From 6f8cfcc44be979d3c7525c26bc9fcaa858ad3a3c Mon Sep 17 00:00:00 2001
From: Chris Rackauckas <accounts@chrisrackauckas.com>
Date: Thu, 11 Apr 2019 15:46:01 -0400
Subject: [PATCH 1/5] simplified interface for declaring parameters

---
 README.md                   | 16 +++++++++-------
 src/variables.jl            | 13 ++++++++++---
 test/derivatives.jl         |  2 +-
 test/simplify.jl            |  2 +-
 test/system_construction.jl | 10 +++++-----
 test/variable_parsing.jl    |  9 +++++----
 6 files changed, 31 insertions(+), 21 deletions(-)

diff --git a/README.md b/README.md
index 258123d3a9..55350b133a 100644
--- a/README.md
+++ b/README.md
@@ -28,7 +28,7 @@ and parameters. Therefore we label them as follows:
 using ModelingToolkit
 
 # Define some variables
-@parameters t() σ() ρ() β()
+@parameters t σ ρ β
 @variables x(t) y(t) z(t)
 @derivatives D'~t
 ```
@@ -80,8 +80,8 @@ state of the previous ODE. This is the nonlinear system defined by where the
 derivatives are zero. We use (unknown) variables for our nonlinear system.
 
 ```julia
-@variables x() y() z()
-@parameters σ() ρ() β()
+@variables x y z
+@parameters σ ρ β
 
 # Define a nonlinear system
 eqs = [0 ~ σ*(y-x),
@@ -166,12 +166,14 @@ including and excluding empty parentheses. When in call format, variables are
 aliased to the given call, allowing implicit use of dependents for convenience.
 
 ```julia
-@parameters t() α() σ
+@dependent_parameters t() α() σ
 @variables w x(t) y() z(t, α, x)
 
 expr = x + y^α + σ(3) * (z - t) - w(t - 1)
 ```
 
+`@parameters` is a simplified tool for defining constant parameters, meaning
+`@parameters t`  is the same as `@dependent_parameters t()`
 
 ### Constants
 
@@ -274,7 +276,7 @@ is accessible via a function-based interface. This means that all macros are
 syntactic sugar in some form. For example, the variable construction:
 
 ```julia
-@parameters t() σ ρ() β()
+@parameters t σ ρ β
 @variables x(t) y(t) z(t)
 @derivatives D'~t
 ```
@@ -297,8 +299,8 @@ D = Differential(t)
 The system building functions can handle intermediate calculations. For example,
 
 ```julia
-@variables x() y() z()
-@parameters σ() ρ() β()
+@variables x y z
+@parameters σ ρ β
 a = y - x
 eqs = [0 ~ σ*a,
        0 ~ x*(ρ-z)-y,
diff --git a/src/variables.jl b/src/variables.jl
index c1f773dbcc..c6ad07f248 100644
--- a/src/variables.jl
+++ b/src/variables.jl
@@ -1,4 +1,4 @@
-export Variable, @variables, @parameters
+export Variable, @variables, @parameters, @dependent_parameters
 
 
 struct Variable <: Function
@@ -29,7 +29,7 @@ Base.convert(::Type{Expr}, c::Constant) = c.value
 
 
 # Build variables more easily
-function _parse_vars(macroname, known, x)
+function _parse_vars(macroname, known, x, add_call = true)
     ex = Expr(:block)
     var_names = Symbol[]
     # if parsing things in the form of
@@ -50,7 +50,11 @@ function _parse_vars(macroname, known, x)
             expr = :($var_name = $Variable($(Meta.quot(var_name)); known = $known)($(_var.args[2:end]...)))
         else
             var_name = _var
-            expr = :($var_name = $Variable($(Meta.quot(var_name)); known = $known))
+            if add_call
+                expr = :($var_name = $Variable($(Meta.quot(var_name)); known = $known)())
+            else
+                expr = :($var_name = $Variable($(Meta.quot(var_name)); known = $known))
+            end
         end
 
         push!(var_names, var_name)
@@ -65,3 +69,6 @@ end
 macro parameters(xs...)
     esc(_parse_vars(:parameters, true, xs))
 end
+macro dependent_parameters(xs...)
+    esc(_parse_vars(:parameters, true, xs, false))
+end
diff --git a/test/derivatives.jl b/test/derivatives.jl
index 1569420da6..194184fca1 100644
--- a/test/derivatives.jl
+++ b/test/derivatives.jl
@@ -2,7 +2,7 @@ using ModelingToolkit
 using Test
 
 # Derivatives
-@parameters t() σ() ρ() β()
+@parameters t σ ρ β
 @variables x(t) y(t) z(t)
 @derivatives D'~t D2''~t Dx'~x
 
diff --git a/test/simplify.jl b/test/simplify.jl
index 0f723fa1ce..be6c1554df 100644
--- a/test/simplify.jl
+++ b/test/simplify.jl
@@ -1,7 +1,7 @@
 using ModelingToolkit
 using Test
 
-@parameters t()
+@parameters t
 @variables x(t) y(t) z(t)
 
 null_op = 0*t
diff --git a/test/system_construction.jl b/test/system_construction.jl
index 2126a2b5b2..88f27e9e98 100644
--- a/test/system_construction.jl
+++ b/test/system_construction.jl
@@ -2,7 +2,7 @@ using ModelingToolkit
 using Test
 
 # Define some variables
-@parameters t() σ() ρ() β()
+@parameters t σ ρ β
 @variables x(t) y(t) z(t)
 @derivatives D'~t
 
@@ -60,7 +60,7 @@ fwt(FW, u, p, 0.2, 0.1)
         du ≈ [11, -3, -7]
     end
 
-    @parameters σ
+    @dependent_parameters σ
     eqs = [D(x) ~ σ(t-1)*(y-x),
            D(y) ~ x*(ρ-z)-y,
            D(z) ~ x*y - β*z]
@@ -127,7 +127,7 @@ test_nlsys_inference("standard", ns, (x, y, z), (σ, ρ, β))
 end
 
 @derivatives D'~t
-@parameters A() B() C()
+@parameters A B C
 _x = y / C
 eqs = [D(x) ~ -A*x,
        D(y) ~ A*x - B*_x]
@@ -140,8 +140,8 @@ de = ODESystem(eqs)
 end
 
 # Now nonlinear system with only variables
-@variables x() y() z()
-@parameters σ() ρ() β()
+@variables x y z
+@parameters σ ρ β
 
 # Define a nonlinear system
 eqs = [0 ~ σ*(y-x),
diff --git a/test/variable_parsing.jl b/test/variable_parsing.jl
index 2b51bbd68b..8a2af68f5d 100644
--- a/test/variable_parsing.jl
+++ b/test/variable_parsing.jl
@@ -1,7 +1,7 @@
 using ModelingToolkit
 using Test
 
-@parameters t()
+@parameters t
 @variables x(t) y(t) # test multi-arg
 @variables z(t) # test single-arg
 x1 = Variable(:x)(t)
@@ -12,10 +12,11 @@ z1 = Variable(:z)(t)
 @test isequal(z1, z)
 
 @parameters begin
-    t()
-    s()
-    σ
+    t
+    s
 end
+@dependent_parameters σ
+
 t1 = Variable(:t; known = true)()
 s1 = Variable(:s; known = true)()
 σ1 = Variable(:σ; known = true)

From 006e459c5560d779f971d65890356a7c6b787779 Mon Sep 17 00:00:00 2001
From: Christopher Rackauckas <Contact@ChrisRackauckas.com>
Date: Sat, 13 Apr 2019 07:13:06 -0400
Subject: [PATCH 2/5] change to implicit () + (..) for uncalled

---
 README.md                   | 10 ++++++----
 src/variables.jl            | 18 ++++++++----------
 test/system_construction.jl |  2 +-
 test/variable_parsing.jl    |  2 +-
 4 files changed, 16 insertions(+), 16 deletions(-)

diff --git a/README.md b/README.md
index 55350b133a..87bc964518 100644
--- a/README.md
+++ b/README.md
@@ -166,14 +166,16 @@ including and excluding empty parentheses. When in call format, variables are
 aliased to the given call, allowing implicit use of dependents for convenience.
 
 ```julia
-@dependent_parameters t() α() σ
-@variables w x(t) y() z(t, α, x)
+@parameters t α σ(..)
+@variables w(..) x(t) y() z(t, α, x)
 
 expr = x + y^α + σ(3) * (z - t) - w(t - 1)
 ```
 
-`@parameters` is a simplified tool for defining constant parameters, meaning
-`@parameters t`  is the same as `@dependent_parameters t()`
+Note that `@parameters` and `@variables` implicitly add `()` to values that
+are not given a call. The former specifies the values as known, while the
+latter specifies it as unknown. `(..)` signifies that the value should be
+left uncalled.
 
 ### Constants
 
diff --git a/src/variables.jl b/src/variables.jl
index c6ad07f248..a8bb1fef1c 100644
--- a/src/variables.jl
+++ b/src/variables.jl
@@ -29,7 +29,7 @@ Base.convert(::Type{Expr}, c::Constant) = c.value
 
 
 # Build variables more easily
-function _parse_vars(macroname, known, x, add_call = true)
+function _parse_vars(macroname, known, x)
     ex = Expr(:block)
     var_names = Symbol[]
     # if parsing things in the form of
@@ -47,14 +47,15 @@ function _parse_vars(macroname, known, x, add_call = true)
 
         if iscall
             var_name = _var.args[1]
-            expr = :($var_name = $Variable($(Meta.quot(var_name)); known = $known)($(_var.args[2:end]...)))
-        else
-            var_name = _var
-            if add_call
-                expr = :($var_name = $Variable($(Meta.quot(var_name)); known = $known)())
-            else
+            if _var.args[end] == :..
                 expr = :($var_name = $Variable($(Meta.quot(var_name)); known = $known))
+            else
+                expr = :($var_name = $Variable($(Meta.quot(var_name)); known = $known)($(_var.args[2:end]...)))
             end
+        else
+            # Implicit 0-args call
+            var_name = _var
+            expr = :($var_name = $Variable($(Meta.quot(var_name)); known = $known)())
         end
 
         push!(var_names, var_name)
@@ -69,6 +70,3 @@ end
 macro parameters(xs...)
     esc(_parse_vars(:parameters, true, xs))
 end
-macro dependent_parameters(xs...)
-    esc(_parse_vars(:parameters, true, xs, false))
-end
diff --git a/test/system_construction.jl b/test/system_construction.jl
index 88f27e9e98..5b550393f4 100644
--- a/test/system_construction.jl
+++ b/test/system_construction.jl
@@ -60,7 +60,7 @@ fwt(FW, u, p, 0.2, 0.1)
         du ≈ [11, -3, -7]
     end
 
-    @dependent_parameters σ
+    @parameters σ(..)
     eqs = [D(x) ~ σ(t-1)*(y-x),
            D(y) ~ x*(ρ-z)-y,
            D(z) ~ x*y - β*z]
diff --git a/test/variable_parsing.jl b/test/variable_parsing.jl
index 8a2af68f5d..d406bdd5a8 100644
--- a/test/variable_parsing.jl
+++ b/test/variable_parsing.jl
@@ -15,7 +15,7 @@ z1 = Variable(:z)(t)
     t
     s
 end
-@dependent_parameters σ
+@parameters σ(..)
 
 t1 = Variable(:t; known = true)()
 s1 = Variable(:s; known = true)()

From 30931ca830cab18e0208723a45812296630fc5bf Mon Sep 17 00:00:00 2001
From: Christopher Rackauckas <Contact@ChrisRackauckas.com>
Date: Sat, 13 Apr 2019 08:06:04 -0400
Subject: [PATCH 3/5] add parameter call finding helper

---
 src/ModelingToolkit.jl       |  1 +
 src/equations.jl             | 11 +++++++++++
 src/variables.jl             |  2 +-
 test/find_parameter_calls.jl | 14 ++++++++++++++
 test/runtests.jl             |  1 +
 5 files changed, 28 insertions(+), 1 deletion(-)
 create mode 100644 test/find_parameter_calls.jl

diff --git a/src/ModelingToolkit.jl b/src/ModelingToolkit.jl
index e5cf37f202..bda7e36667 100644
--- a/src/ModelingToolkit.jl
+++ b/src/ModelingToolkit.jl
@@ -3,6 +3,7 @@ module ModelingToolkit
 export Operation, Expression
 export calculate_jacobian, generate_jacobian, generate_function
 export independent_variables, dependent_variables, parameters
+export find_parameter_calls
 export @register
 
 
diff --git a/src/equations.jl b/src/equations.jl
index ffaa222021..cb107d1c43 100644
--- a/src/equations.jl
+++ b/src/equations.jl
@@ -10,3 +10,14 @@ Base.:(==)(a::Equation, b::Equation) = isequal((a.lhs, a.rhs), (b.lhs, b.rhs))
 Base.:~(lhs::Expression, rhs::Expression) = Equation(lhs, rhs)
 Base.:~(lhs::Expression, rhs::Number    ) = Equation(lhs, rhs)
 Base.:~(lhs::Number    , rhs::Expression) = Equation(lhs, rhs)
+
+function find_parameter_calls(O::Operation,p_calls=Variable[])
+  if O.op isa Variable && O.op.known && !isempty(O.args)
+      push!(p_calls,O.op)
+      find_parameter_calls.(O.args,(p_calls,))
+  else
+      find_parameter_calls.(O.args,(p_calls,))
+  end
+  p_calls
+end
+find_parameter_calls(O,p_calls) = nothing
diff --git a/src/variables.jl b/src/variables.jl
index a8bb1fef1c..2b9dfeced7 100644
--- a/src/variables.jl
+++ b/src/variables.jl
@@ -1,4 +1,4 @@
-export Variable, @variables, @parameters, @dependent_parameters
+export Variable, @variables, @parameters
 
 
 struct Variable <: Function
diff --git a/test/find_parameter_calls.jl b/test/find_parameter_calls.jl
new file mode 100644
index 0000000000..b019ba398d
--- /dev/null
+++ b/test/find_parameter_calls.jl
@@ -0,0 +1,14 @@
+using ModelingToolkit
+using Test
+
+# Define some variables
+@parameters t σ ρ β, α(..)
+@variables x(t) y(t) z(t)
+@derivatives D'~t
+
+eq1 = D(x) ~ σ*(y-x)
+eq2 = D(x) ~ α(t-2)*(y-x)
+
+find_parameter_calls(eq1.rhs,Variable[])
+r = find_parameter_calls(eq2.rhs,Variable[])
+!isempty(r) && r[1].name == :α
diff --git a/test/runtests.jl b/test/runtests.jl
index 00a80ece02..a05ec6d922 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -3,4 +3,5 @@ using ModelingToolkit, Test
 @testset "Parsing Test" begin include("variable_parsing.jl") end
 @testset "Differentiation Test" begin include("derivatives.jl") end
 @testset "Simplify Test" begin include("simplify.jl") end
+@testset "Parameter Call Finding Test" begin include("find_parameter_calls.jl") end
 @testset "System Construction Test" begin include("system_construction.jl") end

From deca13258095253e1bb1eb6256c910893e296bb7 Mon Sep 17 00:00:00 2001
From: Christopher Rackauckas <Contact@ChrisRackauckas.com>
Date: Sat, 13 Apr 2019 08:43:52 -0400
Subject: [PATCH 4/5] fix test

---
 test/find_parameter_calls.jl | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/test/find_parameter_calls.jl b/test/find_parameter_calls.jl
index b019ba398d..e66aa649a5 100644
--- a/test/find_parameter_calls.jl
+++ b/test/find_parameter_calls.jl
@@ -2,7 +2,7 @@ using ModelingToolkit
 using Test
 
 # Define some variables
-@parameters t σ ρ β, α(..)
+@parameters t σ ρ β α(..)
 @variables x(t) y(t) z(t)
 @derivatives D'~t
 

From 0a1b3c2d20c063567bcac90991190b646b0c5779 Mon Sep 17 00:00:00 2001
From: Christopher Rackauckas <Contact@ChrisRackauckas.com>
Date: Sat, 13 Apr 2019 11:55:47 -0400
Subject: [PATCH 5/5] remove parameter call finding

---
 src/ModelingToolkit.jl       |  1 -
 src/equations.jl             | 11 -----------
 test/find_parameter_calls.jl | 14 --------------
 test/runtests.jl             |  1 -
 4 files changed, 27 deletions(-)
 delete mode 100644 test/find_parameter_calls.jl

diff --git a/src/ModelingToolkit.jl b/src/ModelingToolkit.jl
index bda7e36667..e5cf37f202 100644
--- a/src/ModelingToolkit.jl
+++ b/src/ModelingToolkit.jl
@@ -3,7 +3,6 @@ module ModelingToolkit
 export Operation, Expression
 export calculate_jacobian, generate_jacobian, generate_function
 export independent_variables, dependent_variables, parameters
-export find_parameter_calls
 export @register
 
 
diff --git a/src/equations.jl b/src/equations.jl
index cb107d1c43..ffaa222021 100644
--- a/src/equations.jl
+++ b/src/equations.jl
@@ -10,14 +10,3 @@ Base.:(==)(a::Equation, b::Equation) = isequal((a.lhs, a.rhs), (b.lhs, b.rhs))
 Base.:~(lhs::Expression, rhs::Expression) = Equation(lhs, rhs)
 Base.:~(lhs::Expression, rhs::Number    ) = Equation(lhs, rhs)
 Base.:~(lhs::Number    , rhs::Expression) = Equation(lhs, rhs)
-
-function find_parameter_calls(O::Operation,p_calls=Variable[])
-  if O.op isa Variable && O.op.known && !isempty(O.args)
-      push!(p_calls,O.op)
-      find_parameter_calls.(O.args,(p_calls,))
-  else
-      find_parameter_calls.(O.args,(p_calls,))
-  end
-  p_calls
-end
-find_parameter_calls(O,p_calls) = nothing
diff --git a/test/find_parameter_calls.jl b/test/find_parameter_calls.jl
deleted file mode 100644
index e66aa649a5..0000000000
--- a/test/find_parameter_calls.jl
+++ /dev/null
@@ -1,14 +0,0 @@
-using ModelingToolkit
-using Test
-
-# Define some variables
-@parameters t σ ρ β α(..)
-@variables x(t) y(t) z(t)
-@derivatives D'~t
-
-eq1 = D(x) ~ σ*(y-x)
-eq2 = D(x) ~ α(t-2)*(y-x)
-
-find_parameter_calls(eq1.rhs,Variable[])
-r = find_parameter_calls(eq2.rhs,Variable[])
-!isempty(r) && r[1].name == :α
diff --git a/test/runtests.jl b/test/runtests.jl
index a05ec6d922..00a80ece02 100644
--- a/test/runtests.jl
+++ b/test/runtests.jl
@@ -3,5 +3,4 @@ using ModelingToolkit, Test
 @testset "Parsing Test" begin include("variable_parsing.jl") end
 @testset "Differentiation Test" begin include("derivatives.jl") end
 @testset "Simplify Test" begin include("simplify.jl") end
-@testset "Parameter Call Finding Test" begin include("find_parameter_calls.jl") end
 @testset "System Construction Test" begin include("system_construction.jl") end