Feature/strings (#75)

* The assembler supports string opcode

* disabled the string test until implmented

* strings can be printed

11 files changed, 757 insertions, 466 deletions

diff --git a/spasm/src/asm/assembler.cpp b/spasm/src/asm/assembler.cpp
index fadd747..1f69b1a 100644
--- a/spasm/src/asm/assembler.cpp
+++ b/spasm/src/asm/assembler.cpp
@@ -55,6 +55,23 @@ int get_arg_size(const Lexer::Token args[])
                 size = std::max(size, 3);
                 break;
             }
+            case Lexer::Token::StringValue:
+            {
+                const auto length = args[i].value_str().size();
+                if (length > 0xffffffff)
+                {
+                    size = std::max(size, 3);
+                }
+                else if (length > 0xffff)
+                {
+                    size = std::max(size, 2);
+                }
+                else if (length > 0xff)
+                {
+                    size = std::max(size, 1);
+                }
+                break;
+            }
             default:
                 break;
         }
@@ -125,6 +142,12 @@ void Assembler::assemble()
                     assert(args[1].type() == Lexer::Token::Ident);
                     assemble_identifier(args[1]);
                 }
+                else if (type == Lexer::Token::String)
+                {
+                    assert(args[1].type() == Lexer::Token::StringValue);
+                    const auto& s = args[1].value_str();
+                    _bytecode->push_string(s.data(), s.size(), arg_size);
+                }
                 else
                 {
                     if (args[1].type() == Lexer::Token::Integer)
diff --git a/spasm/src/asm/bytecode.cpp b/spasm/src/asm/bytecode.cpp
index cc250ba..70e16c9 100644
--- a/spasm/src/asm/bytecode.cpp
+++ b/spasm/src/asm/bytecode.cpp
@@ -100,6 +100,12 @@ void Bytecode_Memory::push_location(size_t location)
     }
 }
 
+void Bytecode_Memory::push_string(const char* s, size_t length, int size)
+{
+    push_integer(int64_t(length), size);
+    _bytecode.insert(_bytecode.end(), s, s + length);
+}
+
 const Bytecode_Memory::Bytecode& Bytecode_Memory::bytecode() const
 {
     return _bytecode;
diff --git a/spasm/src/asm/bytecode.hpp b/spasm/src/asm/bytecode.hpp
index fb80122..7d0d838 100644
--- a/spasm/src/asm/bytecode.hpp
+++ b/spasm/src/asm/bytecode.hpp
@@ -21,6 +21,7 @@ class Bytecode_Stream
     virtual void push_integer(int64_t, int size) = 0;
     virtual void push_double(double) = 0;
     virtual void push_location(size_t) = 0;
+    virtual void push_string(const char* s, size_t length, int size) = 0;
     virtual void set_location(size_t, size_t) = 0;
     virtual size_t size() const = 0;
 };  // class Bytecode_Stream
@@ -51,6 +52,7 @@ class Bytecode_Memory : public Bytecode_Stream
     virtual void push_double(double) override;
     virtual void push_location(size_t);
     virtual void set_location(size_t, size_t);
+    virtual void push_string(const char* s, size_t length, int size) override;
     virtual size_t size() const;
 
     typedef std::vector<Bytecode_Stream::byte> Bytecode;
diff --git a/spasm/src/asm/lexer.cpp b/spasm/src/asm/lexer.cpp
index 5be7836..996762c 100644
--- a/spasm/src/asm/lexer.cpp
+++ b/spasm/src/asm/lexer.cpp
@@ -1,4 +1,4 @@
-/* Generated by re2c 1.1.1 on Thu Nov 22 14:23:32 2018 */
+/* Generated by re2c 1.1.1 on Wed Nov 28 21:13:09 2018 */
 #line 1 "lexer.re"
 #include <iostream>
 
@@ -34,7 +34,7 @@ bool Lexer::tokenize(TokenStream& ts)
 #line 41 "lexer.cpp"
         {
             char yych;
-            if ((limit - cursor) < 6)
+            if ((limit - cursor) < 7)
                 return true;
             yych = *cursor;
             switch (yych)
@@ -45,12 +45,16 @@ bool Lexer::tokenize(TokenStream& ts)
                     goto yy6;
                 case ' ':
                     goto yy8;
-                case '#':
+                case '"':
                     goto yy11;
-                case '-':
+                case '#':
                     goto yy13;
+                case '\'':
+                    goto yy15;
+                case '-':
+                    goto yy17;
                 case '0':
-                    goto yy14;
+                    goto yy18;
                 case '1':
                 case '2':
                 case '3':
@@ -60,9 +64,9 @@ bool Lexer::tokenize(TokenStream& ts)
                 case '7':
                 case '8':
                 case '9':
-                    goto yy16;
+                    goto yy20;
                 case ':':
-                    goto yy18;
+                    goto yy22;
                 case 'A':
                 case 'B':
                 case 'C':
@@ -107,55 +111,55 @@ bool Lexer::tokenize(TokenStream& ts)
                 case 'x':
                 case 'y':
                 case 'z':
-                    goto yy20;
+                    goto yy24;
                 case 'a':
-                    goto yy23;
+                    goto yy27;
                 case 'c':
-                    goto yy24;
+                    goto yy28;
                 case 'd':
-                    goto yy25;
+                    goto yy29;
                 case 'j':
-                    goto yy26;
+                    goto yy30;
                 case 'l':
-                    goto yy27;
+                    goto yy31;
                 case 'm':
-                    goto yy28;
+                    goto yy32;
                 case 'p':
-                    goto yy29;
+                    goto yy33;
                 case 'r':
-                    goto yy30;
+                    goto yy34;
                 case 's':
-                    goto yy31;
+                    goto yy35;
                 default:
                     goto yy4;
             }
         yy2:
             ++cursor;
-#line 274 "lexer.re"
+#line 290 "lexer.re"
             {
                 ts.push_token(Token(Token::EndInput, lineno));
 
                 break;
             }
-#line 126 "lexer.cpp"
+#line 128 "lexer.cpp"
         yy4:
             ++cursor;
         yy5:
-#line 280 "lexer.re"
+#line 296 "lexer.re"
         {
             return false;
         }
-#line 134 "lexer.cpp"
+#line 136 "lexer.cpp"
         yy6:
             ++cursor;
-#line 267 "lexer.re"
+#line 283 "lexer.re"
             {
                 ++lineno;
                 token_start = cursor;
 
                 continue;
             }
-#line 144 "lexer.cpp"
+#line 146 "lexer.cpp"
         yy8:
             ++cursor;
             if (limit <= cursor)
@@ -169,13 +173,13 @@ bool Lexer::tokenize(TokenStream& ts)
                     goto yy10;
             }
         yy10:
-#line 251 "lexer.re"
+#line 267 "lexer.re"
         {
             token_start = cursor;
 
             continue;
         }
-#line 160 "lexer.cpp"
+#line 162 "lexer.cpp"
         yy11:
             ++cursor;
             if (limit <= cursor)
@@ -183,21 +187,49 @@ bool Lexer::tokenize(TokenStream& ts)
             yych = *cursor;
             switch (yych)
             {
-                case '\n':
-                    goto yy32;
+                case '"':
+                    goto yy36;
+                case '\\':
+                    goto yy38;
                 default:
                     goto yy11;
             }
         yy13:
+            ++cursor;
+            if (limit <= cursor)
+                return true;
+            yych = *cursor;
+            switch (yych)
+            {
+                case '\n':
+                    goto yy40;
+                default:
+                    goto yy13;
+            }
+        yy15:
+            ++cursor;
+            if (limit <= cursor)
+                return true;
+            yych = *cursor;
+            switch (yych)
+            {
+                case '\'':
+                    goto yy36;
+                case '\\':
+                    goto yy42;
+                default:
+                    goto yy15;
+            }
+        yy17:
             yych = *++cursor;
             switch (yych)
             {
                 case '0':
-                    goto yy34;
+                    goto yy44;
                 default:
                     goto yy5;
             }
-        yy14:
+        yy18:
             yych = *(marker = ++cursor);
             switch (yych)
             {
@@ -212,23 +244,23 @@ bool Lexer::tokenize(TokenStream& ts)
                 case '8':
                 case '9':
                 case ':':
-                    goto yy36;
+                    goto yy46;
                 case 'X':
                 case 'x':
-                    goto yy38;
+                    goto yy48;
                 default:
-                    goto yy15;
+                    goto yy19;
             }
-        yy15:
-#line 60 "lexer.re"
+        yy19:
+#line 62 "lexer.re"
         {
             ts.push_token(Token(Token::Integer, lineno, token_start, cursor));
             token_start = cursor;
 
             continue;
         }
-#line 202 "lexer.cpp"
-        yy16:
+#line 222 "lexer.cpp"
+        yy20:
             marker = ++cursor;
             if ((limit - cursor) < 2)
                 return true;
@@ -236,7 +268,7 @@ bool Lexer::tokenize(TokenStream& ts)
             switch (yych)
             {
                 case '.':
-                    goto yy39;
+                    goto yy49;
                 case '0':
                 case '1':
                 case '2':
@@ -247,27 +279,27 @@ bool Lexer::tokenize(TokenStream& ts)
                 case '7':
                 case '8':
                 case '9':
-                    goto yy16;
+                    goto yy20;
                 case ':':
-                    goto yy18;
+                    goto yy22;
                 default:
-                    goto yy15;
+                    goto yy19;
             }
-        yy18:
+        yy22:
             ++cursor;
-#line 256 "lexer.re"
+#line 272 "lexer.re"
             {
                 token_start = cursor;
 
                 continue;
             }
-#line 230 "lexer.cpp"
-        yy20:
+#line 250 "lexer.cpp"
+        yy24:
             ++cursor;
             if (limit <= cursor)
                 return true;
             yych = *cursor;
-        yy21:
+        yy25:
             switch (yych)
             {
                 case '0':
@@ -333,25 +365,25 @@ bool Lexer::tokenize(TokenStream& ts)
                 case 'x':
                 case 'y':
                 case 'z':
-                    goto yy20;
+                    goto yy24;
                 default:
-                    goto yy22;
+                    goto yy26;
             }
-        yy22:
-#line 243 "lexer.re"
+        yy26:
+#line 252 "lexer.re"
         {
             ts.push_token(Token(Token::Ident, lineno, token_start, cursor));
             token_start = cursor;
 
             continue;
         }
-#line 311 "lexer.cpp"
-        yy23:
+#line 331 "lexer.cpp"
+        yy27:
             yych = *++cursor;
             switch (yych)
             {
                 case '0':
-                    goto yy40;
+                    goto yy50;
                 case '1':
                 case '2':
                 case '3':
@@ -361,84 +393,84 @@ bool Lexer::tokenize(TokenStream& ts)
                 case '7':
                 case '8':
                 case '9':
-                    goto yy42;
+                    goto yy52;
                 case 'd':
-                    goto yy44;
+                    goto yy54;
                 default:
-                    goto yy21;
+                    goto yy25;
             }
-        yy24:
+        yy28:
             yych = *++cursor;
             switch (yych)
             {
                 case 'a':
-                    goto yy45;
+                    goto yy55;
                 case 'o':
-                    goto yy46;
+                    goto yy56;
                 default:
-                    goto yy21;
+                    goto yy25;
             }
-        yy25:
+        yy29:
             yych = *++cursor;
             switch (yych)
             {
                 case 'i':
-                    goto yy47;
+                    goto yy57;
                 case 'u':
-                    goto yy48;
+                    goto yy58;
                 default:
-                    goto yy21;
+                    goto yy25;
             }
-        yy26:
+        yy30:
             yych = *++cursor;
             switch (yych)
             {
                 case 'm':
-                    goto yy49;
+                    goto yy59;
                 default:
-                    goto yy21;
+                    goto yy25;
             }
-        yy27:
+        yy31:
             yych = *++cursor;
             switch (yych)
             {
                 case 'a':
-                    goto yy50;
+                    goto yy60;
                 case 'e':
-                    goto yy51;
+                    goto yy61;
                 default:
-                    goto yy21;
+                    goto yy25;
             }
-        yy28:
+        yy32:
             yych = *++cursor;
             switch (yych)
             {
                 case 'o':
-                    goto yy52;
+                    goto yy62;
                 case 'u':
-                    goto yy53;
+                    goto yy63;
                 default:
-                    goto yy21;
+                    goto yy25;
             }
-        yy29:
+        yy33:
             yych = *++cursor;
             switch (yych)
             {
                 case 'o':
-                    goto yy54;
+                    goto yy64;
                 case 'r':
-                    goto yy55;
+                    goto yy65;
                 case 'u':
-                    goto yy56;
+                    goto yy66;
                 default:
-                    goto yy21;
+                    goto yy25;
             }
-        yy30:
+        yy34:
             yych = *++cursor;
             switch (yych)
             {
                 case '0':
-                    goto yy57;
+                    goto yy67;
                 case '1':
                 case '2':
                 case '3':
@@ -448,40 +480,77 @@ bool Lexer::tokenize(TokenStream& ts)
                 case '7':
                 case '8':
                 case '9':
-                    goto yy59;
+                    goto yy69;
                 case 'e':
-                    goto yy61;
+                    goto yy71;
                 default:
-                    goto yy21;
+                    goto yy25;
             }
-        yy31:
+        yy35:
             yych = *++cursor;
             switch (yych)
             {
+                case 't':
+                    goto yy72;
                 case 'u':
-                    goto yy62;
+                    goto yy73;
                 default:
-                    goto yy21;
+                    goto yy25;
             }
-        yy32:
+        yy36:
+            ++cursor;
+#line 259 "lexer.re"
+            {
+                ts.push_token(Token(Token::StringValue, lineno, token_start + 1,
+                                    cursor - 1));
+                token_start = cursor;
+
+                continue;
+            }
+#line 423 "lexer.cpp"
+        yy38:
+            ++cursor;
+            if (limit <= cursor)
+                return true;
+            yych = *cursor;
+            switch (yych)
+            {
+                case '\\':
+                    goto yy38;
+                default:
+                    goto yy11;
+            }
+        yy40:
             ++cursor;
-#line 261 "lexer.re"
+#line 277 "lexer.re"
             {
                 ++lineno;
                 token_start = cursor;
 
                 continue;
             }
-#line 401 "lexer.cpp"
-        yy34:
+#line 441 "lexer.cpp"
+        yy42:
             ++cursor;
-            goto yy15;
-        yy35:
+            if (limit <= cursor)
+                return true;
+            yych = *cursor;
+            switch (yych)
+            {
+                case '\\':
+                    goto yy42;
+                default:
+                    goto yy15;
+            }
+        yy44:
+            ++cursor;
+            goto yy19;
+        yy45:
             ++cursor;
             if (limit <= cursor)
                 return true;
             yych = *cursor;
-        yy36:
+        yy46:
             switch (yych)
             {
                 case '0':
@@ -494,16 +563,16 @@ bool Lexer::tokenize(TokenStream& ts)
                 case '7':
                 case '8':
                 case '9':
-                    goto yy35;
+                    goto yy45;
                 case ':':
-                    goto yy18;
+                    goto yy22;
                 default:
-                    goto yy37;
+                    goto yy47;
             }
-        yy37:
+        yy47:
             cursor = marker;
-            goto yy15;
-        yy38:
+            goto yy19;
+        yy48:
             yych = *++cursor;
             switch (yych)
             {
@@ -529,16 +598,16 @@ bool Lexer::tokenize(TokenStream& ts)
                 case 'd':
                 case 'e':
                 case 'f':
-                    goto yy63;
+                    goto yy74;
                 default:
-                    goto yy37;
+                    goto yy47;
             }
-        yy39:
+        yy49:
             yych = *++cursor;
             switch (yych)
             {
                 case '0':
-                    goto yy66;
+                    goto yy77;
                 case '1':
                 case '2':
                 case '3':
@@ -548,11 +617,11 @@ bool Lexer::tokenize(TokenStream& ts)
                 case '7':
                 case '8':
                 case '9':
-                    goto yy68;
+                    goto yy79;
                 default:
-                    goto yy37;
+                    goto yy47;
             }
-        yy40:
+        yy50:
             yych = *++cursor;
             switch (yych)
             {
@@ -619,12 +688,12 @@ bool Lexer::tokenize(TokenStream& ts)
                 case 'x':
                 case 'y':
                 case 'z':
-                    goto yy20;
+                    goto yy24;
                 default:
-                    goto yy41;
+                    goto yy51;
             }
-        yy41:
-#line 84 "lexer.re"
+        yy51:
+#line 86 "lexer.re"
         {
             Token t(Token::Integer, lineno, token_start + 1, cursor);
             t.set_int(-t.value_int());
@@ -632,8 +701,8 @@ bool Lexer::tokenize(TokenStream& ts)
             token_start = cursor;
             continue;
         }
-#line 547 "lexer.cpp"
-        yy42:
+#line 595 "lexer.cpp"
+        yy52:
             ++cursor;
             if (limit <= cursor)
                 return true;
@@ -650,7 +719,7 @@ bool Lexer::tokenize(TokenStream& ts)
                 case '7':
                 case '8':
                 case '9':
-                    goto yy42;
+                    goto yy52;
                 case 'A':
                 case 'B':
                 case 'C':
@@ -704,130 +773,130 @@ bool Lexer::tokenize(TokenStream& ts)
                 case 'x':
                 case 'y':
                 case 'z':
-                    goto yy20;
+                    goto yy24;
                 default:
-                    goto yy41;
+                    goto yy51;
             }
-        yy44:
+        yy54:
             yych = *++cursor;
             switch (yych)
             {
                 case 'd':
-                    goto yy70;
+                    goto yy81;
                 default:
-                    goto yy21;
+                    goto yy25;
             }
-        yy45:
+        yy55:
             yych = *++cursor;
             switch (yych)
             {
                 case 'l':
-                    goto yy72;
+                    goto yy83;
                 default:
-                    goto yy21;
+                    goto yy25;
             }
-        yy46:
+        yy56:
             yych = *++cursor;
             switch (yych)
             {
                 case 'n':
-                    goto yy73;
+                    goto yy84;
                 default:
-                    goto yy21;
+                    goto yy25;
             }
-        yy47:
+        yy57:
             yych = *++cursor;
             switch (yych)
             {
                 case 'v':
-                    goto yy74;
+                    goto yy85;
                 default:
-                    goto yy21;
+                    goto yy25;
             }
-        yy48:
+        yy58:
             yych = *++cursor;
             switch (yych)
             {
                 case 'p':
-                    goto yy76;
+                    goto yy87;
                 default:
-                    goto yy21;
+                    goto yy25;
             }
-        yy49:
+        yy59:
             yych = *++cursor;
             switch (yych)
             {
                 case 'p':
-                    goto yy78;
+                    goto yy89;
                 default:
-                    goto yy21;
+                    goto yy25;
             }
-        yy50:
+        yy60:
             yych = *++cursor;
             switch (yych)
             {
                 case 'b':
-                    goto yy80;
+                    goto yy91;
                 default:
-                    goto yy21;
+                    goto yy25;
             }
-        yy51:
+        yy61:
             yych = *++cursor;
             switch (yych)
             {
                 case 'q':
-                    goto yy81;
+                    goto yy92;
                 case 's':
-                    goto yy83;
+                    goto yy94;
                 default:
-                    goto yy21;
+                    goto yy25;
             }
-        yy52:
+        yy62:
             yych = *++cursor;
             switch (yych)
             {
                 case 'd':
-                    goto yy84;
+                    goto yy95;
                 default:
-                    goto yy21;
+                    goto yy25;
             }
-        yy53:
+        yy63:
             yych = *++cursor;
             switch (yych)
             {
                 case 'l':
-                    goto yy86;
+                    goto yy97;
                 default:
-                    goto yy21;
+                    goto yy25;
             }
-        yy54:
+        yy64:
             yych = *++cursor;
             switch (yych)
             {
                 case 'p':
-                    goto yy88;
+                    goto yy99;
                 default:
-                    goto yy21;
+                    goto yy25;
             }
-        yy55:
+        yy65:
             yych = *++cursor;
             switch (yych)
             {
                 case 'i':
-                    goto yy90;
+                    goto yy101;
                 default:
-                    goto yy21;
+                    goto yy25;
             }
-        yy56:
+        yy66:
             yych = *++cursor;
             switch (yych)
             {
                 case 's':
-                    goto yy91;
+                    goto yy102;
                 default:
-                    goto yy21;
+                    goto yy25;
             }
-        yy57:
+        yy67:
             yych = *++cursor;
             switch (yych)
             {
@@ -894,12 +963,12 @@ bool Lexer::tokenize(TokenStream& ts)
                 case 'x':
                 case 'y':
                 case 'z':
-                    goto yy20;
+                    goto yy24;
                 default:
-                    goto yy58;
+                    goto yy68;
             }
-        yy58:
-#line 77 "lexer.re"
+        yy68:
+#line 79 "lexer.re"
         {
             ts.push_token(
                 Token(Token::Integer, lineno, token_start + 1, cursor));
@@ -907,8 +976,8 @@ bool Lexer::tokenize(TokenStream& ts)
 
             continue;
         }
-#line 774 "lexer.cpp"
-        yy59:
+#line 822 "lexer.cpp"
+        yy69:
             ++cursor;
             if (limit <= cursor)
                 return true;
@@ -925,7 +994,7 @@ bool Lexer::tokenize(TokenStream& ts)
                 case '7':
                 case '8':
                 case '9':
-                    goto yy59;
+                    goto yy69;
                 case 'A':
                 case 'B':
                 case 'C':
@@ -979,31 +1048,40 @@ bool Lexer::tokenize(TokenStream& ts)
                 case 'x':
                 case 'y':
                 case 'z':
-                    goto yy20;
+                    goto yy24;
                 default:
-                    goto yy58;
+                    goto yy68;
             }
-        yy61:
+        yy71:
             yych = *++cursor;
             switch (yych)
             {
                 case 'a':
-                    goto yy92;
+                    goto yy103;
                 case 't':
-                    goto yy93;
+                    goto yy104;
                 default:
-                    goto yy21;
+                    goto yy25;
             }
-        yy62:
+        yy72:
+            yych = *++cursor;
+            switch (yych)
+            {
+                case 'r':
+                    goto yy106;
+                default:
+                    goto yy25;
+            }
+        yy73:
             yych = *++cursor;
             switch (yych)
             {
                 case 'b':
-                    goto yy95;
+                    goto yy107;
                 default:
-                    goto yy21;
+                    goto yy25;
             }
-        yy63:
+        yy74:
             ++cursor;
             if (limit <= cursor)
                 return true;
@@ -1032,23 +1110,23 @@ bool Lexer::tokenize(TokenStream& ts)
                 case 'd':
                 case 'e':
                 case 'f':
-                    goto yy63;
+                    goto yy74;
                 default:
-                    goto yy65;
+                    goto yy76;
             }
-        yy65:
-#line 93 "lexer.re"
+        yy76:
+#line 95 "lexer.re"
         {
             ts.push_token(Token(Token::XInteger, lineno, token_start, cursor));
             token_start = cursor;
 
             continue;
         }
-#line 896 "lexer.cpp"
-        yy66:
+#line 950 "lexer.cpp"
+        yy77:
             ++cursor;
-        yy67:
-#line 68 "lexer.re"
+        yy78:
+#line 70 "lexer.re"
         {
             ts.push_token(
                 Token(Token::FloatingPoint, lineno, token_start, cursor));
@@ -1056,8 +1134,8 @@ bool Lexer::tokenize(TokenStream& ts)
 
             continue;
         }
-#line 909 "lexer.cpp"
-        yy68:
+#line 963 "lexer.cpp"
+        yy79:
             ++cursor;
             if (limit <= cursor)
                 return true;
@@ -1074,11 +1152,11 @@ bool Lexer::tokenize(TokenStream& ts)
                 case '7':
                 case '8':
                 case '9':
-                    goto yy68;
+                    goto yy79;
                 default:
-                    goto yy67;
+                    goto yy78;
             }
-        yy70:
+        yy81:
             yych = *++cursor;
             switch (yych)
             {
@@ -1145,38 +1223,38 @@ bool Lexer::tokenize(TokenStream& ts)
                 case 'x':
                 case 'y':
                 case 'z':
-                    goto yy20;
+                    goto yy24;
                 default:
-                    goto yy71;
+                    goto yy82;
             }
-        yy71:
-#line 147 "lexer.re"
+        yy82:
+#line 149 "lexer.re"
         {
             ts.push_token(Token(Token::Add, lineno));
             token_start = cursor;
 
             continue;
         }
-#line 1003 "lexer.cpp"
-        yy72:
+#line 1057 "lexer.cpp"
+        yy83:
             yych = *++cursor;
             switch (yych)
             {
                 case 'l':
-                    goto yy97;
+                    goto yy109;
                 default:
-                    goto yy21;
+                    goto yy25;
             }
-        yy73:
+        yy84:
             yych = *++cursor;
             switch (yych)
             {
                 case 's':
-                    goto yy99;
+                    goto yy111;
                 default:
-                    goto yy21;
+                    goto yy25;
             }
-        yy74:
+        yy85:
             yych = *++cursor;
             switch (yych)
             {
@@ -1243,20 +1321,20 @@ bool Lexer::tokenize(TokenStream& ts)
                 case 'x':
                 case 'y':
                 case 'z':
-                    goto yy20;
+                    goto yy24;
                 default:
-                    goto yy75;
+                    goto yy86;
             }
-        yy75:
-#line 168 "lexer.re"
+        yy86:
+#line 170 "lexer.re"
         {
             ts.push_token(Token(Token::Div, lineno));
             token_start = cursor;
 
             continue;
         }
-#line 1092 "lexer.cpp"
-        yy76:
+#line 1146 "lexer.cpp"
+        yy87:
             yych = *++cursor;
             switch (yych)
             {
@@ -1323,20 +1401,20 @@ bool Lexer::tokenize(TokenStream& ts)
                 case 'x':
                 case 'y':
                 case 'z':
-                    goto yy20;
+                    goto yy24;
                 default:
-                    goto yy77;
+                    goto yy88;
             }
-        yy77:
-#line 126 "lexer.re"
+        yy88:
+#line 128 "lexer.re"
         {
             ts.push_token(Token(Token::Dup, lineno));
             token_start = cursor;
 
             continue;
         }
-#line 1169 "lexer.cpp"
-        yy78:
+#line 1223 "lexer.cpp"
+        yy89:
             yych = *++cursor;
             switch (yych)
             {
@@ -1401,33 +1479,33 @@ bool Lexer::tokenize(TokenStream& ts)
                 case 'x':
                 case 'y':
                 case 'z':
-                    goto yy20;
+                    goto yy24;
                 case 'f':
-                    goto yy100;
+                    goto yy112;
                 case 't':
-                    goto yy102;
+                    goto yy114;
                 default:
-                    goto yy79;
+                    goto yy90;
             }
-        yy79:
-#line 196 "lexer.re"
+        yy90:
+#line 198 "lexer.re"
         {
             ts.push_token(Token(Token::Jump, lineno));
             token_start = cursor;
 
             continue;
         }
-#line 1246 "lexer.cpp"
-        yy80:
+#line 1300 "lexer.cpp"
+        yy91:
             yych = *++cursor;
             switch (yych)
             {
                 case 'e':
-                    goto yy104;
+                    goto yy116;
                 default:
-                    goto yy21;
+                    goto yy25;
             }
-        yy81:
+        yy92:
             yych = *++cursor;
             switch (yych)
             {
@@ -1494,29 +1572,29 @@ bool Lexer::tokenize(TokenStream& ts)
                 case 'x':
                 case 'y':
                 case 'z':
-                    goto yy20;
+                    goto yy24;
                 default:
-                    goto yy82;
+                    goto yy93;
             }
-        yy82:
-#line 223 "lexer.re"
+        yy93:
+#line 232 "lexer.re"
         {
             ts.push_token(Token(Token::LessEq, lineno));
             token_start = cursor;
 
             continue;
         }
-#line 1329 "lexer.cpp"
-        yy83:
+#line 1383 "lexer.cpp"
+        yy94:
             yych = *++cursor;
             switch (yych)
             {
                 case 's':
-                    goto yy105;
+                    goto yy117;
                 default:
-                    goto yy21;
+                    goto yy25;
             }
-        yy84:
+        yy95:
             yych = *++cursor;
             switch (yych)
             {
@@ -1583,20 +1661,20 @@ bool Lexer::tokenize(TokenStream& ts)
                 case 'x':
                 case 'y':
                 case 'z':
-                    goto yy20;
+                    goto yy24;
                 default:
-                    goto yy85;
+                    goto yy96;
             }
-        yy85:
-#line 175 "lexer.re"
+        yy96:
+#line 177 "lexer.re"
         {
             ts.push_token(Token(Token::Mod, lineno));
             token_start = cursor;
 
             continue;
         }
-#line 1412 "lexer.cpp"
-        yy86:
+#line 1466 "lexer.cpp"
+        yy97:
             yych = *++cursor;
             switch (yych)
             {
@@ -1663,20 +1741,20 @@ bool Lexer::tokenize(TokenStream& ts)
                 case 'x':
                 case 'y':
                 case 'z':
-                    goto yy20;
+                    goto yy24;
                 default:
-                    goto yy87;
+                    goto yy98;
             }
-        yy87:
-#line 161 "lexer.re"
+        yy98:
+#line 163 "lexer.re"
         {
             ts.push_token(Token(Token::Mul, lineno));
             token_start = cursor;
 
             continue;
         }
-#line 1489 "lexer.cpp"
-        yy88:
+#line 1543 "lexer.cpp"
+        yy99:
             yych = *++cursor;
             switch (yych)
             {
@@ -1742,49 +1820,49 @@ bool Lexer::tokenize(TokenStream& ts)
                 case 'x':
                 case 'y':
                 case 'z':
-                    goto yy20;
+                    goto yy24;
                 case 'r':
-                    goto yy107;
+                    goto yy119;
                 default:
-                    goto yy89;
+                    goto yy100;
             }
-        yy89:
-#line 113 "lexer.re"
+        yy100:
+#line 115 "lexer.re"
         {
             ts.push_token(Token(Token::Pop, lineno));
             token_start = cursor;
 
             continue;
         }
-#line 1566 "lexer.cpp"
-        yy90:
+#line 1620 "lexer.cpp"
+        yy101:
             yych = *++cursor;
             switch (yych)
             {
                 case 'n':
-                    goto yy109;
+                    goto yy121;
                 default:
-                    goto yy21;
+                    goto yy25;
             }
-        yy91:
+        yy102:
             yych = *++cursor;
             switch (yych)
             {
                 case 'h':
-                    goto yy110;
+                    goto yy122;
                 default:
-                    goto yy21;
+                    goto yy25;
             }
-        yy92:
+        yy103:
             yych = *++cursor;
             switch (yych)
             {
                 case 'd':
-                    goto yy112;
+                    goto yy124;
                 default:
-                    goto yy21;
+                    goto yy25;
             }
-        yy93:
+        yy104:
             yych = *++cursor;
             switch (yych)
             {
@@ -1851,20 +1929,29 @@ bool Lexer::tokenize(TokenStream& ts)
                 case 'x':
                 case 'y':
                 case 'z':
-                    goto yy20;
+                    goto yy24;
                 default:
-                    goto yy94;
+                    goto yy105;
             }
-        yy94:
-#line 216 "lexer.re"
+        yy105:
+#line 225 "lexer.re"
         {
             ts.push_token(Token(Token::Ret, lineno));
             token_start = cursor;
 
             continue;
         }
-#line 1661 "lexer.cpp"
-        yy95:
+#line 1715 "lexer.cpp"
+        yy106:
+            yych = *++cursor;
+            switch (yych)
+            {
+                case 'i':
+                    goto yy126;
+                default:
+                    goto yy25;
+            }
+        yy107:
             yych = *++cursor;
             switch (yych)
             {
@@ -1931,20 +2018,20 @@ bool Lexer::tokenize(TokenStream& ts)
                 case 'x':
                 case 'y':
                 case 'z':
-                    goto yy20;
+                    goto yy24;
                 default:
-                    goto yy96;
+                    goto yy108;
             }
-        yy96:
-#line 154 "lexer.re"
+        yy108:
+#line 156 "lexer.re"
         {
             ts.push_token(Token(Token::Sub, lineno));
             token_start = cursor;
 
             continue;
         }
-#line 1738 "lexer.cpp"
-        yy97:
+#line 1798 "lexer.cpp"
+        yy109:
             yych = *++cursor;
             switch (yych)
             {
@@ -2011,29 +2098,29 @@ bool Lexer::tokenize(TokenStream& ts)
                 case 'x':
                 case 'y':
                 case 'z':
-                    goto yy20;
+                    goto yy24;
                 default:
-                    goto yy98;
+                    goto yy110;
             }
-        yy98:
-#line 209 "lexer.re"
+        yy110:
+#line 218 "lexer.re"
         {
             ts.push_token(Token(Token::Call, lineno));
             token_start = cursor;
 
             continue;
         }
-#line 1815 "lexer.cpp"
-        yy99:
+#line 1875 "lexer.cpp"
+        yy111:
             yych = *++cursor;
             switch (yych)
             {
                 case 't':
-                    goto yy114;
+                    goto yy127;
                 default:
-                    goto yy21;
+                    goto yy25;
             }
-        yy100:
+        yy112:
             yych = *++cursor;
             switch (yych)
             {
@@ -2100,20 +2187,20 @@ bool Lexer::tokenize(TokenStream& ts)
                 case 'x':
                 case 'y':
                 case 'z':
-                    goto yy20;
+                    goto yy24;
                 default:
-                    goto yy101;
+                    goto yy113;
             }
-        yy101:
-#line 189 "lexer.re"
+        yy113:
+#line 191 "lexer.re"
         {
             ts.push_token(Token(Token::JumpF, lineno));
             token_start = cursor;
 
             continue;
         }
-#line 1898 "lexer.cpp"
-        yy102:
+#line 1958 "lexer.cpp"
+        yy114:
             yych = *++cursor;
             switch (yych)
             {
@@ -2180,29 +2267,29 @@ bool Lexer::tokenize(TokenStream& ts)
                 case 'x':
                 case 'y':
                 case 'z':
-                    goto yy20;
+                    goto yy24;
                 default:
-                    goto yy103;
+                    goto yy115;
             }
-        yy103:
-#line 182 "lexer.re"
+        yy115:
+#line 184 "lexer.re"
         {
             ts.push_token(Token(Token::JumpT, lineno));
             token_start = cursor;
 
             continue;
         }
-#line 1975 "lexer.cpp"
-        yy104:
+#line 2035 "lexer.cpp"
+        yy116:
             yych = *++cursor;
             switch (yych)
             {
                 case 'l':
-                    goto yy116;
+                    goto yy129;
                 default:
-                    goto yy21;
+                    goto yy25;
             }
-        yy105:
+        yy117:
             yych = *++cursor;
             switch (yych)
             {
@@ -2269,20 +2356,20 @@ bool Lexer::tokenize(TokenStream& ts)
                 case 'x':
                 case 'y':
                 case 'z':
-                    goto yy20;
+                    goto yy24;
                 default:
-                    goto yy106;
+                    goto yy118;
             }
-        yy106:
-#line 229 "lexer.re"
+        yy118:
+#line 238 "lexer.re"
         {
             ts.push_token(Token(Token::Less, lineno));
             token_start = cursor;
 
             continue;
         }
-#line 2058 "lexer.cpp"
-        yy107:
+#line 2118 "lexer.cpp"
+        yy119:
             yych = *++cursor;
             switch (yych)
             {
@@ -2349,29 +2436,29 @@ bool Lexer::tokenize(TokenStream& ts)
                 case 'x':
                 case 'y':
                 case 'z':
-                    goto yy20;
+                    goto yy24;
                 default:
-                    goto yy108;
+                    goto yy120;
             }
-        yy108:
-#line 119 "lexer.re"
+        yy120:
+#line 121 "lexer.re"
         {
             ts.push_token(Token(Token::PopTo, lineno));
             token_start = cursor;
 
             continue;
         }
-#line 2135 "lexer.cpp"
-        yy109:
+#line 2195 "lexer.cpp"
+        yy121:
             yych = *++cursor;
             switch (yych)
             {
                 case 't':
-                    goto yy118;
+                    goto yy131;
                 default:
-                    goto yy21;
+                    goto yy25;
             }
-        yy110:
+        yy122:
             yych = *++cursor;
             switch (yych)
             {
@@ -2437,22 +2524,22 @@ bool Lexer::tokenize(TokenStream& ts)
                 case 'x':
                 case 'y':
                 case 'z':
-                    goto yy20;
+                    goto yy24;
                 case 'r':
-                    goto yy120;
+                    goto yy133;
                 default:
-                    goto yy111;
+                    goto yy123;
             }
-        yy111:
-#line 107 "lexer.re"
+        yy123:
+#line 109 "lexer.re"
         {
             ts.push_token(Token(Token::Push, lineno));
             token_start = cursor;
 
             continue;
         }
-#line 2218 "lexer.cpp"
-        yy112:
+#line 2278 "lexer.cpp"
+        yy124:
             yych = *++cursor;
             switch (yych)
             {
@@ -2519,20 +2606,29 @@ bool Lexer::tokenize(TokenStream& ts)
                 case 'x':
                 case 'y':
                 case 'z':
-                    goto yy20;
+                    goto yy24;
                 default:
-                    goto yy113;
+                    goto yy125;
             }
-        yy113:
-#line 133 "lexer.re"
+        yy125:
+#line 135 "lexer.re"
         {
             ts.push_token(Token(Token::Read, lineno));
             token_start = cursor;
 
             continue;
         }
-#line 2295 "lexer.cpp"
-        yy114:
+#line 2355 "lexer.cpp"
+        yy126:
+            yych = *++cursor;
+            switch (yych)
+            {
+                case 'n':
+                    goto yy135;
+                default:
+                    goto yy25;
+            }
+        yy127:
             yych = *++cursor;
             switch (yych)
             {
@@ -2599,20 +2695,20 @@ bool Lexer::tokenize(TokenStream& ts)
                 case 'x':
                 case 'y':
                 case 'z':
-                    goto yy20;
+                    goto yy24;
                 default:
-                    goto yy115;
+                    goto yy128;
             }
-        yy115:
-#line 202 "lexer.re"
+        yy128:
+#line 204 "lexer.re"
         {
             ts.push_token(Token(Token::Const, lineno));
             token_start = cursor;
 
             continue;
         }
-#line 2372 "lexer.cpp"
-        yy116:
+#line 2438 "lexer.cpp"
+        yy129:
             yych = *++cursor;
             switch (yych)
             {
@@ -2679,20 +2775,20 @@ bool Lexer::tokenize(TokenStream& ts)
                 case 'x':
                 case 'y':
                 case 'z':
-                    goto yy20;
+                    goto yy24;
                 default:
-                    goto yy117;
+                    goto yy130;
             }
-        yy117:
-#line 236 "lexer.re"
+        yy130:
+#line 245 "lexer.re"
         {
             ts.push_token(Token(Token::Label, lineno));
             token_start = cursor;
 
             continue;
         }
-#line 2449 "lexer.cpp"
-        yy118:
+#line 2515 "lexer.cpp"
+        yy131:
             yych = *++cursor;
             switch (yych)
             {
@@ -2759,20 +2855,20 @@ bool Lexer::tokenize(TokenStream& ts)
                 case 'x':
                 case 'y':
                 case 'z':
-                    goto yy20;
+                    goto yy24;
                 default:
-                    goto yy119;
+                    goto yy132;
             }
-        yy119:
-#line 140 "lexer.re"
+        yy132:
+#line 142 "lexer.re"
         {
             ts.push_token(Token(Token::Print, lineno));
             token_start = cursor;
 
             continue;
         }
-#line 2526 "lexer.cpp"
-        yy120:
+#line 2592 "lexer.cpp"
+        yy133:
             yych = *++cursor;
             switch (yych)
             {
@@ -2839,21 +2935,110 @@ bool Lexer::tokenize(TokenStream& ts)
                 case 'x':
                 case 'y':
                 case 'z':
-                    goto yy20;
+                    goto yy24;
                 default:
-                    goto yy121;
+                    goto yy134;
             }
-        yy121:
-#line 101 "lexer.re"
+        yy134:
+#line 103 "lexer.re"
         {
             ts.push_token(Token(Token::PushFrom, lineno));
             token_start = cursor;
 
             continue;
         }
-#line 2603 "lexer.cpp"
+#line 2669 "lexer.cpp"
+        yy135:
+            yych = *++cursor;
+            switch (yych)
+            {
+                case 'g':
+                    goto yy136;
+                default:
+                    goto yy25;
+            }
+        yy136:
+            yych = *++cursor;
+            switch (yych)
+            {
+                case '0':
+                case '1':
+                case '2':
+                case '3':
+                case '4':
+                case '5':
+                case '6':
+                case '7':
+                case '8':
+                case '9':
+                case 'A':
+                case 'B':
+                case 'C':
+                case 'D':
+                case 'E':
+                case 'F':
+                case 'G':
+                case 'H':
+                case 'I':
+                case 'J':
+                case 'K':
+                case 'L':
+                case 'M':
+                case 'N':
+                case 'O':
+                case 'P':
+                case 'Q':
+                case 'R':
+                case 'S':
+                case 'T':
+                case 'U':
+                case 'V':
+                case 'W':
+                case 'X':
+                case 'Y':
+                case 'Z':
+                case '_':
+                case 'a':
+                case 'b':
+                case 'c':
+                case 'd':
+                case 'e':
+                case 'f':
+                case 'g':
+                case 'h':
+                case 'i':
+                case 'j':
+                case 'k':
+                case 'l':
+                case 'm':
+                case 'n':
+                case 'o':
+                case 'p':
+                case 'q':
+                case 'r':
+                case 's':
+                case 't':
+                case 'u':
+                case 'v':
+                case 'w':
+                case 'x':
+                case 'y':
+                case 'z':
+                    goto yy24;
+                default:
+                    goto yy137;
+            }
+        yy137:
+#line 211 "lexer.re"
+        {
+            ts.push_token(Token(Token::String, lineno));
+            token_start = cursor;
+
+            continue;
+        }
+#line 2752 "lexer.cpp"
         }
-#line 284 "lexer.re"
+#line 300 "lexer.re"
     }
     return true;
 }
diff --git a/spasm/src/asm/lexer.re b/spasm/src/asm/lexer.re
index fabeaf7..bdf792d 100644
--- a/spasm/src/asm/lexer.re
+++ b/spasm/src/asm/lexer.re
@@ -56,6 +56,8 @@ NONNEGATIVE     = "0" | ([1-9] DIGIT*) ;
 XINTEGER        = "0" [xX] XDIGIT+ ;
 FLOATING        = "-"? "0" | ([1-9] DIGIT*) "." NONNEGATIVE ;
 IDENTIFIER      = [a-zA-Z_] [0-9a-zA-Z_]* ;
+SSTRING         = "'" ([^']|"\\'")* "'" ;
+DSTRING         = "\"" ([^"]|"\\\"")* "\"" ;
 
 INTEGER         {
                                 ts.push_token (Token (Token::Integer, lineno,
@@ -198,13 +200,20 @@ XINTEGER        {
                                 token_start = cursor;
 
                                 continue;
-                        }
+                }
 "const"         {
                                 ts.push_token (Token (Token::Const, lineno));
                                 token_start = cursor;
 
                                 continue;
-                        }
+                }
+
+"string"        {
+                                ts.push_token (Token (Token::String, lineno));
+                                token_start = cursor;
+
+                                continue;
+                }
 
 "call"          {
                                 ts.push_token (Token (Token::Call, lineno));
@@ -247,6 +256,13 @@ IDENTIFIER      {
 
                                 continue;
                         }
+SSTRING | DSTRING      {
+                                ts.push_token (Token (Token::StringValue, lineno, token_start + 1,
+                                                        cursor - 1));
+                                token_start = cursor;
+
+                                continue;
+                        }
 
 [       ]+              {
                                 token_start = cursor;
diff --git a/spasm/src/asm/token.cpp b/spasm/src/asm/token.cpp
index fa612e3..7582892 100644
--- a/spasm/src/asm/token.cpp
+++ b/spasm/src/asm/token.cpp
@@ -36,6 +36,7 @@ Token::Token(Token::Token_type type,
             break;
         }
         case Ident:
+        case StringValue:
         {
             if (end)
             {
diff --git a/spasm/src/asm/token.hpp b/spasm/src/asm/token.hpp
index 8f18768..2e69108 100644
--- a/spasm/src/asm/token.hpp
+++ b/spasm/src/asm/token.hpp
@@ -31,6 +31,7 @@ class Token
         JumpT = _TwoArgBegin,
         JumpF,
         Const,
+        String,
         _ThreeArgBegin,
         Add = _ThreeArgBegin,
         Sub,
@@ -46,6 +47,7 @@ class Token
         Integer,
         XInteger,
         FloatingPoint,
+        StringValue,
         EndInput,
         NotUsed
     };
diff --git a/spasm/src/spasm.cpp b/spasm/src/spasm.cpp
index 63e09a0..6a62c90 100644
--- a/spasm/src/spasm.cpp
+++ b/spasm/src/spasm.cpp
@@ -131,6 +131,13 @@ Spasm::RunResult Spasm::run()
                 set_local(reg, value);
                 break;
             }
+            case OpCodes::String:
+            {
+                const auto reg = read_reg(size);
+                const auto value = read_string(size);
+                set_local(reg, value);
+                break;
+            }
             case OpCodes::Add:
             {
                 const auto arg0 = read_reg(size);
@@ -461,6 +468,16 @@ void Spasm::push_data(data_t data)
 
 reg_t Spasm::read_reg(size_t size)
 {
+    return read_integer(size);
+}
+
+data_t Spasm::read_number(size_t size)
+{
+    return data_t(double(read_integer(size)));
+}
+
+int64_t Spasm::read_integer(size_t size)
+{
     switch (size)
     {
         case 0:
@@ -488,33 +505,13 @@ reg_t Spasm::read_reg(size_t size)
     return 0;
 }
 
-data_t Spasm::read_number(size_t size)
+data_t Spasm::read_string(size_t size)
 {
-    switch (size)
-    {
-        case 0:
-            return data_t(double(m_ByteCode[m_PC++]));
-        case 1:
-        {
-            auto result = *reinterpret_cast<int16_t*>(&m_ByteCode[0] + m_PC);
-            m_PC += 2;
-            return data_t(double(result));
-        }
-        case 2:
-        {
-            auto result = *reinterpret_cast<int32_t*>(&m_ByteCode[0] + m_PC);
-            m_PC += 4;
-            return data_t(double(result));
-        }
-        case 3:
-        {
-            auto result = *reinterpret_cast<double*>(&m_ByteCode[0] + m_PC);
-            m_PC += 8;
-            return data_t(double(result));
-        }
-    }
-    assert(false && "not reached");
-    return data_t{};
+    const auto length = read_integer(size);
+    const auto s = reinterpret_cast<const char*>(&m_ByteCode[m_PC]);
+    m_PC += length;
+    const auto value = m_Strings.Get(s, length);
+    return data_t(::Spasm::ValueType::String, (void*)value);
 }
 
 }  // namespace SpasmImpl
diff --git a/spasm/src/spasm_impl.hpp b/spasm/src/spasm_impl.hpp
index 2548828..04e809a 100644
--- a/spasm/src/spasm_impl.hpp
+++ b/spasm/src/spasm_impl.hpp
@@ -3,6 +3,7 @@
 
 #include <iostream>
 
+#include <unordered_set>
 #include "types.hpp"
 
 namespace SpasmImpl
@@ -23,6 +24,7 @@ enum OpCodes : char
     JumpT,
     JumpF,
     Const,
+    String,
     Add,
     Sub,
     Mul,
@@ -30,14 +32,29 @@ enum OpCodes : char
     Mod,
     Less,
     LessEq,
-	Greater,
-	GreaterEq,
-	Equal,
-	NotEqual,
+    Greater,
+    GreaterEq,
+    Equal,
+    NotEqual,
     LastIndex = NotEqual,
 };
 static_assert(LastIndex < 0x3f, "Too many opcodes");
 
+class StringTable
+{
+   public:
+    const SPStringValue* Get(const char* s, size_t length)
+    {
+        SPString v(s, length);
+        auto pos = m_Strings.insert(SPStringValue(v));
+        return &(*pos.first);
+    }
+
+   private:
+    typedef std::unordered_set<SPStringValue> StringMap;
+    StringMap m_Strings;
+};
+
 //! The Abstract Stack Machine
 /*!
 ** The machine contains a data stack for operations and control flow and
@@ -93,6 +110,8 @@ class Spasm
     //! Stack for function frames
     FrameStack m_Frames;
 
+    StringTable m_Strings;
+
     //! Input stream for read () operation
     std::istream* istr;
 
@@ -125,11 +144,11 @@ class Spasm
     void less(reg_t a0, reg_t a1, reg_t a2);
     void lesseq(reg_t a0, reg_t a1, reg_t a2);
 
-	void greater(reg_t a0, reg_t a1, reg_t a2);
-	void greatereq(reg_t a0, reg_t a1, reg_t a2);
+    void greater(reg_t a0, reg_t a1, reg_t a2);
+    void greatereq(reg_t a0, reg_t a1, reg_t a2);
 
-	void equal(reg_t a0, reg_t a1, reg_t a2);
-	void not_equal(reg_t a0, reg_t a1, reg_t a2);
+    void equal(reg_t a0, reg_t a1, reg_t a2);
+    void not_equal(reg_t a0, reg_t a1, reg_t a2);
 
     data_t get_local(reg_t reg);
     void set_local(reg_t reg, data_t data);
@@ -137,6 +156,8 @@ class Spasm
     void push_data(data_t);
     reg_t read_reg(size_t size);
     data_t read_number(size_t size);
+    int64_t read_integer(size_t size);
+    data_t read_string(size_t size);
 };
 
 }  // namespace SpasmImpl
diff --git a/spasm/src/string.hpp b/spasm/src/string.hpp
new file mode 100644
index 0000000..8ffb214
--- /dev/null
+++ b/spasm/src/string.hpp
@@ -0,0 +1,43 @@
+#pragma once
+
+#include <string>
+
+namespace SpasmImpl
+{
+typedef std::string SPString;
+
+class SPStringValue
+{
+   public:
+    explicit SPStringValue(SPString s) : m_Value(std::move(s)) {}
+
+    SPStringValue(const SPStringValue&) = delete;
+    SPStringValue(SPStringValue&&) = default;
+    SPStringValue& operator=(const SPStringValue&) = delete;
+    SPStringValue& operator=(SPStringValue&&) = default;
+
+    const SPString& GetValue() const { return m_Value; }
+
+    bool operator==(const SPStringValue& rhs) const
+    {
+        return m_Value == rhs.m_Value;
+    }
+
+    bool operator==(const SPString& rhs) const { return m_Value == rhs; }
+
+   private:
+    SPString m_Value;
+};
+}  // namespace SpasmImpl
+
+namespace std
+{
+template <>
+struct hash<SpasmImpl::SPStringValue>
+{
+    size_t operator()(const SpasmImpl::SPStringValue& v) const
+    {
+        return std::hash<SpasmImpl::SPString>{}(v.GetValue());
+    }
+};
+}  // namespace std
\ No newline at end of file
diff --git a/spasm/src/value.hpp b/spasm/src/value.hpp
index 6569721..d86c0ef 100644
--- a/spasm/src/value.hpp
+++ b/spasm/src/value.hpp
@@ -1,81 +1,66 @@
 #pragma once
 
 #include <cassert>
+#include "string.hpp"
 
 namespace Spasm
 {
-	enum class ValueType
-	{
-		Number,
-		Null,
-		Undefined,
-		Boolean,
-		String,
-		Array,
-		Object,
-		Function,
-	};
+enum class ValueType
+{
+    Number,
+    Null,
+    Undefined,
+    Boolean,
+    String,
+    Array,
+    Object,
+    Function,
+};
 
-	static_assert(int(ValueType::Function) < 8, "Too many types");
+static_assert(int(ValueType::Function) < 8, "Too many types");
 
 struct Value
 {
-	Value()
-	{
-		m_value.as_double = 0.0;
-	}
-
-    explicit Value(double v)
-    {
-        m_value.as_double = v;
-    }
+    Value() { m_value.as_double = 0.0; }
 
-	explicit Value(bool v)
-		: Value(ValueType::Boolean, (size_t)v)
+    explicit Value(double v) { m_value.as_double = v; }
 
-	{
-	}
+    explicit Value(bool v) : Value(ValueType::Boolean, (size_t)v) {}
 
-	Value(ValueType tag, size_t payload)
-	{
-		assert(tag != ValueType::Number && "Zero tag is plain double");
-		assert(!(payload >> 48) && "Use only pointers to the heap.");
-		m_value.as_pointer.pointer = payload;
-		m_value.as_pointer.tag = size_t(tag);
-		m_value.as_pointer.nan = 0x1fff;
-	}
-
-    Value(ValueType tag, void* pointer)
-		: Value(tag, (size_t)pointer)
+    Value(ValueType tag, size_t payload)
     {
+        assert(tag != ValueType::Number && "Zero tag is plain double");
+        assert(!(payload >> 48) && "Use only pointers to the heap.");
+        m_value.as_pointer.pointer = payload;
+        m_value.as_pointer.tag = size_t(tag);
+        m_value.as_pointer.nan = 0x1fff;
     }
 
+    Value(ValueType tag, void* pointer) : Value(tag, (size_t)pointer) {}
+
     struct NanPointer
     {
-        size_t pointer:48;
-        size_t tag:3;
-        size_t nan:13;
+        size_t pointer : 48;
+        size_t tag : 3;
+        size_t nan : 13;
     };
 
     struct CheckType
     {
-        size_t payload: 48;
-        size_t check:16;
+        size_t payload : 48;
+        size_t check : 16;
     };
     union {
         double as_double;
         NanPointer as_pointer;
         CheckType to_check;
-		size_t as_int64;
+        size_t as_int64;
     } m_value;
 
     static_assert(sizeof(size_t) == 8, "unsupported arch");
     static_assert(sizeof(double) == 8, "unsupported arch");
 
-    bool is_double() const
-    {
-        return m_value.to_check.check <= 0xFFF8;
-    }
+    bool is_double() const { return m_value.to_check.check <= 0xFFF8; }
 
     double get_double() const
     {
@@ -83,99 +68,109 @@ struct Value
         return m_value.as_double;
     }
 
-    ValueType get_type() const {
-        return is_double()? ValueType::Number : ValueType(m_value.as_pointer.tag);
+    ValueType get_type() const
+    {
+        return is_double() ? ValueType::Number
+                           : ValueType(m_value.as_pointer.tag);
     }
 
-    void* get_pointer() const {
-        return (void*)(size_t) m_value.as_pointer.pointer;
+    void* get_pointer() const
+    {
+        return (void*)(size_t)m_value.as_pointer.pointer;
     }
 
-	bool get_boolean() const {
-		assert(get_type() == ValueType::Boolean);
-		return m_value.as_pointer.pointer != 0;
-	}
-
-	explicit operator bool() const {
-		// NaN will be true. Assume that is ok.
-		return (get_type() != ValueType::Boolean && m_value.as_int64 != 0) || get_boolean();
-	}
+    bool get_boolean() const
+    {
+        assert(get_type() == ValueType::Boolean);
+        return m_value.as_pointer.pointer != 0;
+    }
 
+    explicit operator bool() const
+    {
+        // NaN will be true. Assume that is ok.
+        return (get_type() != ValueType::Boolean && m_value.as_int64 != 0) ||
+               get_boolean();
+    }
 };
 
 inline std::istream& operator>>(std::istream& input, Value& value)
 {
-	return input >> value.m_value.as_double;
+    return input >> value.m_value.as_double;
 }
 
 inline std::ostream& operator<<(std::ostream& output, const Value& value)
 {
-	switch (value.get_type())

-	{

-	case ValueType::Number:

-		return output << value.m_value.as_double;
-	case ValueType::Boolean:

-		return output << bool(value);
-	default:
-		break;

-	}
-	return output;
+    switch (value.get_type())
+    {
+        case ValueType::Number:
+            return output << value.m_value.as_double;
+        case ValueType::Boolean:
+            return output << bool(value);
+        case ValueType::String:
+        {
+            const auto s = static_cast<const SpasmImpl::SPStringValue*>(
+                value.get_pointer());
+            return output << s->GetValue();
+        }
+        default:
+            break;
+    }
+    return output;
 }
 
 inline Value operator+(const Value& lhs, const Value& rhs)
 {
-	return Value(lhs.get_double() + rhs.get_double());
+    return Value(lhs.get_double() + rhs.get_double());
 }
 
 inline Value operator-(const Value& lhs, const Value& rhs)
 {
-	return Value(lhs.get_double() - rhs.get_double());
+    return Value(lhs.get_double() - rhs.get_double());
 }
 
 inline Value operator*(const Value& lhs, const Value& rhs)
 {
-	return Value(lhs.get_double() * rhs.get_double());
+    return Value(lhs.get_double() * rhs.get_double());
 }
 
 inline Value operator/(const Value& lhs, const Value& rhs)
 {
-	return Value(lhs.get_double() / rhs.get_double());
+    return Value(lhs.get_double() / rhs.get_double());
 }
 
 inline Value operator%(const Value& lhs, const Value& rhs)
 {
-	return Value(double(int64_t(lhs.get_double()) % int64_t(rhs.get_double())));
+    return Value(double(int64_t(lhs.get_double()) % int64_t(rhs.get_double())));
 }
 
-
 inline Value operator<(const Value& lhs, const Value& rhs)
 {
-	return Value(lhs.get_double() < rhs.get_double());
+    return Value(lhs.get_double() < rhs.get_double());
 }
 
 inline Value operator>(const Value& lhs, const Value& rhs)
 {
-	return Value(lhs.get_double() > rhs.get_double());
+    return Value(lhs.get_double() > rhs.get_double());
 }
 
 inline Value operator<=(const Value& lhs, const Value& rhs)
 {
-	return Value(lhs.get_double() <= rhs.get_double());
+    return Value(lhs.get_double() <= rhs.get_double());
 }
 
 inline Value operator>=(const Value& lhs, const Value& rhs)
 {
-	return Value(lhs.get_double() >= rhs.get_double());
+    return Value(lhs.get_double() >= rhs.get_double());
 }
 
 inline Value operator==(const Value& lhs, const Value& rhs)
 {
-	return Value(lhs.get_double() == rhs.get_double());
+    return Value(lhs.get_double() == rhs.get_double());
 }
 
 inline Value operator!=(const Value& lhs, const Value& rhs)
 {
-	return Value(lhs.get_double() != rhs.get_double());
+    return Value(lhs.get_double() != rhs.get_double());
 }
 
-}
\ No newline at end of file
+}  // namespace Spasm
\ No newline at end of file