From a54f5dd3f9e1bd1227e36da438d8cd5432d441a3 Mon Sep 17 00:00:00 2001
From: Eduardo Bart <edub4rt@gmail.com>
Date: Sun, 22 May 2011 00:56:58 -0300
Subject: [PATCH] FML emitter

---
 src/framework/core/configs.cpp |   9 +-
 src/framework/core/resources.h |   1 +
 src/framework/util/fml.cpp     | 422 ++++++++++++---------------------
 src/framework/util/fml.h       | 245 ++++++++++---------
 4 files changed, 281 insertions(+), 396 deletions(-)

diff --git a/src/framework/core/configs.cpp b/src/framework/core/configs.cpp
index f5bff931..77ffb6c5 100644
--- a/src/framework/core/configs.cpp
+++ b/src/framework/core/configs.cpp
@@ -53,11 +53,10 @@ bool Configs::load(const std::string& fileName)
 void Configs::save()
 {
     if(!m_fileName.empty()) {
-        std::stringstream out;
-        foreach(auto pair, m_confsMap) {
-            out << pair.first << ": " << pair.second << std::endl;
-        }
-        g_resources.saveFile(m_fileName, out);
+        FML::Emitter emitter;
+        FML::Node *doc = emitter.createDocument();
+        doc->write(m_confsMap);
+        g_resources.saveFile(m_fileName, emitter.emitDocument());
     }
 }
 
diff --git a/src/framework/core/resources.h b/src/framework/core/resources.h
index d690d447..3a9904c3 100644
--- a/src/framework/core/resources.h
+++ b/src/framework/core/resources.h
@@ -49,6 +49,7 @@ public:
     bool loadFile(const std::string& fileName, std::iostream& out);
 
     bool saveFile(const std::string& fileName, const uchar *data, uint size);
+    bool saveFile(const std::string& fileName, const std::string& data) { return saveFile(fileName, (const uchar*)data.c_str(), data.size()); }
     bool saveFile(const std::string& fileName, std::istream& in);
 
     bool deleteFile(const std::string& fileName);
diff --git a/src/framework/util/fml.cpp b/src/framework/util/fml.cpp
index bdc31076..b2ad3510 100644
--- a/src/framework/util/fml.cpp
+++ b/src/framework/util/fml.cpp
@@ -1,217 +1,88 @@
 #include "fml.h"
 
-#include <boost/algorithm/string.hpp>
-#include <boost/tokenizer.hpp>
-
-namespace FML {
-
-
-///////////////////////////////////////////////////////////////////////////////
-// Utilities
-
-bool fml_convert(const std::string& input, bool& b)
+namespace FML
 {
-    std::string names[5][2] = { { "1", "0" },
-    { "y", "n" },
-    { "yes", "no" },
-    { "true", "false" },
-    { "on", "off" } };
-    std::string processedInput = input;
-    boost::trim(processedInput);
-    boost::to_lower(processedInput);
-    for(int i=0;i<5;i++) {
-        if(names[i][0] == processedInput) {
-            b = true;
-            return true;
-        }
 
-        if(names[i][1] == processedInput) {
+bool fml_convert(const std::string& input, bool& b) {
+    static std::string validNames[2][4] = {{"true","yes","on","1"}, {"false","no","off","0"}};
+    bool ret = false;
+    for(int i=0;i<4;++i) {
+        if(input == validNames[0][i]) {
+            b = true;
+            ret = true;
+            break;
+        } else if(input == validNames[1][i]) {
             b = false;
-            return true;
+            ret = true;
+            break;
         }
     }
-    return false;
+    return ret;
 }
 
-bool fml_convert(const std::string& input, std::string& output) {
+bool fml_convert(const std::string& input, std::string& output)
+{
     output = input;
     return true;
 }
 
-std::string fml_int2str(int v)
-{
-    std::stringstream ss;
-    ss << v;
-    return ss.str();
+Node* Node::at(const std::string& childTag) const  {
+    int i=0;
+    while(i<size() && at(i)->tag()!=childTag)
+        ++i;
+    return at(i);
 }
 
-///////////////////////////////////////////////////////////////////////////////
-// Node
-
-Node::~Node()
+Node* Node::createNode(std::string tag)
 {
-    for(NodeList::iterator it = m_children.begin(); it != m_children.end(); ++it)
-        delete (*it);
+    Node* node = new Node;
+    node->setTag(tag);
+    addNode(node);
+    return node;
 }
 
-std::string Node::what() const
-{
-    if(m_parser)
-        return m_parser->what();
-    return std::string();
-}
-
-Node* Node::at(const std::string& childTag) const
-{
-    for(NodeList::const_iterator it = m_children.begin(); it != m_children.end(); ++it) {
-        if((*it)->tag() == childTag)
-            return (*it);
-    }
-    return NULL;
-}
-
-Node* Node::at(int pos) const
-{
-    if(pos < 0 || pos >= size())
-        return NULL;
-    return m_children[pos];
-}
-
-void Node::addNode(Node *node)
-{
+void Node::addNode(Node* node) {
     if(node->hasTag() && node->hasValue()) {
-        // remove nodes wit the same tag
-        for(NodeList::iterator it = m_children.begin(); it != m_children.end(); ++it) {
-            if((*it)->tag() == node->tag()) {
-                delete (*it);
-                m_children.erase(it);
-                break;
-            }
+        if(Node* other = at(node->tag())) {
+            if(removeNode(other))
+                delete node;
         }
     }
     m_children.push_back(node);
     node->setParent(this);
 }
 
-std::string Node::generateErrorMessage(const std::string& message) const
-{
+bool Node::removeNode(Node* node) {
+    for(NodeList::iterator it = m_children.begin(); it != m_children.end(); ++it) {
+        if((*it) == node) {
+            m_children.erase(it);
+            return true;
+        }
+    }
+    return false;
+}
+
+std::string Node::generateErrorMessage(const std::string& message) const {
     std::stringstream ss;
     ss << "FML error";
-    if(!(what().empty()))
+    if(!what().empty())
         ss << " in '" << what() << "'";
-    if(m_line > 0) {
+    if(m_line > 0)
         ss << " at line " << m_line;
-        if(hasTag())
-            ss << ", in node '" << tag() << "'";
-    }
+    if(m_line > 0 && hasTag())
+        ss << ", in node '" << tag() << "'";
     ss << ": " << message;
     return ss.str();
 }
 
-std::string Node::emitValue()
-{
-    std::string tmpValue = value();
-
-    bool shouldQuote = false;
-    if(tmpValue.find_first_of("\\") != std::string::npos) {
-        boost::replace_all(tmpValue, "\\", "\\\\");
-        shouldQuote = true;
-    }
-    if(tmpValue.find_first_of("\"") != std::string::npos) {
-        boost::replace_all(tmpValue, "\"", "\\\"");
-        shouldQuote = true;
-    }
-    if(tmpValue.find_first_of("\n") != std::string::npos) {
-        boost::replace_all(tmpValue, "\n", "\\n");
-        shouldQuote = true;
-    }
-
-    if(shouldQuote) {
-        tmpValue.append("\"");
-        tmpValue.insert(0, "\"");
-    }
-
-    return tmpValue;
-}
-
-std::string Node::emit(int depth)
-{
-    std::stringstream ss;
-    std::stringstream inlinestr;
-    bool shouldInline = false;
-
-    for(int i=1;i<depth;++i)
-        ss << "  ";
-
-    if(depth > 0) {
-        shouldInline = true;
-
-        if(hasTag())
-            ss << tag();
-
-        if(hasValue()) {
-            if(hasTag())
-                ss << ": ";
-            else
-                ss << "- ";
-            ss << emitValue();
-            ss << std::endl;
-            shouldInline = false;
-        }
-
-        if(size() > 8 || size() == 0)
-            shouldInline = false;
-    }
-
-    if(shouldInline) {
-        inlinestr << "[";
-        for(NodeList::const_iterator it = m_children.begin(); it != m_children.end(); ++it) {
-            Node* child = (*it);
-            if(child->hasTag() || ss.str().length() > 31) {
-                shouldInline = false;
-                break;
-            } else {
-                if(it != m_children.begin())
-                    inlinestr << ", ";
-                inlinestr << child->emitValue();
-            }
-        }
-        inlinestr << "]";
-    }
-
-    if(shouldInline) {
-        ss << ": " << inlinestr.str() << std::endl;
-    } else {
-        if(!hasValue())
-            ss << std::endl;
-
-        for(NodeList::const_iterator it = m_children.begin(); it != m_children.end(); ++it)
-            ss << (*it)->emit(depth+1);
-    }
-
-    return ss.str();
-}
-
-///////////////////////////////////////////////////////////////////////////////
-// Parser
-
-Parser::~Parser()
-{
-    if(m_rootNode)
-        delete m_rootNode;
-}
-
 void Parser::load(std::istream& in)
 {
-    // initialize root node
     if(m_rootNode)
         delete m_rootNode;
-    m_rootNode = new Node();
+    m_rootNode = new Node(what());
     m_rootNode->setTag("root");
-
     m_currentParent = m_rootNode;
-    m_currentDepth = 0;
-    m_currentLine = 0;
+    m_currentDepth = m_currentLine = 0;
     m_multilineMode = DONT_MULTILINE;
     m_multilineData.clear();
 
@@ -222,7 +93,6 @@ void Parser::load(std::istream& in)
         parseLine(line);
     }
 
-    // stop multilining if enabled
     if(isMultilining())
         stopMultilining();
 }
@@ -239,49 +109,43 @@ void Parser::parseLine(std::string& line)
     // trim left whitespaces
     boost::trim_left(line);
 
-    // skip comment lines
-    if(line[0] == '#')
-        return;
-
-    // skip empty lines
-    if(line.empty())
+    // skip comment or empty lines
+    if(line[0] == '#' || line.empty())
         return;
 
+    // calculate depth
     int depth = 0;
-    if(numSpaces != std::string::npos) {
+    if(numSpaces != std::string::npos)
         depth = numSpaces / 2;
-        // check for syntax error
-        if(numSpaces % 2 != 0) {
-            throwError("file must be idented every 2 whitespaces", m_currentLine);
-            return;
-        }
-    }
+
+    // check for syntax error
+    if(numSpaces != std::string::npos && numSpaces % 2 != 0)
+        throwError("file must be idented every 2 whitespaces", m_currentLine);
 
     // a depth above
     if(depth == m_currentDepth+1) {
         // change current parent to the previous added node
         m_currentParent = m_previousNode;
-    // a depth below, change parent to previus parent and add new node inside previuos parent
+        // a depth below, change parent to previus parent and add new node inside previuos parent
     } else if(depth < m_currentDepth) {
         // change current parent to the the new depth parent
         for(int i=0;i<m_currentDepth-depth;++i)
             m_currentParent = m_currentParent->parent();
-    // else if nots the same depth it's a syntax error
+        // else if nots the same depth it's a syntax error
     } else if(depth != m_currentDepth) {
         throwError("invalid indentation level", m_currentLine);
-        return;
     }
 
     // update current depth
     m_currentDepth = depth;
 
     // add node
-    Node *node = parseNode(line);
-    m_currentParent->addNode(node);
+    Node* node = m_currentParent->createNode();
+    parseNode(node, line);
     m_previousNode = node;
 }
 
-Node *Parser::parseNode(std::string& line)
+void Parser::parseNode(Node* node, std::string& line)
 {
     // determine node tag and value
     std::string tag;
@@ -292,61 +156,75 @@ Node *Parser::parseNode(std::string& line)
     if(dotsPos != std::string::npos) {
         tag = line.substr(0, dotsPos);
         value = line.substr(dotsPos+1);
-    }
-    // its a node that has a value but no tag
-    else if(line[0] == '-') {
+    } else if(line[0] == '-') // its a node that has a value but no tag
         value = line.substr(1);
-    }
-    // its a node that has only a tag
-    else {
+    else // its a node that has only a tag
         tag = line;
-    }
 
-    // trim the tag and value
+    // set node tag
     boost::trim(tag);
-    boost::trim(value);
-
-    // create the node
-    Node *node = new Node(this);
-    node->setLine(m_currentLine);
     node->setTag(tag);
 
-    // process node value
-    if(!value.empty()) {
-        // multiline text scalar
-        if(value[0] == '|') {
-            startMultilining(value);
-        }
-        // sequence
-        else if(value[0] == '[') {
-            if(boost::ends_with(value, "]")) {
-                value.erase(value.length()-1, 1);
-                value.erase(0, 1);
-                boost::trim(value);
-                boost::tokenizer<boost::escaped_list_separator<char> > tokens(value);
-                for(boost::tokenizer<boost::escaped_list_separator<char> >::iterator it = tokens.begin(); it != tokens.end(); ++it) {
-                    std::string tmp = (*it);
-                    boost::trim(tmp);
-                    if(!tmp.empty()) {
-                        Node *child = new Node(this);
-                        child->setLine(m_currentLine);
-                        child->setValue(tmp);
-                        node->addNode(child);
-                    }
-                }
-            } else
-                throwError("missing ']' in sequence", m_currentLine);
-        }
-        // text scalar
-        else {
-            node->setValue(parseTextScalar(value));
-        }
-    }
+    // set node line
+    node->setLine(m_currentLine);
 
-    return node;
+    // process node value
+    parseNodeValue(node, value);
 }
 
-std::string Parser::parseTextScalar(std::string value)
+void Parser::parseNodeValue(Node* node, std::string& value)
+{
+    boost::trim(value);
+    if(value.empty())
+        return;
+
+    // multiline text scalar
+    if(value[0] == '|') {
+        // determine multiline mode
+        m_multilineMode = MULTILINE_DONT_FOLD;
+        if(value.length() == 2) {
+            switch(value[1]) {
+                case '-':
+                    m_multilineMode = MULTILINE_FOLD_BLOCK;
+                    break;
+                case '+':
+                    m_multilineMode = MULTILINE_FOLD_FLOW;
+                    break;
+                default:
+                    throwError("invalid multiline identifier", m_currentLine);
+                    break;
+            }
+        }
+        m_currentDepth++;
+    }
+    // sequence
+    else if(value[0] == '[') {
+        if(!boost::ends_with(value, "]"))
+            throwError("missing ']' in sequence", m_currentLine);
+
+        // erase '[' and ']'
+        value.erase(value.length()-1, 1);
+        value.erase(0, 1);
+
+        // split commas
+        boost::tokenizer<boost::escaped_list_separator<char> > tokens(value);
+        for(boost::tokenizer<boost::escaped_list_separator<char> >::iterator it = tokens.begin(); it != tokens.end(); ++it) {
+            std::string tmp = (*it);
+            boost::trim(tmp);
+            if(!tmp.empty()) {
+                Node* child = node->createNode();
+                child->setLine(m_currentLine);
+                child->setValue(tmp);
+            }
+        }
+    }
+    // text scalar
+    else {
+        node->setValue(parseTextValue(value));
+    }
+}
+
+std::string Parser::parseTextValue(std::string value)
 {
     if(value[0] == '"' && value[value.length()-1] == '"') {
         value =  value.substr(1, value.length()-2);
@@ -358,35 +236,12 @@ std::string Parser::parseTextScalar(std::string value)
     return value;
 }
 
-void Parser::startMultilining(const std::string& param)
-{
-    m_multilineMode = MULTILINE_DONT_FOLD;
-    m_currentDepth++;
-    if(param.length() == 2) {
-        switch(param[1]) {
-            case '-':
-                m_multilineMode = MULTILINE_FOLD_BLOCK;
-                break;
-            case '+':
-                m_multilineMode = MULTILINE_FOLD_FLOW;
-                break;
-            default:
-                throwError("invalid multiline identifier", m_currentLine);
-                break;
-        }
-    }
-}
-
 void Parser::stopMultilining()
 {
     // remove all new lines at the end
     if(m_multilineMode == MULTILINE_DONT_FOLD || m_multilineMode == MULTILINE_FOLD_BLOCK) {
-        while(true) {
-            int lastPos = m_multilineData.length()-1;
-            if(m_multilineData[lastPos] != '\n')
-                break;
-            m_multilineData.erase(lastPos, 1);
-        }
+        while(*m_multilineData.rbegin() == '\n')
+            m_multilineData.erase(m_multilineData.length()-1, 1);
     }
 
     if(m_multilineMode == MULTILINE_FOLD_BLOCK)
@@ -405,7 +260,7 @@ bool Parser::parseMultiline(std::string line)
 
     // depth above or equal current depth, add the text to the multiline
     if(numSpaces != std::string::npos && (int)numSpaces >= m_currentDepth*2) {
-        m_multilineData += parseTextScalar(line.substr(m_currentDepth*2)) + "\n";
+        m_multilineData += parseTextValue(line.substr(m_currentDepth*2)) + "\n";
         return true;
         // depth below the current depth, check if it is a node
     } else if(numSpaces == std::string::npos || (int)numSpaces < m_currentDepth*2) {
@@ -435,4 +290,35 @@ void Parser::throwError(const std::string& message, int line)
     throw Exception(ss.str());
 }
 
-} // namespace FML {
+std::string Emitter::emitNodeValue(Node* node)
+{
+    std::string value = node->value();
+    if(value[0] == '"' || *value.rbegin() == '"' || value.find("\n") != std::string::npos) {
+        boost::replace_all(value, "\\", "\\\\");
+        boost::replace_all(value, "\"", "\\\"");
+        boost::replace_all(value, "\n", "\\n");
+        value.append("\"");
+        value.insert(0, "\"");
+    }
+    return value;
+}
+
+std::string Emitter::emitNode(Node* node, int currentDepth)
+{
+    std::stringstream ss;
+    for(int i=1;i<currentDepth;++i)
+        ss << "  ";
+    if(currentDepth > 0) {
+        if(node->hasTag())
+            ss << node->tag();
+        if(node->hasValue())
+            ss << (node->hasTag() ? ": " : "- ") << emitNodeValue(node) << std::endl;
+        else
+            ss << std::endl;
+    }
+    for(int i=0;i<node->size();++i)
+        ss << emitNode(node->at(i), currentDepth+1);
+    return ss.str();
+}
+
+}
diff --git a/src/framework/util/fml.h b/src/framework/util/fml.h
index 86222783..2b9f2980 100644
--- a/src/framework/util/fml.h
+++ b/src/framework/util/fml.h
@@ -1,62 +1,53 @@
-#ifndef FML_H
-#define FML_H
+#ifndef __FML_H
+#define __FML_H
 
 #include <sstream>
 #include <string>
 #include <vector>
+#include <list>
 #include <iterator>
 #include <map>
-#include <iostream>
 #include <stdexcept>
 #include <typeinfo>
 
+#include <boost/algorithm/string.hpp>
+#include <boost/tokenizer.hpp>
 #include <boost/utility.hpp>
-#include <boost/foreach.hpp>
 
 namespace FML {
 
-///////////////////////////////////////////////////////////////////////////////
-// Utilities
-
 bool fml_convert(const std::string& input, bool& b);
 bool fml_convert(const std::string& input, std::string& output);
 
 template <typename V, typename T>
-bool fml_convert(const V& in, T& out) {
-    std::stringstream ss;
-    ss << in;
-    ss >> out;
-    return !!ss;
-}
+bool fml_convert(const V& in, T& out) { std::stringstream ss; ss << in; ss >> out; return !!ss; }
 
-std::string fml_int2str(int v);
+inline std::string fml_tostr(bool b) { return (b ? "true" : "false"); }
 
-///////////////////////////////////////////////////////////////////////////////
-// Exception
+template < typename T>
+std::string fml_tostr(T v) { std::stringstream ss; ss << v; return ss.str(); }
 
 class Exception : public std::runtime_error {
 public:
-    explicit Exception(const std::string& what) : std::runtime_error(what) {}
+    Exception(const std::string& what) : std::runtime_error(what) {}
 };
 
-
-///////////////////////////////////////////////////////////////////////////////
-// Node
-
 class Parser;
 
 class Node : boost::noncopyable
 {
 public:
     typedef std::vector<Node*> NodeList;
+    typedef NodeList::iterator iterator;
+    typedef NodeList::const_iterator const_iterator;
 
-    Node(Parser* parser = 0) : m_parser(parser), m_parent(0), m_line(0) { }
-    ~Node();
+    Node(std::string what = "") : m_parent(0), m_line(0), m_what(what) { }
+    ~Node() { for(int i=0;i<size();++i) delete at(i); }
 
     bool hasTag() const { return !m_tag.empty(); }
     bool hasChildren() const { return size() > 0; }
     bool hasValue() const { return !m_value.empty(); }
-    bool hasNode(const std::string childTag) const { return at(childTag) != 0; }
+    bool hasNode(const std::string ctag) const { return at(ctag) != 0; }
 
     void setTag(std::string tag) { m_tag = tag; }
     void setLine(int line) { m_line = line; }
@@ -67,11 +58,7 @@ public:
     int line() const { return m_line; }
     int size() const { return m_children.size(); }
     Node* parent() { return m_parent; }
-    std::string what() const;
-
-    // iterators
-    typedef NodeList::iterator iterator;
-    typedef NodeList::const_iterator const_iterator;
+    std::string what() const { return (m_parent  ? m_parent->what() : m_what); }
 
     iterator begin() { return m_children.begin(); }
     iterator end() { return m_children.end(); }
@@ -81,38 +68,22 @@ public:
     Node* front() const { return at(0); }
     Node* back() const { return at(size()-1); }
 
-    // util for generating error message
-    std::string generateErrorMessage(const std::string& message) const;
     void throwError(const std::string& message) const { throw Exception(generateErrorMessage(message)); }
 
-    // extracting values operator
-    template <typename T>
-    friend bool operator >> (const Node& node, T& value);
+    Node* at(const std::string& ctag) const;
+    Node* at(int pos) const { return ((pos < size() && pos >= 0) ? m_children[pos] : 0); }
 
-    // get nodes
-    Node* at(const std::string& childTag) const;
-    Node* at(int pos) const;
+    std::string value(const std::string& def = "") const { return (m_value.empty() ? def : m_value); }
+    std::string valueAt(const std::string ctag, const std::string& def = "") const { Node* c = at(ctag); return (c ? c->value() : def); }
+    std::string valueAt(int pos, const std::string& def = "") const { Node* n = at(pos); return (n ? n->value() : def); }
 
-    // get values
-    std::string value(const std::string& def = std::string()) const  {
-        if(!m_value.empty())
-            return m_value;
-        return def;
-    }
+    Node* createNode(std::string tag = "");
+    void addNode(Node* node);
+    bool removeNode(Node* node);
 
-    std::string valueAt(const std::string childTag, const std::string& def = std::string()) const {
-        if(Node* node = at(childTag))
-            return node->value();
-        return def;
-    }
+    std::string generateErrorMessage(const std::string& message) const;
 
-    std::string valueAt(int pos, const std::string& def = std::string()) const {
-        if(Node* node = at(pos))
-            return node->value();
-        return def;
-    }
-
-    // read values into memory
+    // read into memory
     template <typename T>
     void read(T* v) const {
         if(!(*this >> *v))
@@ -120,8 +91,8 @@ public:
     }
 
     template <typename T>
-    bool readAt(const std::string& childTag, T* v) const {
-        if(Node* node = at(childTag)) {
+    bool readAt(const std::string& ctag, T* v) const {
+        if(Node* node = at(ctag)) {
             node->read<T>(v);
             return true;
         }
@@ -137,102 +108,114 @@ public:
         return false;
     }
 
-    // read values
+    // read returning the result
     template <typename T>
-    T read() const {
+    T read() const { T v; read<T>(&v);  return v;}
+
+    template <typename T>
+    T readAt(const std::string& ctag) const {
         T v;
-        read<T>(&v);
+        if(!readAt(ctag, &v))
+            throw Exception(generateErrorMessage("child node " + ctag + " not found"));
         return v;
     }
 
-    template <typename T>
-    T readAt(const std::string& childTag) const {
-        if(Node* node = at(childTag))
-            return node->read<T>();
-        throw Exception(generateErrorMessage("child node " + childTag + " not found"));
-        return T();
-    }
-
     template <typename T>
     T readAt(int pos) const {
-        if(Node* node = at(pos))
-            return node->read<T>();
-        throw Exception(generateErrorMessage("child node at pos " + fml_int2str(pos) + " not found"));
-        return T();
+        T v;
+        if(!readAt(pos, &v))
+            throw Exception(generateErrorMessage("child node at pos " + fml_tostr(pos) + " not found"));
+        return v;
     }
 
-    // read values with defaults
+    // read with default supplied
     template <typename T>
-    T readAt(const std::string& childTag, const T& def) const {
-        if(Node* node = at(childTag))
-            return node->read<T>();
-        else
-            return def;
+    T readAt(const std::string& ctag, const T& def) const { Node* c = at(ctag); return (c ? c->read<T>() : def); }
+
+    template <typename T>
+    T readAt(int pos, const T& def) const { Node* c = at(pos); return (c ? c->read<T>() : def); }
+
+    // writing
+    template <typename T>
+    void write(T v) {
+        if(!(*this << v))
+            throw Exception(generateErrorMessage("failed to cast to string node value of type " + std::string(typeid(T).name())));
     }
 
     template <typename T>
-    T readAt(int pos, const T& def) const {
-        if(Node* node = at(pos))
-            return node->read<T>();
-        else
-            return def;
+    void writeIn(int pos, T v) {
+        Node* c;
+        while(!at(pos))
+            c = createNode();
+        c->write<T>(v);
     }
 
-    void addNode(Node* node);
-
-    std::string emitValue();
-    std::string emit(int depth = 0);
+    template <typename T>
+    void writeIn(const std::string& ctag, T v) {
+        Node* c = createNode(ctag);
+        c->write<T>(v);
+    }
 
 private:
-    Parser* m_parser;
     Node* m_parent;
     int m_line;
+    std::string m_what;
     NodeList m_children;
     std::string m_tag;
     std::string m_value;
 };
 
-
-///////////////////////////////////////////////////////////////////////////////
-// Node operators
+// read operators
+template <typename T>
+bool operator >> (const Node& node, T& v) { return fml_convert(node.value(), v); }
 
 template <typename T>
-bool operator >> (const Node& node, T& v)
-{
-    return fml_convert(node.value(), v);
+bool operator >> (const Node& node, std::vector<T>& v) {
+    v.resize(node.size());
+    for(unsigned i=0;i<node.size();++i)
+        v[i] = node.readAt<T>(i);
+    return true;
 }
 
 template <typename T>
-bool operator >> (const Node& node, std::vector<T>& v)
-{
-    std::vector<T>& tmp;
-    tmp.resize(node.size());
+bool operator >> (const Node& node, std::list<T>& v) {
     for(unsigned i=0;i<node.size();++i)
-        v[i] = node.readAt<T>(i);
-    v = tmp;
+        v.push_back(node.readAt<T>(i));
     return true;
 }
 
 template <typename K, typename T>
-bool operator >> (const Node& node, std::map<K, T>& m)
-{
-    std::map<K, T> tmp;
-    for(Node::const_iterator it = node.begin(); it != node.end(); ++it) {
-        K k;
-        T v;
-        if(fml_convert<std::string, K>((*it)->tag(), k)) {
-            (*it)->read(&v);
-            tmp[k] = v;
-        } else
-            return false;
-    }
-    m = tmp;
+bool operator >> (const Node& node, std::map<K, T>& m) {
+    for(int i=0;i<node.size();++i)
+        m[node.at(i)->read<K>()] = node.at(i)->read<T>();
     return true;
 }
 
+// write operators
+template <typename T>
+bool operator << (Node& node, const T& v) { node.setValue(fml_tostr(v)); return true; }
 
-///////////////////////////////////////////////////////////////////////////////
-// Parser
+template <typename T>
+bool operator << (Node& node, const std::vector<T>& v) {
+    for(unsigned i=0;i<v.size();++i)
+        node.createNode()->write(v[i]);
+    return true;
+}
+
+template <typename T>
+bool operator << (Node& node, const std::list<T>& v) {
+    for(unsigned i=0;i<v.size();++i)
+        node.createNode()->write(v[i]);
+    return true;
+}
+
+template <typename K, typename T>
+bool operator << (Node& node, const std::map<K, T>& m) {
+    typename std::map<K, T>::const_iterator it;
+    for(it = m.begin(); it != m.end(); ++it)
+        node.createNode(fml_tostr(it->first))->write(it->second);
+    return true;
+}
 
 class Parser
 {
@@ -246,24 +229,24 @@ class Parser
 public:
     Parser(std::string what = std::string()) : m_rootNode(0), m_what(what) { }
     Parser(std::istream& in, std::string what = std::string()) : m_rootNode(0), m_what(what) { load(in); }
-    ~Parser();
-
-    void load(std::istream& in);
+    ~Parser() { if(m_rootNode) delete m_rootNode; }
 
     Node* getDocument() const { return m_rootNode; }
     std::string what() { return m_what; }
 
+    void load(std::istream& in);
+
 protected:
     void parseLine(std::string& line);
-    Node* parseNode(std::string& line);
-    std::string parseTextScalar(std::string value);
+    void parseNode(Node* node, std::string& line);
+    void parseNodeValue(Node* node, std::string& value);
+    std::string parseTextValue(std::string value);
 
-    void startMultilining(const std::string& param);
     void stopMultilining();
     bool parseMultiline(std::string line);
     bool isMultilining() { return m_multilineMode != DONT_MULTILINE; }
 
-    void throwError(const std::string& message, int line = 0);
+    void throwError(const std::string& message, int line);
 
 private:
     int m_currentDepth;
@@ -276,6 +259,22 @@ private:
     std::string m_what;
 };
 
+class Emitter
+{
+public:
+    Emitter() : m_rootNode(0) { }
+    ~Emitter() { if(m_rootNode) delete m_rootNode; }
+
+    Node* createDocument() { m_rootNode = new Node; return m_rootNode; }
+    std::string emitDocument() { if(m_rootNode) return emitNode(m_rootNode, 0); return std::string(); }
+
+    static std::string emitNodeValue(Node* node);
+    static std::string emitNode(Node* node, int currentDepth = 0);
+
+private:
+    Node* m_rootNode;
+};
+
 } // namespace FML {
 
-#endif // FML_H
+#endif // __FML_H