make .where truly upside down

* better error messages
AnyDSL · Apr 25, 2024 · c9de8cf · c9de8cf
1 parent 2ce91c0
commit c9de8cf
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Showing 6 changed files with 32 additions and 22 deletions.
diff --git a/include/thorin/ast/ast.h b/include/thorin/ast/ast.h
@@ -344,14 +344,14 @@ class BlockExpr : public Expr {
 /// `decls e` or `e .where decls` if @p where is `true`.
 class DeclExpr : public Expr {
 public:
-    DeclExpr(Loc loc, Ptrs<ValDecl>&& decls, Ptr<Expr>&& expr, bool where)
+    DeclExpr(Loc loc, Ptrs<ValDecl>&& decls, Ptr<Expr>&& expr, bool is_where)
         : Expr(loc)
         , decls_(std::move(decls))
         , expr_(std::move(expr))
-        , where_(where) {}
+        , is_where_(is_where) {}
 
     const auto& decls() const { return decls_; }
-    bool where() const { return where_; }
+    bool is_where() const { return is_where_; }
     const Expr* expr() const { return expr_.get(); }
 
     void bind(Scopes&) const override;
@@ -362,7 +362,7 @@ class DeclExpr : public Expr {
 
     Ptrs<ValDecl> decls_;
     Ptr<Expr> expr_;
-    bool where_;
+    bool is_where_;
 };
 
 /// `.Type level`

diff --git a/lit/regex/match_manual.thorin b/lit/regex/match_manual.thorin
@@ -17,11 +17,6 @@
 .con .extern main[mem: %mem.M, argc: .I32, argv: %mem.Ptr («⊤:.Nat; %mem.Ptr («⊤:.Nat; .I8», 0)», 0), exit : .Cn [%mem.M, .I32]] =
     (exit, match_argument) # (%core.icmp.ug (argc, 1I32)) (mem, 0I32)
     .where
-        .con error(mem: %mem.M, i : .I32) =
-            reject (mem, 0I32)
-            .where
-                .con reject[mem: %mem.M, .Idx Top] = exit (mem, 0I32);
-            .end
         .con match_argument[mem: %mem.M, .I32] =
             .let arg1             = %mem.lea (Top, ‹Top; %mem.Ptr («⊤:.Nat; .I8», 0)›, 0) (argv, 1I32);
             .let (`mem, to_match) = %mem.load (mem, arg1);
@@ -45,10 +40,6 @@
                                     .let is_end    = %core.icmp.e (c, '\0');
                                     (not_end, error)#is_end (mem, new_i)
                                     .where
-                                        .con not_a(mem: %mem.M, i: .I32) =
-                                            .let is_match_b = %core.icmp.e (c, 'b');
-                                            (error, state1)#is_match_b (mem, i);
-
                                         .con not_end(mem: %mem.M, i: .I32) =
                                             .let is_match_a = %core.icmp.e (c, 'a');
                                             (not_a, state2)#is_match_a (mem, i)
@@ -60,22 +51,30 @@
                                                     .let is_end    = %core.icmp.e (c, '\0');
                                                     (not_end, accept)#is_end (mem, new_i)
                                                     .where
-                                                        .con not_a(mem: %mem.M, i: .I32) =
-                                                            .let is_match_b = %core.icmp.e (c, 'b');
-                                                            (error, state1)#is_match_b (mem, i);
-
                                                         .con not_end(mem: %mem.M, i: .I32) =
                                                             .let is_match_a = %core.icmp.e (c, 'a');
                                                             (not_a, state2)#is_match_a (mem, i);
 
                                                         .con accept[mem: %mem.M, .I32] =
                                                             exit (mem, 1I32);
+
+                                                        .con not_a(mem: %mem.M, i: .I32) =
+                                                            .let is_match_b = %core.icmp.e (c, 'b');
+                                                            (error, state1)#is_match_b (mem, i);
                                                     .end
-                                            .end
+                                            .end;
+                                        .con not_a(mem: %mem.M, i: .I32) =
+                                            .let is_match_b = %core.icmp.e (c, 'b');
+                                            (error, state1)#is_match_b (mem, i);
                                     .end
                             .end
                     .end
-            .end
+            .end;
+        .con error(mem: %mem.M, i : .I32) =
+            reject (mem, 0I32)
+            .where
+                .con reject[mem: %mem.M, .Idx Top] = exit (mem, 0I32);
+            .end;
     .end
 
 // CHECK-NOT: %regex.
diff --git a/src/thorin/ast/bind.cpp b/src/thorin/ast/bind.cpp
@@ -125,7 +125,10 @@ void LitExpr::bind(Scopes& s) const {
 }
 
 void DeclExpr::bind(Scopes& s) const {
-    for (const auto& decl : decls()) decl->bind(s);
+    if (is_where())
+        for (const auto& decl : decls() | std::ranges::views::reverse) decl->bind(s);
+    else
+        for (const auto& decl : decls()) decl->bind(s);
     expr()->bind(s);
 }
 

diff --git a/src/thorin/ast/emit.cpp b/src/thorin/ast/emit.cpp
@@ -179,7 +179,10 @@ Ref LitExpr::emit_(Emitter& e) const {
 }
 
 Ref DeclExpr::emit_(Emitter& e) const {
-    for (const auto& decl : decls()) decl->emit(e);
+    if (is_where())
+        for (const auto& decl : decls() | std::ranges::views::reverse) decl->emit(e);
+    else
+        for (const auto& decl : decls()) decl->emit(e);
     return expr()->emit(e);
 }
 

diff --git a/src/thorin/ast/parser.cpp b/src/thorin/ast/parser.cpp
@@ -242,7 +242,12 @@ Ptr<Expr> Parser::parse_infix_expr(Tracker track, Ptr<Expr>&& lhs, Prec curr_pre
                 lex();
                 auto decls = parse_decls();
                 lhs        = ptr<DeclExpr>(track, std::move(decls), std::move(lhs), true);
+
+                bool where = ahead().tag() == Tag::K_where;
                 expect(Tag::K_end, "end of a .where declaration block");
+                if (where)
+                    ast().note(lhs->loc().anew_finis(),
+                               "did you accidentally end your declaration expression with a ';'?");
                 return lhs;
             }
             default: return lhs;

diff --git a/src/thorin/ast/stream.cpp b/src/thorin/ast/stream.cpp
@@ -90,7 +90,7 @@ std::ostream& LitExpr::stream(Tab& tab, std::ostream& os) const {
 }
 
 std::ostream& DeclExpr::stream(Tab& tab, std::ostream& os) const {
-    if (where()) {
+    if (is_where()) {
         tab.println(os, "{} .where", S(tab, expr()));
         ++tab;
         for (const auto& decl : decls()) tab.println(os, "{}", S(tab, decl.get()));