[lmi-commits] [lmi] master 5ad29f9 6/8: Generalize class wx_table_generator more robustly

[Greg Chicares]

branch: master
commit 5ad29f9b030468c7848411ff894913d5df922167
Author: Gregory W. Chicares <address@hidden>
Commit: Gregory W. Chicares <address@hidden>

    Generalize class wx_table_generator more robustly
    
    Replaced switch-on-enum with tag dispatch. Wrote a separate ctor for
    each use case. Initialized all scalar data members in ctor-initializer.
    
    This approach preserves the readability of its predecessor in that all
    initializations are grouped together for each use case. It improves
    robustness by performing initialization in the ctor-initializer; that
    is deemed to be worth adding about twenty extra lines.
    
    The only data member not mentioned in a ctor-initializer is the vector,
    which has its own default ctor.
    
    It seems inoffensive enough to duplicate the first five lines of both
    ctors; refactoring could of course turn those into a single line.
---
 group_quote_pdf_gen_wx.cpp  |  4 +--
 ledger_pdf_generator_wx.cpp |  4 +--
 wx_table_generator.cpp      | 81 +++++++++++++++++++++++++--------------------
 wx_table_generator.hpp      | 20 +++++++----
 4 files changed, 63 insertions(+), 46 deletions(-)

diff --git a/group_quote_pdf_gen_wx.cpp b/group_quote_pdf_gen_wx.cpp
index e94cf7e..da00dbf 100644
--- a/group_quote_pdf_gen_wx.cpp
+++ b/group_quote_pdf_gen_wx.cpp
@@ -725,11 +725,11 @@ void group_quote_pdf_generator_wx::save(std::string 
const& output_filename)
         }
 
     wx_table_generator table_gen
-        (vc
+        (group_quote_style_tag{}
+        ,vc
         ,pdf_writer.dc()
         ,pdf_writer.get_horz_margin()
         ,pdf_writer.get_page_width()
-        ,e_group_quote_style
         );
 
     output_aggregate_values(pdf_writer, table_gen, &pos_y);
diff --git a/ledger_pdf_generator_wx.cpp b/ledger_pdf_generator_wx.cpp
index 4dfaab0..cb5b14e 100644
--- a/ledger_pdf_generator_wx.cpp
+++ b/ledger_pdf_generator_wx.cpp
@@ -379,11 +379,11 @@ class using_illustration_table
         pdf_dc.SetFont(font);
 
         return wx_table_generator
-            (vc
+            (illustration_style_tag{}
+            ,vc
             ,writer.dc()
             ,writer.get_horz_margin()
             ,writer.get_page_width()
-            ,e_illustration_style
             );
     }
 };
diff --git a/wx_table_generator.cpp b/wx_table_generator.cpp
index 6858ba7..5a4880a 100644
--- a/wx_table_generator.cpp
+++ b/wx_table_generator.cpp
@@ -231,18 +231,23 @@ void increase_to_if_smaller(T& first, T second)
 } // Unnamed namespace.
 
 wx_table_generator::wx_table_generator
-    (std::vector<column_parameters> const& vc
+    (group_quote_style_tag                 // tag not referenced
+    ,std::vector<column_parameters> const& vc
     ,wxDC&                                 dc
     ,int                                   left_margin
     ,int                                   total_width
-    ,enum_pdf_table_style                  style
     )
-    :dc_(dc)
-    ,left_margin_(left_margin)
-    ,total_width_(total_width)
-    ,char_height_(dc_.GetCharHeight())
-    ,column_margin_(dc_.GetTextExtent("M").x)
-    ,max_header_lines_(1)
+    :dc_               (dc)
+    ,left_margin_      (left_margin)
+    ,total_width_      (total_width)
+    ,char_height_      (dc_.GetCharHeight())
+    // Arbitrarily use 1.333 line spacing.
+    ,row_height_       ((4 * char_height_ + 2) / 3)
+    ,column_margin_    (dc_.GetTextExtent("M").x)
+    ,max_header_lines_ (1)
+    ,draw_separators_  (true)
+    ,use_bold_headers_ (true)
+    ,align_right_      (false)
 {
     for(auto const& i : vc)
         {
@@ -250,35 +255,41 @@ wx_table_generator::wx_table_generator
         }
     compute_column_widths();
 
-    switch(style)
+    // Set a pen with zero width to make grid lines thin,
+    // and round cap style so that they combine seamlessly.
+    wxPen pen(*wxBLACK, 0);
+    pen.SetCap(wxCAP_ROUND);
+    dc_.SetPen(pen);
+}
+
+wx_table_generator::wx_table_generator
+    (illustration_style_tag                // tag not referenced
+    ,std::vector<column_parameters> const& vc
+    ,wxDC&                                 dc
+    ,int                                   left_margin
+    ,int                                   total_width
+    )
+    :dc_               (dc)
+    ,left_margin_      (left_margin)
+    ,total_width_      (total_width)
+    ,char_height_      (dc_.GetCharHeight())
+    ,row_height_       (char_height_)
+    ,column_margin_    (dc_.GetTextExtent("M").x)
+    ,max_header_lines_ (1)
+    ,draw_separators_  (false)
+    ,use_bold_headers_ (false)
+    // For the nonce, columns are centered by default because
+    // that's what group quotes need; this flag forces right
+    // alignment for illustrations.
+    ,align_right_      (true)
+{
+    for(auto const& i : vc)
         {
-        case e_illustration_style:
-            {
-            row_height_ = char_height_;
-            draw_separators_ = false;
-            use_bold_headers_ = false;
-            // For the nonce, columns are centered by default because
-            // that's what group quotes need; this flag forces right
-            // alignment for illustrations.
-            align_right_ = true;
-            dc_.SetPen(illustration_rule_color);
-            }
-            break;
-        case e_group_quote_style:
-            {
-            // Arbitrarily use 1.333 line spacing.
-            row_height_ = (4 * char_height_ + 2) / 3;
-            draw_separators_ = true;
-            use_bold_headers_ = true;
-            align_right_ = false;
-            // Set a pen with zero width to make grid lines thin,
-            // and round cap style so that they combine seamlessly.
-            wxPen pen(*wxBLACK, 0);
-            pen.SetCap(wxCAP_ROUND);
-            dc_.SetPen(pen);
-            }
-            break;
+        enroll_column(i.header, i.widest_text);
         }
+    compute_column_widths();
+
+    dc_.SetPen(illustration_rule_color);
 }
 
 wx_table_generator::wx_table_generator(wx_table_generator const&) = default;
diff --git a/wx_table_generator.hpp b/wx_table_generator.hpp
index ba5fffb..7e0524b 100644
--- a/wx_table_generator.hpp
+++ b/wx_table_generator.hpp
@@ -41,15 +41,13 @@ struct column_parameters
     std::string widest_text;
 };
 
-/// Specialized style used as a wx_table_generator ctor argument.
+/// Specialized styles for first wx_table_generator ctor argument.
 ///
 /// It would be possible to derive a distinct class for each use case,
 /// but style differences are not great enough to warrant that.
 
-enum enum_pdf_table_style
-    {e_illustration_style
-    ,e_group_quote_style
-    };
+class group_quote_style_tag  {};
+class illustration_style_tag {};
 
 // Color of rules and borders in illustrations.
 wxColor const illustration_rule_color(0x00, 0x2f, 0x6c);
@@ -72,11 +70,19 @@ class wx_table_generator
     static int const rows_per_group = 5;
 
     wx_table_generator
-        (std::vector<column_parameters> const& vc
+        (group_quote_style_tag
+        ,std::vector<column_parameters> const& vc
+        ,wxDC&                                 dc
+        ,int                                   left_margin
+        ,int                                   total_width
+        );
+
+    wx_table_generator
+        (illustration_style_tag
+        ,std::vector<column_parameters> const& vc
         ,wxDC&                                 dc
         ,int                                   left_margin
         ,int                                   total_width
-        ,enum_pdf_table_style                  style
         );
 
     wx_table_generator(wx_table_generator const&);