From b08c67cbf112469b79a614ed764bb4ce5501351c Mon Sep 17 00:00:00 2001
From: hanahsa <me@hanahsa.com>
Date: Fri, 11 Apr 2025 21:16:38 +1000
Subject: [PATCH] fragment variables

---
 src/query/ast.rs                              |  2 +
 src/query/format.rs                           | 10 ++++
 src/query/grammar.rs                          | 56 +++++++++++++++----
 .../queries/fragment_spread_arguments.graphql |  7 +++
 tests/queries/fragment_variables.graphql      |  3 +
 tests/query_roundtrips.rs                     |  8 +++
 6 files changed, 74 insertions(+), 12 deletions(-)
 create mode 100644 tests/queries/fragment_spread_arguments.graphql
 create mode 100644 tests/queries/fragment_variables.graphql

diff --git a/src/query/ast.rs b/src/query/ast.rs
index 1be1c7f..ffc5a82 100644
--- a/src/query/ast.rs
+++ b/src/query/ast.rs
@@ -43,6 +43,7 @@ pub enum Definition<'a, T: Text<'a>> {
 pub struct FragmentDefinition<'a, T: Text<'a>> {
     pub position: Pos,
     pub name: T::Value,
+    pub variable_definitions: Vec<VariableDefinition<'a, T>>,
     pub type_condition: TypeCondition<'a, T>,
     pub directives: Vec<Directive<'a, T>>,
     pub selection_set: SelectionSet<'a, T>,
@@ -118,6 +119,7 @@ pub struct Field<'a, T: Text<'a>> {
 pub struct FragmentSpread<'a, T: Text<'a>> {
     pub position: Pos,
     pub fragment_name: T::Value,
+    pub arguments: Vec<(T::Value, Value<'a, T>)>,
     pub directives: Vec<Directive<'a, T>>,
 }
 
diff --git a/src/query/format.rs b/src/query/format.rs
index 872dd3d..de0e978 100644
--- a/src/query/format.rs
+++ b/src/query/format.rs
@@ -54,6 +54,15 @@ impl<'a, T: Text<'a>> Displayable for FragmentDefinition<'a, T> {
         f.indent();
         f.write("fragment ");
         f.write(self.name.as_ref());
+        if !self.variable_definitions.is_empty() {
+            f.write("(");
+            self.variable_definitions[0].display(f);
+            for var in &self.variable_definitions[1..] {
+                f.write(", ");
+                var.display(f);
+            }
+            f.write(")");
+        }
         f.write(" ");
         self.type_condition.display(f);
         format_directives(&self.directives, f);
@@ -322,6 +331,7 @@ impl<'a, T: Text<'a>> Displayable for FragmentSpread<'a, T> {
         f.indent();
         f.write("...");
         f.write(self.fragment_name.as_ref());
+        format_arguments(&self.arguments, f);
         format_directives(&self.directives, f);
         f.endline();
     }
diff --git a/src/query/grammar.rs b/src/query/grammar.rs
index cf31bec..49d66ca 100644
--- a/src/query/grammar.rs
+++ b/src/query/grammar.rs
@@ -67,12 +67,20 @@ where
                     },
                 )
                 .map(Selection::InlineFragment)
-                .or((position(), name::<'a, S>(), parser(directives))
-                    .map(|(position, fragment_name, directives)| FragmentSpread {
-                        position,
-                        fragment_name,
-                        directives,
-                    })
+                .or((
+                    position(),
+                    name::<'a, S>(),
+                    parser(arguments),
+                    parser(directives),
+                )
+                    .map(
+                        |(position, fragment_name, arguments, directives)| FragmentSpread {
+                            position,
+                            fragment_name,
+                            arguments,
+                            directives,
+                        },
+                    )
                     .map(Selection::FragmentSpread)),
         ))
         .parse_stream(input)
@@ -219,17 +227,41 @@ pub fn fragment_definition<'a, T: Text<'a>>(
     (
         position().skip(ident("fragment")),
         name::<'a, T>(),
+        optional(
+            punct("(")
+                .with(many1(
+                    (
+                        position(),
+                        punct("$").with(name::<'a, T>()).skip(punct(":")),
+                        parser(parse_type),
+                        optional(punct("=").with(parser(default_value))),
+                    )
+                        .map(|(position, name, var_type, default_value)| {
+                            VariableDefinition {
+                                position,
+                                name,
+                                var_type,
+                                default_value,
+                            }
+                        }),
+                ))
+                .skip(punct(")")),
+        )
+        .map(|vars| vars.unwrap_or_default()),
         ident("on").with(name::<'a, T>()).map(TypeCondition::On),
         parser(directives),
         parser(selection_set),
     )
         .map(
-            |(position, name, type_condition, directives, selection_set)| FragmentDefinition {
-                position,
-                name,
-                type_condition,
-                directives,
-                selection_set,
+            |(position, name, variable_definitions, type_condition, directives, selection_set)| {
+                FragmentDefinition {
+                    position,
+                    name,
+                    variable_definitions,
+                    type_condition,
+                    directives,
+                    selection_set,
+                }
             },
         )
         .parse_stream(input)
diff --git a/tests/queries/fragment_spread_arguments.graphql b/tests/queries/fragment_spread_arguments.graphql
new file mode 100644
index 0000000..d896b6f
--- /dev/null
+++ b/tests/queries/fragment_spread_arguments.graphql
@@ -0,0 +1,7 @@
+query {
+  node {
+    id
+    ...something(arg: "test")
+    ...somethingElse(arg2: $var)
+  }
+}
diff --git a/tests/queries/fragment_variables.graphql b/tests/queries/fragment_variables.graphql
new file mode 100644
index 0000000..8a6abc8
--- /dev/null
+++ b/tests/queries/fragment_variables.graphql
@@ -0,0 +1,3 @@
+fragment frag($arg: String!) on Friend {
+  node
+}
diff --git a/tests/query_roundtrips.rs b/tests/query_roundtrips.rs
index 7451f20..9eb3bb0 100644
--- a/tests/query_roundtrips.rs
+++ b/tests/query_roundtrips.rs
@@ -152,6 +152,10 @@ fn fragment_spread() {
     roundtrip_default("fragment_spread");
 }
 #[test]
+fn fragment_spread_arguments() {
+    roundtrip_default("fragment_spread_arguments");
+}
+#[test]
 fn minimal_mutation() {
     roundtrip_default("minimal_mutation");
 }
@@ -160,6 +164,10 @@ fn fragment() {
     roundtrip_default("fragment");
 }
 #[test]
+fn fragment_variables() {
+    roundtrip_default("fragment_variables");
+}
+#[test]
 fn directive_args() {
     roundtrip_default("directive_args");
 }