close #351; issue with Bool type and arithmetic (#352)

* close #351; issue with  Bool type and arithmetic

Project.toml

@@ -1,6 +1,6 @@
 name = "SymPy"
 uuid = "24249f21-da20-56a4-8eb1-6a02cf4ae2e6"
-version = "1.0.22"
+version = "1.0.23"
 
 
 [deps]

src/mathops.jl

@@ -19,3 +19,16 @@
 \(x::SymbolicObject, y::SymbolicObject) = (y'/x')' # ?
 
 inv(x::Sym) = x.__pow__(Sym(-1))
+
+# special case Boolean; issue   351
+# promotion for Boolean here is to 0 or  1,  not False,  True
++(x::Bool, y::SymbolicObject) = Sym(Int(x)).__add__(y)
++(x::SymbolicObject, y::Bool) = x.__add__(Int(y))
+*(x::Bool, y::SymbolicObject) = Sym(Int(x)).__mul__(y)
+*(x::SymbolicObject, y::Bool) = x.__mul__(Int(y))
+-(x::Bool, y::SymbolicObject) = Sym(Int(x)).__sub__(y)
+-(x::SymbolicObject, y::Bool) = x.__sub__(Int(y))
+/(x::Bool, y::SymbolicObject) = Sym(Int(x)).__div__(y)
+/(x::SymbolicObject, y::Bool) = x.__div__(Int(y))
+^(x::Bool, y::SymbolicObject) = Sym(Int(x)).__pow__(y)
+^(x::SymbolicObject, y::Bool) = x.__pow__(Int(y))

test/tests.jl

@@ -608,7 +608,7 @@ end
     @test eltype(A*A) == Sym
     @test eltype(A*ones(2,2)) == Sym
     @test eltype(A*Diagonal([1,1])) == Sym
-    @test_broken eltype(A * I(2)) == Sym
+    VERSION >= v"1.2.0"  && @test eltype(A * I(2)) == Sym
 
     ## Issue 328 with E -> e
     @vars x
@@ -654,6 +654,11 @@ end
     @test lambdify(PI^4*xreal)(256) == 256 * pi^4
 
 
-
+    ## Issue 351 booleans  and arithmetic operations
+    @test 1  + true  ==  2 == true +  1 
+    @test 1 - true  == 0 ==   true -  1
+    @test 1 * true == 1 == true * 1
+    @test 1/true == 1  == true/1
+    @test true^1  ==  1  ==  1^true
 
 end