allow use of begin blocks inside enum definitions (#25424)

NEWS.md

@@ -40,6 +40,9 @@ New language features
   * Field access via dot-syntax can now be overloaded by adding methods to
     `Base.getproperty` and `Base.setproperty!` ([#1974]).
 
+  * Values for `Enum`s can now be specified inside of a `begin` block when using the
+    `@enum` macro ([#25424]).
+
 Language changes
 ----------------
 
@@ -1162,3 +1165,4 @@ Command-line option changes
 [#25184]: https://github.com/JuliaLang/julia/issues/25184
 [#25231]: https://github.com/JuliaLang/julia/issues/25231
 [#25365]: https://github.com/JuliaLang/julia/issues/25365
+[#25424]: https://github.com/JuliaLang/julia/issues/25424

base/Enums.jl

@@ -46,6 +46,15 @@ julia> f(apple)
 "I'm a Fruit with value: 1"
 ```
 
+Values can also be specified inside a `begin` block, e.g.
+
+```julia
+@enum EnumName begin
+    value1
+    value2
+end
+```
+
 `BaseType`, which defaults to [`Int32`](@ref), must be a primitive subtype of `Integer`.
 Member values can be converted between the enum type and `BaseType`. `read` and `write`
 perform these conversions automatically.
@@ -69,7 +78,12 @@ macro enum(T, syms...)
     lo = hi = 0
     i = zero(basetype)
     hasexpr = false
+
+    if length(syms) == 1 && syms[1] isa Expr && syms[1].head == :block
+        syms = syms[1].args
+    end
     for s in syms
+        s isa LineNumberNode && continue
         if isa(s, Symbol)
             if i == typemin(basetype) && !isempty(vals)
                 throw(ArgumentError("overflow in value \"$s\" of Enum $typename"))

test/enums.jl

@@ -148,3 +148,11 @@ let b = IOBuffer()
     seekstart(b)
     @test deserialize(b) === apple
 end
+
+# test block form
+@enum BritishFood begin
+    blackpudding = 1
+    scotchegg    = 2
+    haggis       = 4
+end
+@test Int(haggis) == 4