support JuliaLowering

Author: oscarddssmith

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}
@@ -577,6 +577,13 @@ function build_tree(::Type{Expr}, stream::ParseStream;
     only(_fixup_Expr_children!(SyntaxHead(K"None",EMPTY_FLAGS), loc, Any[entry.ex]))
 end
 
+
+function build_tree(::Type{Tuple{Expr, SyntaxNode}}, stream::ParseStream;
+                    filename=nothing, first_line=1, kws...)
+    syntaxtree = build_tree(SyntaxNode, stream, filename, first_line, kws...)
+    Expr.(syntaxtree)
+end
+
 function _to_expr(node)
     file = sourcefile(node)
     if is_leaf(node)

src/hooks.jl

@@ -136,7 +136,11 @@ end
 # Debug log file for dumping parsed code
 const _debug_log = Ref{Union{Nothing,IO}}(nothing)
 
-function core_parser_hook(code, filename::String, lineno::Int, offset::Int, options::Symbol)
+function core_parser_hook_for_lowering(code, filename::String, lineno::Int, offset::Int, options::Symbol)
+    core_parser_hook(code, filename::String, lineno::Int, offset::Int, options::Symbol, true)
+end
+
+function core_parser_hook(code, filename::String, lineno::Int, offset::Int, options::Symbol, for_lowering=false)
     try
         # TODO: Check that we do all this input wrangling without copying the
         # code buffer
@@ -233,7 +237,7 @@ function core_parser_hook(code, filename::String, lineno::Int, offset::Int, opti
             #
             # show_diagnostics(stdout, stream.diagnostics, code)
             #
-            ex = build_tree(Expr, stream; filename=filename, first_line=lineno)
+            ex = build_tree(for_lowering ? Tuple{Expr, SyntaxNode} : Expr, stream; filename=filename, first_line=lineno)
         end
 
         # Note the next byte in 1-based indexing is `last_byte(stream) + 1` but
@@ -292,7 +296,7 @@ _default_system_parser = _has_v1_6_hooks ? Core._parse : nothing
 
 
 # hook into InteractiveUtils.@activate
-activate!() = enable_in_core!()
+activate!(enable=true) = enable_in_core!(enable)
 
 """
     enable_in_core!([enable=true; freeze_world_age=true, debug_filename=nothing])
@@ -319,7 +323,10 @@ function enable_in_core!(enable=true; freeze_world_age = true,
         close(_debug_log[])
         _debug_log[] = nothing
     end
-    if enable
+    if enable == :JuliaLowering
+        world_age = freeze_world_age ? Base.get_world_counter() : typemax(UInt)
+        _set_core_parse_hook(fix_world_age(core_parser_hook_for_lowering, world_age))
+    elseif enable
         world_age = freeze_world_age ? Base.get_world_counter() : typemax(UInt)
         _set_core_parse_hook(fix_world_age(core_parser_hook, world_age))
     else