add activate! function as alias to enable_in_core!

src/expr.jl

@@ -140,7 +140,7 @@ function _string_to_Expr(args)
         #   """\n  a\n  b""" ==>  "a\nb"
         return only(args2)
     else
-        # This only happens when the kind is K"string" or when an error has occurred. 
+        # This only happens when the kind is K"string" or when an error has occurred.
         return Expr(:string, args2...)
     end
 end
@@ -159,7 +159,7 @@ function _fixup_Expr_children!(head, loc, args)
         arg = args[i]
         was_parens = @isexpr(arg, :parens)
         arg = _strip_parens(arg)
-        if @isexpr(arg, :(=)) && eq_to_kw_in_call && i > 1 
+        if @isexpr(arg, :(=)) && eq_to_kw_in_call && i > 1
             arg = Expr(:kw, arg.args...)
         elseif k != K"parens" && @isexpr(arg, :., 1) && arg.args[1] isa Tuple
             h, a = arg.args[1]::Tuple{SyntaxHead,Any}

src/hooks.jl

@@ -290,6 +290,9 @@ end
 
 _default_system_parser = _has_v1_6_hooks ? Core._parse : nothing
 
+# hook into InteractiveUtils.@activate
+activate!(enable=true) = enable_in_core!(enable)
+
 """
     enable_in_core!([enable=true; freeze_world_age=true, debug_filename=nothing])
 

src/syntax_tree.jl

@@ -131,7 +131,8 @@ numchildren(node::TreeNode) = (isnothing(node.children) ? 0 : length(node.childr
 Base.getindex(node::AbstractSyntaxNode, i::Int) = children(node)[i]
 Base.getindex(node::AbstractSyntaxNode, rng::UnitRange) = view(children(node), rng)
 Base.firstindex(node::AbstractSyntaxNode) = 1
-Base.lastindex(node::AbstractSyntaxNode) = length(children(node))
+Base.length(node::AbstractSyntaxNode) = length(children(node))
+Base.lastindex(node::AbstractSyntaxNode) = length(node)
 
 function Base.setindex!(node::SN, x::SN, i::Int) where {SN<:AbstractSyntaxNode}
     children(node)[i] = x