gsc_test_ytree: task now fails successfully

i have realized that a lot of the complexity and cognitive overhead
is downstream from trying to prematurely handle errors.

so i'm going to do the erlang thing and just assert/assume everything
worked perfectly and let the errors speak for themselves.

so re "task fails successfully": now instead of getting an NYI that
looks like a success result, we're now properly getting an error.

test/gsc_test_ytree.erl

@@ -23,8 +23,7 @@ main() ->
                        | using
                        .
 
--record(ct, {ok       = ok   :: ok | {error, any()},
-             payable  = none :: none | false | true,
+-record(ct, {payable  = none :: none | false | true,
              main     = none :: none | false | true,
              contract = none :: none | tk(),
              con      = none :: none | tk(),
@@ -43,8 +42,7 @@ main() ->
                    | contract_meta().
 
 % @doc ys = syntax stem
--record(ys, {ok        = ok      :: ok | {error, any()},
-             target    = signal  :: syntax_target(),
+-record(ys, {target    = signal  :: syntax_target(),
              signal              :: [tk()],
              stem_meta           :: stem_meta(),
              forest              :: [#ys{}]}).
@@ -58,6 +56,11 @@ handle_src_str(SrcStr) ->
     io:format("~tp~n", [Result]).
 
 
+-spec gulp(Target, Signal) -> Result when
+        Target :: syntax_target(),
+        Signal :: [tk()],
+        Result :: {gulp, syntax_stem()} | {error, any()}.
+
 gulp(file, Sig) ->
     gulp({block_of, top_decl}, Sig);
 gulp({block_of, X}, Sig) ->
@@ -96,11 +99,25 @@ gulp(contract, Sig) ->
         signal = Sig,
         stem_meta = CtMeta,
         forest = Forest};
+% Decl ::= 'type'     Id ['(' TVar* ')'] '=' TypeAlias
+%        | 'record'   Id ['(' TVar* ')'] '=' RecordType
+%        | 'datatype' Id ['(' TVar* ')'] '=' DataType
+%        | 'let'      Id [':' Type]      '=' Expr
+%        | (EModifier* 'entrypoint' | FModifier* 'function') Block(FunDecl)
+%        | Using
+gulp(decl, Sig) ->
+    NewTarget =
+        case strings(1, Sig) of
+            ["type"]     -> type;
+            ["record"]   -> record;
+            ["datatype"] -> datatype;
+            ["let"]      -> 'let';
+            ["using"]    -> using;
+            _            -> fn
+        end,
+    gulp(NewTarget, Sig);
 gulp(NyiTarget, Sig) ->
-    #ys{target    = NyiTarget,
-        signal    = Sig,
-        stem_meta = {nyi, NyiTarget},
-        forest    = []}.
+    error({nyi, [?MODULE, gulp, NyiTarget, Sig]}).
 
 
 %% ['payable'] ['main'] 'contract' Con [Implement] '=' Block(Decl)
@@ -122,20 +139,20 @@ slurp(M = #ct{contract = none}, Sig) ->
         [Tk = #tk{str = "contract"} | Rest] ->
             slurp(M#ct{contract = Tk}, Rest);
         _ ->
-            M#ct{ok = {error, no_keyword_contract}}
+            error(no_keyword_contract)
     end;
 slurp(M = #ct{con = none}, Sig) ->
     case Sig of
         [Tk = #tk{shape = con} | Rest] ->
             slurp(M#ct{con = Tk}, Rest);
-        [Tk = #tk{str = Irregar} | _] ->
-            M#ct{ok = {error, {illegal_contract_name, Irregar}}};
+        [#tk{str = Irregar} | _] ->
+            error(illegal_contract_name, Irregar);
         [] ->
-            M#ct{ok = {error, no_contract_name}}
+            error(no_contract_name)
     end;
 slurp(M = #ct{impls = none}, Sig) ->
     case Sig of
-        [Tk = #tk{str = ":"} | Rest] ->
+        [#tk{str = ":"} | Rest] ->
             {slurp, Impls, NewRest} = slurp({sep1, con, ","}, Rest),
             NewM = M#ct{impls = {true, Impls}},
             slurp(NewM, NewRest);
@@ -147,17 +164,17 @@ slurp(M = #ct{'=' = none}, Sig) ->
         [Tk = #tk{str = "="} | Rest] ->
             {slurp, M#ct{'=' = Tk}, Rest};
         _ ->
-            M#ct{ok = {error, no_token_eq}}
+            error("where the fuck my = be at nigga")
     end;
 slurp({sep1, TkShape, SepByStr}, Tks) ->
     case Tks of
         [Tk = #tk{shape = TkShape} | Rest] ->
             slurp_sep1_ii([Tk], TkShape, SepByStr, Rest);
         _ ->
-            {error, irregar}
+            error(irregar)
     end;
-slurp(M, Tks) ->
-    {slurp, {nyi, M}, Tks}.
+slurp(BadMeta, BadTokens) ->
+    error({nyi, [?MODULE, slurp, BadMeta, BadTokens]}).
 
 
 slurp_sep1_ii(Stk, TkShape, SepByStr, Sig) ->