Parse an expression of a tuple to Differentials

Author: YingboMa

src/differentials.jl

@@ -61,9 +61,10 @@ _repeat_apply(f, n) = n == 1 ? f : f ∘ _repeat_apply(f, n-1)
 function _differential_macro(x)
     ex = Expr(:block)
     lhss = Symbol[]
+    x = x isa Tuple && first(x).head == :tuple ? first(x).args : x # tuple handling
     x = flatten_expr!(x)
     for di in x
-        @assert di isa Expr && di.args[1] == :~ "@derivatives expects a form that looks like `@derivatives D''~t E'~t`"
+        @assert di isa Expr && di.args[1] == :~ "@derivatives expects a form that looks like `@derivatives D''~t E'~t` or `@derivatives (D''~t), (E'~t)`"
         lhs = di.args[2]
         rhs = di.args[3]
         order, lhs = count_order(lhs)

test/derivatives.jl

@@ -6,6 +6,8 @@ using Test
 @variables x(t) y(t) z(t)
 @derivatives D'~t D2''~t
 
+@test @macroexpand(@derivatives D'~t D2''~t) == @macroexpand(@derivatives (D'~t), (D2''~t))
+
 @test isequal(expand_derivatives(D(t)), 1)
 @test isequal(expand_derivatives(D(D(t))), 0)