Parse begin/end in ref as Expr

base/show.jl

@@ -2542,6 +2542,8 @@ function show_unquoted(io::IO, ex::Expr, indent::Int, prec::Int, quote_level::In
         # we want to show bad ASTs reasonably to make errors understandable.
         lambda_io = IOContext(io, :SOURCE_SLOTNAMES => false)
         show_unquoted_expr_fallback(lambda_io, ex, indent, quote_level)
+    elseif get(io, beginsym, false) && head in (:begin, :end)
+        print(io, head)
     else
         unhandled = true
     end

base/views.jl

@@ -18,16 +18,14 @@ replace_ref_begin_end!(ex) = replace_ref_begin_end_!(ex, nothing)[1]
 # replace_ref_begin_end_!(ex,withex) returns (new ex, whether withex was used)
 function replace_ref_begin_end_!(ex, withex)
     used_withex = false
-    if isa(ex,Symbol)
-        if ex === :begin
+    if isa(ex,Expr)
+        if ex.head === :begin
             withex === nothing && error("Invalid use of begin")
             return withex[1], true
-        elseif ex === :end
+        elseif ex.head === :end
             withex === nothing && error("Invalid use of end")
             return withex[2], true
-        end
-    elseif isa(ex,Expr)
-        if ex.head === :ref
+        elseif ex.head === :ref
             ex.args[1], used_withex = replace_ref_begin_end_!(ex.args[1], withex)
             S = isa(ex.args[1],Symbol) ? ex.args[1]::Symbol : gensym(:S) # temp var to cache ex.args[1] if needed
             used_S = false # whether we actually need S

deps/JuliaSyntax.version

@@ -1,4 +1,4 @@
-JULIASYNTAX_BRANCH = main
-JULIASYNTAX_SHA1 = 46723f071d5b2efcb21ca6757788028afb91cc13
+JULIASYNTAX_BRANCH = mlechu/fix-end-parsing
+JULIASYNTAX_SHA1 = 17be4e33b713d4e0f41f5ae3c5abcaef68bd9c90
 JULIASYNTAX_GIT_URL := https://github.com/JuliaLang/JuliaSyntax.jl.git
 JULIASYNTAX_TAR_URL = https://api.github.com/repos/JuliaLang/JuliaSyntax.jl/tarball/$1

deps/checksums/JuliaSyntax-17be4e33b713d4e0f41f5ae3c5abcaef68bd9c90.tar.gz/md5

@@ -0,0 +1 @@
+45dd003f87f340d4316fa97e920e1c91

deps/checksums/JuliaSyntax-17be4e33b713d4e0f41f5ae3c5abcaef68bd9c90.tar.gz/sha512

@@ -0,0 +1 @@
+b80b06044dbacef4ca17140ba7fd3e7ca867dfeebae77e972e5287e3ff18d328884c9f6a5377a4e9c65642614a586c38dd91226a079aa60d74db0225f7ef9fa9

src/ast.scm

@@ -405,7 +405,8 @@
 
 ;; identify some expressions that are safe to repeat
 (define (effect-free? e)
-  (or (not (pair? e)) (ssavalue? e) (sym-dot? e) (quoted? e) (memq (car e) '(null true false))))
+  (or (not (pair? e)) (ssavalue? e) (sym-dot? e) (quoted? e)
+      (memq (car e) '(null true false begin end))))
 
 ;; get the variable name part of a declaration, x::int => x
 (define (decl-var v)

src/julia-parser.scm

@@ -182,7 +182,7 @@
 (define space-sensitive #f)
 ; seeing `for` stops parsing macro arguments and makes a generator
 (define for-generator #f)
-; treat 'end' like a normal symbol instead of a reserved word
+; treat begin/end like special symbols instead of reserved words
 (define end-symbol #f)
 ; treat newline like ordinary whitespace instead of as a potential separator
 (define whitespace-newline #f)
@@ -1624,7 +1624,7 @@
         (parse-imports s word))
        ((do)
         (error "invalid \"do\" syntax"))
-       (else (error "unhandled reserved word")))))))
+       (else (error (string "unhandled reserved word " word))))))))
 
 (define (parse-do s)
   (with-bindings
@@ -2545,6 +2545,10 @@
                     (symbol str)))
                  ((eq? t 'true)  '(true))
                  ((eq? t 'false) '(false))
+                 ;; issue #57269: a[var"begin"] -> 'begin
+                 ;;               a[begin]      -> '(begin)
+                 ((and end-symbol (eq? t 'begin)) '(begin))
+                 ((and end-symbol (eq? t 'end)) '(end))
                  (else t)))
 
           ;; parens or tuple

src/julia-syntax.scm

@@ -113,8 +113,8 @@
 
 ;; replace `begin` and `end` for the closest ref expression, so doesn't go inside nested refs
 (define (replace-beginend ex a n tuples last)
-  (cond ((eq? ex 'end)                (end-val a n tuples last))
-        ((eq? ex 'begin)              (begin-val a n tuples last))
+  (cond ((equal? ex '(begin))         (begin-val a n tuples last))
+        ((equal? ex '(end))           (end-val a n tuples last))
         ((or (atom? ex) (quoted? ex)) ex)
         ((eq? (car ex) 'ref)
          ;; inside ref only replace within the first argument
@@ -1612,7 +1612,7 @@
              (idxs (cddr lhs))
              (rhs  (caddr e)))
          (let* ((reuse (and (pair? a)
-                            (contains (lambda (x) (eq? x 'end))
+                            (contains (lambda (x) (equal? x '(end)))
                                       idxs)))
                 (arr   (if reuse (make-ssavalue) a))
                 (stmts (if reuse `((= ,arr ,(expand-forms a))) '()))
@@ -1870,7 +1870,9 @@
   (let ((a    (cadr e))
         (idxs (cddr e)))
     (let* ((reuse (and (pair? a)
-                       (contains (lambda (x) (or (eq? x 'begin) (eq? x 'end)))
+                       (contains (lambda (x)
+                                   (or (equal? x '(begin))
+                                       (equal? x '(end))))
                                  idxs)))
            (arr   (if reuse (make-ssavalue) a))
            (stmts (if reuse `((= ,arr ,a)) '())))

test/show.jl

@@ -2377,13 +2377,14 @@ end
 
 # begin/end indices
 @weak_test_repr "a[begin, end, (begin; end)]"
-@test_broken repr(Base.remove_linenums!(:(a[begin, end, (begin; end)]))) == ":(a[begin, end, (begin;\n          end)])"
+@test repr(Base.remove_linenums!(:(a[begin, end, (begin; end)]))) == ":(a[begin, end, (begin;\n          end)])"
 @weak_test_repr "a[begin, end, let x=1; (x+1;); end]"
-@test_broken repr(Base.remove_linenums!(:(a[begin, end, let x=1; (x+1;); end]))) ==
+@test repr(Base.remove_linenums!(:(a[begin, end, let x=1; (x+1;); end]))) ==
         ":(a[begin, end, let x = 1\n          begin\n              x + 1\n          end\n      end])"
 @test_repr "a[(bla;)]"
 @test_repr "a[(;;)]"
 @weak_test_repr "a[x -> f(x)]"
+@test_broken @weak_test_repr """:([1,2,3,4][:end === :end ? end : var"end"])"""
 
 @testset "Base.Iterators" begin
     @test sprint(show, enumerate("test")) == "enumerate(\"test\")"

test/syntax.jl

@@ -4198,6 +4198,16 @@ module Ambig57404
 end
 @test Ambig57404.S == 1
 
+# #57269
+@testset """var"begin"/var"end" in array index""" begin
+    @test (let var"end" = 1; (1:10)[var"end"]; end) === 1
+    @test (let var"end" = 1; (1:10)[end]; end) === 10
+    @test (let var"begin" = 2; (1:10)[2var"begin" + 1]; end) === 5
+    @test ((1:10)[end === 10 ? end : begin]) === 10
+    @test_throws ArgumentError (let var"begin" = nothing; (1:10)[var"begin"]; end)
+    @test (let a=[1]; a[end]::Int = 100; end) === 100
+end
+
 # Issue #56904 - lambda linearized twice
 @test (let; try 3; finally try 1; f(() -> x); catch x; end; end; x = 7; end) === 7
 @test (let; try 3; finally try 4; finally try 1; f(() -> x); catch x; end; end; end; x = 7; end) === 7