diff --git a/doc/grammar.bnf b/doc/grammar.bnf
index c80f9bf..5024392 100644
--- a/doc/grammar.bnf
+++ b/doc/grammar.bnf
@@ -17,7 +17,7 @@ LITERAL ::=
 | INDEX
 | opar EXPR cpar
 INDEX ::= 
-| TUPLE osquare (EXPR (comma EXPR)*)? csquare
+| (TUPLE|str) osquare (EXPR (comma EXPR)*)? csquare
 TUPLE ::=
 | opar EXPR+ cpar
-BUILTIN ::= num | bool
+BUILTIN ::= num | bool | str
diff --git a/lib/ccm.c b/lib/ccm.c
index 5a0012f..692272c 100644
--- a/lib/ccm.c
+++ b/lib/ccm.c
@@ -1,4 +1,5 @@
 #include "ccm.h"
+#include "str.h"
 
 void ccm_init(ccm_t* self)
 {
@@ -45,10 +46,14 @@ CCM ccm_from_value(ccm_t* self, value_t* value)
             return ccm_to_num(self, value->data.num, value->line);
         } break;
 
+        case TYPE_STR: {
+            return ccm_to_str(self, value->data.str, value->line);
+        } break;
+
         case TYPE_BOOLEAN: {
             return ccm_to_boolean(
-                self, 
-                value->data.boolean, 
+                self,
+                value->data.boolean,
                 value->line
             );
         } break;
@@ -64,14 +69,14 @@ CCM ccm_from_value(ccm_t* self, value_t* value)
             }
 
             return ccm_to_tuple(
-                self, 
-                vec, 
+                self,
+                vec,
                 value->line
             );
         } break;
 
         default: {
-            fprintf(stderr, 
+            fprintf(stderr,
                     "cannot convert value of type <%s> to CCM\n",
                     TypeStr[value->type]);
             abort();
@@ -165,6 +170,31 @@ CCM ccm_to_boolean(ccm_t* self, int value, int line)
     return self->values.size - 1;
 }
 
+int ccm_is_str(ccm_t* self, CCM value)
+{
+    assert(self);
+    return ((value_t*) self->values.data[value])->type == TYPE_STR;
+}
+
+char* ccm_from_str(ccm_t* self, CCM value)
+{
+    assert(self);
+    return ((value_t*) self->values.data[value])->data.str;
+}
+
+CCM ccm_to_str(ccm_t* self, char* value, int line)
+{
+    assert(self);
+    assert(value);
+
+    value_t* val = malloc(sizeof(value_t));
+    value_init_str(val, value, line);
+
+    vec_push(&self->values, val);
+
+    return self->values.size - 1;
+}
+
 void ccm_push(ccm_t* self, CCM value)
 {
     assert(self);
@@ -191,7 +221,7 @@ void ccm_in(ccm_t* self)
     assert(self);
     CCM ccm_rhs = ccm_pop(self);
     CCM ccm_lhs = ccm_pop(self);
-    
+
     int line = ((value_t*) self->values.data[ccm_lhs])->line;
 
     if (!ccm_is_tuple(self, ccm_rhs))
@@ -200,7 +230,7 @@ void ccm_in(ccm_t* self)
         return;
     }
 
-    
+
     vec_t* rhs = ccm_from_tuple(self, ccm_rhs);
     value_t* val = ((value_t*)self->values.data[ccm_lhs]);
 
@@ -223,6 +253,21 @@ void ccm_add(ccm_t* self)
     CCM ccm_lhs = ccm_pop(self);
     int line = ((value_t*) self->values.data[ccm_lhs])->line;
 
+    if (ccm_is_str(self, ccm_rhs)
+        && ccm_is_str(self, ccm_lhs))
+    {
+        char const* lhs = ccm_from_str(self, ccm_lhs);
+        char const* rhs = ccm_from_str(self, ccm_rhs);
+
+        str_t s;
+        str_init(&s);
+        str_push_cstr(&s, lhs);
+        str_push_cstr(&s, rhs);
+        ccm_push(self, ccm_to_str(self, s.value, line));
+        str_free(&s);
+        return;
+    }
+
     double rhs = ccm_from_num(self, ccm_rhs);
     double lhs = ccm_from_num(self, ccm_lhs);
 
@@ -260,6 +305,32 @@ void ccm_mul(ccm_t* self)
     CCM ccm_lhs = ccm_pop(self);
     int line = ((value_t*) self->values.data[ccm_lhs])->line;
 
+    if (ccm_is_str(self, ccm_rhs)
+    && ccm_is_num(self, ccm_lhs))
+    {
+        CCM tmp = ccm_lhs;
+        ccm_lhs = ccm_rhs;
+        ccm_rhs = tmp;
+    }
+
+    if (ccm_is_str(self, ccm_lhs)
+    && ccm_is_num(self, ccm_rhs))
+    {
+        int count = ccm_from_num(self, ccm_rhs);
+        char const* val = ccm_from_str(self, ccm_lhs);
+        str_t s;
+        str_init(&s);
+
+        for (int i=0; i<count; i++)
+        {
+            str_push_cstr(&s, val);
+        }
+
+        ccm_push(self, ccm_to_str(self, s.value, line));
+        str_free(&s);
+        return;
+    }
+
     double rhs = ccm_from_num(self, ccm_rhs);
     double lhs = ccm_from_num(self, ccm_lhs);
 
diff --git a/lib/ccm.h b/lib/ccm.h
index f33c7c9..7744c06 100644
--- a/lib/ccm.h
+++ b/lib/ccm.h
@@ -33,6 +33,10 @@ int ccm_is_boolean(ccm_t* self, CCM value);
 int ccm_from_boolean(ccm_t* self, CCM value);
 CCM ccm_to_boolean(ccm_t* self, int value, int line);
 
+int ccm_is_str(ccm_t* self, CCM value);
+char* ccm_from_str(ccm_t* self, CCM value);
+CCM ccm_to_str(ccm_t* self, char* value, int line);
+
 void ccm_push(ccm_t* self, CCM value);
 CCM ccm_pop(ccm_t* self);
 CCM ccm_top(ccm_t* self, int depth);
diff --git a/lib/compiler.c b/lib/compiler.c
index 142bd6f..7537469 100644
--- a/lib/compiler.c
+++ b/lib/compiler.c
@@ -77,6 +77,17 @@ void compiler_compile(compiler_t* self,
             }
         } break;
 
+        case NODE_STR: {
+            size_t id = prog_add_new_constant(
+                prog,
+                ccm_to_str(&self->module->ccm,
+                           node->value,
+                           node->line)
+            );
+
+            prog_add_instr(prog, OP_PUSH, id);
+        } break;
+
         case NODE_NUM: {
             size_t id = prog_add_new_constant(
                 prog,
diff --git a/lib/exec.c b/lib/exec.c
index a918c43..4ebc617 100644
--- a/lib/exec.c
+++ b/lib/exec.c
@@ -46,40 +46,81 @@ void exec_instr(exec_t* self,
     {
         case OP_INDEX: {
             CCM ccm_target = ccm_pop(ccm);
-            vec_t* target = ccm_from_tuple(ccm, ccm_target);
+
             value_t* result = NULL;
 
-            for (int i=0; i<param; i++)
+            if (ccm_is_str(ccm, ccm_target))
             {
+                int line =
+                    ((value_t*)ccm->values.data[ccm_target])->line
+                ;
+
+                if (param != 1)
+                {
+                    err_push(&self->err, line,
+                             "index out of bounds");
+                    return;
+                }
+
+                char const* target =
+                    ccm_from_str(ccm, ccm_target);
+
+                size_t size = strlen(target);
+
                 CCM ccm_idx = ccm_pop(ccm);
                 int idx = ccm_from_num(ccm, ccm_idx);
 
                 if (idx < 0)
                 {
-                    idx = target->size + idx;
+                    idx = size + idx;
                 }
 
-                if (idx < 0 || idx >= (ssize_t) target->size)
+                if (idx < 0 || idx >= (ssize_t) size)
                 {
-                    assert(target->size > 0);
-                    err_push(&self->err, ((value_t*)target->data[0])->line,
+                    assert(size > 0);
+                    err_push(&self->err, line,
                              "index out of bounds");
                     return;
                 }
 
-                value_t* val = target->data[idx];
+                char buf[2] = {target[idx], '\0'};
+                ccm_push(ccm, ccm_to_str(ccm, buf, line));
+            }
+            else if (ccm_is_tuple(ccm, ccm_target))
+            {
+                vec_t* target = ccm_from_tuple(ccm, ccm_target);
 
-                if (i == param - 1)
+                for (int i=0; i<param; i++)
                 {
-                    result = val;
-                }
-                else
-                {
-                    target = val->data.tuple;
+                    CCM ccm_idx = ccm_pop(ccm);
+                    int idx = ccm_from_num(ccm, ccm_idx);
+
+                    if (idx < 0)
+                    {
+                        idx = target->size + idx;
+                    }
+
+                    if (idx < 0 || idx >= (ssize_t) target->size)
+                    {
+                        assert(target->size > 0);
+                        err_push(&self->err, ((value_t*)target->data[0])->line,
+                                 "index out of bounds");
+                        return;
+                    }
+
+                    value_t* val = target->data[idx];
+
+                    if (i == param - 1) {
+                        result = val;
+                    } else {
+                        target = val->data.tuple;
+                    }
                 }
+                ccm_push(ccm, ccm_from_value(ccm, result));
+            } else {
+                assert(0);
             }
 
-            ccm_push(ccm, ccm_from_value(ccm, result));
             self->pc++;
         } break;
 
@@ -106,7 +147,7 @@ void exec_instr(exec_t* self,
                 self->pc++;
             }
             else
-            {
+        {
                 self->pc = param;
             }
         } break;
@@ -124,7 +165,7 @@ void exec_instr(exec_t* self,
             }
 
             if (value_equals(values->data[0],
-                              values->data[1]) == !oracle)
+                             values->data[1]) == !oracle)
             {
                 char lhs[CCM_STRLEN];
                 value_str(values->data[0], lhs, CCM_STRLEN);
diff --git a/lib/lexer.c b/lib/lexer.c
index 91cede6..dca1c3c 100644
--- a/lib/lexer.c
+++ b/lib/lexer.c
@@ -144,6 +144,11 @@ node_t* lexer_try_new_next(lexer_t* self)
 
     node_t* node = NULL;
 
+    if ( (node = lexer_try_new_str(self)) )
+    {
+        return node;
+    }
+
     if ( (node = lexer_try_new_num(self)) )
     {
         return node;
@@ -360,3 +365,73 @@ node_t* lexer_try_new_num(lexer_t* self)
 
     return node;
 }
+
+node_t* lexer_try_new_str(lexer_t* self)
+{
+    assert(self);
+    size_t cursor = self->cursor;
+    str_t value;
+    str_init(&value);
+
+    if (cursor >= strlen(self->source)
+    || self->source[cursor] != '"')
+    {
+        str_free(&value);
+        return NULL;
+    }
+
+    cursor++;
+
+    while (cursor < strlen(self->source)
+    && self->source[cursor] != '"')
+    {
+        if (self->source[cursor] == '\\'
+        && cursor + 1 < strlen(self->source))
+        {
+            switch (self->source[cursor + 1])
+            {
+                case '\\': {
+                    str_push(&value, '\\');
+                } break;
+                case 'n': {
+                    str_push(&value, '\n');
+                } break;
+                case 'r': {
+                    str_push(&value, '\r');
+                } break;
+                case 't': {
+                    str_push(&value, '\t');
+                } break;
+                case 'e': {
+                    str_push(&value, '\e');
+                } break;
+                case '"': {
+                    str_push(&value, '"');
+                } break;
+            }
+
+            cursor += 2;
+        }
+        else {
+            str_push(&value, self->source[cursor]);
+            cursor++;
+        }
+    }
+
+    if (cursor >= strlen(self->source)
+    || self->source[cursor] != '"')
+    {
+        str_free(&value);
+        return NULL;
+    }
+
+    cursor++;
+    self->cursor = cursor;
+    node_t* node = malloc(sizeof(node_t));
+    node_init(node, NODE_STR, value.value, self->line);
+
+    str_free(&value);
+
+    return node;
+}
+
diff --git a/lib/lexer.h b/lib/lexer.h
index 0f43bd9..eee9c75 100644
--- a/lib/lexer.h
+++ b/lib/lexer.h
@@ -53,4 +53,5 @@ node_t* lexer_try_new_text(lexer_t* self,
                            int has_value);
 
 node_t* lexer_try_new_num(lexer_t* self);
+node_t* lexer_try_new_str(lexer_t* self);
 #endif
diff --git a/lib/module.c b/lib/module.c
index f85e42e..42218e4 100644
--- a/lib/module.c
+++ b/lib/module.c
@@ -45,12 +45,7 @@ int module_load(module_t* self, char const* path)
     parser_init(&parser, &lexer);
 
     node_t* ast = parser_try_new_parse(&parser);
-
-    if (!ast)
-    {
-        goto free_parser;
-    }
-
+    
     if (!err_is_ok(&lexer.err) || !err_is_ok(&parser.err))
     {
         err_print_stack_trace(&lexer.err);
@@ -58,6 +53,12 @@ int module_load(module_t* self, char const* path)
         err_push(&self->err, lexer.line, "invalid module");
         goto free_parser;
     }
+
+    if (!ast)
+    {
+        goto free_parser;
+    }
+
     compiler_t compiler;
     compiler_init(&compiler, self);
 
diff --git a/lib/node.h b/lib/node.h
index abb679d..dbba48c 100644
--- a/lib/node.h
+++ b/lib/node.h
@@ -11,7 +11,8 @@ G(NODE_POW), G(NODE_ADD), G(NODE_SUB), G(NODE_MUL), \
 G(NODE_DIV), G(NODE_MOD), G(NODE_COMMA), G(NODE_TUPLE), \
 G(NODE_ASSERT_EQ), G(NODE_ASSERT_NE), G(NODE_BOOL), \
 G(NODE_AND), G(NODE_OR), G(NODE_NOT), G(NODE_IN), \
-G(NODE_OSQUARE), G(NODE_CSQUARE), G(NODE_INDEX)
+G(NODE_OSQUARE), G(NODE_CSQUARE), G(NODE_INDEX), \
+G(NODE_STR)
 
 CCM_ENUM_H(NodeKind, NODE_KIND);
 
diff --git a/lib/parser.c b/lib/parser.c
index 186cfab..0903fe1 100644
--- a/lib/parser.c
+++ b/lib/parser.c
@@ -22,7 +22,14 @@ void parser_free(parser_t* self)
 node_t* parser_try_new_parse(parser_t* self)
 {
     assert(self);
-    return CCM_TRY(parser_try_new_module);
+    node_t* res = CCM_TRY(parser_try_new_module);
+
+    if (self->lexer->cursor < (ssize_t)strlen(self->lexer->source))
+    {
+        err_push(&self->err, res ? res->line : 0, "unexpected end");
+    }
+
+    return res;
 }
 
 node_t* parser_try_new_rule_ll1(parser_t* self,
@@ -427,6 +434,7 @@ node_t* parser_try_new_literal(parser_t* self)
             return tuple;
         }
 
+
         if (!lexer_consume_next(self->lexer, NODE_OPAR))
         {
             return NULL;
@@ -448,6 +456,13 @@ node_t* parser_try_new_literal(parser_t* self)
         return expr;
     }
 
+    if (lexer_peek_kind(self->lexer, NODE_STR, 0)
+        && lexer_peek_kind(self->lexer, NODE_OSQUARE, 1))
+    {
+        node_t* target = CCM_TRY(parser_try_new_builtin);
+        return CCM_TRY_LL1(parser_try_new_index, target);
+    }
+
     return CCM_TRY(parser_try_new_builtin);
 }
 
@@ -484,11 +499,6 @@ node_t* parser_try_new_index(parser_t* self, node_t* target)
     return node;
 }
 
-node_t* parser_try_new_expr_lst(parser_t* self)
-{
-    assert(self);
-}
-
 node_t* parser_try_new_tuple(parser_t* self)
 {
     assert(self);
@@ -554,6 +564,7 @@ node_t* parser_try_new_builtin(parser_t* self)
         (
             node->kind == NODE_NUM
             || node->kind == NODE_BOOL
+            || node->kind == NODE_STR
         )
     )
     {
diff --git a/lib/parser.h b/lib/parser.h
index f1b0e17..d75b796 100644
--- a/lib/parser.h
+++ b/lib/parser.h
@@ -36,7 +36,6 @@ node_t* parser_try_new_not(parser_t* self);
 node_t* parser_try_new_pow(parser_t* self);
 node_t* parser_try_new_literal(parser_t* self);
 node_t* parser_try_new_index(parser_t* self, node_t* target);
-node_t* parser_try_new_expr_lst(parser_t* self);
 node_t* parser_try_new_tuple(parser_t* self);
 node_t* parser_try_new_builtin(parser_t* self);
 
diff --git a/lib/type.h b/lib/type.h
index e9fb731..9f1a0eb 100644
--- a/lib/type.h
+++ b/lib/type.h
@@ -6,7 +6,8 @@
 #define TYPES(G) \
 G(TYPE_NUM), \
 G(TYPE_TUPLE), \
-G(TYPE_BOOLEAN)
+G(TYPE_BOOLEAN), \
+G(TYPE_STR)
 
 CCM_ENUM_H(Type, TYPES);
 
diff --git a/lib/value.c b/lib/value.c
index fb9af44..480007c 100644
--- a/lib/value.c
+++ b/lib/value.c
@@ -25,6 +25,16 @@ void value_init_boolean(value_t* self, int boolean, int line)
     self->line = line;
 }
 
+void value_init_str(value_t* self, char const* value, int line)
+{
+    assert(self);
+    assert(value);
+
+    self->data.str = strdup(value);
+    self->type = TYPE_STR;
+    self->line = line;
+}
+
 value_t* value_new_clone(value_t* self)
 {
     assert(self);
@@ -33,6 +43,9 @@ value_t* value_new_clone(value_t* self)
 
     switch (self->type)
     {
+        case TYPE_STR: {
+            value_init_str(value, self->data.str, self->line);
+        } break;
         case TYPE_NUM: {
             value_init_num(value, self->data.num, self->line);
         } break;
@@ -72,6 +85,11 @@ void value_free(value_t* self)
         vec_free(self->data.tuple);
         free(self->data.tuple);
     }
+
+    if (self->type == TYPE_STR)
+    {
+        free(self->data.str);
+    }
 }
 
 size_t value_str(value_t* self, char* buffer, size_t size)
@@ -82,6 +100,11 @@ size_t value_str(value_t* self, char* buffer, size_t size)
 
     switch (self->type)
     {
+        case TYPE_STR: {
+            sz += snprintf(buffer + sz, size - sz, "%s",
+                           self->data.str);
+        } break;
+
         case TYPE_NUM: {
             sz += snprintf(buffer + sz, size - sz, "%lf",
                            self->data.num);
@@ -129,6 +152,10 @@ int value_equals(value_t* self, value_t* rhs)
 
     switch (self->type)
     {
+        case TYPE_STR: {
+            return strcmp(self->data.str, rhs->data.str) == 0;
+        } break;
+
         case TYPE_NUM: {
             return self->data.num == rhs->data.num;
         } break;
diff --git a/lib/value.h b/lib/value.h
index c150d53..931d117 100644
--- a/lib/value.h
+++ b/lib/value.h
@@ -10,6 +10,7 @@ typedef struct {
         double num;
         vec_t* tuple;
         int boolean;
+        char* str;
     } data;
 
     Type type;
@@ -19,6 +20,7 @@ typedef struct {
 void value_init_num(value_t* self, double num, int line);
 void value_init_new_tuple(value_t* self, vec_t* values, int line);
 void value_init_boolean(value_t* self, int boolean, int line);
+void value_init_str(value_t* self, char const* value, int line);
 value_t* value_new_clone(value_t* self);
 void value_free(value_t* self);