function negation and composition: !f, f∘g

Author: StefanKarpinski

base/exports.jl

@@ -256,6 +256,7 @@ export
     ~,
     :,
     =>,
+    ∘,
     A_ldiv_B!,
     A_ldiv_Bc,
     A_ldiv_Bt,

base/operators.jl

@@ -328,9 +328,14 @@ eltype(::Type{Any}) = Any
 eltype(t::DataType) = eltype(supertype(t))
 eltype(x) = eltype(typeof(x))
 
-# function pipelining
+# function pipelining, composition & negation
+
 |>(x, f) = f(x)
 
+∘(f, g) = (x...)->f(g(x...))
+
+!(f::Function) = (x...)->!f(x...)
+
 # array shape rules
 
 function promote_shape(a::Tuple{Int,}, b::Tuple{Int,})
@@ -672,6 +677,7 @@ export
     ∪,
     √,
     ∛,
+    ∘,
     colon,
     hcat,
     vcat,
@@ -685,6 +691,6 @@ import ..this_module: !, !=, $, %, .%, ÷, .÷, &, *, +, -, .!=, .+, .-, .*, ./,
     .>=, .\, .^, /, //, <, <:, <<, <=, ==, >, >=, >>, .>>, .<<, >>>,
     <|, |>, \, ^, |, ~, !==, ===, >:, colon, hcat, vcat, hvcat, getindex, setindex!,
     transpose, ctranspose,
-    ≥, ≤, ≠, .≥, .≤, .≠, ⋅, ×, ∈, ∉, ∋, ∌, ⊆, ⊈, ⊊, ∩, ∪, √, ∛
+    ≥, ≤, ≠, .≥, .≤, .≠, ⋅, ×, ∈, ∉, ∋, ∌, ⊆, ⊈, ⊊, ∩, ∪, √, ∛, ∘
 
 end