adds binary and integer options to variable metadata

Author: ValentinKaisermayer

src/variables.jl

@@ -286,3 +286,37 @@ end
 function hasdescription(x)
     getdescription(x) != ""
 end
+
+## binary variables =================================================================
+struct VariableBinary end
+Symbolics.option_to_metadata_type(::Val{:binary}) = VariableBinary
+
+isbinary(x::Num) = isbinary(Symbolics.unwrap(x))
+
+"""
+    isbinary(x)
+
+Determine if a variable is binary.
+"""
+function isbinary(x)
+    p = Symbolics.getparent(x, nothing)
+    p === nothing || (x = p)
+    return Symbolics.getmetadata(x, VariableBinary, false)
+end
+
+## integer variables =================================================================
+struct VariableInteger end
+Symbolics.option_to_metadata_type(::Val{:integer}) = VariableInteger
+
+isinteger(x::Num) = isinteger(Symbolics.unwrap(x))
+
+"""
+    isinteger(x)
+
+Determine if a variable is integer.
+"""
+function isinteger(x)
+    p = Symbolics.getparent(x, nothing)
+    p === nothing || (x = p)
+    return Symbolics.getmetadata(x, VariableInteger, false)
+end

test/test_variable_metadata.jl

@@ -82,3 +82,19 @@ sp = Set(p)
 @named sys = ODESystem([u ~ p], t)
 
 @test_nowarn show(stdout, "text/plain", sys)
+
+@testset "binary" begin
+    @parameters t
+    @variables u(t) [binary = true]
+    @parameters p [binary = true]
+    @test isbinary(u)
+    @test isbinary(p)
+end
+
+@testset "integer" begin
+    @parameters t
+    @variables u(t) [integer = true]
+    @parameters p [integer = true]
+    @test isinteger(u)
+    @test isinteger(p)
+end