diff --git a/CMakeLists.txt b/CMakeLists.txt
index 3a1e9d8..86397fa 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,5 +1,5 @@
 cmake_minimum_required(VERSION 3.0)
-project(expr VERSION 1.3.0)
+project(expr VERSION 1.3.1)
 include(cmake/CPM.cmake)
 configure_file(src/config.h.in config.h)
 set(CMAKE_CXX_STANDARD 20)
diff --git a/include/parser/driver.h b/include/parser/driver.h
index a4e5e73..9d1d816 100644
--- a/include/parser/driver.h
+++ b/include/parser/driver.h
@@ -10,8 +10,11 @@ struct driver {
     explicit driver(const symbol_table_t& env);
     const symbol_table_t& environment{};
     symbol_table_t result{};
+    symbol_value_t error{};
+    symbol_value_t expression_result{};
 
     int parse(const std::string& f);
+    auto get_symbol(const std::string& identifier) -> symbol_value_t;
     std::string file;
     bool trace_parsing;
 
diff --git a/src/parser/driver.cpp b/src/parser/driver.cpp
index 429bcd9..48c3fde 100644
--- a/src/parser/driver.cpp
+++ b/src/parser/driver.cpp
@@ -8,7 +8,7 @@ driver::driver(const symbol_table_t& map) : trace_parsing (false), trace_scannin
 int driver::parse(const std::string &f) {
     if(f.empty()) {
 #ifdef DEFAULT_EXPRESSION_VALUE
-        result["expression_result"] = DEFAULT_EXPRESSION_VALUE;
+        expression_result = DEFAULT_EXPRESSION_VALUE;
 #endif
         return 0;
     }
@@ -17,7 +17,20 @@ int driver::parse(const std::string &f) {
     scan_begin();
     yy::parser parse(*this);
     parse.set_debug_level(trace_parsing);
-    int res = parse();
-    scan_end();
-    return res;
+    try {
+        int res = parse();
+        scan_end();
+        return res;
+    } catch(std::exception& e) {
+        error = e.what();
+        return 1;
+    }
+}
+
+auto driver::get_symbol(const std::string &identifier) -> symbol_value_t {
+#ifndef NDEBUG
+    if(!environment.contains(identifier))
+        throw std::out_of_range(identifier + " not found");
+#endif
+    return environment.at(identifier);
 }
diff --git a/src/parser/parser.y b/src/parser/parser.y
index 63a29f7..b7deb82 100644
--- a/src/parser/parser.y
+++ b/src/parser/parser.y
@@ -62,61 +62,59 @@
 %token <float> FLOAT "float"
 %token <bool> BOOL "bool"
 %token <std::string> STRING "string"
-%nterm <symbol_value_t> exp cmp op
+%nterm <symbol_value_t> lit exp
 %printer { yyo << $$; } <*>;
 
+%left OR
+%left AND
+%left GT GE EE NE LE LT
+%left PLUS MINUS STAR SLASH
+%precedence LPAREN NOT
 %%
 %start unit;
 unit:
   statements    { }
-| cmp           { drv.result["expression_result"] = $1; }
+| exp           { drv.expression_result = $1; }
 ;
 
 statements:
-  %empty                    {}
-| statement                 {}
-| statement ";" statements  {}
+  %empty               {}
+| statement statements {}
 ;
 
 statement:
-  "identifier" ":=" cmp                          { drv.result[$1] = $3; }
-| "type" "identifier" ":=" cmp                   { drv.result[$2] = $4; }
-| "access_modifier" "type" "identifier" ":=" cmp { drv.result[$3] = $5; }
+  "identifier" ASSIGN exp                          { drv.result[$1] = $3; }
+| "type" "identifier" ASSIGN exp                   { drv.result[$2] = $4; }
+| "access_modifier" "type" "identifier" ASSIGN exp { drv.result[$3] = $5; }
+| statement TERM                                   { }
 ;
 
-%left "+" "-";
-%left "*" "/";
-%precedence "||" "&&";
-
-cmp:
-  op "||" op    { $$ = or_($1,$3); }
-| op "&&" op    { $$ = and_($1,$3); }
-| "!" op        { $$ = not_($2); }
-| op            { $$ = $1; }
-| "(" op ")"    { $$ = $2; }
-;
-
-op:
-  exp "+" exp   { $$ = $1 + $3; }
-| exp "-" exp   { $$ = $1 - $3; }
-| exp "*" exp   { $$ = $1 * $3; }
-| exp "/" exp   { $$ = $1 / $3; }
-| exp ">"  exp  { $$ = gt_($1,$3); }
-| exp ">=" exp  { $$ = ge_($1,$3); }
-| exp "==" exp  { $$ = ee_($1,$3); }
-| exp "!=" exp  { $$ = ne_($1,$3); }
-| exp "<=" exp  { $$ = le_($1,$3); }
-| exp "<"  exp  { $$ = lt_($1,$3); }
-| exp           { $$ = $1; }
+exp:
+  lit                   { $$ = $1; }
+| exp PLUS exp          { $$ = $1 + $3; }
+| exp MINUS exp         { $$ = $1 - $3; }
+| exp STAR exp          { $$ = $1 * $3; }
+| exp SLASH exp         { $$ = $1 / $3; }
+| exp GT  exp           { $$ = gt_($1,$3); }
+| exp GE exp            { $$ = ge_($1,$3); }
+| exp EE exp            { $$ = ee_($1,$3); }
+| exp NE exp            { $$ = ne_($1,$3); }
+| exp LE exp            { $$ = le_($1,$3); }
+| exp LT  exp           { $$ = lt_($1,$3); }
+| exp OR exp            { $$ = or_($1,$3); }
+| exp AND exp           { $$ = and_($1,$3); }
+| NOT exp               { $$ = not_($2); }
+| LPAREN exp RPAREN     { $$ = $2; }
 ;
 
-exp:
-  cmp           { $$ = $1; }
-| "number"      { $$ = $1; }
-| "float"       { $$ = $1; }
-| "string"      { $$ = $1; }
-| "bool"        { $$ = $1; }
-| "identifier"  { $$ = drv.environment.at($1); }
+lit:
+  "number"       { $$ = $1; }
+| MINUS "number" { $$ = -$2; }
+| "float"        { $$ = $1; }
+| MINUS "float"  { $$ = -$2; }
+| "string"       { $$ = $1; }
+| "bool"         { $$ = $1; }
+| "identifier"   { $$ = drv.get_symbol($1); }
 ;
 %%
 
diff --git a/src/parser/scanner.l b/src/parser/scanner.l
index ffe75ab..10956b8 100644
--- a/src/parser/scanner.l
+++ b/src/parser/scanner.l
@@ -93,9 +93,9 @@
 %{
  // TODO: Remove [ðđ€\(\)]
 %}
-id     [a-z_A-Z][a-zA-Z_.0-9ðđ€\(\)]*
-int    [0-9]+
-flt    [0-9]+[.][0-9]+f
+id     [a-z_A-Z]([.ðđ€\(\)a-zA-Z_0-9]*[a-zA-Z_0-9]+)?
+int    [0-9]+[Ll]?
+flt    [0-9]+[.][0-9]+[fd]?
 bool   [Ff]alse|[Tt]rue
 str    \"(\\.|[^"\\])*\"
 blank  [ \t\r]
@@ -114,7 +114,7 @@ type   int|long|float|double|string|bool|var|auto
   loc.step();
 %}
 {blank}+   loc.step();
-\n+        loc.lines(yyleng); loc.step();
+\n+        { loc.lines(yyleng); loc.step(); }
 
 "-"        return yy::parser::make_MINUS  (loc);
 "+"        return yy::parser::make_PLUS   (loc);