store RTNode in Builtin

3 files changed, 32 insertions, 19 deletions

diff --git a/alv/base/builtin.moon b/alv/base/builtin.moon
index 5f46f37..54f7433 100644
--- a/alv/base/builtin.moon
+++ b/alv/base/builtin.moon
@@ -29,10 +29,18 @@ class Builtin
   -- - perform scope effects
   -- - wrap all child-results
   --
+  -- @function eval
   -- @tparam Scope scope the active scope
   -- @tparam {AST,...} tail the arguments to this expression
   -- @treturn RTNode the result of this evaluation
-  eval: (scope, tail) => error "not implemented"
+
+  --- store the evaluation result for access by editor and return it.
+  --
+  -- This should always be called via `super` as the last statement in all
+  -- overriden `eval` methods.
+  --
+  -- @tparam RTNode node the evaluation result
+  eval: (@node) => @node
 
   --- free resources
   destroy: =>
@@ -54,6 +62,9 @@ class Builtin
   --- the identity of `cell`.
   -- @tfield Tag tag
 
+  --- the last result of `eval`.
+  -- @tfield RTNode node
+
 --- static functions
 -- @section static
 
diff --git a/alv/builtins.moon b/alv/builtins.moon
index 9cccbb9..9966f3b 100644
--- a/alv/builtins.moon
+++ b/alv/builtins.moon
@@ -37,7 +37,7 @@ doc = Constant.meta
       assert #tail == 1, "'doc' takes exactly one parameter"
 
       node = L\push tail[1]\eval, scope
-      with RTNode children: { def }
+      super with RTNode children: { def }
         meta = node.result.meta
         L\print "(doc #{tail[1]}):\n#{format_meta meta}\n"
 
@@ -64,7 +64,7 @@ Define the symbols `sym1`, `sym2`, … to resolve to the values of `val-expr1`,
           with val_expr\eval scope
             scope\set name, \make_ref!
 
-      RTNode :children
+      super RTNode :children
 
 use = Constant.meta
   meta:
@@ -83,7 +83,7 @@ All arguments have to be evaltime constant."
         value = node\const!
         scope\use value\unwrap 'scope', "'use' only works on scopes"
 
-      RTNode!
+      super RTNode!
 
 require_ = Constant.meta
   meta:
@@ -101,7 +101,7 @@ require_ = Constant.meta
       name = node\const!\unwrap 'str'
 
       L\trace @, "loading module #{name}"
-      COPILOT\require name
+      super COPILOT\require name
 
 import_ = Constant.meta
   meta:
@@ -121,7 +121,7 @@ current scope."
         name = child\unwrap T.sym
         with COPILOT\require name
           scope\set name, \make_ref!
-      RTNode :children
+      super RTNode :children
 
 import_star = Constant.meta
   meta:
@@ -139,7 +139,7 @@ Requires modules `sym1`, `sym2`, … and merges them into the current scope."
       children = for i, child in ipairs tail
         with COPILOT\require child\unwrap T.sym
           scope\use .result\unwrap T.scope
-      RTNode :children
+      super RTNode :children
 
 export_ = Constant.meta
   meta:
@@ -153,7 +153,7 @@ Evaluate `expr1`, `expr2`, … in a new Scope and return scope."
     eval: (scope, tail) =>
       new_scope = Scope scope
       children = [expr\eval new_scope for expr in *tail]
-      RTNode :children, result: Constant.wrap new_scope
+      super RTNode :children, result: Constant.wrap new_scope
 
 export_star = Constant.meta
   meta:
@@ -180,7 +180,7 @@ Copies the containing scope if no symbols are given."
           with node = scope\get name
             new_scope\set name, node
 
-      RTNode :children, result: Constant.wrap new_scope
+      super RTNode :children, result: Constant.wrap new_scope
 
 fn = Constant.meta
   meta:
@@ -202,7 +202,7 @@ function is invoked."
         assert param.type == T.sym, "function parameter declaration has to be a symbol"
         param
 
-      RTNode result: with Constant.wrap FnDef param_symbols, body, scope
+      super RTNode result: with Constant.wrap FnDef param_symbols, body, scope
         .meta = {
           summary: "(user defined function)"
           examples: { "(??? #{table.concat [p! for p in *param_symbols], ' '})" }
@@ -237,7 +237,7 @@ function is invoked."
           examples: { "(#{name} #{table.concat [p! for p in *param_symbols], ' '})" }
 
       scope\set name, RTNode :result
-      RTNode!
+      super RTNode!
 
 do_expr = Constant.meta
   meta:
@@ -252,7 +252,7 @@ Evaluate `expr1`, `expr2`, … and return the value of the last expression."
       scope = Scope scope
       children = [expr\eval scope for expr in *tail]
       last = children[#children]
-      RTNode :children, result: last and last.result
+      super RTNode :children, result: last and last.result
 
 if_ = Constant.meta
   meta:
@@ -274,10 +274,12 @@ to `then-expr`, otherwise it is equivalent to `else-xpr` if given, or nil otherw
       xif = L\push xif\eval, scope
       xif = xif\const!\unwrap!
 
-      if xif
+      super if xif
         xthen\eval scope
       elseif xelse
         xelse\eval scope
+      else
+        RTNode!
 
 trace_ = Constant.meta
   meta:
@@ -290,7 +292,7 @@ trace_ = Constant.meta
       L\trace "evaling #{@}"
       assert #tail == 1, "'trace!' takes exactly one parameter"
 
-      with node = L\push tail[1]\eval, scope
+      super with node = L\push tail[1]\eval, scope
         L\print "trace! #{tail[1]\stringify 2}: #{node.result}"
 
 trace = Constant.meta
@@ -319,7 +321,7 @@ trace = Constant.meta
         Constant.str tail[1]\stringify 2
         tail[1]
       }
-      inner\eval scope
+      super inner\eval scope
 
 print_ = Constant.meta
   meta:
@@ -510,7 +512,7 @@ with a different set of arguments, e.g. to sum the first `5` integers:
 
       tag = @tag\clone Tag.parse '-1'
       inner = Cell tag, inner
-      inner\eval def_scope
+      super inner\eval def_scope
 
 recur = Constant.meta
   meta:
@@ -545,7 +547,7 @@ bound to `nv2`…
       node = clone\eval fn_scope
 
       table.insert children, node
-      RTNode :children, result: node.result
+      super RTNode :children, result: node.result
 
 
 Scope.from_table {
diff --git a/alv/invoke.moon b/alv/invoke.moon
index 9acb77c..6962f4d 100644
--- a/alv/invoke.moon
+++ b/alv/invoke.moon
@@ -75,7 +75,7 @@ class op_invoke extends Builtin
       for input in @op\all_inputs!
         input\finish_setup!
 
-    RTNode :children, result: @op.out, op: @op
+    super RTNode :children, result: @op.out, op: @op
 
   --- The `Op` instance.
   --
@@ -123,7 +123,7 @@ class fn_invoke extends Builtin
     node = Error.wrap frame, clone\eval, fn_scope
 
     table.insert children, node
-    RTNode :children, result: node.result
+    super RTNode :children, result: node.result
 
 {
   :op_invoke, :fn_invoke