Merge eval-ast and macro expansion into EVAL

See issue kanaka#587.
 * Merge eval-ast and eval into a single conditional.
 * Print "EVAL: $ast" at the top of EVAL.
 * Expand macros during the apply phase, removing lots of duplicate
   tests, and increasing the overall consistency by allowing the macro
   to be computed instead of referenced by name (`((defmacro! cond
   (...)))` is currently illegal for example).
 * Remove macroexpand and quasiquoteexpand special forms.

These tests fail:
 * objpascal: I have no such error with a more recent compiler
 * groovy: stack overflow during test of recursive functions.
   Did work after first push.
 * elm: most probably unrelated, this directory is unchanged

While reformatting process/step*.txt, use a pseudo-syntax inspired by
pattern matching.

The changes have not been propagated to:
 * ada 2-9
 * awk 2-9
 * bash 2-9
 * basic 2-A
 * bbc-basic 2-9
 * c 2-9
 * c.2 2-9
 * chuck 2-A
 * clojure 2-9
 * coffee 2-9
 * common-lisp 2-9
 * cpp 2-9
 * crystal 2-A
 * cs 2-9
 * d 2-9
 * dart 2-9
 * elisp 2-9
 * elixir 2-9
 * elm 2-9
 * erlang 2-9
 * es6 2-9
 * factor 2-9
 * fantom 2-9
 * fennel 2-9
 * forth 2-A
 * fsharp 2-9
 * gnu-smalltalk 2-9
 * go 2-9
 * groovy 2-9
 * guile 2-9
 * haskell 2-9
 * haxe 2-9
 * hy 2-A
 * io 2-A
 * janet 2-A
 * java 2-9
 * java-truffle 2-A
 * jq 2-A
 * js 2-9
 * julia 2-9
 * kotlin 2-9
 * livescript 2-A
 * logo 2-9
 * lua 2-A
 * make 2-9
 * matlab 2-A
 * miniMAL 2-9
 * nasm 2-9
 * nim 2-9
 * objc 2-A
 * objpascal 2-9
 * ocaml 2-9
 * perl 2-9
 * perl6 2-9
 * php 2-9
 * picolisp 2-9
 * pike 2-9
 * plpgsql 2-A
 * plsql 2-A
 * powershell 2-A
 * ps 2-9
 * python 2-9
 * python.2 2-9
 * r 2-9
 * racket 2-9
 * rexx 2-A
 * rpython 2-9
 * ruby 2-9
 * rust 2-9
 * scala 2-A
 * scheme 2-9
 * skew 2-9
 * sml 2-9
 * swift 2-A
 * swift3 2-A
 * swift4 2-A
 * swift5 2-A
 * tcl 2-9
 * ts 2-9
 * vala 2-A
 * vb 2-9
 * vhdl 2-9
 * vimscript 2-9
 * wasm 2-A
 * wren 2-9
 * xslt 2-A
 * yorick 2-9
 * zig 2-A

impls/ada.2/step7_quote.adb

@@ -167,9 +167,6 @@ procedure Step7_Quote is
                   Ast    => Ast.Sequence.all.Data (3),
                   Env    => Env));
             end;
-         elsif First.Str.all = "quasiquoteexpand" then
-            Err.Check (Ast.Sequence.all.Length = 2, "expected 1 parameter");
-            return Quasiquote (Ast.Sequence.all.Data (2));
          elsif First.Str.all = "quasiquote" then
             Err.Check (Ast.Sequence.all.Length = 2, "expected 1 parameter");
             Ast := Quasiquote (Ast.Sequence.all.Data (2));

impls/ada.2/step8_macros.adb

@@ -59,7 +59,6 @@ procedure Step8_Macros is
       --  True when the environment has been created in this recursion
       --  level, and has not yet been referenced by a closure. If so,
       --  we can reuse it instead of creating a subenvironment.
-      Macroexpanding : Boolean  := False;
       First          : Types.T;
    begin
       <<Restart>>
@@ -183,14 +182,6 @@ procedure Step8_Macros is
                   Ast    => Ast.Sequence.all.Data (3),
                   Env    => Env));
             end;
-         elsif First.Str.all = "macroexpand" then
-            Err.Check (Ast.Sequence.all.Length = 2, "expected 1 parameter");
-            Macroexpanding := True;
-            Ast := Ast.Sequence.all.Data (2);
-            goto Restart;
-         elsif First.Str.all = "quasiquoteexpand" then
-            Err.Check (Ast.Sequence.all.Length = 2, "expected 1 parameter");
-            return Quasiquote (Ast.Sequence.all.Data (2));
          elsif First.Str.all = "quasiquote" then
             Err.Check (Ast.Sequence.all.Length = 2, "expected 1 parameter");
             Ast := Quasiquote (Ast.Sequence.all.Data (2));
@@ -217,24 +208,10 @@ procedure Step8_Macros is
       case First.Kind is
       when Kind_Macro =>
          --  Use the unevaluated arguments.
-         if Macroexpanding then
-            --  Evaluate the macro with tail call optimization.
-            if not Env_Reusable then
-               Env := Envs.New_Env (Outer => First.Fn.all.Env);
-               Env_Reusable := True;
-            end if;
-            Env.all.Set_Binds
-              (Binds => First.Fn.all.Params.all.Data,
-               Exprs => Ast.Sequence.all.Data (2 .. Ast.Sequence.all.Length));
-            Ast := First.Fn.all.Ast;
-            goto Restart;
-         else
-            --  Evaluate the macro normally.
-            Ast := First.Fn.all.Apply
-              (Ast.Sequence.all.Data (2 .. Ast.Sequence.all.Length));
-            --  Then evaluate the result with TCO.
-            goto Restart;
-         end if;
+         Ast := First.Fn.all.Apply
+           (Ast.Sequence.all.Data (2 .. Ast.Sequence.all.Length));
+         --  Then evaluate the result with TCO.
+         goto Restart;
       when Types.Kind_Function =>
          null;
       when others =>
@@ -260,11 +237,7 @@ procedure Step8_Macros is
       end;
    exception
       when Err.Error =>
-         if Macroexpanding then
-            Err.Add_Trace_Line ("macroexpand", Ast);
-         else
-            Err.Add_Trace_Line ("eval", Ast);
-         end if;
+         Err.Add_Trace_Line ("eval", Ast);
          raise;
    end Eval;
 

impls/ada.2/step9_try.adb

@@ -59,7 +59,6 @@ procedure Step9_Try is
       --  True when the environment has been created in this recursion
       --  level, and has not yet been referenced by a closure. If so,
       --  we can reuse it instead of creating a subenvironment.
-      Macroexpanding : Boolean  := False;
       First          : Types.T;
    begin
       <<Restart>>
@@ -183,14 +182,6 @@ procedure Step9_Try is
                   Ast    => Ast.Sequence.all.Data (3),
                   Env    => Env));
             end;
-         elsif First.Str.all = "macroexpand" then
-            Err.Check (Ast.Sequence.all.Length = 2, "expected 1 parameter");
-            Macroexpanding := True;
-            Ast := Ast.Sequence.all.Data (2);
-            goto Restart;
-         elsif First.Str.all = "quasiquoteexpand" then
-            Err.Check (Ast.Sequence.all.Length = 2, "expected 1 parameter");
-            return Quasiquote (Ast.Sequence.all.Data (2));
          elsif First.Str.all = "quasiquote" then
             Err.Check (Ast.Sequence.all.Length = 2, "expected 1 parameter");
             Ast := Quasiquote (Ast.Sequence.all.Data (2));
@@ -247,24 +238,10 @@ procedure Step9_Try is
       case First.Kind is
       when Kind_Macro =>
          --  Use the unevaluated arguments.
-         if Macroexpanding then
-            --  Evaluate the macro with tail call optimization.
-            if not Env_Reusable then
-               Env := Envs.New_Env (Outer => First.Fn.all.Env);
-               Env_Reusable := True;
-            end if;
-            Env.all.Set_Binds
-              (Binds => First.Fn.all.Params.all.Data,
-               Exprs => Ast.Sequence.all.Data (2 .. Ast.Sequence.all.Length));
-            Ast := First.Fn.all.Ast;
-            goto Restart;
-         else
-            --  Evaluate the macro normally.
-            Ast := First.Fn.all.Apply
-              (Ast.Sequence.all.Data (2 .. Ast.Sequence.all.Length));
-            --  Then evaluate the result with TCO.
-            goto Restart;
-         end if;
+         Ast := First.Fn.all.Apply
+           (Ast.Sequence.all.Data (2 .. Ast.Sequence.all.Length));
+         --  Then evaluate the result with TCO.
+         goto Restart;
       when Types.Kind_Function =>
          null;
       when others =>
@@ -290,11 +267,7 @@ procedure Step9_Try is
       end;
    exception
       when Err.Error =>
-         if Macroexpanding then
-            Err.Add_Trace_Line ("macroexpand", Ast);
-         else
-            Err.Add_Trace_Line ("eval", Ast);
-         end if;
+         Err.Add_Trace_Line ("eval", Ast);
          raise;
    end Eval;
 

impls/ada.2/stepa_mal.adb

@@ -60,7 +60,6 @@ procedure StepA_Mal is
       --  True when the environment has been created in this recursion
       --  level, and has not yet been referenced by a closure. If so,
       --  we can reuse it instead of creating a subenvironment.
-      Macroexpanding : Boolean  := False;
       First          : Types.T;
    begin
       <<Restart>>
@@ -184,14 +183,6 @@ procedure StepA_Mal is
                   Ast    => Ast.Sequence.all.Data (3),
                   Env    => Env));
             end;
-         elsif First.Str.all = "macroexpand" then
-            Err.Check (Ast.Sequence.all.Length = 2, "expected 1 parameter");
-            Macroexpanding := True;
-            Ast := Ast.Sequence.all.Data (2);
-            goto Restart;
-         elsif First.Str.all = "quasiquoteexpand" then
-            Err.Check (Ast.Sequence.all.Length = 2, "expected 1 parameter");
-            return Quasiquote (Ast.Sequence.all.Data (2));
          elsif First.Str.all = "quasiquote" then
             Err.Check (Ast.Sequence.all.Length = 2, "expected 1 parameter");
             Ast := Quasiquote (Ast.Sequence.all.Data (2));
@@ -248,24 +239,10 @@ procedure StepA_Mal is
       case First.Kind is
       when Kind_Macro =>
          --  Use the unevaluated arguments.
-         if Macroexpanding then
-            --  Evaluate the macro with tail call optimization.
-            if not Env_Reusable then
-               Env := Envs.New_Env (Outer => First.Fn.all.Env);
-               Env_Reusable := True;
-            end if;
-            Env.all.Set_Binds
-              (Binds => First.Fn.all.Params.all.Data,
-               Exprs => Ast.Sequence.all.Data (2 .. Ast.Sequence.all.Length));
-            Ast := First.Fn.all.Ast;
-            goto Restart;
-         else
-            --  Evaluate the macro normally.
-            Ast := First.Fn.all.Apply
-              (Ast.Sequence.all.Data (2 .. Ast.Sequence.all.Length));
-            --  Then evaluate the result with TCO.
-            goto Restart;
-         end if;
+         Ast := First.Fn.all.Apply
+           (Ast.Sequence.all.Data (2 .. Ast.Sequence.all.Length));
+         --  Then evaluate the result with TCO.
+         goto Restart;
       when Types.Kind_Function =>
          null;
       when others =>
@@ -296,11 +273,7 @@ procedure StepA_Mal is
       end;
    exception
       when Err.Error =>
-         if Macroexpanding then
-            Err.Add_Trace_Line ("macroexpand", Ast);
-         else
-            Err.Add_Trace_Line ("eval", Ast);
-         end if;
+         Err.Add_Trace_Line ("eval", Ast);
          raise;
    end Eval;