Mutable field access

src/eval/mod.rs

@@ -1000,8 +1000,9 @@ impl Access for Expr {
         scp: &'a mut Scopes,
     ) -> TypResult<Location<'a>> {
         match self {
-            Expr::Ident(ident) => ident.access(ctx, scp),
-            Expr::FuncCall(call) => call.access(ctx, scp),
+            Expr::Ident(v) => v.access(ctx, scp),
+            Expr::FieldAccess(v) => v.access(ctx, scp),
+            Expr::FuncCall(v) => v.access(ctx, scp),
             _ => bail!(self.span(), "cannot mutate a temporary value"),
         }
     }
@@ -1023,6 +1024,26 @@ impl Access for Ident {
     }
 }
 
+impl Access for FieldAccess {
+    fn access<'a>(
+        &self,
+        ctx: &mut Context,
+        scp: &'a mut Scopes,
+    ) -> TypResult<Location<'a>> {
+        let guard = self.object().access(ctx, scp)?;
+        try_map(guard, |value| {
+            Ok(match value {
+                Value::Dict(dict) => dict.get_mut(self.field().take()),
+                v => bail!(
+                    self.object().span(),
+                    "expected dictionary, found {}",
+                    v.type_name(),
+                ),
+            })
+        })
+    }
+}
+
 impl Access for FuncCall {
     fn access<'a>(
         &self,

tests/typ/code/dict.typ

@@ -17,10 +17,14 @@
 ---
 // Test lvalue and rvalue access.
 {
-  let dict = (a: 1, b: 1)
-  dict("b") += 1
-  dict("c") = 3
-  test(dict, (a: 1, b: 2, c: 3))
+  let dict = (a: 1, "b b": 1)
+  dict("b b") += 1
+  dict.state = (ok: true, err: false)
+  test(dict, (a: 1, "b b": 2, state: (ok: true, err: false)))
+  test(dict.state.ok, true)
+  dict("state").ok = false
+  test(dict.state.ok, false)
+  test(dict.state.err, false)
 }
 
 ---
@@ -58,3 +62,14 @@
 // Error: 12-16 expected identifier or string, found boolean
 // Error: 17-18 expected expression, found colon
 {(:1 b:"", true::)}
+
+---
+// Error: 3-15 cannot mutate a temporary value
+{ (key: value).other = "some" }
+
+---
+{
+  let object = none
+  // Error: 3-9 expected dictionary, found none
+  object.property = "value"
+}