From 9843a0f8c14232a98385d3a88c4622d5f8081dcd Mon Sep 17 00:00:00 2001
From: Yingbo Ma <mayingbo5@gmail.com>
Date: Wed, 26 May 2021 14:06:26 -0400
Subject: [PATCH 1/3] Use at register for `sign`

---
 src/extra_functions.jl | 4 ++--
 test/overloads.jl      | 2 +-
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/extra_functions.jl b/src/extra_functions.jl
index 34d101458..8b38a23cb 100644
--- a/src/extra_functions.jl
+++ b/src/extra_functions.jl
@@ -2,9 +2,9 @@
 @register Base.getindex(x,i) # define one and only one promotion rule
 @register Base.binomial(n,k)
 
-Base.sign(x::Symbolic) = Term{Int}(sign, [x])
-Base.sign(x::Num) = Num(sign(value(x)))
+@register Base.sign(x)::Int
 derivative(::typeof(sign), args::NTuple{1,Any}, ::Val{1}) = 0
+
 @register Base.signbit(x)::Bool
 derivative(::typeof(signbit), args::NTuple{1,Any}, ::Val{1}) = 0
 derivative(::typeof(abs), args::NTuple{1,Any}, ::Val{1}) = IfElse.ifelse(signbit(args[1]),-one(args[1]),one(args[1]))
diff --git a/test/overloads.jl b/test/overloads.jl
index db1fa1019..713f174b4 100644
--- a/test/overloads.jl
+++ b/test/overloads.jl
@@ -168,7 +168,7 @@ eqs = [
 @test [2 1 -1; -3 1 -1; 0 1 -5] * Symbolics.solve_for(eqs, [x, y, z]) == [2; -2; -2]
 @test isequal(Symbolics.solve_for(2//1*x + y - 2//1*z ~ 9//1*x, 1//1*x), 1//7*y - 2//7*z)
 
-@test isequal(sign(x), Num(SymbolicUtils.Term{Int}(sign, [x])))
+@test isequal(sign(x), Num(SymbolicUtils.Term{Int}(sign, [Symbolics.value(x)])))
 @test isequal(sign(Num(1)), Num(1))
 @test isequal(sign(Num(-1)), Num(-1))
 

From fd6250cc807ddef930da11cd5d688263f163b112 Mon Sep 17 00:00:00 2001
From: Yingbo Ma <mayingbo5@gmail.com>
Date: Wed, 26 May 2021 16:15:06 -0400
Subject: [PATCH 2/3] Eagerly evaluate registered function if arguments are not
 symbolic

---
 src/register.jl | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/register.jl b/src/register.jl
index f387caeec..d85f64c80 100644
--- a/src/register.jl
+++ b/src/register.jl
@@ -1,3 +1,4 @@
+using SymbolicUtils: Symbolic
 """
     @register(expr, define_promotion = true, Ts = [Num, Symbolic, Real])
 
@@ -50,7 +51,12 @@ macro register(expr, define_promotion = true, Ts = [Num, Symbolic, Real])
         push!(ex.args, quote
             function $f($(setinds(args, symbolic_args, ts)...))
                 wrap =  any(x->typeof(x) <: $Num, tuple($(setinds(args, symbolic_args, ts)...),)) ? $Num : $identity
-                wrap($Term{$ret_type}($f, [$(map(name, args)...)]))
+                args = ($(map(name, args)...),)
+                if all(arg -> !(arg isa $Symbolic), args)
+                    $f(args...,)
+                else
+                    wrap($Term{$ret_type}($f, collect(args)))
+                end
             end
         end)
     end

From 40b9447f4c185cc2f860c4b64de715cdaba5038c Mon Sep 17 00:00:00 2001
From: Yingbo Ma <mayingbo5@gmail.com>
Date: Wed, 26 May 2021 16:26:12 -0400
Subject: [PATCH 3/3] Remember to wrap

---
 src/register.jl   | 2 +-
 test/overloads.jl | 1 +
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/register.jl b/src/register.jl
index d85f64c80..1570e438d 100644
--- a/src/register.jl
+++ b/src/register.jl
@@ -53,7 +53,7 @@ macro register(expr, define_promotion = true, Ts = [Num, Symbolic, Real])
                 wrap =  any(x->typeof(x) <: $Num, tuple($(setinds(args, symbolic_args, ts)...),)) ? $Num : $identity
                 args = ($(map(name, args)...),)
                 if all(arg -> !(arg isa $Symbolic), args)
-                    $f(args...,)
+                    wrap($f(args...,))
                 else
                     wrap($Term{$ret_type}($f, collect(args)))
                 end
diff --git a/test/overloads.jl b/test/overloads.jl
index 713f174b4..5c3e6fcee 100644
--- a/test/overloads.jl
+++ b/test/overloads.jl
@@ -169,6 +169,7 @@ eqs = [
 @test isequal(Symbolics.solve_for(2//1*x + y - 2//1*z ~ 9//1*x, 1//1*x), 1//7*y - 2//7*z)
 
 @test isequal(sign(x), Num(SymbolicUtils.Term{Int}(sign, [Symbolics.value(x)])))
+@test sign(Num(1)) isa Num
 @test isequal(sign(Num(1)), Num(1))
 @test isequal(sign(Num(-1)), Num(-1))