renaming isexception to isfailure in analogy to the Scala datatype and to remove confusion between Const{Exception} and plain Exception

:100644 100644 bcff955 70ef31c M	src/Try.jl
:100644 100644 07ed659 46eef62 M	src/promote_type.jl

Author: Stephan Sahm

src/DataTypesBasic.jl

@@ -36,7 +36,7 @@ module DataTypesBasic
 export Identity, isidentity, Const,
   Option, isoption, issome, isnone, iftrue, iffalse, getOption,
   Either, either, @either, iseither, isleft, isright, getleft, getright, getOption, getleftOption, getrightOption, flip_left_right,
-  Try, @Try, @TryCatch, istry, issuccess, isexception, Thrown, MultipleExceptions,
+  Try, @Try, @TryCatch, istry, issuccess, isfailure, Thrown, MultipleExceptions,
   ContextManager, @ContextManager
 
 using Compat

src/Try.jl

@@ -184,14 +184,14 @@ issuccess(::Identity) = true
 issuccess(::Const{<:Exception}) = false
 
 """
-    isexception(::Identity) = false
-    isexception(::Const{<:Exception}) = true
+    isfailure(::Identity) = false
+    isfailure(::Const{<:Exception}) = true
 
 Similar to [`isleft`](@ref), but only defined for `Const{<:Exception}`. Will
 throw MethodError when applied on other `Const`.
 """
-isexception(::Identity) = false
-isexception(::Const{<:Exception}) = true
+isfailure(::Identity) = false
+isfailure(::Const{<:Exception}) = true
 
 Base.eltype(::Type{Try{T}}) where T = T
 Base.eltype(::Type{Try}) = Any

src/promote_type.jl

@@ -81,7 +81,7 @@ function either_promote_type_fix(T, S)
     a = @TryCatch MethodError promote_rule(T, S)
     b = @TryCatch MethodError promote_rule(S, T)
 
-    if isexception(a) && isexception(b)
+    if isfailure(a) && isfailure(b)
         error("Could not `promote_type{T=$T, S=$S}`, as both `promote_rule(T, S)` and `promote_rule(S, T)` result in
                MethodErrors: $a, $b.")
     elseif issuccess(a) && issuccess(b)

test/Try.jl

@@ -16,9 +16,9 @@ using Test
 @test !issuccess(@Try error("hi"))
 @test_throws MethodError issuccess(Const("other"))
 
-@test isexception(@Try error("hi"))
-@test !isexception(@Try 5)
-@test_throws MethodError isexception(Const("other"))
+@test isfailure(@Try error("hi"))
+@test !isfailure(@Try 5)
+@test_throws MethodError isfailure(Const("other"))
 
 @test Thrown(ErrorException("one"), []) == Thrown(ErrorException("one"), [])
 @test repr(Thrown(ErrorException("some"), [])) == """Thrown(ErrorException("some"))"""