[texo] Full rewrite of inner representation.

22 files changed, 1074 insertions, 631 deletions

diff --git a/src/exporter.cpp b/src/exporter.cpp
index 3baa99e..b9a5b3f 100644
--- a/src/exporter.cpp
+++ b/src/exporter.cpp
@@ -1,10 +1,15 @@
 #include "exporter.hpp"
 
 
-void TexoExporter::Put(const ScriptVariable &str)
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+ * Texo Exporter
+ */
+bool TexoExporter::Put(const ScriptVariable &str)
 {
+    bool ok = true;
     const int len = str.Length();
-    for (int i = 0; i < len; ++i) {
-        Put(str[i]);
+    for (int i = 0; ok && i < len; ++i) {
+        ok = Put(str[i]);
     }
+    return ok;
 }
diff --git a/src/exporter.hpp b/src/exporter.hpp
index 6a0be93..a20f695 100644
--- a/src/exporter.hpp
+++ b/src/exporter.hpp
@@ -4,10 +4,14 @@
 #include <scrvar.hpp>
 
 
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+ * Texo Exporter
+ * Texo interface for outputting.
+ */
 class TexoExporter {
 public:
-    virtual void Put(char c) = 0;
-    virtual void Put(const ScriptVariable &str);
+    virtual bool Put(char c) = 0;
+    virtual bool Put(const ScriptVariable &str);
 };
 
 
diff --git a/src/file.cpp b/src/file.cpp
index ae41bde..221ff81 100644
--- a/src/file.cpp
+++ b/src/file.cpp
@@ -1,15 +1,21 @@
 #include "file.hpp"
 
 
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+ * Texo File Exporter
+ */
 TexoExporterFile::TexoExporterFile(FILE *file): file(file)
 {}
 
-void TexoExporterFile::Put(char c)
+
+bool TexoExporterFile::Put(char c)
 {
     fputc(c, file);
+    return !ferror(file);
 }
 
-void TexoExporterFile::Put(const ScriptVariable &str)
+bool TexoExporterFile::Put(const ScriptVariable &str)
 {
     fwrite(str.c_str(), 1, str.Length(), file);
+    return !ferror(file);
 }
diff --git a/src/file.hpp b/src/file.hpp
index 1cfea0b..5f8adb6 100644
--- a/src/file.hpp
+++ b/src/file.hpp
@@ -5,12 +5,18 @@
 #include <stdio.h>
 
 
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+ * Texo File Exporter
+ * Simple utility class to make output into FILE *variable.
+ */
 class TexoExporterFile: public TexoExporter {
 public:
     TexoExporterFile(FILE *file);
 
-    void Put(char c);
-    void Put(const ScriptVariable &str);
+
+    bool Put(char c);
+    bool Put(const ScriptVariable &str);
+
 
 private:
     FILE *file;
diff --git a/src/html.cpp b/src/html.cpp
index f40b8bd..ed67781 100644
--- a/src/html.cpp
+++ b/src/html.cpp
@@ -2,188 +2,153 @@
 
 
 TexoProducerHTML::TexoProducerHTML(TexoExporter &exporter):
-    TexoProducer(exporter), opened_block(none)
+    TexoProducerStrict(exporter)
 {}
 
-void TexoProducerHTML::End()
+
+bool TexoProducerHTML::TruePut(char c)
 {
-    Close();
-    opened_block = none;
+    switch (c) {
+    case '<': return exporter.Put("&lt;");  break;
+    case '>': return exporter.Put("&gt;");  break;
+    case '&': return exporter.Put("&amp;"); break;
+    default:  return exporter.Put(c);
+    }
 }
 
-void TexoProducerHTML::Put(const Texo &piece)
+
+bool TexoProducerHTML::StartCode()
 {
-    switch (piece.c) {
-    case '<': exporter.Put("&lt;");  break;
-    case '>': exporter.Put("&gt;");  break;
-    case '&': exporter.Put("&amp;"); break;
-    default:  exporter.Put(piece.c); break;
-    }
+    return exporter.Put("\n<pre>\n");
 }
 
-void TexoProducerHTML::Put(const TexoHeader &piece)
+bool TexoProducerHTML::StartHeader(int level)
 {
-    Close();
-    if (piece.level <= 1) {
-        exporter.Put("\n<h6>\n");
-        opened_block = header_6;
-    } else if (piece.level == 2) {
-        exporter.Put("\n<h5>\n");
-        opened_block = header_5;
-    } else if (piece.level == 3) {
-        exporter.Put("\n<h4>\n");
-        opened_block = header_4;
-    } else if (piece.level == 4) {
-        exporter.Put("\n<h3>\n");
-        opened_block = header_3;
-    } else if (piece.level == 5) {
-        exporter.Put("\n<h2>\n");
-        opened_block = header_2;
+    if (level <= 1) {
+        return exporter.Put("\n<h6>\n");
+    } else if (level == 2) {
+        return exporter.Put("\n<h5>\n");
+    } else if (level == 3) {
+        return exporter.Put("\n<h4>\n");
+    } else if (level == 4) {
+        return exporter.Put("\n<h3>\n");
+    } else if (level == 5) {
+        return exporter.Put("\n<h2>\n");
     } else {
-        exporter.Put("\n<h1>\n");
-        opened_block = header_1;
+        return exporter.Put("\n<h1>\n");
     }
 }
 
-void TexoProducerHTML::Put(const TexoParagraph &piece)
+bool TexoProducerHTML::StartParagraph()
 {
-    Close();
-    opened_block = paragraph;
-    exporter.Put("\n<p>\n");
+    return exporter.Put("\n<p>\n");
 }
 
-void TexoProducerHTML::Put(const TexoCode &piece)
+bool TexoProducerHTML::StartQuote()
 {
-    Close();
-    opened_block = code;
-    exporter.Put("\n<pre>\n");
+    return exporter.Put("\n<blockquote><p>\n");
 }
 
-void TexoProducerHTML::Put(const TexoQuote &piece)
+bool TexoProducerHTML::CloseCode()
 {
-    Close();
-    opened_block = quote;
-    exporter.Put("\n<blockquote><p>\n");
+    return exporter.Put("\n</pre>\n");
 }
 
-void TexoProducerHTML::Put(const TexoMono &piece)
+bool TexoProducerHTML::CloseHeader(int level)
 {
-    static bool closing = false;
-    if (closing) {
-        exporter.Put("</code>");
+    if (level <= 1) {
+        return exporter.Put("\n</h6>\n");
+    } else if (level == 2) {
+        return exporter.Put("\n</h5>\n");
+    } else if (level == 3) {
+        return exporter.Put("\n</h4>\n");
+    } else if (level == 4) {
+        return exporter.Put("\n</h3>\n");
+    } else if (level == 5) {
+        return exporter.Put("\n</h2>\n");
     } else {
-        exporter.Put("<code>");
+        return exporter.Put("\n</h1>\n");
     }
-    closing = !closing;
 }
 
-void TexoProducerHTML::Put(const TexoBold &piece)
+bool TexoProducerHTML::CloseParagraph()
 {
-    static bool closing = false;
-    if (closing) {
-        exporter.Put("</b>");
-    } else {
-        exporter.Put("<b>");
-    }
-    closing = !closing;
+    return exporter.Put("\n</p>\n");
 }
 
-void TexoProducerHTML::Put(const TexoItalic &piece)
+bool TexoProducerHTML::CloseQuote()
 {
-    static bool closing = false;
-    if (closing) {
-        exporter.Put("</i>");
-    } else {
-        exporter.Put("<i>");
-    }
-    closing = !closing;
+    return exporter.Put("\n</p></blockquote>\n");
 }
 
-void TexoProducerHTML::Put(const TexoUnderline &piece)
+
+bool TexoProducerHTML::StartBold()       { return exporter.Put("<b>"); }
+bool TexoProducerHTML::StartItalic()     { return exporter.Put("<i>"); }
+bool TexoProducerHTML::StartMono()       { return exporter.Put("<code>"); }
+bool TexoProducerHTML::StartStrike()     { return exporter.Put("<del>"); }
+bool TexoProducerHTML::StartUnderline()  { return exporter.Put("<ins>"); }
+
+bool TexoProducerHTML::CloseBold()       { return exporter.Put("</b>"); }
+bool TexoProducerHTML::CloseItalic()     { return exporter.Put("</i>"); }
+bool TexoProducerHTML::CloseMono()       { return exporter.Put("</code>"); }
+bool TexoProducerHTML::CloseStrike()     { return exporter.Put("</del>"); }
+bool TexoProducerHTML::CloseUnderline()  { return exporter.Put("</ins>"); }
+
+bool TexoProducerHTML::StartLink(
+    const ScriptVariable &link,
+    const ScriptVariable &title
+)
 {
-    static bool closing = false;
-    if (closing) {
-        exporter.Put("</ins>");
-    } else {
-        exporter.Put("<ins>");
+    bool ok = true;
+    if (link != "") {
+        ok = ok && exporter.Put("<a href='");
+        ok = ok && exporter.Put(link);
+        if (title != "") {
+            ok = ok && exporter.Put("' title='");
+            ok = ok && exporter.Put(title);
+        }
+        ok = ok && exporter.Put("'>");
     }
-    closing = !closing;
+    return ok;
 }
 
-void TexoProducerHTML::Put(const TexoStrike &piece)
+bool TexoProducerHTML::CloseLink(
+    const ScriptVariable &link,
+    const ScriptVariable &title
+)
 {
-    static bool closing = false;
-    if (closing) {
-        exporter.Put("</del>");
+    if (link != "") {
+        return exporter.Put("</a>");
     } else {
-        exporter.Put("<del>");
+        return true;
     }
-    closing = !closing;
 }
 
-void TexoProducerHTML::Put(const TexoImage &piece)
-{
-    if (piece.path != "") {
-        bool link  = piece.link != "";
-        bool title = piece.title != "";
-        if (link) {
-            exporter.Put("<a href='");
-            exporter.Put(piece.link);
-            if (title) {
-                exporter.Put("' title='");
-                exporter.Put(piece.title);
-            }
-            exporter.Put("'>");
-        }
-        exporter.Put("<img src='");
-        exporter.Put(piece.path);
-        if (piece.alt != "") {
-            exporter.Put("' alt='");
-            exporter.Put(piece.alt);
-        }
-        if (title) {
-            exporter.Put("' title='");
-            exporter.Put(piece.title);
-        }
-        exporter.Put("'/>");
-        if (link) {
-            exporter.Put("</a>");
-        }
-    }
-}
 
-void TexoProducerHTML::Put(const TexoLink &piece)
+bool TexoProducerHTML::TruePutImage(
+    const ScriptVariable &src,
+    const ScriptVariable &alt,
+    const ScriptVariable &title
+)
 {
-    if (piece.text != "" && piece.link != "") {
-        exporter.Put("<a href='");
-        exporter.Put(piece.link);
-        if (piece.title != "") {
-            exporter.Put("' title='");
-            exporter.Put(piece.title);
+    bool ok = true;
+    if (src != "") {
+        ok = ok && exporter.Put("<img src='");
+        ok = ok && exporter.Put(src);
+        if (alt != "") {
+            ok = ok && exporter.Put("' alt='");
+            ok = ok && exporter.Put(alt);
+        }
+        if (title != "") {
+            ok = ok && exporter.Put("' title='");
+            ok = ok && exporter.Put(title);
         }
-        exporter.Put("'>");
-        exporter.Put(piece.text);
-        exporter.Put("</a>");
+        ok = ok && exporter.Put("'/>");
     }
+    return ok;
 }
 
-void TexoProducerHTML::Put(const TexoHorizontalRule &piece)
-{
-    exporter.Put("\n<hr/>\n");
-}
-
-void TexoProducerHTML::Close()
+bool TexoProducerHTML::TruePutHorizontalRule()
 {
-    switch (opened_block) {
-    case none:                                         break;
-    case header_1:  exporter.Put("\n</h1>\n");             break;
-    case header_2:  exporter.Put("\n</h2>\n");             break;
-    case header_3:  exporter.Put("\n</h3>\n");             break;
-    case header_4:  exporter.Put("\n</h4>\n");             break;
-    case header_5:  exporter.Put("\n</h5>\n");             break;
-    case header_6:  exporter.Put("\n</h6>\n");             break;
-    case paragraph: exporter.Put("\n</p>\n");              break;
-    case quote:     exporter.Put("\n</p></blockquote>\n"); break;
-    case code:      exporter.Put("\n</pre>\n");            break;
-    }
+    return exporter.Put("\n<hr/>\n");
 }
diff --git a/src/html.hpp b/src/html.hpp
index b96200f..aa22cf1 100644
--- a/src/html.hpp
+++ b/src/html.hpp
@@ -6,44 +6,44 @@
 #include "importer.hpp"
 
 
-class TexoProducerHTML: public TexoProducer {
+class TexoProducerHTML: public TexoProducerStrict {
 public:
     TexoProducerHTML(TexoExporter &exporter);
 
-    void End();
-
-    void Put(const Texo &piece);
-
-    void Put(const TexoHeader &piece);
-    void Put(const TexoParagraph &piece);
-    void Put(const TexoCode &piece);
-    void Put(const TexoQuote &piece);
-
-    void Put(const TexoMono &piece);
-    void Put(const TexoBold &piece);
-    void Put(const TexoItalic &piece);
-    void Put(const TexoUnderline &piece);
-    void Put(const TexoStrike &piece);
-
-    void Put(const TexoImage &piece);
-    void Put(const TexoLink &piece);
-    void Put(const TexoHorizontalRule &piece);
-
-private:
-    void Close();
-
-    enum {
-        none = 0,
-        header_1,
-        header_2,
-        header_3,
-        header_4,
-        header_5,
-        header_6,
-        paragraph,
-        code,
-        quote
-    } opened_block;
+protected:
+    bool TruePut(char c);
+
+    bool StartCode();
+    bool StartHeader(int level);
+    bool StartParagraph();
+    bool StartQuote();
+
+    bool CloseCode();
+    bool CloseHeader(int level);
+    bool CloseParagraph();
+    bool CloseQuote();
+
+    bool StartBold();
+    bool StartItalic();
+    bool StartMono();
+    bool StartStrike();
+    bool StartUnderline();
+
+    bool CloseBold();
+    bool CloseItalic();
+    bool CloseMono();
+    bool CloseStrike();
+    bool CloseUnderline();
+
+    bool StartLink(const ScriptVariable &link, const ScriptVariable &title);
+    bool CloseLink(const ScriptVariable &link, const ScriptVariable &title);
+
+    bool TruePutImage(
+        const ScriptVariable &src,
+        const ScriptVariable &alt,
+        const ScriptVariable &title
+    );
+    bool TruePutHorizontalRule();
 };
 
 
diff --git a/src/importer.cpp b/src/importer.cpp
index af475a5..73ff060 100644
--- a/src/importer.cpp
+++ b/src/importer.cpp
@@ -1,27 +1,58 @@
 #include "importer.hpp"
 
 
-TexoImporter::TexoImporter(TexoProducer &producer): producer(producer)
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+ * Texo Importer
+ */
+TexoImporter::TexoImporter(TexoProducer &producer):
+    producer(producer), ok(true)
 {}
 
-void TexoImporter::End()
+TexoImporter::~TexoImporter()  { End(); }
+
+
+bool TexoImporter::End()
+{
+    return ok = ok && TrueEnd();
+}
+
+bool TexoImporter::Put(char c)
+{
+    return ok = ok && TruePut(c);
+}
+
+bool TexoImporter::Put(const ScriptVariable &s)
 {
-    producer.End();
+    return ok = ok && TruePut(s);
 }
 
-void TexoImporter::Put(const ScriptVariable &str)
+bool TexoImporter::Put(FILE *f)
+{
+    return ok = ok && TruePut(f);
+}
+
+
+bool TexoImporter::TrueEnd()
+{
+    return producer.End();
+}
+
+
+bool TexoImporter::TruePut(const ScriptVariable &str)
 {
     const int len = str.Length();
-    for (int i = 0; i < len; ++i) {
-        Put(str[i]);
+    for (int i = 0; ok && i < len; ++i) {
+        ok = TruePut(str[i]);
     }
+    return ok;
 }
 
-void TexoImporter::Put(FILE *file)
+bool TexoImporter::TruePut(FILE *file)
 {
     if (file) {
-        for (int c = fgetc(file); c != EOF; c = fgetc(file)) {
-            Put(c);
+        for (int c = fgetc(file); ok && c != EOF; c = fgetc(file)) {
+            ok = TruePut(c);
         }
     }
+    return ok;
 }
diff --git a/src/importer.hpp b/src/importer.hpp
index 3a31fab..9280a34 100644
--- a/src/importer.hpp
+++ b/src/importer.hpp
@@ -5,18 +5,34 @@
 #include <stdio.h>
 
 
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+ * Texo Importer
+ * Texo interface for parsers from input characters into inner representation,
+ * described by Texo Producer.
+ */
 class TexoImporter {
 public:
     TexoImporter(TexoProducer &producer);
+    ~TexoImporter();
 
-    virtual void End();
 
-    virtual void Put(char c) = 0;
-    virtual void Put(const ScriptVariable &str);
-    virtual void Put(FILE *file);
+    bool End();
+    bool Put(char c);
+    bool Put(const ScriptVariable &s);
+    bool Put(FILE *f);
+
 
 protected:
+    virtual bool TrueEnd();
+
+
+    virtual bool TruePut(char c) = 0;
+    virtual bool TruePut(const ScriptVariable &str);
+    virtual bool TruePut(FILE *file);
+
+
     TexoProducer &producer;
+    bool         ok;
 };
 
 
diff --git a/src/lines.cpp b/src/lines.cpp
index bacf048..c7b605b 100644
--- a/src/lines.cpp
+++ b/src/lines.cpp
@@ -1,85 +1,91 @@
 #include "lines.hpp"
 
 
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+ * Texo Lines Producer
+ */
 TexoProducerLines::TexoProducerLines(TexoExporter &exporter):
     TexoProducer(exporter), newline(true)
 {}
 
-void TexoProducerLines::End()
+
+bool TexoProducerLines::End()
 {
     if (!newline) {
         exporter.Put('\n');
         newline = true;
     }
+    return true;
 }
 
-void TexoProducerLines::Put(const Texo &piece)
+
+bool TexoProducerLines::Put(char c)
 {
-    if (piece.c == '\n') {
+    if (c == '\n') {
         if (!newline) {
             exporter.Put(' ');
             newline = true;
         }
     } else {
-        exporter.Put(piece.c);
+        exporter.Put(c);
         newline = false;
     }
+    return true;
 }
 
-void TexoProducerLines::Put(const TexoParagraph &piece)
+
+bool TexoProducerLines::Paragraph()
 {
     if (!newline) {
         exporter.Put('\n');
         newline = true;
     }
+    return true;
 }
 
-void TexoProducerLines::Put(const TexoQuote &piece)
+bool TexoProducerLines::Quote()
 {
     if (!newline) {
         exporter.Put('\n');
     }
     exporter.Put("> ");
     newline = false;
+    return true;
 }
 
 
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+ * Texo Lines Importer
+ */
 TexoImporterLines::TexoImporterLines(TexoProducer &producer):
     TexoImporter(producer), newline(true), quote(false)
 {}
 
-void TexoImporterLines::Put(char c)
+
+bool TexoImporterLines::TruePut(char c)
 {
     if (c == '\n') {
         if (!newline) {
             newline = true;
             quote   = false;
         }
+        return true;
     } else if (newline) {
+        newline = false;
         if (c == '>') {
-            producer.Put(TexoQuote());
             quote = true;
+            return producer.Quote();
         } else {
-            producer.Put(TexoParagraph());
-            producer.Put(c);
+            return producer.Paragraph() && producer.Put(c);
         }
-        newline = false;
     } else if (quote) {
         if (c != ' ') {
             quote = false;
-            producer.Put(c);
+            return producer.Put(c);
+        } else {
+            return true;
         }
     } else {
-        producer.Put(c);
+        return producer.Put(c);
     }
 }
-
-void TexoImporterLines::Put(const ScriptVariable &str)
-{
-    TexoImporter::Put(str);
-}
-
-void TexoImporterLines::Put(FILE *file)
-{
-    TexoImporter::Put(file);
-}
diff --git a/src/lines.hpp b/src/lines.hpp
index d6ce555..7049919 100644
--- a/src/lines.hpp
+++ b/src/lines.hpp
@@ -6,29 +6,40 @@
 #include "importer.hpp"
 
 
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+ * Texo Lines Producer
+ */
 class TexoProducerLines: public TexoProducer {
 public:
     TexoProducerLines(TexoExporter &exporter);
 
-    void End();
 
-    void Put(const Texo &piece);
+    bool End();
+
+
+    bool Put(char c);
+
+
+    bool Paragraph();
+    bool Quote();
 
-    void Put(const TexoParagraph &piece);
-    void Put(const TexoQuote &piece);
 
 private:
     bool newline;
 };
 
 
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+ * Texo Lines Importer
+ */
 class TexoImporterLines: public TexoImporter {
 public:
     TexoImporterLines(TexoProducer &producer);
 
-    void Put(char c);
-    void Put(const ScriptVariable &str);
-    void Put(FILE *file);
+
+protected:
+    bool TruePut(char c);
+
 
 private:
     bool newline;
diff --git a/src/markdown.cpp b/src/markdown.cpp
index facba67..6931461 100644
--- a/src/markdown.cpp
+++ b/src/markdown.cpp
@@ -6,186 +6,180 @@ TexoProducerMarkdown::TexoProducerMarkdown(TexoExporter &exporter):
     quoted(false), newline(false), header(false), code(false), nospace(true)
 {}
 
-void TexoProducerMarkdown::End()
+bool TexoProducerMarkdown::End()
 {
     if (!newline) {
-        exporter.Put('\n');
         newline = true;
+        return exporter.Put('\n');
     }
+    return true;
 }
 
-void TexoProducerMarkdown::Put(const Texo &piece)
+bool TexoProducerMarkdown::Put(char c)
 {
-    char c = piece.c;
+    bool ok = true;
     if (c == '\n') {
         if (code) {
-            exporter.Put('\n');
+            ok = exporter.Put('\n');
         } else if (quoted) {
-            exporter.Put("\n> ");
+            ok = exporter.Put("\n> ");
         } else if (!nospace) {
             if (header || newline) {
-                exporter.Put(' ');
+                ok = exporter.Put(' ');
             } else {
-                exporter.Put('\n');
+                ok      = exporter.Put('\n');
                 newline = true;
             }
         }
     } else {
         if (c == '*' || c == '_' || c == '`' || c == '+' || c == '~') {
-            exporter.Put('\\');
+            ok = exporter.Put('\\');
         }
-        exporter.Put(c);
+        ok = ok && exporter.Put(c);
         newline = false;
         nospace = false;
     }
+    return ok;
 }
 
-void TexoProducerMarkdown::Put(const TexoHeader &piece)
+
+bool TexoProducerMarkdown::Code()
 {
-    Close();
-    if (piece.level <= 1) {
-        exporter.Put("###### ");
-    } else if (piece.level == 2) {
-        exporter.Put("##### ");
-    } else if (piece.level == 3) {
-        exporter.Put("#### ");
-    } else if (piece.level == 4) {
-        exporter.Put("### ");
-    } else if (piece.level == 5) {
-        exporter.Put("## ");
+    bool ok = Close();
+    code = true;
+    return ok && exporter.Put("```\n");
+}
+
+bool TexoProducerMarkdown::Header(int level)
+{
+    bool ok = Close();
+    if (level <= 1) {
+        ok = ok && exporter.Put("###### ");
+    } else if (level == 2) {
+        ok = ok && exporter.Put("##### ");
+    } else if (level == 3) {
+        ok = ok && exporter.Put("#### ");
+    } else if (level == 4) {
+        ok = ok && exporter.Put("### ");
+    } else if (level == 5) {
+        ok = ok && exporter.Put("## ");
     } else {
-        exporter.Put("# ");
+        ok = ok && exporter.Put("# ");
     }
-    header  = true;
+    header = true;
+    return ok;
 }
 
-void TexoProducerMarkdown::Put(const TexoParagraph &piece)
+bool TexoProducerMarkdown::Paragraph()
 {
-    Close();
+    return Close();
 }
 
-void TexoProducerMarkdown::Put(const TexoCode &piece)
+bool TexoProducerMarkdown::Quote()
 {
-    Close();
-    exporter.Put("```\n");
-    code = true;
-}
-
-void TexoProducerMarkdown::Put(const TexoQuote &piece)
-{
-    Close();
-    exporter.Put("> ");
+    bool ok = Close();
     quoted = true;
+    return ok && exporter.Put("> ");
 }
 
-void TexoProducerMarkdown::Put(const TexoMono &piece)
-{
-    exporter.Put("`");
-    newline = false;
-    nospace = false;
-}
 
-void TexoProducerMarkdown::Put(const TexoBold &piece)
-{
-    exporter.Put("**");
-    newline = false;
-    nospace = false;
-}
+bool TexoProducerMarkdown::Mono()       { return Mod("`"); }
+bool TexoProducerMarkdown::Bold()       { return Mod("**"); }
+bool TexoProducerMarkdown::Italic()     { return Mod("_"); }
+bool TexoProducerMarkdown::Underline()  { return Mod("++"); }
+bool TexoProducerMarkdown::Strike()     { return Mod("~~"); }
 
-void TexoProducerMarkdown::Put(const TexoItalic &piece)
+bool TexoProducerMarkdown::Link(
+    const ScriptVariable &link,
+    const ScriptVariable &title
+)
 {
-    exporter.Put("_");
-    newline = false;
-    nospace = false;
-}
-
-void TexoProducerMarkdown::Put(const TexoUnderline &piece)
-{
-    exporter.Put("++");
-    newline = false;
-    nospace = false;
-}
-
-void TexoProducerMarkdown::Put(const TexoStrike &piece)
-{
-    exporter.Put("~~");
-    newline = false;
-    nospace = false;
+    bool ok = Link();
+    if (link != "") {
+        ok = ok && exporter.Put('[');
+        link_link  = link;
+        link_title = title;
+    }
+    return ok;
 }
 
-void TexoProducerMarkdown::Put(const TexoImage &piece)
+bool TexoProducerMarkdown::Link()
 {
-    if (piece.path != "") {
-        const bool link = piece.link != "";
-        if (link) {
-            exporter.Put('[');
-        }
-        exporter.Put("![");
-        exporter.Put(piece.alt);
-        exporter.Put("](");
-        exporter.Put(piece.path);
-        if (piece.title != "") {
-            exporter.Put(" \"");
-            exporter.Put(piece.title);
-            exporter.Put('"');
-        }
-        exporter.Put(')');
-        if (link) {
-            exporter.Put("](");
-            exporter.Put(piece.link);
-            if (piece.title != "") {
-                exporter.Put(" \"");
-                exporter.Put(piece.title);
-                exporter.Put('"');
-            }
-            exporter.Put(')');
+    bool ok = true;
+    if (link_link != "") {
+        ok = ok && exporter.Put("](");
+        ok = ok && exporter.Put(link_link);
+        if (link_title != "") {
+            ok = ok && exporter.Put(" \"");
+            ok = ok && exporter.Put(link_title);
+            ok = ok && exporter.Put('"');
         }
+        ok = ok && exporter.Put(')');
     }
-    newline = false;
-    nospace = false;
-}
-
-void TexoProducerMarkdown::Put(const TexoLink &piece)
-{
-    if (piece.text != "") {
-        exporter.Put('[');
-        exporter.Put(piece.text);
-        exporter.Put("](");
-        exporter.Put(piece.link);
-        if (piece.title != "") {
-            exporter.Put(" \"");
-            exporter.Put(piece.title);
-            exporter.Put('"');
+    return ok;
+}
+
+
+bool TexoProducerMarkdown::PutImage(
+    const ScriptVariable &src,
+    const ScriptVariable &alt,
+    const ScriptVariable &title
+)
+{
+    bool ok = true;
+    if (src != "") {
+        ok = ok && exporter.Put("![");
+        ok = ok && exporter.Put(alt);
+        ok = ok && exporter.Put("](");
+        ok = ok && exporter.Put(src);
+        if (title != "") {
+            ok = ok && exporter.Put(" \"");
+            ok = ok && exporter.Put(title);
+            ok = ok && exporter.Put('"');
         }
-        exporter.Put(')');
+        ok = ok && exporter.Put(')');
     }
     newline = false;
     nospace = false;
+    return ok;
 }
 
-void TexoProducerMarkdown::Put(const TexoHorizontalRule &piece)
+bool TexoProducerMarkdown::PutHorizontalRule()
 {
+    bool ok = true;
     if (!newline && !nospace) {
-        exporter.Put('\n');
+        ok = ok && exporter.Put('\n');
     }
-    exporter.Put("--------------------------------------------------\n");
     nospace = true;
+    return ok && exporter.Put(
+        "--------------------------------------------------\n"
+    );
 }
 
-void TexoProducerMarkdown::Close()
+
+bool TexoProducerMarkdown::Mod(const ScriptVariable &str)
 {
+    newline = false;
+    nospace = false;
+    return exporter.Put(str);
+}
+
+bool TexoProducerMarkdown::Close()
+{
+    bool ok = true;
     if (code) {
-        exporter.Put("\n```");
+        ok = exporter.Put("\n```");
         code    = false;
         nospace = false;
         newline = false;
     }
     if (!newline && !nospace) {
-        exporter.Put("\n\n");
+        ok = ok && exporter.Put("\n\n");
     }
     header  = false;
     quoted  = false;
     nospace = true;
+    return ok;
 }
 
 
@@ -193,10 +187,10 @@ TexoImporterMarkdown::TexoImporterMarkdown(TexoProducer &producer):
     TexoImporter(producer), state(start)
 {}
 
-void TexoImporterMarkdown::Put(char c)
+
+bool TexoImporterMarkdown::TruePut(char c)
 {
     switch (state) {
-    case error:                          break;
     case start:         Start(c);        break;
     case text:          Text(c);         break;
     case header_text:   HeaderText(c);   break;
@@ -218,17 +212,9 @@ void TexoImporterMarkdown::Put(char c)
     case header_pre:    HeaderPre(c);    break;
     case code:          Code(c);         break;
     }
+    return ok;
 }
 
-void TexoImporterMarkdown::Put(const ScriptVariable &str)
-{
-    TexoImporter::Put(str);
-}
-
-void TexoImporterMarkdown::Put(FILE *file)
-{
-    TexoImporter::Put(file);
-}
 
 void TexoImporterMarkdown::Start(char c)
 {
@@ -238,17 +224,17 @@ void TexoImporterMarkdown::Start(char c)
         state        = header;
         header_level = 6;
     } else if (c == '>') {
-        producer.Put(TexoQuote());
+        ok    = producer.Quote();
         state = quote_pre;
     } else if (c == '-') {
-        producer.Put(TexoParagraph());
+        ok              = producer.Paragraph();
         state           = rule;
         rule_dash_count = 1;
     } else if (c == '`') {
         state            = code;
         code_quote_count = 1;
     } else {
-        producer.Put(TexoParagraph());
+        ok    = producer.Paragraph();
         state = text;
         Put(c);
     }
@@ -258,14 +244,14 @@ void TexoImporterMarkdown::Text(char c)
 {
     back = text;
     switch (c) {
-    case '\\': state = backslash; break;
-    case '\n': state = newline;   break;
-    case '*':  state = asterisk;  break;
-    case '_':  state = underline; break;
-    case '+':  state = plus;      break;
-    case '~':  state = tilde;     break;
-    case '`':  Backquote();       break;
-    default:   producer.Put(c);
+    case '\\': state = backslash;    break;
+    case '\n': state = newline;      break;
+    case '*':  state = asterisk;     break;
+    case '_':  state = underline;    break;
+    case '+':  state = plus;         break;
+    case '~':  state = tilde;        break;
+    case '`':  Backquote();          break;
+    default:   ok = producer.Put(c);
     }
 }
 
@@ -273,14 +259,14 @@ void TexoImporterMarkdown::HeaderText(char c)
 {
     back = header_text;
     switch (c) {
-    case '\\': state = backslash; break;
-    case '\n': state = paragraph; break;
-    case '*':  state = asterisk;  break;
-    case '_':  state = underline; break;
-    case '+':  state = plus;      break;
-    case '~':  state = tilde;     break;
-    case '`':  Backquote();       break;
-    default:   producer.Put(c);
+    case '\\': state = backslash;    break;
+    case '\n': state = paragraph;    break;
+    case '*':  state = asterisk;     break;
+    case '_':  state = underline;    break;
+    case '+':  state = plus;         break;
+    case '~':  state = tilde;        break;
+    case '`':  Backquote();          break;
+    default:   ok = producer.Put(c);
     }
 }
 
@@ -303,14 +289,14 @@ void TexoImporterMarkdown::QuoteText(char c)
     case '+':  state = plus;          break;
     case '~':  state = tilde;         break;
     case '`':  Backquote();           break;
-    default:   producer.Put(c);
+    default:   ok = producer.Put(c);
     }
 }
 
 void TexoImporterMarkdown::QuoteNewline(char c)
 {
     if (c == '>') {
-        producer.Put('\n');
+        ok    = producer.Put('\n');
         state = quote_pre;
     } else {
         state = paragraph;
@@ -322,14 +308,13 @@ void TexoImporterMarkdown::CodeText(char c)
 {
     back = code_text;
     switch (c) {
-    case '\\': state = backslash;    break;
-    case '\n': state = code_newline; break;
-    case '*':  state = asterisk;     break;
-    case '_':  state = underline;    break;
-    case '+':  state = plus;         break;
-    case '~':  state = tilde;        break;
-    case '`':  state = error;        break;
-    default:   producer.Put(c);
+    case '\\': state = backslash;       break;
+    case '\n': state = code_newline;    break;
+    case '*':  state = asterisk;        break;
+    case '_':  state = underline;       break;
+    case '+':  state = plus;            break;
+    case '~':  state = tilde;           break;
+    default:   ok    = producer.Put(c);
     }
 }
 
@@ -339,9 +324,9 @@ void TexoImporterMarkdown::CodeNewline(char c)
         state            = code_end;
         code_quote_count = 1;
     } else {
-        producer.Put('\n');
+        ok    = producer.Put('\n');
         state = code_text;
-        CodeText(c);
+        Put(c);
     }
 }
 
@@ -353,16 +338,16 @@ void TexoImporterMarkdown::CodeEnd(char c)
         if (code_quote_count == 3) {
             state = paragraph;
         } else {
-            state = error;
+            ok = false;
         }
     } else {
-        state = error;
+        ok = false;
     }
 }
 
 void TexoImporterMarkdown::Backslash(char c)
 {
-    producer.Put(c);
+    ok    = producer.Put(c);
     state = back;
 }
 
@@ -370,9 +355,9 @@ void TexoImporterMarkdown::Asterisk(char c)
 {
     state = back;
     if (c == '*') {
-        producer.Put(TexoBold());
+        ok = producer.Bold();
     } else {
-        producer.Put(TexoItalic());
+        ok = producer.Italic();
         Put(c);
     }
 }
@@ -381,9 +366,9 @@ void TexoImporterMarkdown::Underline(char c)
 {
     state = back;
     if (c == '_') {
-        producer.Put(TexoBold());
+        ok = producer.Bold();
     } else {
-        producer.Put(TexoItalic());
+        ok = producer.Italic();
         Put(c);
     }
 }
@@ -392,9 +377,9 @@ void TexoImporterMarkdown::Plus(char c)
 {
     state = back;
     if (c == '+') {
-        producer.Put(TexoUnderline());
+        ok = producer.Underline();
     } else {
-        producer.Put('+');
+        ok = producer.Put('+');
         Put(c);
     }
 }
@@ -403,9 +388,9 @@ void TexoImporterMarkdown::Tilde(char c)
 {
     state = back;
     if (c == '~') {
-        producer.Put(TexoStrike());
+        ok = producer.Strike();
     } else {
-        producer.Put('~');
+        ok = producer.Put('~');
         Put(c);
     }
 }
@@ -418,7 +403,7 @@ void TexoImporterMarkdown::Newline(char c)
         state        = header;
         header_level = 6;
     } else if (c == '>') {
-        producer.Put(TexoQuote());
+        ok    = producer.Quote();
         state = quote_pre;
     } else if (c == '-') {
         state           = rule;
@@ -427,9 +412,9 @@ void TexoImporterMarkdown::Newline(char c)
         state            = code;
         code_quote_count = 1;
     } else {
-        producer.Put('\n');
+        ok    = producer.Put('\n');
         state = text;
-        Text(c);
+        Put(c);
     }
 }
 
@@ -438,15 +423,15 @@ void TexoImporterMarkdown::Rule(char c)
     if (c == '-') {
         ++rule_dash_count;
     } else if (c == '\n' && rule_dash_count >= 3) {
-        producer.Put(TexoHorizontalRule());
+        ok    = producer.PutHorizontalRule();
         state = newline;
     } else {
-        producer.Put(' ');
-        for (int i = 0; i < rule_dash_count; ++i) {
-            producer.Put('-');
+        ok = producer.Put(' ');
+        for (int i = 0; ok && i < rule_dash_count; ++i) {
+            ok = producer.Put('-');
         }
         state = text;
-        Text(c);
+        Put(c);
     }
 }
 
@@ -456,19 +441,19 @@ void TexoImporterMarkdown::Paragraph(char c)
         state        = header;
         header_level = 6;
     } else if (c == '>') {
-        producer.Put(TexoQuote());
+        ok    = producer.Quote();
         state = quote_pre;
     } else if (c == '-') {
-        producer.Put(TexoParagraph());
+        ok              = producer.Paragraph();
         state           = rule;
         rule_dash_count = 1;
     } else if (c == '`') {
         state            = code;
         code_quote_count = 1;
     } else if (c != '\n') {
-        producer.Put(TexoParagraph());
+        ok    = producer.Paragraph();
         state = text;
-        Text(c);
+        Put(c);
     }
 }
 
@@ -478,13 +463,13 @@ void TexoImporterMarkdown::Header(char c)
         if (header_level > 1) {
             --header_level;
         } else {
-            state = error;
+            ok = false;
         }
     } else if (c == ' ') {
-        producer.Put(TexoHeader(header_level));
+        ok    = producer.Header(header_level);
         state = header_pre;
     } else {
-        state = error;
+        ok = false;
     }
 }
 
@@ -502,17 +487,17 @@ void TexoImporterMarkdown::Code(char c)
         ++code_quote_count;
     } else  if (c == '\n') {
         if (code_quote_count == 3) {
-            producer.Put(TexoCode());
+            ok    = producer.Code();
             state = code_text;
         } else {
-            state = error;
+            ok = false;
         }
     } else {
-        state = error;
+        ok = false;
     }
 }
 
 void TexoImporterMarkdown::Backquote()
 {
-    producer.Put(TexoMono());
+    ok = producer.Mono();
 }
diff --git a/src/markdown.hpp b/src/markdown.hpp
index f9b25f4..ee8aee8 100644
--- a/src/markdown.hpp
+++ b/src/markdown.hpp
@@ -10,33 +10,44 @@ class TexoProducerMarkdown: public TexoProducer {
 public:
     TexoProducerMarkdown(TexoExporter &exporter);
 
-    void End();
+    bool End();
 
-    void Put(const Texo &piece);
+    bool Put(char c);
 
-    void Put(const TexoHeader &piece);
-    void Put(const TexoParagraph &piece);
-    void Put(const TexoCode &piece);
-    void Put(const TexoQuote &piece);
+    bool Code();
+    bool Header(int level);
+    bool Paragraph();
+    bool Quote();
 
-    void Put(const TexoMono &piece);
-    void Put(const TexoBold &piece);
-    void Put(const TexoItalic &piece);
-    void Put(const TexoUnderline &piece);
-    void Put(const TexoStrike &piece);
+    bool Bold();
+    bool Italic();
+    bool Mono();
+    bool Strike();
+    bool Underline();
 
-    void Put(const TexoImage &piece);
-    void Put(const TexoLink &piece);
-    void Put(const TexoHorizontalRule &piece);
+    bool Link(const ScriptVariable &link, const ScriptVariable &title);
+    bool Link();
+
+    bool PutImage(
+        const ScriptVariable &src,
+        const ScriptVariable &alt,
+        const ScriptVariable &title
+    );
+    bool PutHorizontalRule();
 
 private:
-    void Close();
+    bool Mod(const ScriptVariable &str);
+    bool Close();
+    bool CloseLink();
 
     bool quoted;
     bool newline;
     bool header;
     bool code;
     bool nospace;
+
+    ScriptVariable link_link;
+    ScriptVariable link_title;
 };
 
 
@@ -44,13 +55,13 @@ class TexoImporterMarkdown: public TexoImporter {
 public:
     TexoImporterMarkdown(TexoProducer &producer);
 
-    void Put(char c);
-    void Put(const ScriptVariable &str);
-    void Put(FILE *file);
+
+protected:
+    bool TruePut(char c);
+
 
 private:
     enum State {
-        error,
         start,
         text,
         header_text,
diff --git a/src/plain.cpp b/src/plain.cpp
index 8b3d470..9e9280e 100644
--- a/src/plain.cpp
+++ b/src/plain.cpp
@@ -1,82 +1,100 @@
 #include "plain.hpp"
 
 
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+ * Texo Plain Producer
+ */
 TexoProducerPlain::TexoProducerPlain(TexoExporter &exporter):
     TexoProducer(exporter), quoted(false), newline(false), nospace(true)
 {}
 
-void TexoProducerPlain::End()
+
+bool TexoProducerPlain::End()
 {
     if (!newline) {
         exporter.Put('\n');
         newline = true;
     }
+    return true;
 }
 
-void TexoProducerPlain::Put(const Texo &piece)
+
+bool TexoProducerPlain::Put(char c)
 {
-    if (piece.c == '\n') {
+    if (c == '\n') {
         if (quoted) {
-            exporter.Put("\n> ");
+            return exporter.Put("\n> ");
         } else if (!nospace) {
             if (newline) {
-                exporter.Put(' ');
+                return exporter.Put(' ');
             } else {
-                exporter.Put('\n');
                 newline = true;
+                return exporter.Put('\n');
             }
+        } else {
+            return true;
         }
     } else {
-        exporter.Put(piece.c);
         newline = false;
         nospace = false;
+        return exporter.Put(c);
     }
 }
 
-void TexoProducerPlain::Put(const TexoParagraph &piece)
+
+bool TexoProducerPlain::Paragraph()
 {
+    quoted  = false;
     if (!nospace) {
-        exporter.Put("\n\n");
+        nospace = true;
+        return exporter.Put("\n\n");
+    } else {
+        return true;
     }
-    quoted  = false;
-    nospace = true;
 }
 
-void TexoProducerPlain::Put(const TexoQuote &piece)
+bool TexoProducerPlain::Quote()
 {
+    quoted = true;
     if (!nospace) {
-        exporter.Put("\n\n");
+        return exporter.Put("\n\n> ");
+    } else {
+        return exporter.Put("> ");
     }
-    exporter.Put("> ");
-    quoted = true;
 }
 
-void TexoProducerPlain::Put(const TexoHorizontalRule &piece)
+bool TexoProducerPlain::PutHorizontalRule()
 {
+    bool ok = true;
     if (!newline && !nospace) {
-        exporter.Put('\n');
+        ok = exporter.Put('\n');
     }
-    exporter.Put("--------------------------------------------------\n");
     nospace = true;
+    return ok && exporter.Put(
+        "--------------------------------------------------\n"
+    );
 }
 
 
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+ * Texo Plain Importer
+ */
 TexoImporterPlain::TexoImporterPlain(TexoProducer &producer):
     TexoImporter(producer), state(text)
-{
-    producer.Put(TexoParagraph());
-}
+{}
+
 
-void TexoImporterPlain::End()
+bool TexoImporterPlain::TrueEnd()
 {
     if (state == rule) {
-        producer.Put(TexoHorizontalRule());
+        ok    = producer.PutHorizontalRule();
         state = text;
     }
-    producer.End();
+    return ok && producer.End();
 }
 
-void TexoImporterPlain::Put(char c)
+
+bool TexoImporterPlain::TruePut(char c)
 {
     switch (state) {
     case text:           Text(c);          break;
@@ -88,23 +106,15 @@ void TexoImporterPlain::Put(char c)
     case rule:           Rule(c);          break;
     case paragraph_rule: ParagraphRule(c); break;
     }
+    return ok;
 }
 
-void TexoImporterPlain::Put(const ScriptVariable &str)
-{
-    TexoImporter::Put(str);
-}
-
-void TexoImporterPlain::Put(FILE *file)
-{
-    TexoImporter::Put(file);
-}
 
 void TexoImporterPlain::Text(char c)
 {
     switch (c) {
-    case '\n': state = newline; break;
-    default:   producer.Put(c); break;
+    case '\n': state = newline;         break;
+    default:   ok    = producer.Put(c); break;
     }
 }
 
@@ -114,26 +124,30 @@ void TexoImporterPlain::Newline(char c)
         state = paragraph;
     } else if (c == '-') {
         dash_count = 1;
-        state = rule;
+        state      = rule;
     } else {
-        producer.Put('\n');
         state = text;
-        Text(c);
+        ok    = producer.Put('\n');
+        if (ok) {
+            Text(c);
+        }
     }
 }
 
 void TexoImporterPlain::Paragraph(char c)
 {
     if (c == '>') {
-        producer.Put(TexoQuote());
+        ok    = producer.Quote();
         state = quote_pre;
     } else if (c == '-') {
         dash_count = 1;
-        state = paragraph_rule;
+        state      = paragraph_rule;
     } else if (c != '\n') {
-        producer.Put(TexoParagraph());
         state = text;
-        Text(c);
+        ok    = producer.Paragraph();
+        if (ok) {
+            Text(c);
+        }
     }
 }
 
@@ -148,49 +162,55 @@ void TexoImporterPlain::QuotePre(char c)
 void TexoImporterPlain::Quote(char c)
 {
     switch (c) {
-    case '\n': state = quote_newline; break;
-    default:   producer.Put(c);       break;
+    case '\n': state = quote_newline;   break;
+    default:   ok    = producer.Put(c); break;
     }
 }
 
 void TexoImporterPlain::QuoteNewline(char c)
 {
     if (c == '>') {
-        producer.Put('\n');
+        ok    = producer.Put('\n');
         state = quote_pre;
     } else if (c == '\n') {
         state = paragraph;
     } else if (c == '-') {
         dash_count = 1;
-        state = paragraph_rule;
+        state      = paragraph_rule;
     } else {
-        producer.Put(TexoParagraph());
         state = text;
-        Text(c);
+        ok    = producer.Paragraph();
+        if (ok) {
+            Text(c);
+        }
     }
 }
 
 void TexoImporterPlain::Rule(char c)
 {
     if (c == '\n') {
-        producer.Put(TexoHorizontalRule());
+        ok    = producer.PutHorizontalRule();
         state = text;
     } else if (c == '-') {
         ++dash_count;
     } else {
-        producer.Put('\n');
-        for (;dash_count > 0; --dash_count) {
-            producer.Put('-');
+        ok = producer.Put('\n');
+        for (; ok && dash_count > 0; --dash_count) {
+            ok = producer.Put('-');
         }
         state = text;
-        Text(c);
+        if (ok) {
+            Text(c);
+        }
     }
 }
 
 void TexoImporterPlain::ParagraphRule(char c)
 {
     if (c == '\n') {
-        producer.Put(TexoParagraph());
+        ok = producer.Paragraph();
+    }
+    if (ok) {
+        Rule(c);
     }
-    Rule(c);
 }
diff --git a/src/plain.hpp b/src/plain.hpp
index 13a2c0c..66ee5f1 100644
--- a/src/plain.hpp
+++ b/src/plain.hpp
@@ -6,18 +6,21 @@
 #include "importer.hpp"
 
 
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+ * Texo Plain Producer
+ */
 class TexoProducerPlain: public TexoProducer {
 public:
     TexoProducerPlain(TexoExporter &exporter);
 
-    void End();
+    bool End();
 
-    void Put(const Texo &piece);
+    bool Put(char c);
 
-    void Put(const TexoParagraph &piece);
-    void Put(const TexoQuote &piece);
+    bool Paragraph();
+    bool Quote();
 
-    void Put(const TexoHorizontalRule &piece);
+    bool PutHorizontalRule();
 
 private:
     bool quoted;
@@ -26,15 +29,20 @@ private:
 };
 
 
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+ * Texo Plain Importer
+ */
 class TexoImporterPlain: public TexoImporter {
 public:
     TexoImporterPlain(TexoProducer &producer);
 
-    void End();
 
-    void Put(char c);
-    void Put(const ScriptVariable &str);
-    void Put(FILE *file);
+protected:
+    bool TrueEnd();
+
+
+    bool TruePut(char c);
+
 
 private:
     enum State {
diff --git a/src/producer.cpp b/src/producer.cpp
index 2c60d48..c650459 100644
--- a/src/producer.cpp
+++ b/src/producer.cpp
@@ -1,43 +1,314 @@
 #include "producer.hpp"
 
 
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+ * Texo Producer
+ */
 TexoProducer::TexoProducer(TexoExporter &exporter): exporter(exporter)
-{}
+{}  // Just save exporter for future use.
+
+
+bool TexoProducer::End()
+{  // By default, no checks performed, so no error produced.
+    return true;
+}
+
+
+bool TexoProducer::Put(char c)
+{  // By default characters are not escaped, error means error in exporter.
+    return exporter.Put(c);
+}
+
+
+// Block Signal Handlers
+// By default, nothing has to be done, and no error produced,
+// except for paragraphs, which must be implemented.
+bool TexoProducer::Code()             { return true; }
+bool TexoProducer::Header(int level)  { return true; }
+bool TexoProducer::Quote()            { return true; }
+
+
+// Modificator Signal Handlers
+// By default, nothing has to be done, and no error produced.
+bool TexoProducer::Bold()             { return true; }
+bool TexoProducer::Italic()           { return true; }
+bool TexoProducer::Mono()             { return true; }
+bool TexoProducer::Strike()           { return true; }
+bool TexoProducer::Underline()        { return true; }
 
-void TexoProducer::End()
+bool TexoProducer::Link(
+    const ScriptVariable &link,
+    const ScriptVariable &title
+)
+{
+    return true;
+}
+
+bool TexoProducer::Link()
+{
+    return true;
+}
+
+
+bool TexoProducer::PutImage(
+    const ScriptVariable &src,
+    const ScriptVariable &alt,
+    const ScriptVariable &title
+)
+{
+    return true;
+}
+
+bool TexoProducer::PutHorizontalRule()
+{
+    return true;
+}
+
+
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+ * Texo Strict Producer
+ */
+TexoProducerStrict::TexoProducerStrict(TexoExporter &exporter):
+    TexoProducer(exporter), block(block_none), opened(0)
 {}
 
-void TexoProducer::Put(char c)
+
+bool TexoProducerStrict::End()
 {
-    Put(Texo(c));
+    bool ok = CloseBlock();
+    block   = block_none;
+    return ok;
 }
 
-void TexoProducer::Put(const Texo &piece)
+
+bool TexoProducerStrict::Put(char c)
 {
-    exporter.Put(piece.c);
+    return Start() && TruePut(c);
 }
 
-void TexoProducer::Put(const TexoHeader &piece)
+
+bool TexoProducerStrict::Code()
 {
-    Put(TexoParagraph());
+    if (CloseBlock()) {
+        block = code;
+        return StartCode();
+    } else {
+        return false;
+    }
 }
 
-void TexoProducer::Put(const TexoQuote &piece)
+bool TexoProducerStrict::Header(int level)
 {
-    Put(TexoParagraph());
+    if (CloseBlock()) {
+        block        = header;
+        header_level = level;
+        return StartHeader(level);
+    } else {
+        return false;
+    }
 }
 
-void TexoProducer::Put(const TexoCode &piece)
+bool TexoProducerStrict::Paragraph()
 {
-    Put(TexoParagraph());
+    if (CloseBlock()) {
+        block = paragraph;
+        return StartParagraph();
+    } else {
+        return false;
+    }
 }
 
-void TexoProducer::Put(const TexoMono &piece)            {}
-void TexoProducer::Put(const TexoBold &piece)            {}
-void TexoProducer::Put(const TexoItalic &piece)          {}
-void TexoProducer::Put(const TexoUnderline &piece)       {}
-void TexoProducer::Put(const TexoStrike &piece)          {}
+bool TexoProducerStrict::Quote()
+{
+    if (CloseBlock()) {
+        block = quote;
+        return StartQuote();
+    } else {
+        return false;
+    }
+}
+
+
+bool TexoProducerStrict::Bold()
+{
+    return SwitchMod(bold);
+}
+
+bool TexoProducerStrict::Italic()
+{
+    return SwitchMod(italic);
+}
+
+bool TexoProducerStrict::Mono()
+{
+    return SwitchMod(mono);
+}
+
+bool TexoProducerStrict::Strike()
+{
+    return SwitchMod(strike);
+}
 
-void TexoProducer::Put(const TexoImage &piece)           {}
-void TexoProducer::Put(const TexoLink &piece)            {}
-void TexoProducer::Put(const TexoHorizontalRule &piece)  {}
+bool TexoProducerStrict::Underline()
+{
+    return SwitchMod(underline);
+}
+
+bool TexoProducerStrict::Link(
+    const ScriptVariable &path,
+    const ScriptVariable &title
+)
+{
+    if (IsOpened(link)) {
+        int closed = CloseMods(link);
+        if (closed >= 0) {
+            return Reopen(closed);
+        } else {
+            return false;
+        }
+    } else {
+        link_link  = &path;
+        link_title = &title;
+        return Start() && OpenMod(link);
+    }
+}
+
+bool TexoProducerStrict::Link()
+{
+    if (IsOpened(link)) {
+        int closed = CloseMods(link);
+        if (closed >= 0) {
+            return Reopen(closed);
+        } else {
+            return false;
+        }
+    }
+    return true;
+}
+
+bool TexoProducerStrict::PutImage(
+    const ScriptVariable &src,
+    const ScriptVariable &alt,
+    const ScriptVariable &title
+)
+{
+    return Start() && TruePutImage(src, alt, title);
+}
+
+bool TexoProducerStrict::PutHorizontalRule()
+{
+    return Start() && TruePutHorizontalRule();
+}
+
+
+bool TexoProducerStrict::Start()
+{
+    if (!block) {
+        block = paragraph;
+        return StartParagraph();
+    } else {
+        return true;
+    }
+}
+
+bool TexoProducerStrict::CloseBlock()
+{
+    if (CloseMods()) {
+        switch (block) {
+        case block_none: return true;
+        case code:       return CloseCode();
+        case header:     return CloseHeader(header_level);
+        case paragraph:  return CloseParagraph();
+        case quote:      return CloseQuote();
+        }
+        return true;  // Inpossible, since all cases are in switch.
+    } else {
+        return false;
+    }
+}
+
+bool TexoProducerStrict::SwitchMod(Mod mod)
+{
+    if (IsOpened(mod)) {
+        int closed = CloseMods(mod);
+        if (closed >= 0) {
+            return Reopen(closed);
+        } else {
+            return false;
+        }
+    } else {
+        return Start() && OpenMod(mod);
+    }
+}
+
+bool TexoProducerStrict::OpenMod(Mod mod)
+{
+    mods[opened] = mod;
+    ++opened;
+    switch (mod) {
+    case bold:      return StartBold();
+    case italic:    return StartItalic();
+    case link:      return StartLink(*link_link, *link_title);
+    case mono:      return StartMono();
+    case strike:    return StartStrike();
+    case underline: return StartUnderline();
+    }
+    return true;  // Inpossible, since all cases are in switch.
+}
+
+bool TexoProducerStrict::CloseMod(Mod mod)
+{
+    switch (mod) {
+    case bold:      return CloseBold();
+    case italic:    return CloseItalic();
+    case link:      return CloseLink(*link_link, *link_title);
+    case mono:      return CloseMono();
+    case strike:    return CloseStrike();
+    case underline: return CloseUnderline();
+    }
+    return true;  // Inpossible, since all cases are in switch.
+}
+
+int TexoProducerStrict::CloseMods(Mod last)
+{
+    const int old = opened;
+    while (opened) {
+        Mod top = mods[--opened];
+        if (CloseMod(top)) {
+            if (top == last) {
+                return old - opened;
+            }
+        } else {
+            return -1;
+        }
+    }
+    return old - opened;
+}
+
+bool TexoProducerStrict::CloseMods()
+{
+    bool ok = true;
+    while (ok && opened) {
+        ok = CloseMod(mods[--opened]);
+    }
+    return ok;
+}
+
+bool TexoProducerStrict::Reopen(int closed)
+{
+    bool ok         = true;
+    int  new_opened = opened + closed;
+    while (ok && opened != new_opened) {
+        ok = OpenMod(mods[opened]);
+    }
+    return ok;
+}
+
+bool TexoProducerStrict::IsOpened(Mod mod) const
+{
+    bool is = false;
+    for (int i = opened - 1; !is && i >= 0; --i) {
+        is = mods[i] == mod;
+    }
+    return is;
+}
diff --git a/src/producer.hpp b/src/producer.hpp
index 62e098d..f55cb91 100644
--- a/src/producer.hpp
+++ b/src/producer.hpp
@@ -1,37 +1,192 @@
 #ifndef TEXO_INCLUDED_PRODUCER
 #define TEXO_INCLUDED_PRODUCER
 
-#include "texo.hpp"
 #include "exporter.hpp"
 
 
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+ * Texo Producer
+ * Texo interface for producing output based on inner representation.
+ */
 class TexoProducer {
 public:
-    TexoProducer(TexoExporter &exporter);
+    TexoProducer(TexoExporter &exporter);  // Setup exporter used for output.
 
-    virtual void End();
 
-    virtual void Put(char c);
-    virtual void Put(const Texo &piece);
+    virtual bool End();  // Notify producer, what input is ended.
 
-    virtual void Put(const TexoHeader &piece);
-    virtual void Put(const TexoParagraph &piece) = 0;
-    virtual void Put(const TexoCode &piece);
-    virtual void Put(const TexoQuote &piece);
 
-    virtual void Put(const TexoMono &piece);
-    virtual void Put(const TexoBold &piece);
-    virtual void Put(const TexoItalic &piece);
-    virtual void Put(const TexoUnderline &piece);
-    virtual void Put(const TexoStrike &piece);
+    virtual bool Put(char c);  // Output c, possibly escaping it.
+
+
+    // Block Signal Handlers
+    // Only one can be opened at one moment.
+    virtual bool Code();
+    virtual bool Header(int level);
+    virtual bool Paragraph() = 0;
+    virtual bool Quote();
+
+
+    // Modificator Signal Handlers
+    // Independently switch one of text modificators.
+    virtual bool Bold();
+    virtual bool Italic();
+    virtual bool Mono();
+    virtual bool Strike();
+    virtual bool Underline();
+
+    // Switch link to given or switch it off, if no one is given.
+    virtual bool Link(
+        const ScriptVariable &link,
+        const ScriptVariable &title
+    );
+    virtual bool Link();
+
+
+    virtual bool PutImage(
+        const ScriptVariable &src,
+        const ScriptVariable &alt,
+        const ScriptVariable &title
+    );
+    virtual bool PutHorizontalRule();
 
-    virtual void Put(const TexoImage &piece);
-    virtual void Put(const TexoLink &piece);
-    virtual void Put(const TexoHorizontalRule &piece);
 
 protected:
     TexoExporter &exporter;
 };
 
 
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+ * Texo Strict Producer
+ * Converts switch-signal interface of Texo Producer into
+ * sequence of start/close signals with disjoint modificator sections,
+ * as well as block sections, which are provided on top level.
+ */
+class TexoProducerStrict: public TexoProducer {
+public:
+    TexoProducerStrict(TexoExporter &exporter);
+
+
+    bool End();
+
+
+    bool Put(char c);
+
+
+    bool Code();
+    bool Header(int level);
+    bool Paragraph();
+    bool Quote();
+
+
+    bool Bold();
+    bool Italic();
+    bool Mono();
+    bool Strike();
+    bool Underline();
+
+    bool Link(const ScriptVariable &path, const ScriptVariable &title);
+    bool Link();
+
+    bool PutImage(
+        const ScriptVariable &src,
+        const ScriptVariable &alt,
+        const ScriptVariable &title
+    );
+    bool PutHorizontalRule();
+
+
+protected:
+    virtual bool TruePut(char c) = 0;
+
+    virtual bool StartCode()            = 0;
+    virtual bool StartHeader(int level) = 0;
+    virtual bool StartParagraph()       = 0;
+    virtual bool StartQuote()           = 0;
+
+    virtual bool CloseCode()            = 0;
+    virtual bool CloseHeader(int level) = 0;
+    virtual bool CloseParagraph()       = 0;
+    virtual bool CloseQuote()           = 0;
+
+
+    virtual bool StartBold()      = 0;
+    virtual bool StartItalic()    = 0;
+    virtual bool StartMono()      = 0;
+    virtual bool StartStrike()    = 0;
+    virtual bool StartUnderline() = 0;
+
+    virtual bool CloseBold()      = 0;
+    virtual bool CloseItalic()    = 0;
+    virtual bool CloseMono()      = 0;
+    virtual bool CloseStrike()    = 0;
+    virtual bool CloseUnderline() = 0;
+
+    virtual bool StartLink(
+        const ScriptVariable &link,
+        const ScriptVariable &title
+    ) = 0;
+    virtual bool CloseLink(
+        const ScriptVariable &link,
+        const ScriptVariable &title
+    ) = 0;
+
+
+    virtual bool TruePutImage(
+        const ScriptVariable &src,
+        const ScriptVariable &alt,
+        const ScriptVariable &title
+    ) = 0;
+    virtual bool TruePutHorizontalRule() = 0;
+
+
+private:
+    enum Block {
+        block_none = 0,
+        code,
+        header,
+        paragraph,
+        quote
+    } block;
+
+    int header_level;
+
+
+    enum Mod {
+        bold,
+        italic,
+        link,
+        mono,
+        strike,
+        underline
+    } mods[6];
+    int opened;
+
+    const ScriptVariable *link_link;
+    const ScriptVariable *link_title;
+
+
+    bool Start();  // Open paragraph if no block is opened.
+
+    bool CloseBlock();
+
+    bool SwitchMod(Mod mod);
+
+    bool OpenMod(Mod mod);
+
+    bool CloseMod(Mod mod);
+
+    // Close all opened mods sequentially, down to (including) last,
+    // returning count of closed mods, or negative number in case of error.
+    int  CloseMods(Mod last);
+
+    // Close all opened mods.
+    bool CloseMods();
+
+    bool Reopen(int closed);
+
+    bool IsOpened(Mod mod) const;
+};
+
+
 #endif
diff --git a/src/script.cpp b/src/script.cpp
new file mode 100644
index 0000000..d335ff0
--- /dev/null
+++ b/src/script.cpp
@@ -0,0 +1,21 @@
+#include "script.hpp"
+
+
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+ * Texo String Exporter
+ */
+TexoExporterString::TexoExporterString(ScriptVariable &str): str(str)
+{}
+
+
+bool TexoExporterString::Put(char c)
+{
+    str += c;
+    return true;
+}
+
+bool TexoExporterString::Put(const ScriptVariable &addon)
+{
+    str += addon;
+    return true;
+}
diff --git a/src/script.hpp b/src/script.hpp
new file mode 100644
index 0000000..77f75df
--- /dev/null
+++ b/src/script.hpp
@@ -0,0 +1,25 @@
+#ifndef TEXO_INCLUDED_SCRIPT
+#define TEXO_INCLUDED_SCRIPT
+
+#include "exporter.hpp"
+
+/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
+ * Texo String Exporter
+ * Simple utility class to make output into Script Variable,
+ * which can be easily transformed into C string via c_str method.
+ */
+class TexoExporterString: public TexoExporter {
+public:
+    TexoExporterString(ScriptVariable &str);
+
+
+    bool Put(char c);
+    bool Put(const ScriptVariable &addon);
+
+
+private:
+    ScriptVariable &str;
+};
+
+
+#endif
diff --git a/src/str.cpp b/src/str.cpp
deleted file mode 100644
index 463a8dc..0000000
--- a/src/str.cpp
+++ /dev/null
@@ -1,15 +0,0 @@
-#include "str.hpp"
-
-
-TexoExporterString::TexoExporterString(ScriptVariable &str): str(str)
-{}
-
-void TexoExporterString::Put(char c)
-{
-    str += c;
-}
-
-void TexoExporterString::Put(const ScriptVariable &addon)
-{
-    str += addon;
-}
diff --git a/src/str.hpp b/src/str.hpp
deleted file mode 100644
index c7cecfc..0000000
--- a/src/str.hpp
+++ /dev/null
@@ -1,19 +0,0 @@
-#ifndef TEXO_INCLUDED_STR
-#define TEXO_INCLUDED_STR
-
-#include "exporter.hpp"
-
-
-class TexoExporterString: public TexoExporter {
-public:
-    TexoExporterString(ScriptVariable &str);
-
-    void Put(char c);
-    void Put(const ScriptVariable &addon);
-
-private:
-    ScriptVariable &str;
-};
-
-
-#endif
diff --git a/src/texo.cpp b/src/texo.cpp
deleted file mode 100644
index 99d74f8..0000000
--- a/src/texo.cpp
+++ /dev/null
@@ -1,8 +0,0 @@
-#include "texo.hpp"
-
-
-Texo::Texo(char c): c(c)
-{}
-
-TexoHeader::TexoHeader(int level): level(level)
-{}
diff --git a/src/texo.hpp b/src/texo.hpp
deleted file mode 100644
index b8ae394..0000000
--- a/src/texo.hpp
+++ /dev/null
@@ -1,61 +0,0 @@
-#ifndef TEXO_INCLUDED_TEXO
-#define TEXO_INCLUDED_TEXO
-
-#include <scrvar.hpp>
-
-
-struct Texo {
-    Texo(char c);
-    char c;
-};
-
-
-/*
- * Texo Blocks
- */
-struct TexoHeader {
-    TexoHeader(int level);
-    int level;  // Number >= 1, bigger for bigger.
-};
-
-struct TexoParagraph {};
-
-struct TexoCode {};
-
-struct TexoQuote {};
-
-
-/*
- * Texo Decorators
- */
-struct TexoMono {};
-
-struct TexoBold {};
-
-struct TexoItalic {};
-
-struct TexoUnderline {};
-
-struct TexoStrike {};
-
-
-/*
- * Texo Signals
- */
-struct TexoImage {
-    ScriptVariable path;
-    ScriptVariable title;
-    ScriptVariable alt;
-    ScriptVariable link;
-};
-
-struct TexoLink {
-    ScriptVariable text;
-    ScriptVariable link;
-    ScriptVariable title;
-};
-
-struct TexoHorizontalRule {};
-
-
-#endif