support dots for unary operators (#20249)

* support dots for unary operators (closes #14161)
* docs for unary dot operators
* work around #20249

NEWS.md

@@ -34,6 +34,7 @@ Language changes
     the `broadcast` call `(⨳).(a, b)`.  Hence, one no longer defines methods
     for `.*` etcetera.  This also means that "dot operations" automatically
     fuse into a single loop, along with other dot calls `f.(x)`. ([#17623])
+    Similarly for unary operators ([#20249]).
 
   * Newly defined methods are no longer callable from the same dynamic runtime
     scope they were defined in ([#17057]).

doc/src/manual/functions.md

@@ -660,7 +660,7 @@ julia> @. X = sin(cos(Y)) # equivalent to X .= sin.(cos.(Y))
  -0.608083
 ```
 
-Operators like `.*` are handled with the same mechanism:
+Binary (or unary) operators like `.+` are handled with the same mechanism:
 they are equivalent to `broadcast` calls and are fused with other nested "dot" calls.
  `X .+= Y` etcetera is equivalent to `X .= X .+ Y` and results in a fused in-place assignment;
  see also [dot operators](@ref man-dot-operators).

doc/src/manual/mathematical-operations.md

@@ -135,7 +135,9 @@ to perform `^` element-by-element on arrays. For example,
 `[1,2,3] ^ 3` is not defined, since there is no standard
 mathematical meaning to "cubing" an array, but `[1,2,3] .^ 3`
 is defined as computing the elementwise
-(or "vectorized") result `[1^3, 2^3, 3^3]`.
+(or "vectorized") result `[1^3, 2^3, 3^3]`.  Similarly for unary
+operators like `!` or `√`, there is a corresponding `.√` that
+applies the operator elementwise.
 
 ```jldoctest
 julia> [1,2,3] .^ 3

src/julia-parser.scm

@@ -65,10 +65,11 @@
                      t))
 (define (operator-precedence op) (get prec-table op 0))
 
-(define unary-ops '(+ - ! ¬ ~ |<:| |>:| √ ∛ ∜))
+(define unary-ops (append! '(|<:| |>:| ~)
+                           (add-dots '(+ - ! ¬ √ ∛ ∜))))
 
 ; operators that are both unary and binary
-(define unary-and-binary-ops '(+ - $ & ~))
+(define unary-and-binary-ops '(+ - $ & ~ |.+| |.-|))
 
 ; operators that are special forms, not function names
 (define syntactic-operators
@@ -93,9 +94,9 @@
 
 (define operators
   (filter (lambda (x) (not (is-word-operator? x)))
-          (list* '~ '! '¬ '-> '√ '∛ '∜ ctrans-op trans-op vararg-op
-                 (delete-duplicates
-                   (apply append (map eval prec-names))))))
+          (delete-duplicates
+           (list* '-> ctrans-op trans-op vararg-op
+                  (append unary-ops (apply append (map eval prec-names)))))))
 
 (define op-chars
   (delete-duplicates
@@ -200,7 +201,7 @@
                                     (loop newop (peek-char port)))
                              str))
                        str))))
-        (if (or (equal? str "--") (equal? str ".!"))
+        (if (equal? str "--")
             (error (string "invalid operator \"" str "\"")))
         (string->symbol str))))
 

test/broadcast.jl

@@ -327,6 +327,11 @@ let g = Int[], ⊕ = (a,b) -> let c=a+2b; push!(g, c); c; end
     @test g == [21,221,24,424,27,627] # test for loop fusion
 end
 
+# Fused unary operators
+@test .√[3,4,5] == sqrt.([3,4,5])
+@test .![true, true, false] == [false, false, true]
+@test .-[1,2,3] == -[1,2,3] == .+[-1,-2,-3] == [-1,-2,-3]
+
 # PR 16988
 @test Base.promote_op(+, Bool) === Int
 @test isa(broadcast(+, [true]), Array{Int,1})

test/nullable.jl

@@ -467,10 +467,10 @@ sqr(x) = x^2
 @test Nullable(2) .^ Nullable{Int}()  |> isnull_oftype(Int)
 
 # multi-arg broadcast
-@test Nullable(1) .+ Nullable(1) .+ Nullable(1) .+ Nullable(1) .+ Nullable(1) .+
-    Nullable(1) === Nullable(6)
-@test Nullable(1) .+ Nullable(1) .+ Nullable(1) .+ Nullable{Int}() .+
-    Nullable(1) .+ Nullable(1) |> isnull_oftype(Int)
+@test (Nullable(1) .+ Nullable(1) .+ Nullable(1) .+ Nullable(1) .+ Nullable(1) .+
+       Nullable(1) === Nullable(6))
+@test (Nullable(1) .+ Nullable(1) .+ Nullable(1) .+ Nullable{Int}() .+
+       Nullable(1) .+ Nullable(1) |> isnull_oftype(Int))
 
 # these are not inferrable because there are too many arguments
 us = map(Nullable, 1:20)