CLEANUP: Special case for unary named tuples in `@relation` macro.

src/programs/RelationalPrograms.jl

@@ -192,6 +192,7 @@ function parse_relation_call(call)
       (nothing, parse_relation_kw_args(args)...)
     Expr(:tuple) => (nothing, nothing, Symbol[])
     Expr(:tuple, args...) => (nothing, parse_relation_inferred_args(args)...)
+    Expr(:(=), args...) => (nothing, parse_relation_inferred_args([call])...)
 
     _ => error("Invalid syntax in relation $call")
   end

test/programs/RelationalPrograms.jl

@@ -93,6 +93,10 @@ d2 = @relation ((start=u, stop=w) where (u,w,v)) ->
   (E(src=u, tgt=v); E(src=v, tgt=w))
 @test d1 == d2
 
+# Special case: unary named tuple syntax.
+parsed = @relation ((src=v) where (v, w)) -> E(src=v, tgt=w)
+@test parsed[:outer_port_name] == [:src]
+
 # Special case: closed diagram.
 if VERSION >= v"1.5"
   d1 = @relation ((;) where (v,)) -> E(src=v, tgt=v)