Move pretty-printing 'modes' into a callback hook

This way, the pretty-printer does not have to know about middle::ty.

(This is a preparation for separating the AST functionality into a
separate crate.)

src/comp/driver/rustc.rs

@@ -12,6 +12,7 @@
 import middle::ty;
 import middle::typeck;
 import middle::tstate::ck;
+import pretty::pp;
 import pretty::pprust;
 import pretty::ppaux;
 import back::link;
@@ -24,6 +25,7 @@
 import std::option::none;
 import std::str;
 import std::vec;
+import std::int;
 import std::io;
 import std::run;
 import std::getopts;
@@ -127,22 +129,67 @@ fn compile_input(session::session sess, ast::crate_cfg cfg, str input,
 
 fn pretty_print_input(session::session sess, ast::crate_cfg cfg,
                       str input, pp_mode ppm) {
+    fn ann_paren_for_expr(&ppaux::ann_node node) {
+        alt (node) {
+            case (ppaux::node_expr(?s, ?expr)) {
+                pprust::popen(s);
+            }
+            case (_) {}
+        }
+    }
+    fn ann_typed_post(&ty::ctxt tcx, &ppaux::ann_node node) {
+        alt (node) {
+            case (ppaux::node_expr(?s, ?expr)) {
+                pp::space(s.s);
+                pp::word(s.s, "as");
+                pp::space(s.s);
+                pp::word(s.s, ppaux::ty_to_str(tcx, ty::expr_ty(tcx, expr)));
+                pprust::pclose(s);
+            }
+            case (_) {}
+        }
+    }
+    fn ann_identified_post(&ppaux::ann_node node) {
+        alt (node) {
+            case (ppaux::node_item(?s, ?item)) {
+                pp::space(s.s);
+                pprust::synth_comment(s, int::to_str(item.id, 10u));
+            }
+            case (ppaux::node_block(?s, ?blk)) {
+                pp::space(s.s);
+                pprust::synth_comment(s, "block " +
+                                      int::to_str(blk.node.id, 10u));
+            }
+            case (ppaux::node_expr(?s, ?expr)) {
+                pp::space(s.s);
+                pprust::synth_comment(s, int::to_str(expr.id, 10u));
+                pprust::pclose(s);
+            }
+            case (_) {}
+        }
+    }
+
     auto p = front::parser::new_parser(sess, cfg, input, 0u, 0);
     auto crate = parse_input(sess, p, input);
-    auto mode;
+    auto ann;
     alt (ppm) {
         case (ppm_typed) {
             auto amap = middle::ast_map::map_crate(*crate);
             auto d = resolve::resolve_crate(sess, amap, crate);
             auto ty_cx = ty::mk_ctxt(sess, d._0, d._1, amap);
             typeck::check_crate(ty_cx, crate);
-            mode = ppaux::mo_typed(ty_cx);
+            ann = rec(pre=ann_paren_for_expr,
+                      post=bind ann_typed_post(ty_cx, _));
+        }
+        case (ppm_identified) {
+            ann = rec(pre=ann_paren_for_expr,
+                      post=ann_identified_post);
+        }
+        case (ppm_normal) {
+            ann = ppaux::no_ann();
         }
-        case (ppm_normal) { mode = ppaux::mo_untyped; }
-        case (ppm_identified) { mode = ppaux::mo_identified; }
     }
-    pprust::print_crate(sess, crate, input, std::io::stdout(),
-                        mode);
+    pprust::print_crate(sess, crate, input, std::io::stdout(), ann);
 }
 
 fn version(str argv0) {

src/comp/pretty/ppaux.rs

@@ -337,6 +337,22 @@ fn next_comment(&ps s) -> option::t[lexer::cmnt] {
     }
 }
 
+// The ps is stored here to prevent recursive type.
+// FIXME use a nominal tag instead
+tag ann_node {
+    node_block(ps, ast::block);
+    node_item(ps, @ast::item);
+    node_expr(ps, @ast::expr);
+    node_pat(ps, @ast::pat);
+}
+type pp_ann = rec(fn(&ann_node node) pre,
+                  fn(&ann_node node) post);
+
+fn no_ann() -> pp_ann {
+    fn ignore(&ann_node node) {}
+    ret rec(pre=ignore, post=ignore);
+}
+
 type ps =
     @rec(pp::printer s,
          option::t[codemap] cm,
@@ -345,7 +361,7 @@ fn next_comment(&ps s) -> option::t[lexer::cmnt] {
          mutable uint cur_cmnt,
          mutable uint cur_lit,
          mutable vec[pp::breaks] boxes,
-         mode mode);
+         pp_ann ann);
 
 fn ibox(&ps s, uint u) {
     vec::push(s.boxes, pp::inconsistent);
@@ -354,8 +370,6 @@ fn ibox(&ps s, uint u) {
 
 fn end(&ps s) { vec::pop(s.boxes); pp::end(s.s); }
 
-tag mode { mo_untyped; mo_typed(ctxt); mo_identified; }
-
 fn rust_printer(io::writer writer) -> ps {
     let vec[pp::breaks] boxes = [];
     ret @rec(s=pp::mk_printer(writer, default_columns),
@@ -365,7 +379,7 @@ fn rust_printer(io::writer writer) -> ps {
              mutable cur_cmnt=0u,
              mutable cur_lit=0u,
              mutable boxes=boxes,
-             mode=mo_untyped);
+             ann=no_ann());
 }
 
 const uint indent_unit = 4u;

src/comp/pretty/pprust.rs

@@ -10,7 +10,6 @@
 import front::codemap;
 import front::codemap::codemap;
 import front::ast;
-import middle::ty;
 import util::common;
 import option::some;
 import option::none;
@@ -29,7 +28,7 @@
 import ppaux::*;
 
 fn print_crate(session sess, @ast::crate crate, str filename,
-               io::writer out, mode mode) {
+               io::writer out, &pp_ann ann) {
     let vec[pp::breaks] boxes = [];
     auto r = lexer::gather_comments_and_literals(sess, filename);
     auto s =
@@ -40,7 +39,7 @@ fn print_crate(session sess, @ast::crate crate, str filename,
              mutable cur_cmnt=0u,
              mutable cur_lit=0u,
              mutable boxes=boxes,
-             mode=mode);
+             ann=ann);
     print_mod(s, crate.node.module, crate.node.attrs);
     eof(s.s);
 }
@@ -297,6 +296,8 @@ fn print_item(&ps s, &@ast::item item) {
     hardbreak_if_not_bol(s);
     maybe_print_comment(s, item.span.lo);
     print_outer_attributes(s, item.attrs);
+    auto ann_node = node_item(s, item);
+    s.ann.pre(ann_node);
     alt (item.node) {
         case (ast::item_const(?ty, ?expr)) {
             head(s, "const");
@@ -470,15 +471,7 @@ fn print_field(&ps s, &ast::obj_field field) {
             print_block(s, dt.body);
         }
     }
-
-    // Print the node ID if necessary. TODO: type as well.
-    alt (s.mode) {
-        case (mo_identified) {
-            space(s.s);
-            synth_comment(s, int::to_str(item.id, 10u));
-        }
-        case (_) {/* no-op */ }
-    }
+    s.ann.post(ann_node);
 }
 
 fn print_outer_attributes(&ps s, vec[ast::attribute] attrs) {
@@ -530,6 +523,8 @@ fn print_stmt(&ps s, &ast::stmt st) {
 
 fn print_block(&ps s, ast::block blk) {
     maybe_print_comment(s, blk.span.lo);
+    auto ann_node = node_block(s, blk);
+    s.ann.pre(ann_node);
     bopen(s);
     for (@ast::stmt st in blk.node.stmts) { print_stmt(s, *st) }
     alt (blk.node.expr) {
@@ -541,15 +536,7 @@ fn print_block(&ps s, ast::block blk) {
         case (_) { }
     }
     bclose(s, blk.span);
-
-    // Print the node ID if necessary: TODO: type as well.
-    alt (s.mode) {
-        case (mo_identified) {
-            space(s.s);
-            synth_comment(s, "block " + int::to_str(blk.node.id, 10u));
-        }
-        case (_) {/* no-op */ }
-    }
+    s.ann.post(ann_node);
 }
 
 fn print_if(&ps s, &@ast::expr test, &ast::block block,
@@ -597,11 +584,8 @@ fn do_else(&ps s, option::t[@ast::expr] els) {
 fn print_expr(&ps s, &@ast::expr expr) {
     maybe_print_comment(s, expr.span.lo);
     ibox(s, indent_unit);
-    alt (s.mode) {
-        case (mo_untyped) {/* no-op */ }
-        case (mo_typed(_)) { popen(s); }
-        case (mo_identified) { popen(s); }
-    }
+    auto ann_node = node_expr(s, expr);
+    s.ann.pre(ann_node);
     alt (expr.node) {
         case (ast::expr_vec(?exprs, ?mut, ?kind)) {
             ibox(s, indent_unit);
@@ -926,23 +910,7 @@ fn print_opt(&ps s, &option::t[@ast::expr] expr) {
 
         }
     }
-    // Print the type or node ID if necessary.
-
-    alt (s.mode) {
-        case (mo_untyped) {/* no-op */ }
-        case (mo_typed(?tcx)) {
-            space(s.s);
-            word(s.s, "as");
-            space(s.s);
-            word(s.s, ppaux::ty_to_str(tcx, ty::expr_ty(tcx, expr)));
-            pclose(s);
-        }
-        case (mo_identified) {
-            space(s.s);
-            synth_comment(s, int::to_str(expr.id, 10u));
-            pclose(s);
-        }
-    }
+    s.ann.post(ann_node);
     end(s);
 }
 
@@ -960,16 +928,6 @@ fn print_decl(&ps s, &@ast::decl decl) {
                 }
                 case (_) {
                     word_nbsp(s, "auto");
-
-                    // Print the type or node ID if necessary.
-                    alt (s.mode) {
-                        case (mo_untyped) {/* no-op */ }
-                        case (mo_typed(?tcx)) {
-                            auto lty = ty::node_id_to_type(tcx, loc.node.id);
-                            word_space(s, ppaux::ty_to_str(tcx, lty));
-                        }
-                        case (mo_identified) {/* no-op */ }
-                    }
                 }
             }
             word(s.s, loc.node.ident);
@@ -1015,6 +973,8 @@ fn print_path(&ps s, &ast::path path) {
 
 fn print_pat(&ps s, &@ast::pat pat) {
     maybe_print_comment(s, pat.span.lo);
+    auto ann_node = node_pat(s, pat);
+    s.ann.pre(ann_node);
     alt (pat.node) {
         case (ast::pat_wild) { word(s.s, "_"); }
         case (ast::pat_bind(?id)) { word(s.s, "?" + id); }
@@ -1028,15 +988,7 @@ fn print_pat(&ps s, &@ast::pat pat) {
             }
         }
     }
-
-    // Print the node ID if necessary. TODO: type as well.
-    alt (s.mode) {
-        case (mo_identified) {
-            space(s.s);
-            synth_comment(s, int::to_str(pat.id, 10u));
-        }
-        case (_) {/* no-op */ }
-    }
+    s.ann.post(ann_node);
 }
 
 fn print_fn(&ps s, ast::fn_decl decl, ast::proto proto, str name,

src/comp/util/common.rs

@@ -25,7 +25,6 @@
 import pretty::pprust::print_fn;
 import pretty::pprust::print_type;
 import pretty::ppaux::print_literal;
-import pretty::ppaux::mo_untyped;
 import pretty::pp::mk_printer;
 
 type filename = str;