Redesigned the format_t class

6 files changed, 97 insertions, 86 deletions

diff --git a/src/exprbase.h b/src/exprbase.h
index 605c30f7..d2bf5a6d 100644
--- a/src/exprbase.h
+++ b/src/exprbase.h
@@ -118,7 +118,8 @@ public:
     return str;
   }
   void set_text(const string& txt) {
-    str = txt;
+    str	     = txt;
+    compiled = false;
   }
 
   void parse(const string& str, const parse_flags_t& flags = PARSE_DEFAULT) {
@@ -128,9 +129,7 @@ public:
   virtual void parse(std::istream&,
 		     const parse_flags_t& = PARSE_DEFAULT,
 		     const optional<string>& original_string = none) {
-    str	     = original_string ? *original_string : "<stream>";
-    context  = NULL;
-    compiled = false;
+    set_text(original_string ? *original_string : "<stream>");
   }
 	   
   void     mark_uncompiled() {
@@ -185,7 +184,9 @@ public:
     context = scope;
   }
 
-  virtual string context_to_str() const = 0;
+  virtual string context_to_str() const {
+    return empty_string;
+  }
 
   string print_to_str() const {
     std::ostringstream out;
@@ -203,8 +204,8 @@ public:
     return out.str();
   }
 
-  virtual void print(std::ostream& out) const = 0;
-  virtual void dump(std::ostream& out) const = 0;
+  virtual void print(std::ostream&) const {}
+  virtual void dump(std::ostream&) const {}
 
   result_type preview(std::ostream& out, scope_t& scope) const {
     out << _("--- Input expression ---") << std::endl;
diff --git a/src/format.cc b/src/format.cc
index f3f52f20..d949c350 100644
--- a/src/format.cc
+++ b/src/format.cc
@@ -61,8 +61,12 @@ void format_t::element_t::dump(std::ostream& out) const
   out << std::dec << int(max_width);
 
   switch (type) {
-  case STRING: out << "   str: '" << chars << "'" << std::endl; break;
-  case EXPR:   out << "  expr: "   << expr << std::endl; break;
+  case STRING:
+    out << "   str: '" << boost::get<string>(data) << "'" << std::endl;
+    break;
+  case EXPR:
+    out << "  expr: "   << boost::get<expr_t>(data) << std::endl;
+    break;
   }
 }
 
@@ -117,7 +121,7 @@ format_t::element_t * format_t::parse_elements(const string& fmt,
 
     if (q != buf) {
       current->type  = element_t::STRING;
-      current->chars = string(buf, q);
+      current->data = string(buf, q);
       q = buf;
 
       current->next.reset(new element_t);
@@ -128,14 +132,14 @@ format_t::element_t * format_t::parse_elements(const string& fmt,
       p++;
       current->type = element_t::STRING;
       switch (*p) {
-      case 'b': current->chars = "\b"; break;
-      case 'f': current->chars = "\f"; break;
-      case 'n': current->chars = "\n"; break;
-      case 'r': current->chars = "\r"; break;
-      case 't': current->chars = "\t"; break;
-      case 'v': current->chars = "\v"; break;
-      case '\\': current->chars = "\\"; break;
-      default: current->chars = string(1, *p); break;
+      case 'b':  current->data = string("\b");  break;
+      case 'f':  current->data = string("\f");  break;
+      case 'n':  current->data = string("\n");  break;
+      case 'r':  current->data = string("\r");  break;
+      case 't':  current->data = string("\t");  break;
+      case 'v':  current->data = string("\v");  break;
+      case '\\': current->data = string("\\");  break;
+      default:   current->data = string(1, *p); break;
       }
       continue;
     }
@@ -171,8 +175,8 @@ format_t::element_t * format_t::parse_elements(const string& fmt,
 
     switch (*p) {
     case '%':
-      current->type  = element_t::STRING;
-      current->chars = "%";
+      current->type = element_t::STRING;
+      current->data = string("%");
       break;
 
     case '$': {
@@ -207,7 +211,7 @@ format_t::element_t * format_t::parse_elements(const string& fmt,
       if (format_amount) p++;
 
       current->type = element_t::EXPR;
-      current->expr = parse_single_expression(p, ! format_amount);
+      current->data = parse_single_expression(p, ! format_amount);
 
       // Wrap the subexpression in calls to justify and scrub
       if (format_amount) {
@@ -216,7 +220,7 @@ format_t::element_t * format_t::parse_elements(const string& fmt,
 	else
 	  p++;
 
-	expr_t::ptr_op_t op = current->expr.get_op();
+	expr_t::ptr_op_t op = boost::get<expr_t>(current->data).get_op();
 
 	expr_t::ptr_op_t amount_op;
 	expr_t::ptr_op_t colorize_op;
@@ -238,8 +242,10 @@ format_t::element_t * format_t::parse_elements(const string& fmt,
 	expr_t::ptr_op_t arg2_node(new expr_t::op_t(expr_t::op_t::VALUE));
 	expr_t::ptr_op_t arg3_node(new expr_t::op_t(expr_t::op_t::VALUE));
 
-	arg1_node->set_value(current->min_width > 0 ? long(current->min_width) : -1);
-	arg2_node->set_value(current->max_width > 0 ? long(current->max_width) : -1);
+	arg1_node->set_value(current->min_width > 0 ?
+			     long(current->min_width) : -1);
+	arg2_node->set_value(current->max_width > 0 ?
+			     long(current->max_width) : -1);
 	arg3_node->set_value(! current->has_flags(ELEMENT_ALIGN_LEFT));
 
 	current->min_width = 0;
@@ -264,7 +270,7 @@ format_t::element_t * format_t::parse_elements(const string& fmt,
 	call2_node->set_left(justify_node);
 	call2_node->set_right(args3_node);
 
-	string prev_expr = current->expr.text();
+	string prev_expr = boost::get<expr_t>(current->data).text();
 
 	if (colorize_op) {
 	  expr_t::ptr_op_t ansify_if_node(new expr_t::op_t(expr_t::op_t::IDENT));
@@ -278,21 +284,18 @@ format_t::element_t * format_t::parse_elements(const string& fmt,
 	  call3_node->set_left(ansify_if_node);
 	  call3_node->set_right(args4_node);
 
-	  current->expr = expr_t(call3_node);
+	  current->data = expr_t(call3_node);
 	} else {
-	  current->expr = expr_t(call2_node);
+	  current->data = expr_t(call2_node);
 	}
 
-	current->expr.set_text(prev_expr);
+	boost::get<expr_t>(current->data).set_text(prev_expr);
       }
       break;
     }
 
     default:
-      current->type  = element_t::EXPR;
-      current->chars = string(FMT_PREFIX) + *p;
-      current->expr.parse(current->chars);
-      break;
+      throw_(format_error, _("Unrecognized formatting character: %1") << *p);
     }
   }
 
@@ -304,15 +307,17 @@ format_t::element_t * format_t::parse_elements(const string& fmt,
       current->next.reset(new element_t);
       current = current->next.get();
     }
-    current->type  = element_t::STRING;
-    current->chars = string(buf, q);
+    current->type = element_t::STRING;
+    current->data = string(buf, q);
   }
 
   return result.release();
 }
 
-void format_t::format(std::ostream& out_str, scope_t& scope)
+string format_t::real_calc(scope_t& scope)
 {
+  std::ostringstream out_str;
+
   for (element_t * elem = elements.get(); elem; elem = elem->next.get()) {
     std::ostringstream out;
     string name;
@@ -326,20 +331,22 @@ void format_t::format(std::ostream& out_str, scope_t& scope)
     case element_t::STRING:
       if (elem->min_width > 0)
 	out.width(elem->min_width);
-      out << elem->chars;
+      out << boost::get<string>(elem->data);
       break;
 
-    case element_t::EXPR:
+    case element_t::EXPR: {
+      expr_t& expr(boost::get<expr_t>(elem->data));
       try {
-	elem->expr.compile(scope);
+
+	expr.compile(scope);
 
 	value_t value;
-	if (elem->expr.is_function()) {
+	if (expr.is_function()) {
 	  call_scope_t args(scope);
 	  args.push_back(long(elem->max_width));
-	  value = elem->expr.get_function()(args);
+	  value = expr.get_function()(args);
 	} else {
-	  value = elem->expr.calc(scope);
+	  value = expr.calc(scope);
 	}
 	DEBUG("format.expr", "value = (" << value << ")");
 
@@ -348,10 +355,11 @@ void format_t::format(std::ostream& out_str, scope_t& scope)
       }
       catch (const calc_error&) {
 	add_error_context(_("While calculating format expression:"));
-	add_error_context(elem->expr.context_to_str());
+	add_error_context(expr.context_to_str());
 	throw;
       }
       break;
+    }
 
     default:
       assert(false);
@@ -375,6 +383,8 @@ void format_t::format(std::ostream& out_str, scope_t& scope)
       out_str << out.str();
     }
   }
+
+  return out_str.str();
 }
 
 string format_t::truncate(const unistring&  ustr,
diff --git a/src/format.h b/src/format.h
index 8043594b..516b6d7e 100644
--- a/src/format.h
+++ b/src/format.h
@@ -50,20 +50,20 @@ class unistring;
 
 DECLARE_EXCEPTION(format_error, std::runtime_error);
 
-class format_t : public noncopyable
+class format_t : public expr_base_t<string>
 {
+  typedef expr_base_t<string> base_type;
+
   struct element_t : public supports_flags<>
   {
 #define ELEMENT_ALIGN_LEFT 0x01
 
     enum kind_t { STRING, EXPR };
 
-    kind_t	type;
-    std::size_t min_width;
-    std::size_t max_width;
-    string	chars;
-    expr_t	expr;
-
+    kind_t			 type;
+    std::size_t			 min_width;
+    std::size_t			 max_width;
+    variant<string, expr_t>	 data;
     scoped_ptr<struct element_t> next;
 
     element_t() throw()
@@ -83,8 +83,7 @@ class format_t : public noncopyable
 	type	  = elem.type;
 	min_width = elem.min_width;
 	max_width = elem.max_width;
-	chars	  = elem.chars;
-	expr	  = elem.expr;
+	data	  = elem.data;
       }
       return *this;
     }
@@ -124,25 +123,28 @@ private:
 				    const optional<format_t&>& tmpl);
 
 public:
-  format_t() {
+  format_t() : base_type() {
     TRACE_CTOR(format_t, "");
   }
-  format_t(const string& _format) {
+  format_t(const string& _str, scope_t * context = NULL)
+    : base_type(context) {
     TRACE_CTOR(format_t, "const string&");
-    parse(_format);
+    if (! _str.empty())
+      parse_format(_str);
   }
   ~format_t() {
     TRACE_DTOR(format_t);
   }
 
-  void parse(const string& _format, const optional<format_t&>& tmpl = none) {
+  void parse_format(const string& _format,
+		    const optional<format_t&>& tmpl = none) {
     elements.reset(parse_elements(_format, tmpl));
-    format_string = _format;
+    set_text(_format);
   }
 
-  void format(std::ostream& out, scope_t& scope);
+  virtual result_type real_calc(scope_t& scope);
 
-  void dump(std::ostream& out) const {
+  virtual void dump(std::ostream& out) const {
     for (const element_t * elem = elements.get();
 	 elem;
 	 elem = elem->next.get())
@@ -154,12 +156,6 @@ public:
 			 const std::size_t account_abbrev_length = 0);
 };
 
-#define FMT_PREFIX "fmt_"
-#define FMT_PREFIX_LEN 4
-
-#define WANT_FMT()					\
-  (std::strncmp(p, FMT_PREFIX, FMT_PREFIX_LEN) == 0)
-
 } // namespace ledger
 
 #endif // _FORMAT_H
diff --git a/src/output.cc b/src/output.cc
index eee84553..2a6f0c20 100644
--- a/src/output.cc
+++ b/src/output.cc
@@ -51,17 +51,19 @@ format_posts::format_posts(report_t&	 _report,
   const char * f = format.c_str();
 
   if (const char * p = std::strstr(f, "%/")) {
-    first_line_format.parse(string(f, 0, p - f));
+    first_line_format.parse_format(string(f, 0, p - f));
     const char * n = p + 2;
     if (const char * p = std::strstr(n, "%/")) {
-      next_lines_format.parse(string(n, 0, p - n), first_line_format);
-      between_format.parse(string(p + 2), first_line_format);
+      next_lines_format.parse_format(string(n, 0, p - n),
+				     first_line_format);
+      between_format.parse_format(string(p + 2),
+				  first_line_format);
     } else {
-      next_lines_format.parse(n, first_line_format);
+      next_lines_format.parse_format(string(n), first_line_format);
     }
   } else {
-    first_line_format.parse(format);
-    next_lines_format.parse(format);
+    first_line_format.parse_format(format);
+    next_lines_format.parse_format(format);
   }
 }
 
@@ -80,7 +82,7 @@ void format_posts::operator()(post_t& post)
       if (last_xact != post.xact) {
 	if (last_xact) {
 	  bind_scope_t xact_scope(report, *last_xact);
-	  between_format.format(out, xact_scope);
+	  out << between_format(xact_scope);
 	}
 	print_item(out, *post.xact);
 	out << '\n';
@@ -96,16 +98,16 @@ void format_posts::operator()(post_t& post)
     if (last_xact != post.xact) {
       if (last_xact) {
 	bind_scope_t xact_scope(report, *last_xact);
-	between_format.format(out, xact_scope);
+	out << between_format(xact_scope);
       }
-      first_line_format.format(out, bound_scope);
+      out << first_line_format(bound_scope);
       last_xact = post.xact;
     }
     else if (last_post && last_post->date() != post.date()) {
-      first_line_format.format(out, bound_scope);
+      out << first_line_format(bound_scope);
     }
     else {
-      next_lines_format.format(out, bound_scope);
+      out << next_lines_format(bound_scope);
     }
 
     post.xdata().add_flags(POST_EXT_DISPLAYED);
@@ -122,17 +124,17 @@ format_accounts::format_accounts(report_t&     _report,
   const char * f = format.c_str();
 
   if (const char * p = std::strstr(f, "%/")) {
-    account_line_format.parse(string(f, 0, p - f));
+    account_line_format.parse_format(string(f, 0, p - f));
     const char * n = p + 2;
     if (const char * p = std::strstr(n, "%/")) {
-      total_line_format.parse(string(n, 0, p - n), account_line_format);
-      separator_format.parse(string(p + 2), account_line_format);
+      total_line_format.parse_format(string(n, 0, p - n), account_line_format);
+      separator_format.parse_format(string(p + 2), account_line_format);
     } else {
-      total_line_format.parse(n, account_line_format);
+      total_line_format.parse_format(n, account_line_format);
     }
   } else {
-    account_line_format.parse(format);
-    total_line_format.parse(format, account_line_format);
+    account_line_format.parse_format(format);
+    total_line_format.parse_format(format, account_line_format);
   }
 }
 
@@ -148,7 +150,8 @@ std::size_t format_accounts::post_account(account_t& account, const bool flat)
     account.xdata().add_flags(ACCOUNT_EXT_DISPLAYED);
 
     bind_scope_t bound_scope(report, account);
-    account_line_format.format(report.output_stream, bound_scope);
+    static_cast<std::ostream&>(report.output_stream)
+      << account_line_format(bound_scope);
 
     return 1;
   }
@@ -213,8 +216,8 @@ void format_accounts::flush()
   if (displayed > 1 &&
       ! report.HANDLED(no_total) && ! report.HANDLED(percent)) {
     bind_scope_t bound_scope(report, *report.session.journal->master);
-    separator_format.format(out, bound_scope);
-    total_line_format.format(out, bound_scope);
+    out << separator_format(bound_scope);
+    out << total_line_format(bound_scope);
   }
 
   out.flush();
diff --git a/src/precmd.cc b/src/precmd.cc
index 277e7b89..92483dc8 100644
--- a/src/precmd.cc
+++ b/src/precmd.cc
@@ -148,7 +148,7 @@ value_t format_command(call_scope_t& args)
   out << std::endl << _("--- Formatted string ---") << std::endl;
   bind_scope_t bound_scope(args, *post);
   out << '"';
-  fmt.format(out, bound_scope);
+  out << fmt(bound_scope);
   out << "\"\n";
 
   return NULL_VALUE;
diff --git a/src/scope.h b/src/scope.h
index cd7d93c7..44ca3229 100644
--- a/src/scope.h
+++ b/src/scope.h
@@ -54,7 +54,8 @@ struct symbol_t
     OPTION,
     PRECOMMAND,
     COMMAND,
-    DIRECTIVE
+    DIRECTIVE,
+    FORMAT
   };
 
   kind_t	   kind;