remove Next and Prev

Author: vyudu

src/discretedomain.jl

@@ -70,19 +70,6 @@ Base.literal_pow(f::typeof(^), D::Shift, ::Val{n}) where {n} = Shift(D.t, D.step
 
 hasshift(eq::Equation) = hasshift(eq.lhs) || hasshift(eq.rhs)
 
-"""
-    Next(x)
-
-An alias for Shift(t, 1)(x).
-"""
-Next(x) = Shift(t, 1)(x)
-"""
-    Prev(x)
-
-An alias for Shift(t, -1)(x).
-"""
-Prev(x) = Shift(t, -1)(x)
-
 """
     hasshift(O)
 

src/systems/discrete_system/implicit_discrete_system.jl

@@ -268,17 +268,17 @@ function generate_function(
     iv = get_iv(sys)
     # Algebraic equations get shifted forward 1, to match with differential equations
     exprs = map(equations(sys)) do eq
-        _iszero(eq.lhs) ? distribute_shift(Next(eq.rhs)) : (eq.rhs - eq.lhs)
+        _iszero(eq.lhs) ? distribute_shift(Shift(iv, 1)(eq.rhs)) : (eq.rhs - eq.lhs)
     end
 
     # Handle observables in algebraic equations, since they are shifted
     obs = observed(sys)
-    shifted_obs = Symbolics.Equation[distribute_shift(Next(eq)) for eq in obs]
+    shifted_obs = Symbolics.Equation[distribute_shift(Shift(iv, 1)(eq)) for eq in obs]
     obsidxs = observed_equations_used_by(sys, exprs; obs = shifted_obs)
     extra_assignments = [Assignment(shifted_obs[i].lhs, shifted_obs[i].rhs)
                          for i in obsidxs]
 
-    u_next = map(Next, dvs)
+    u_next = map(Shift(iv, 1), dvs)
     u = dvs
     build_function_wrapper(
         sys, exprs, u_next, u, ps..., iv; p_start = 3, extra_assignments, kwargs...)