fix #9503 plus another proposal on comparison and iteration syntax

NEWS.md

@@ -32,6 +32,12 @@ Language changes
   * A warning is always given when a method is overwritten (previously, this was done only when the new
     and old definitions were in separate modules) ([#14759]).
 
+  * `A <: B` is parsed as `Expr(:(<:), :A, :B)` in all cases ([#9503]). This also applies to the
+    `>:` operator.
+
+  * Simple 2-argument comparisons like `A < B` are parsed as calls intead of using the
+    `:comparison` expression type.
+
 Command-line option changes
 ---------------------------
 
@@ -1690,6 +1696,7 @@ Too numerous to mention.
 [#9434]: https://github.com/JuliaLang/julia/issues/9434
 [#9452]: https://github.com/JuliaLang/julia/issues/9452
 [#9487]: https://github.com/JuliaLang/julia/issues/9487
+[#9503]: https://github.com/JuliaLang/julia/issues/9503
 [#9569]: https://github.com/JuliaLang/julia/issues/9569
 [#9575]: https://github.com/JuliaLang/julia/issues/9575
 [#9578]: https://github.com/JuliaLang/julia/issues/9578
@@ -1793,4 +1800,6 @@ Too numerous to mention.
 [#14469]: https://github.com/JuliaLang/julia/issues/14469
 [#14759]: https://github.com/JuliaLang/julia/issues/14759
 [#14798]: https://github.com/JuliaLang/julia/issues/14798
+[#15192]: https://github.com/JuliaLang/julia/issues/15192
 [#15242]: https://github.com/JuliaLang/julia/issues/15242
+[#15258]: https://github.com/JuliaLang/julia/issues/15258

base/linalg/cholesky.jl

@@ -276,15 +276,15 @@ end
 
 function det(C::Cholesky)
     dd = one(eltype(C))
-    for i in 1:size(C.factors,1) dd *= abs2(C.factors[i,i]) end
+    for i in 1:size(C.factors,1); dd *= abs2(C.factors[i,i]) end
     dd
 end
 
 det(C::CholeskyPivoted) = C.rank < size(C.factors, 1) ? real(zero(eltype(C))) : prod(abs2(diag(C.factors)))
 
 function logdet(C::Cholesky)
     dd = zero(eltype(C))
-    for i in 1:size(C.factors,1) dd += log(C.factors[i,i]) end
+    for i in 1:size(C.factors,1); dd += log(C.factors[i,i]) end
     dd + dd # instead of 2.0dd which can change the type
 end
 

base/linalg/dense.jl

@@ -248,7 +248,7 @@ function expm!{T<:BlasFloat}(A::StridedMatrix{T})
         LAPACK.gesv!(V-U, X)
 
         if s > 0            # squaring to reverse dividing by power of 2
-            for t=1:si X *= X end
+            for t=1:si; X *= X end
         end
     end
 
@@ -264,10 +264,10 @@ function expm!{T<:BlasFloat}(A::StridedMatrix{T})
     end
 
     if ilo > 1       # apply lower permutations in reverse order
-        for j in (ilo-1):-1:1 rcswap!(j, Int(scale[j]), X) end
+        for j in (ilo-1):-1:1; rcswap!(j, Int(scale[j]), X) end
     end
     if ihi < n       # apply upper permutations in forward order
-        for j in (ihi+1):n    rcswap!(j, Int(scale[j]), X) end
+        for j in (ihi+1):n;    rcswap!(j, Int(scale[j]), X) end
     end
     X
 end

base/sparse/cholmod.jl

@@ -1517,7 +1517,7 @@ end
 function logdet{Tv<:VTypes}(F::Factor{Tv})
     f = unsafe_load(get(F.p))
     res = zero(Tv)
-    for d in diag(F) res += log(abs(d)) end
+    for d in diag(F); res += log(abs(d)) end
     f.is_ll!=0 ? 2res : res
 end
 

base/sparse/linalg.jl

@@ -6,14 +6,14 @@ import Base.LinAlg: checksquare
 
 # Convert from 1-based to 0-based indices
 function decrement!{T<:Integer}(A::AbstractArray{T})
-    for i in 1:length(A) A[i] -= one(T) end
+    for i in 1:length(A); A[i] -= one(T) end
     A
 end
 decrement{T<:Integer}(A::AbstractArray{T}) = decrement!(copy(A))
 
 # Convert from 0-based to 1-based indices
 function increment!{T<:Integer}(A::AbstractArray{T})
-    for i in 1:length(A) A[i] += one(T) end
+    for i in 1:length(A); A[i] += one(T) end
     A
 end
 increment{T<:Integer}(A::AbstractArray{T}) = increment!(copy(A))

base/sparse/sparsematrix.jl

@@ -3084,7 +3084,7 @@ spdiagm(B::AbstractVector, d::Number=0) = spdiagm((B,), (d,))
 function expandptr{T<:Integer}(V::Vector{T})
     if V[1] != 1 throw(ArgumentError("first index must be one")) end
     res = similar(V, (Int64(V[end]-1),))
-    for i in 1:(length(V)-1), j in V[i]:(V[i+1] - 1) res[j] = i end
+    for i in 1:(length(V)-1), j in V[i]:(V[i+1] - 1); res[j] = i end
     res
 end
 

base/strings/basic.jl

@@ -39,7 +39,7 @@ getindex(s::AbstractString, i::Integer) = s[Int(i)]
 getindex{T<:Integer}(s::AbstractString, r::UnitRange{T}) = s[Int(first(r)):Int(last(r))]
 # TODO: handle other ranges with stride ±1 specially?
 getindex(s::AbstractString, v::AbstractVector) =
-    sprint(length(v), io->(for i in v write(io,s[i]) end))
+    sprint(length(v), io->(for i in v; write(io,s[i]) end))
 
 symbol(s::AbstractString) = symbol(bytestring(s))
 

base/test.jl

@@ -151,6 +151,11 @@ Returns a `Pass` `Result` if it does, a `Fail` `Result` if it is
 """
 macro test(ex)
     orig_ex = Expr(:quote,ex)
+    # Normalize comparison operator calls to :comparison expressions
+    if isa(ex, Expr) && ex.head == :call && length(ex.args)==3 &&
+        Base.operator_precedence(ex.args[1]) == Base.operator_precedence(:(==))
+        ex = Expr(:comparison, ex.args[2], ex.args[1], ex.args[3])
+    end
     # If the test is a comparison
     if isa(ex, Expr) && ex.head == :comparison
         # Generate a temporary for every term in the expression

src/julia-parser.scm

@@ -780,12 +780,21 @@
   (let loop ((ex (parse-pipes s))
              (first #t))
     (let ((t (peek-token s)))
-      (if (not (is-prec-comparison? t))
-          ex
-          (begin (take-token s)
-                 (if first
-                     (loop (list 'comparison ex t (parse-pipes s)) #f)
-                     (loop (append ex (list t (parse-pipes s))) #f)))))))
+      (cond ((is-prec-comparison? t)
+             (begin (take-token s)
+                    (if first
+                        (loop (list 'comparison ex t (parse-pipes s)) #f)
+                        (loop (append ex (list t (parse-pipes s))) #f))))
+            (first ex)
+            ((length= ex 4)
+             ;; only a single comparison; special chained syntax not required
+             (let ((op   (caddr ex))
+                   (arg1 (cadr ex))
+                   (arg2 (cadddr ex)))
+               (if (or (eq? op '|<:|) (eq? op '|>:|))
+                   `(,op ,arg1 ,arg2)
+                   `(call ,op ,arg1 ,arg2))))
+            (else ex)))))
 
 (define closing-token?
   (let ((closer? (Set '(else elseif catch finally #\, #\) #\] #\} #\;))))
@@ -905,13 +914,6 @@
         (else
          ex)))))
 
-;; convert (comparison a <: b) to (<: a b)
-(define (subtype-syntax e)
-  (if (and (pair? e) (eq? (car e) 'comparison)
-           (length= e 4) (eq? (caddr e) '|<:|))
-      `(<: ,(cadr e) ,(cadddr e))
-      e))
-
 (define (parse-unary-prefix s)
   (let ((op (peek-token s)))
     (if (syntactic-unary-op? op)
@@ -1031,8 +1033,7 @@
                                      (string (deparse ex) " " (deparse t))
                                      (string (deparse ex) (deparse t))))
              (take-token s)
-             (loop (list* 'curly ex
-                          (map subtype-syntax (parse-arglist s #\} )))))
+             (loop (list* 'curly ex (parse-arglist s #\} ))))
             ((#\")
              (if (and (symbol? ex) (not (operator? ex))
                       (not (ts:space? s)))
@@ -1066,7 +1067,7 @@
                           " expected \"end\", got \"" t "\""))))))
 
 (define (parse-subtype-spec s)
-  (subtype-syntax (parse-comparison s)))
+  (parse-comparison s))
 
 ;; parse expressions or blocks introduced by syntactic reserved words
 (define (parse-resword s word)
@@ -1399,14 +1400,20 @@
 
 ;; as above, but allows both "i=r" and "i in r"
 (define (parse-iteration-spec s)
-  (let ((r (parse-eq* s)))
-    (cond ((and (pair? r) (eq? (car r) '=))  r)
-          ((eq? r ':)  r)
-          ((and (length= r 4) (eq? (car r) 'comparison)
-                (or (eq? (caddr r) 'in) (eq? (caddr r) '∈)))
-           `(= ,(cadr r) ,(cadddr r)))
-          (else
-           (error "invalid iteration specification")))))
+  (let* ((lhs (parse-pipes s))
+         (t   (peek-token s)))
+    (cond ((memq t '(= in ∈))
+           (take-token s)
+           (let* ((rhs (parse-pipes s))
+                  (t   (peek-token s)))
+             #;(if (not (or (closing-token? t) (newline? t)))
+                 ;; should be: (error "invalid iteration specification")
+                 (syntax-deprecation s (string "for " (deparse `(= ,lhs ,rhs)) " " t)
+                                     (string "for " (deparse `(= ,lhs ,rhs)) "; " t)))
+             `(= ,lhs ,rhs)))
+          ((and (eq? lhs ':) (closing-token? t))
+           ':)
+          (else (error "invalid iteration specification")))))
 
 (define (parse-comma-separated-iters s)
   (let loop ((ranges '()))

src/julia-syntax.scm

@@ -1482,6 +1482,10 @@
                                             `(call (top next) ,coll ,state))
                    ,body))))))))
 
+;; convert an operator parsed as (op a b) to (call op a b)
+(define (syntactic-op-to-call e)
+  `(call ,(car e) ,(expand-forms (cadr e)) ,(expand-forms (caddr e))))
+
 ;; table mapping expression head to a function expanding that form
 (define expand-table
   (table
@@ -1518,9 +1522,8 @@
    (lambda (e)
      `(call (top getfield) ,(expand-forms (cadr e)) ,(expand-forms (caddr e))))
 
-   'in
-   (lambda (e)
-     `(call in ,(expand-forms (cadr e)) ,(expand-forms (caddr e))))
+   '|<:| syntactic-op-to-call
+   '|>:| syntactic-op-to-call
 
    'const  expand-const-decl
    'local  expand-local-or-global-decl

test/parse.jl

@@ -22,9 +22,9 @@ let
                        ("5.≥x", "5.>=x"),
                        ("5.≤x", "5.<=x")]
         ex1 = parse(ex1); ex2 = parse(ex2)
-        @test ex1.head === :comparison && (ex1.head === ex2.head)
-        @test ex1.args[1] === 5 && ex2.args[1] === 5
-        @test is(eval(Main, ex1.args[2]), eval(Main, ex2.args[2]))
+        @test ex1.head === :call && (ex1.head === ex2.head)
+        @test ex1.args[2] === 5 && ex2.args[2] === 5
+        @test is(eval(Main, ex1.args[1]), eval(Main, ex2.args[1]))
         @test ex1.args[3] === :x && (ex1.args[3] === ex2.args[3])
     end
 end
@@ -291,7 +291,7 @@ for T in (UInt8,UInt16,UInt32,UInt64)
     @test_throws OverflowError parse(T,string(big(typemax(T))+1))
 end
 
-@test parse("1 == 2|>3") == Expr(:comparison, 1, :(==), Expr(:call, :(|>), 2, 3))
+@test parse("1 == 2|>3") == Expr(:call, :(==), 1, Expr(:call, :(|>), 2, 3))
 
 # issue #12501 and pr #12502
 parse("""
@@ -365,3 +365,9 @@ let a⊂b = reduce(&, x ∈ b for x in a) && length(b)>length(a)
     @test !([1,2] ⊂ [1,3,4])
     @test !([1,2] ⊂ [1,2])
 end
+
+# issue #9503
+@test parse("x<:y") == Expr(:(<:), :x, :y)
+@test parse("x>:y") == Expr(:(>:), :x, :y)
+@test parse("x<:y<:z").head === :comparison
+@test parse("x>:y<:z").head === :comparison