Add ability to emit errors in json + capture symbol name in error_entry

source/common.h

@@ -986,6 +986,13 @@ static cmdline_processor::register_flag cmd_print_colon_errors(
     []{ flag_print_colon_errors = true; }
 );
 
+static auto flag_json_errors = false;
+static cmdline_processor::register_flag cmd_json_errors(
+    9,
+    "json-errors",
+    "Emit errors in json - for use in language server tools",
+    []{ flag_json_errors = true; }
+);
 
 //-----------------------------------------------------------------------
 //
@@ -997,6 +1004,7 @@ struct error_entry
 {
     source_position where;
     std::string     msg;
+    std::string     symbol;
     bool            internal = false;
     bool            fallback = false;   // only emit this message if there was nothing better
 
@@ -1012,6 +1020,21 @@ struct error_entry
         , fallback{f}
     { }
 
+    /// An overload allowing the passing in of the symbol associated with the error
+    error_entry(
+        source_position  w,
+        std::string_view m,
+        std::string_view s,
+        bool             i = false,
+        bool             f = false
+    )
+        : where{w}
+        , msg{m}
+        , symbol{s}
+        , internal{i}
+        , fallback{f}
+    { }
+
     auto operator==(error_entry const& that)
         -> bool
     {
@@ -1024,29 +1047,38 @@ struct error_entry
     auto print(auto& o, std::string const& file) const
         -> void
     {
-        o << file ;
-        if (where.lineno > 0) {
-            if (flag_print_colon_errors) {
-                o << ":" << (where.lineno);
-                if (where.colno >= 0) {
-                    o << ":" << where.colno;
+        if (flag_json_errors) {
+            o << "{ \"file\": \"" << file << "\""
+              << ", \"line\": " << where.lineno 
+              << ", \"column\": " << where.colno
+              << ", \"error\": \"" << msg << "\""
+              << ", \"symbol\": \"" << symbol << "\""
+              << "}\n";
+        }
+        else {
+            o << file ;
+            if (where.lineno > 0) {
+                if (flag_print_colon_errors) {
+                    o << ":" << (where.lineno);
+                    if (where.colno >= 0) {
+                        o << ":" << where.colno;
+                    }
                 }
-            }
-            else {
-                o << "("<< (where.lineno);
-                if (where.colno >= 0) {
-                    o << "," << where.colno;
+                else {
+                    o << "("<< (where.lineno);
+                    if (where.colno >= 0) {
+                        o << "," << where.colno;
+                    }
+                    o  << ")";
                 }
-                o  << ")";
             }
+            o << ":";
+            if (internal) {
+                o << " internal compiler";
+            }
+            o << " error: " << msg << "\n";
         }
-        o << ":";
-        if (internal) {
-            o << " internal compiler";
-        }
-        o << " error: " << msg << "\n";
     }
-
 };
 
 

source/parse.h

@@ -6069,15 +6069,17 @@ class parser
         auto m = std::string{msg};
         auto i = done() ? -1 : 0;
         assert (peek(i));
+        auto s = peek(i)->to_string();
+
         if (include_curr_token) {
-            m += std::string(" (at '") + peek(i)->to_string() + "')";
+            m += std::string(" (at '") + s + "')";
         }
         if (
             err_pos == source_position{}
         ) {
             err_pos = peek(i)->position();
         }
-        errors.emplace_back( err_pos, m, false, fallback );
+        errors.emplace_back( err_pos, m, s, false, fallback );
     }
 
     auto error(

source/sema.h

@@ -1264,7 +1264,8 @@ class sema
                             errors.emplace_back(
                                 sym.identifier->position(),
                                 "local variable " + name
-                                    + " is used before it was initialized");
+                                    + " is used before it was initialized",
+                                name );
                         }
                         return sym.standalone_assignment_to;
                     }

source/to_cpp1.h

@@ -5374,6 +5374,7 @@ class cppfront
             //  so write it once to keep the guidance consistent
             assert (n.parent_declaration && n.parent_declaration->name());
             auto error_msg = "an operator= body must start with a series of 'member = value;' initialization statements for each of the type-scope objects in the same order they are declared, or the member must have a default initializer (in type '" + n.parent_declaration->name()->to_string() + "')";
+            auto error_symbol = n.parent_declaration->name()->to_string();
 
             //  If this constructor's type has data members, handle their initialization
             //      - objects is the list of this type's declarations
@@ -5522,7 +5523,8 @@ class cppfront
                     );
                     errors.emplace_back(
                         stmt_pos,
-                        error_msg
+                        error_msg,
+                        error_symbol
                     );
                     return;
                 }
@@ -5651,7 +5653,8 @@ class cppfront
                 );
                 errors.emplace_back(
                     (*object)->position(),
-                    error_msg
+                    error_msg,
+                    error_symbol
                 );
                 return;
             }