diff --git a/src/jsil/jsil_language.cpp b/src/jsil/jsil_language.cpp
index c363a5396e0..8b0d543c949 100644
--- a/src/jsil/jsil_language.cpp
+++ b/src/jsil/jsil_language.cpp
@@ -62,12 +62,11 @@ bool jsil_languaget::parse(
   parse_path=path;
 
   // parsing
+  jsil_parsert jsil_parser{message_handler};
   jsil_parser.clear();
   jsil_parser.set_file(path);
   jsil_parser.in=&instream;
-  jsil_parser.log.set_message_handler(message_handler);
 
-  jsil_scanner_init();
   bool result=jsil_parser.parse();
 
   // save result
@@ -137,12 +136,10 @@ bool jsil_languaget::to_expr(
   std::istringstream instream(code);
 
   // parsing
-
+  jsil_parsert jsil_parser{message_handler};
   jsil_parser.clear();
   jsil_parser.set_file(irep_idt());
   jsil_parser.in=&instream;
-  jsil_parser.log.set_message_handler(message_handler);
-  jsil_scanner_init();
 
   bool result=jsil_parser.parse();
 
diff --git a/src/jsil/jsil_parser.cpp b/src/jsil/jsil_parser.cpp
index de11bc731e8..234f6510212 100644
--- a/src/jsil/jsil_parser.cpp
+++ b/src/jsil/jsil_parser.cpp
@@ -10,13 +10,3 @@ Author: Michael Tautschnig, tautschn@amazon.com
 /// Jsil Language
 
 #include "jsil_parser.h"
-
-jsil_parsert jsil_parser;
-
-extern char *yyjsiltext;
-
-int yyjsilerror(const std::string &error)
-{
-  jsil_parser.parse_error(error, yyjsiltext);
-  return 0;
-}
diff --git a/src/jsil/jsil_parser.h b/src/jsil/jsil_parser.h
index 2aad7767e34..c77e492259b 100644
--- a/src/jsil/jsil_parser.h
+++ b/src/jsil/jsil_parser.h
@@ -16,16 +16,24 @@ Author: Michael Tautschnig, tautschn@amazon.com
 
 #include "jsil_parse_tree.h"
 
-int yyjsilparse();
+class jsil_parsert;
+int yyjsilparse(jsil_parsert &);
+void jsil_scanner_init(jsil_parsert &);
 
 class jsil_parsert:public parsert
 {
 public:
+  explicit jsil_parsert(message_handlert &message_handler)
+    : parsert(message_handler)
+  {
+  }
+
   jsil_parse_treet parse_tree;
 
   virtual bool parse() override
   {
-    return yyjsilparse()!=0;
+    jsil_scanner_init(*this);
+    return yyjsilparse(*this) != 0;
   }
 
   virtual void clear() override
@@ -41,9 +49,4 @@ class jsil_parsert:public parsert
   std::string string_literal;
 };
 
-extern jsil_parsert jsil_parser;
-
-int yyjsilerror(const std::string &error);
-void jsil_scanner_init();
-
 #endif // CPROVER_JSIL_JSIL_PARSER_H
diff --git a/src/jsil/parser.y b/src/jsil/parser.y
index 7488353d034..31c96d972ed 100644
--- a/src/jsil/parser.y
+++ b/src/jsil/parser.y
@@ -1,13 +1,27 @@
 %{
 
 // #define YYDEBUG 1
-#define PARSER jsil_parser
+#define PARSER (*jsil_parser)
 
 #include "jsil_parser.h"
 
 int yyjsillex();
 extern char *yyjsiltext;
 
+static jsil_parsert *jsil_parser;
+int yyjsilparse(void);
+int yyjsilparse(jsil_parsert &_jsil_parser)
+{
+  jsil_parser = &_jsil_parser;
+  return yyjsilparse();
+}
+
+int yyjsilerror(const std::string &error)
+{
+  jsil_parser->parse_error(error, yyjsiltext);
+  return 0;
+}
+
 #define YYSTYPE unsigned
 #define YYSTYPE_IS_TRIVIAL 1
 
diff --git a/src/jsil/scanner.l b/src/jsil/scanner.l
index 1ed37abebfa..4ec6cef9336 100755
--- a/src/jsil/scanner.l
+++ b/src/jsil/scanner.l
@@ -17,13 +17,23 @@
 #include <ansi-c/literals/convert_float_literal.h>
 #include <ansi-c/literals/convert_string_literal.h>
 
-#define PARSER jsil_parser
+#define PARSER (*jsil_parser)
 #define YYSTYPE unsigned
 
 #include "jsil_parser.h"
 #include "jsil_y.tab.h"
 // extern int yyjsildebug;
 
+static jsil_parsert *jsil_parser;
+void jsil_scanner_init(jsil_parsert &_jsil_parser)
+{
+  jsil_parser = &_jsil_parser;
+  YY_FLUSH_BUFFER;
+  BEGIN(0);
+}
+
+int yyjsilerror(const std::string &error);
+
 #define loc() \
   { newstack(yyjsillval); PARSER.set_source_location(parser_stack(yyjsillval)); }
 
@@ -71,14 +81,6 @@ string_lit      ["]{s_char}*["]
 %x STRING_LITERAL_COMMENT
 %x STATEMENTS
 
-%{
-void jsil_scanner_init()
-{
-  // yyjsildebug=1;
-  YY_FLUSH_BUFFER;
-  BEGIN(0);
-}
-%}
  /* %option debug */
 
 %%
diff --git a/src/util/parser.h b/src/util/parser.h
index 70a796ec4a9..c19aeb58977 100644
--- a/src/util/parser.h
+++ b/src/util/parser.h
@@ -12,6 +12,7 @@ Author: Daniel Kroening, kroening@kroening.com
 #ifndef CPROVER_UTIL_PARSER_H
 #define CPROVER_UTIL_PARSER_H
 
+#include "deprecate.h"
 #include "expr.h"
 #include "message.h"
 
@@ -39,7 +40,13 @@ class parsert
     last_line.clear();
   }
 
+  DEPRECATED(SINCE(2023, 12, 20, "use parsert(message_handler) instead"))
   parsert():in(nullptr) { clear(); }
+  explicit parsert(message_handlert &message_handler)
+    : in(nullptr), log(message_handler)
+  {
+    clear();
+  }
   virtual ~parsert() { }
 
   // The following are for the benefit of the scanner