefinitionId>> + 'a {
         self.ast
             .lookup(self.id)
diff --git a/cynic-parser/src/lexer/tokens.rs b/cynic-parser/src/lexer/tokens.rs
index 31602532..1c652501 100644
--- a/cynic-parser/src/lexer/tokens.rs
+++ b/cynic-parser/src/lexer/tokens.rs
@@ -98,6 +98,9 @@ pub enum Token<'a> {
     #[token("null")]
     Null,
 
+    #[token("implements")]
+    Implements,
+
     // IntegerPart:    -?(0|[1-9][0-9]*)
     // FractionalPart: \\.[0-9]+
     // ExponentPart:   [eE][+-]?[0-9]+
@@ -262,6 +265,7 @@ impl fmt::Display for Token<'_> {
             Token::True => "true",
             Token::False => "false",
             Token::Null => "null,",
+            Token::Implements => "implements",
         };
         f.write_str(message)
     }
diff --git a/cynic-parser/src/lib.rs b/cynic-parser/src/lib.rs
index 545000f3..d04faf98 100644
--- a/cynic-parser/src/lib.rs
+++ b/cynic-parser/src/lib.rs
@@ -43,13 +43,13 @@ mod tests {
     fn test_basic_object() {
         insta::assert_snapshot!(
             parse_type_system_document(r#"
-                type MyType @hello {
+                type MyType implements Blah & Bloo @hello {
                     field: Whatever @hello(name: ["string"]),
                     other: [[Int!]]!
                 }"#
             ).to_sdl(),
             @r###"
-        type MyType @hello {
+        type MyType implements Blah & Bloo @hello {
           field: Whatever@hello(name: ("string"))
           other: [[Int!]]!
         }
diff --git a/cynic-parser/src/printer.rs b/cynic-parser/src/printer.rs
index 927d16c9..ae7bab46 100644
--- a/cynic-parser/src/printer.rs
+++ b/cynic-parser/src/printer.rs
@@ -66,9 +66,21 @@ impl<'a> Pretty<'a, BoxAllocator> for NodeDisplay<'a, SchemaDefinitionId> {
 
 impl<'a> Pretty<'a, BoxAllocator> for NodeDisplay<'a, ObjectDefinitionId> {
     fn pretty(self, allocator: &'a BoxAllocator) -> pretty::DocBuilder<'a, BoxAllocator, ()> {
-        allocator
+        let mut builder = allocator
             .text(format!("type {}", self.0.name()))
-            .append(allocator.space())
+            .append(allocator.space());
+
+        let interfaces = self.0.implements_interfaces().collect::<Vec<_>>();
+
+        if !interfaces.is_empty() {
+            builder = builder
+                .append(allocator.text("implements"))
+                .append(allocator.space())
+                .append(allocator.intersperse(interfaces, " & "))
+                .append(allocator.space());
+        }
+
+        builder
             .append(allocator.intersperse(self.0.directives().map(NodeDisplay), allocator.line()))
             .append(allocator.space())
             .append(allocator.text("{"))
diff --git a/cynic-parser/src/schema.lalrpop b/cynic-parser/src/schema.lalrpop
index 1840232a..7076f982 100644
--- a/cynic-parser/src/schema.lalrpop
+++ b/cynic-parser/src/schema.lalrpop
@@ -32,13 +32,29 @@ pub RootOperationTypeDefinition: RootOperationTypeDefinition = {
 }
 
 pub ObjectDefinition: ObjectDefinition = {
-    ty <name:Name> <directives:Directive*> <fields:FieldsDefinition?> => ObjectDefinition {
+    ty <name:Name> <implements:ImplementsInterfaces?> <directives:Directive*> <fields:FieldsDefinition?> => ObjectDefinition {
         name,
         directives,
+        implements: implements.unwrap_or_default(),
         fields: fields.unwrap_or_default ()
     }
 };
 
+ImplementsInterfaces: Vec<StringId> = {
+    <interfaces:ImplementsInterfaces> "&" <name:NamedType> => {
+        let mut interfaces = interfaces;
+        interfaces.push(name);
+        interfaces
+    },
+    implements "&"? <name:NamedType> => {
+        vec![name]
+    }
+}
+
+ImplementItem: StringId = {
+    "&" <name:NamedType> => name,
+}
+
 FieldsDefinition: Vec<NodeId> = {
     "{" <fields:FieldDefinition+> "}" => fields
 };
@@ -160,6 +176,7 @@ Ident: &'input str = {
     true => "true",
     false => "false",
     null => "null",
+    implements => "implements",
 }
 
 extern {
@@ -183,6 +200,7 @@ extern {
         "!" => lexer::Token::Exclamation,
         "=" => lexer::Token::Equals,
         "@" => lexer::Token::At,
+        "&" => lexer::Token::Ampersand,
 
         RawIdent => lexer::Token::Identifier(<&'input str>),
 
@@ -200,5 +218,6 @@ extern {
         true => lexer::Token::True,
         false => lexer::Token::False,
         null => lexer::Token::Null,
+        implements => lexer::Token::Implements,
     }
 }
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