Split syntax configurations code:switch_cases and `code:switch_case…

…s_oneline`. This is so that syntax files for languages that don't need special handling for oneline statements (like Go) do not have to handle `oneline` conditional (which may be confusing and unexpected).
skvadrik · Nov 26, 2023 · af41fd9 · af41fd9
1 parent 9a0fdfa
commit af41fd9
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Showing 9 changed files with 59 additions and 43 deletions.
diff --git a/bootstrap/src/default_syntax_c.cc b/bootstrap/src/default_syntax_c.cc
@@ -38,11 +38,13 @@ const char* DEFAULT_SYNTAX_C =
     "        indent [case: case] dedent\n"
     "    topindent \"}\" nl;\n"
     "\n"
-    "code:switch_cases = (oneline\n"
-    "    ? [case{0:-2}: case nl]\n"
-    "      [case{-1}:   case \" \" [stmt: stmt]]\n"
-    "    : [case: case nl]\n"
-    "        indent [stmt: stmt] dedent);\n"
+    "code:switch_cases =\n"
+    "    [case: case nl]\n"
+    "        indent [stmt: stmt] dedent;\n"
+    "\n"
+    "code:switch_cases_oneline =\n"
+    "    [case{0:-2}: case nl]\n"
+    "    [case{-1}:   case \" \" [stmt: stmt]];\n"
     "\n"
     "code:switch_case_range = (case_ranges\n"
     "    ? topindent \"case \" [val{0}: val] (multival ? \" ... \" [val{-1}: val]) \":\"\n"

diff --git a/bootstrap/src/default_syntax_go.cc b/bootstrap/src/default_syntax_go.cc
@@ -37,8 +37,7 @@ const char* DEFAULT_SYNTAX_GO =
     "    [case{0:-2}: topindent case nl\n"
     "        indent topindent \"fallthrough\" dedent nl]\n"
     "    [case{-1}: topindent case nl]\n"
-    "        // `topindent` is needed in `oneline` case because re2c renders it in a special way\n"
-    "        indent (oneline ? topindent) [stmt: stmt] dedent;\n"
+    "        indent [stmt: stmt] dedent;\n"
     "\n"
     "code:switch_case_range = \"case \" [val{0}: val] [val{1:-1}: \",\" val] \":\";\n"
     "\n"

diff --git a/bootstrap/src/default_syntax_rust.cc b/bootstrap/src/default_syntax_rust.cc
@@ -36,11 +36,14 @@ const char* DEFAULT_SYNTAX_RUST =
     "    topindent \"}\" nl;\n"
     "\n"
     "code:switch_cases =\n"
-    "    [case{0:-2}: topindent case \" |\" nl] (oneline\n"
-    "    ? [case{-1}: topindent case \" => \" [stmt: stmt]]\n"
-    "    : [case{-1}: topindent case \" => {\" nl\n"
-    "          indent [stmt: stmt] dedent\n"
-    "      topindent \"}\" nl]);\n"
+    "    [case{0:-2}: topindent case \" |\" nl]\n"
+    "    [case{-1}:   topindent case \" => {\" nl\n"
+    "        indent [stmt: stmt] dedent\n"
+    "    topindent \"}\" nl];\n"
+    "\n"
+    "code:switch_cases_oneline =\n"
+    "    [case{0:-2}: topindent case \" |\" nl]\n"
+    "    [case{-1}:   topindent case \" => \" [stmt: stmt]];\n"
     "\n"
     "code:switch_case_range = [val{0}: val] (multival ? \" ..= \" [val{-1}: val]);\n"
     "\n"

diff --git a/include/syntax/c b/include/syntax/c
@@ -37,11 +37,13 @@ code:switch =
         indent [case: case] dedent
     topindent "}" nl;
 
-code:switch_cases = (oneline
-    ? [case{0:-2}: case nl]
-      [case{-1}:   case " " [stmt: stmt]]
-    : [case: case nl]
-        indent [stmt: stmt] dedent);
+code:switch_cases =
+    [case: case nl]
+        indent [stmt: stmt] dedent;
+
+code:switch_cases_oneline =
+    [case{0:-2}: case nl]
+    [case{-1}:   case " " [stmt: stmt]];
 
 code:switch_case_range = (case_ranges
     ? topindent "case " [val{0}: val] (multival ? " ... " [val{-1}: val]) ":"

diff --git a/include/syntax/go b/include/syntax/go
@@ -36,8 +36,7 @@ code:switch_cases =
     [case{0:-2}: topindent case nl
         indent topindent "fallthrough" dedent nl]
     [case{-1}: topindent case nl]
-        // `topindent` is needed in `oneline` case because re2c renders it in a special way
-        indent (oneline ? topindent) [stmt: stmt] dedent;
+        indent [stmt: stmt] dedent;
 
 code:switch_case_range = "case " [val{0}: val] [val{1:-1}: "," val] ":";
 

diff --git a/include/syntax/rust b/include/syntax/rust
@@ -35,11 +35,14 @@ code:switch =
     topindent "}" nl;
 
 code:switch_cases =
-    [case{0:-2}: topindent case " |" nl] (oneline
-    ? [case{-1}: topindent case " => " [stmt: stmt]]
-    : [case{-1}: topindent case " => {" nl
-          indent [stmt: stmt] dedent
-      topindent "}" nl]);
+    [case{0:-2}: topindent case " |" nl]
+    [case{-1}:   topindent case " => {" nl
+        indent [stmt: stmt] dedent
+    topindent "}" nl];
+
+code:switch_cases_oneline =
+    [case{0:-2}: topindent case " |" nl]
+    [case{-1}:   topindent case " => " [stmt: stmt]];
 
 code:switch_case_range = [val{0}: val] (multival ? " ..= " [val{-1}: val]);
 

diff --git a/src/codegen/pass4_render.cc b/src/codegen/pass4_render.cc
@@ -336,7 +336,7 @@ class RenderSwitchCaseBlock : public OutputCallback {
     bool oneline;
 
   public:
-    RenderSwitchCaseBlock(RenderContext& rctx, const CodeCase* code)
+    RenderSwitchCaseBlock(RenderContext& rctx, const CodeCase* code, bool oneline)
             : rctx(rctx)
             , code(code)
             , curr_stmt(nullptr)
@@ -345,12 +345,8 @@ class RenderSwitchCaseBlock : public OutputCallback {
             , curr_range(0)
             , last_range(0)
             , nranges(code->kind == CodeCase::Kind::RANGES ? code->ranges->size : 1)
-            , oneline(false) {
-        const Code* head = code->body->head;
-        for (const Code* s = head; s; s = s->next) ++nstmt;
-        oneline = head != nullptr
-               && head->next == nullptr
-               && (head->kind == CodeKind::STMT || head->kind == CodeKind::TEXT);
+            , oneline(oneline) {
+        for (const Code* s = code->body->head; s; s = s->next) ++nstmt;
     }
 
     void render_var(const char* var) override {
@@ -416,14 +412,6 @@ class RenderSwitchCaseBlock : public OutputCallback {
         return false;
     }
 
-    bool eval_cond(const char* var) {
-        if (strcmp(var, "oneline") == 0) {
-            return oneline;
-        }
-        UNREACHABLE();
-        return false;
-    }
-
     FORBID_COPY(RenderSwitchCaseBlock);
 };
 
@@ -433,19 +421,31 @@ class RenderSwitch : public OutputCallback {
     const CodeCase* curr_case;
     const CodeCase* last_case;
     size_t ncases;
+    const bool specialize_oneline;
 
   public:
     RenderSwitch(RenderContext& rctx, const CodeSwitch* code)
-            : rctx(rctx), code(code), curr_case(nullptr), last_case(nullptr), ncases(0) {
+            : rctx(rctx)
+            , code(code)
+            , curr_case(nullptr)
+            , last_case(nullptr)
+            , ncases(0)
+            , specialize_oneline(rctx.stx.have_conf("code:switch_cases_oneline")) {
         for (const CodeCase* c = code->cases->head; c; c = c->next) ++ncases;
     }
 
     void render_var(const char* var) override {
         if (strcmp(var, "expr") == 0) {
             rctx.os << code->expr;
         } else if (strcmp(var, "case") == 0) {
-            RenderSwitchCaseBlock callback(rctx, curr_case);
-            rctx.stx.gen_code(rctx.os, rctx.opts, "code:switch_cases", callback);
+            const Code* s = curr_case->body->head;
+            bool oneline = specialize_oneline
+               && s != nullptr
+               && s->next == nullptr
+               && (s->kind == CodeKind::STMT || s->kind == CodeKind::TEXT);
+            const char* conf = oneline ? "code:switch_cases_oneline" : "code:switch_cases";
+            RenderSwitchCaseBlock callback(rctx, curr_case, oneline);
+            rctx.stx.gen_code(rctx.os, rctx.opts, conf, callback);
         } else {
             render_global_var(rctx, var);
         }

diff --git a/src/codegen/syntax.cc b/src/codegen/syntax.cc
@@ -63,7 +63,10 @@ Stx::Stx(OutAllocator& alc)
         {"expr"}, {"case"}, {}
     };
     allowed_code_confs["code:switch_cases"] = {
-        {}, {"case", "stmt"}, {"oneline"}
+        {}, {"case", "stmt"}, {}
+    };
+    allowed_code_confs["code:switch_cases_oneline"] = {
+        {}, {"case", "stmt"}, {}
     };
     allowed_code_confs["code:switch_case_range"] = {
         {}, {"val"}, {"multival"}
@@ -257,6 +260,10 @@ Ret Stx::validate_conf_code(const StxConf* conf) {
     return Ret::OK;
 }
 
+bool Stx::have_conf(const char* name) const {
+    return confs.find(name) != confs.end();
+}
+
 void Stx::push_list_on_stack(const StxCode* x) {
     if (x == nullptr) return;
     push_list_on_stack(x->next);

diff --git a/src/codegen/syntax.h b/src/codegen/syntax.h
@@ -151,6 +151,7 @@ class Stx {
     Ret validate_conf_expr(const StxConf* conf);
     Ret validate_conf_code(const StxConf* conf);
 
+    bool have_conf(const char* name) const;
     void gen_code(std::ostream& os, const opt_t* opts, const char* name, OutputCallback& callback);
 };