v3: cosmetic code, .is_a?(X) replaces .class==X (& some defined? & nil? tests)

45 files changed, 236 insertions, 247 deletions

diff --git a/data/doc/sisu/CHANGELOG_v3 b/data/doc/sisu/CHANGELOG_v3
index 7d05b400..b2c5b02b 100644
--- a/data/doc/sisu/CHANGELOG_v3
+++ b/data/doc/sisu/CHANGELOG_v3
@@ -35,6 +35,7 @@ http://www.jus.uio.no/sisu/pkg/src/sisu_3.3.3.orig.tar.xz
   * true ? x : y
   * if, else, remove some semicolons (;) replace with newlines
   * if true ; x, remove semicolons replace with "then"
+  * .is_a?(X) replaces .class==X (& for some defined? and nil? tests)
 
 * v3: sisu -v, provide version information, fix
 
diff --git a/lib/sisu/v3/cgi_pgsql.rb b/lib/sisu/v3/cgi_pgsql.rb
index d2c13132..83a1cecf 100644
--- a/lib/sisu/v3/cgi_pgsql.rb
+++ b/lib/sisu/v3/cgi_pgsql.rb
@@ -75,7 +75,7 @@ module  SiSU_CGI_PgSQL
         available_db_table=`psql --list`                            # system call requires psql
         available_db=available_db_table.scan(/(#{Db[:name_prefix]}\S+)/) if not available_db_table.nil?
         if available_db \
-        and available_db.class==Array
+        and available_db.is_a?(Array)
           available_db.flatten.each do |x|
             serve << x.gsub(/#{Db[:name_prefix]}(\S+)/,'\1')
           end
diff --git a/lib/sisu/v3/cgi_sql_common.rb b/lib/sisu/v3/cgi_sql_common.rb
index 5a044d5f..94026ce7 100644
--- a/lib/sisu/v3/cgi_sql_common.rb
+++ b/lib/sisu/v3/cgi_sql_common.rb
@@ -1024,8 +1024,9 @@ module SiSU_CGI_SQL
               if cgi['view']=~/text/ \
               or (cgi['view']!~/index/ and cgi['search'] !~/search db/)      #% txt endnotes
                 @counter_endn_ocn+=1
-                matched_endnote=(@search_regx.to_s.class==String && @search_regx.to_s=~/\S\S+/) \
-                ? matched=e['body'].gsub(/(<a\s+href="https?:\/\/[^><\s]+#{@search_regx}[^>]+?>|#{@search_regx})/mi,%{<span style="background-color: #{@color_match}">\\1</span>})
+                matched_endnote=(@search_regx.to_s.is_a?(String) \
+                && @search_regx.to_s=~/\S\S+/) \
+                ? (matched=e['body'].gsub(/(<a\s+href="https?:\/\/[^><\s]+#{@search_regx}[^>]+?>|#{@search_regx})/mi,%{<span style="background-color: #{@color_match}">\\1</span>}))
                 : e['body']
                 output=%{#{title}<hr><font size="2">note <b><a href="#{path_endnotes(location,@ln)}#_#{e['nr']}">#{e['nr']}</a></b> referred to from ocn <a href="#{path_html_doc(location,@ln)}##{e['ocn']}">#{e['ocn']}</a>:</font> #{matched_endnote}}
               else #elsif cgi['view']=~/index/      #doc #FIX                           #% idx endnotes
diff --git a/lib/sisu/v3/dal.rb b/lib/sisu/v3/dal.rb
index 79e12e2d..a03ed55c 100644
--- a/lib/sisu/v3/dal.rb
+++ b/lib/sisu/v3/dal.rb
@@ -445,18 +445,18 @@ module SiSU_DAL
     end
     def make_marshal_content
       marshal_dal=@make.marshal.dal_content
-      File.open(marshal_dal,'w'){|f| Marshal.dump(@data,f)} if @data.class==Array
+      File.open(marshal_dal,'w'){|f| Marshal.dump(@data,f)} if @data.is_a?(Array)
     end
     def make_marshal_metadata
       marshal_dal=@make.marshal.dal_metadata
-      File.open(marshal_dal,'w'){|f| Marshal.dump(@data,f)} if @data.class==Array
+      File.open(marshal_dal,'w'){|f| Marshal.dump(@data,f)} if @data.is_a?(Array)
     end
     def idx_html_hard_output
       if @md.book_idx \
       and @md.opt.cmd =~/M/
         filename_meta=@cf.file_meta_idx_html
-        unless @data.nil? #REMOVE earliest possible
-          @data.each {|s| p s.inspect + "\n" unless s.class==String}
+        if @data.is_a?(Array)
+          @data.each {|s| p s.inspect + "\n" unless s.is_a?(String)}
           @data.each {|s| filename_meta.puts s.strip + "\n" unless s.strip.empty?}
         end
       else
@@ -466,27 +466,27 @@ module SiSU_DAL
     end
     def make_marshal_idx_sst_html_seg
       marshal_dal=@make.marshal.dal_idx_sst_rel_html_seg
-      File.open(marshal_dal,'w'){|f| Marshal.dump(@data,f)} if @data.class==Array
+      File.open(marshal_dal,'w'){|f| Marshal.dump(@data,f)} if @data.is_a?(Array)
     end
     def make_marshal_idx_sst_rel
       marshal_dal=@make.marshal.dal_idx_sst_rel
-      File.open(marshal_dal,'w'){|f| Marshal.dump(@data,f)} if @data.class==Array
+      File.open(marshal_dal,'w'){|f| Marshal.dump(@data,f)} if @data.is_a?(Array)
     end
     def make_marshal_idx_html
       marshal_dal=@make.marshal.dal_idx_html
-      File.open(marshal_dal,'w'){|f| Marshal.dump(@data,f)} if @data.class==Array
+      File.open(marshal_dal,'w'){|f| Marshal.dump(@data,f)} if @data.is_a?(Array)
     end
     def make_marshal_idx_xhtml
       marshal_dal=@make.marshal.dal_idx_xhtml
-      File.open(marshal_dal,'w'){|f| Marshal.dump(@data,f)} if @data.class==Array
+      File.open(marshal_dal,'w'){|f| Marshal.dump(@data,f)} if @data.is_a?(Array)
     end
     def make_marshal_map_nametags
       marshal_dal=@make.marshal.dal_map_nametags
-      File.open(marshal_dal,'w'){|f| Marshal.dump(@data,f)} if @data.class==Hash
+      File.open(marshal_dal,'w'){|f| Marshal.dump(@data,f)} if @data.is_a?(Hash)
     end
     def make_marshal_map_name_ocn_htmlseg
       marshal_dal=@make.marshal.dal_map_ocn_htmlseg
-      File.open(marshal_dal,'w'){|f| Marshal.dump(@data,f)} if @data.class==Hash
+      File.open(marshal_dal,'w'){|f| Marshal.dump(@data,f)} if @data.is_a?(Hash)
     end
   end
   class Make
diff --git a/lib/sisu/v3/dal_character_check.rb b/lib/sisu/v3/dal_character_check.rb
index df14e1aa..f20d4106 100644
--- a/lib/sisu/v3/dal_character_check.rb
+++ b/lib/sisu/v3/dal_character_check.rb
@@ -93,7 +93,7 @@ module SiSU_DAL_CharacterCheck
             end
           end
         end
-        @tuned_file << dob unless dob.nil?
+        @tuned_file << dob if dob.is_a?(Object)
       end
       @tuned_file=@tuned_file.flatten.compact
       [@tuned_file,@endnote_array]
diff --git a/lib/sisu/v3/dal_doc_str.rb b/lib/sisu/v3/dal_doc_str.rb
index 0abaf4d0..6bde88e2 100644
--- a/lib/sisu/v3/dal_doc_str.rb
+++ b/lib/sisu/v3/dal_doc_str.rb
@@ -363,8 +363,8 @@ module SiSU_DAL_DocumentStructureExtract
             t_o=SiSU_DAL_DocumentStructure::ObjectComment.new.comment(h) #t_o=SiSU_DAL_DocumentStructure::ObjectLayout.new.insert(h)
             t_o
           else
-            if t_o !~/^table\{/ \
-            and not t_o.nil?
+            if t_o.is_a?(String) \
+            and t_o !~/^table\{/
               t_o=t_o.gsub(/^\n+/m,''). #check added for ruby 1.9.2 not needed in 1.8 series (tested in v2)
                 gsub(/\n+/m,"#{Mx[:tc_p]}")
               @rows += t_o + Mx[:tc_c]
@@ -385,8 +385,7 @@ module SiSU_DAL_DocumentStructureExtract
             t_o=SiSU_DAL_DocumentStructure::ObjectComment.new.comment(h) #t_o=SiSU_DAL_DocumentStructure::ObjectLayout.new.insert(h)
           end
           if @@flag['code'] \
-          and t_o.class==String \
-          and not t_o.nil? #you may need to introduce t_o.class==String test more widely
+          and t_o.is_a?(String)
             sub_array=t_o.dup + "#{Mx[:br_nl]}"
             @line_mode=sub_array.scan(/.+/)
             @line_mode=[]
@@ -461,7 +460,7 @@ module SiSU_DAL_DocumentStructureExtract
           if @@flag['poem'] \
           or @@flag['group'] \
           or @@flag['alt']
-            if t_o.class==String
+            if t_o.is_a?(String)
               t_o=t_o.gsub(/\n/m,"#{Mx[:br_nl]}").
                 gsub(/[ ][ ]/m,"#{Mx[:nbsp]*2}").
                 gsub(/#{Mx[:nbsp]}\s/,"#{Mx[:nbsp]*2}")
@@ -527,7 +526,7 @@ module SiSU_DAL_DocumentStructureExtract
       lines.each do |line|
         line=if line =~/\S/ \
         and line !~/^code\{|^\}code/ \
-        and line.class != Hash
+        and not line.is_a?(Hash)
           @@counter+=1 if @@flag['code']
           line=line.gsub(/\s\s/,"#{Mx[:nbsp]*2}").
             gsub(/#{Mx[:nbsp]}\s/,"#{Mx[:nbsp]*2}")
diff --git a/lib/sisu/v3/dal_hash_digest.rb b/lib/sisu/v3/dal_hash_digest.rb
index c30048db..8718c461 100644
--- a/lib/sisu/v3/dal_hash_digest.rb
+++ b/lib/sisu/v3/dal_hash_digest.rb
@@ -72,13 +72,13 @@ module SiSU_DAL_Hash
       sha_ =(@env.digest.type=='sha256' ? true : false)
       sha_ ? (require 'digest/sha2') : (require 'digest/md5')
       data.each do |t_o|
-        unless t_o.obj.class==Array
+        unless t_o.obj.is_a?(Array)
           t_o.obj=t_o.obj.strip
         end
         if (t_o.of !=:structure \
         && t_o.of !=:comment \
         && t_o.of !=:layout) \
-        && t_o.ocn.class==Fixnum
+        && t_o.ocn.is_a?(Fixnum)
           if sha_
             for hash_class in [ Digest::SHA256 ]
               @tuned_file << stamped(t_o,hash_class)
diff --git a/lib/sisu/v3/dal_idx.rb b/lib/sisu/v3/dal_idx.rb
index 63735bde..a90217c4 100644
--- a/lib/sisu/v3/dal_idx.rb
+++ b/lib/sisu/v3/dal_idx.rb
@@ -79,7 +79,11 @@ module SiSU_DAL_BookIndex
         && dob.ln==4
           @seg=dob.name
         end
-        idx_array << "#{dob.idx}~#{dob.ocn}~#{@seg}" if defined? dob.idx and not (dob.idx.nil? or dob.idx.empty?)
+        if defined? dob.idx \
+        and dob.idx.is_a?(String) \
+        and not dob.idx.empty?
+          idx_array << "#{dob.idx}~#{dob.ocn}~#{@seg}"
+        end
         tuned_file << dob if dob
       end
       idx_array=construct_idx_array(idx_array) if idx_array.length > 0
@@ -193,7 +197,7 @@ module SiSU_DAL_BookIndex
       idx[:xhtml] << %{\n<p class="letter" id="numeral">0 - 9</p>}
       the_idx.each do |i|
         i.each do |x|
-          if x.class==String
+          if x.is_a?(String)
             f=/^(\S)/.match(x)[1]
             if letter < f
               while letter < f
@@ -216,11 +220,11 @@ module SiSU_DAL_BookIndex
             @q=idx[:html].index(idx[:html].last)
             @r=idx[:xhtml].index(idx[:xhtml].last)
             print "\n" + x + ', ' if @md.opt.cmd =~/V/
-          elsif x.class==Array
+          elsif x.is_a?(Array)
             p 'array error? -->'
             print x
-          elsif x.class==Hash
-            if x['term_node_lev1'].class==Array
+          elsif x.is_a?(Hash)
+            if x['term_node_lev1'].is_a?(Array)
               x['term_node_lev1'].each do |a|
                 if a[:range]
                   idx[:sst_rel_html_seg][@o]=idx[:sst_rel_html_seg][@o] + %{#{Mx[:lnk_o]}#{a[:range]}#{Mx[:lnk_c]}#{Mx[:rel_o]}/#{a[:seg]}.html##{a[:ocn]}#{Mx[:rel_c]}, }
@@ -283,13 +287,13 @@ module SiSU_DAL_BookIndex
     def screen_print(the_idx)
       the_idx.each do |i|
         i.each do |x|
-          if x.class==String
+          if x.is_a?(String)
             print "\n" + x + ', '
-          elsif x.class==Array
+          elsif x.is_a?(Array)
             p 'array error? -->'
             print x
-          elsif x.class==Hash
-            if x['term_node_lev1'].class==Array
+          elsif x.is_a?(Hash)
+            if x['term_node_lev1'].is_a?(Array)
               x['term_node_lev1'].each do |a|
                 if a[:range]
                   print a[:range] + ', '
diff --git a/lib/sisu/v3/dal_numbering.rb b/lib/sisu/v3/dal_numbering.rb
index 4c7ad642..f81563f3 100644
--- a/lib/sisu/v3/dal_numbering.rb
+++ b/lib/sisu/v3/dal_numbering.rb
@@ -82,7 +82,7 @@ module SiSU_DAL_Numbering
         && dob.ocn_ #and dob.obj !~ /#{Mx[:gr_o]}Th|#{Mx[:tc_o]}#{Mx[:tc_p]}#{Mx[:tc_p]}/ #FIX
           dob.obj=dob.obj.gsub(/(.+)\n/,'\1 ') #messy, but idea is that tables should retain breaks
         end
-        unless dob.obj.class==Array
+        unless dob.obj.is_a?(Array)
           dob.obj=dob.obj.gsub(/^\s+/,'').
             gsub(/\s$/,"\n")
         end
@@ -160,7 +160,7 @@ module SiSU_DAL_Numbering
             if dob.ln==no1
               t_no1+=1; t_no2=0; t_no3=0
               title_no="#{t_no1}"
-              if not @md.seg_names.nil? \
+              if @md.seg_names.is_a?(Array) \
               and not @md.seg_names.include?(title_no)
                 if dob.ln==no1
                   dob.name="#{title_no}" if not dob.name
@@ -303,7 +303,7 @@ module SiSU_DAL_Numbering
             possible_seg_name=$1
             possible_seg_name=possible_seg_name.gsub(/(?:[:,-]|\W)/,'.').
               gsub(/\.$/,'')
-            if not @md.seg_names.nil? \
+            if @md.seg_names.is_a?(Array) \
             and not @md.seg_names.include?(possible_seg_name)
               dob.name=possible_seg_name
               dob.tags=[dob.name,dob.tags].flatten if dob.name !~/^\d+$/
@@ -313,7 +313,7 @@ module SiSU_DAL_Numbering
           end
           if dob.ln==4 \
           and dob.name                                     #extract segment name from embedded document structure info
-            if not @md.seg_names.nil? \
+            if @md.seg_names.is_a?(Array) \
             and not @md.seg_names.include?(dob.name)
               dob.tags=[dob.name,dob.tags].flatten if dob.name !~/^\d+$/
               @md.seg_names << dob.name
@@ -323,7 +323,7 @@ module SiSU_DAL_Numbering
           and not dob.name                                 #if still no segment name, provide a numerical one
             pf='_'                                         #pg='' #may use e.g. '' or '~' or '_'
             segn_auto="#{pf}#{art_filename_auto.to_s}"
-            if not @md.seg_names.nil? \
+            if @md.seg_names.is_a?(Array) \
             and not @md.seg_names.include?(segn_auto)
              dob.name=segn_auto
              dob.tags=[dob.name,dob.tags].flatten if dob.name !~/^\d+$/ #check whether will work across file types with stop signs
diff --git a/lib/sisu/v3/dal_syntax.rb b/lib/sisu/v3/dal_syntax.rb
index 839fb399..b21f94a5 100644
--- a/lib/sisu/v3/dal_syntax.rb
+++ b/lib/sisu/v3/dal_syntax.rb
@@ -238,7 +238,7 @@ module SiSU_DAL_Syntax
     def substitutions(dob)
       dob=dob.dup
       dob=if defined? @md.make.substitute[:match_and_replace] \
-      and @md.make.substitute[:match_and_replace].class == Array
+      and @md.make.substitute[:match_and_replace].is_a?(Array)
         dob=if dob.is !=:meta \
         && dob.is !=:heading_insert \
         && dob.is !=:code \
diff --git a/lib/sisu/v3/db_columns.rb b/lib/sisu/v3/db_columns.rb
index 5ae17707..7c4fa9eb 100644
--- a/lib/sisu/v3/db_columns.rb
+++ b/lib/sisu/v3/db_columns.rb
@@ -295,7 +295,7 @@ module SiSU_DbColumns
         end
         def tuple
           t=if defined? @md.creator.author_detail \
-          and @md.creator.author_detail.class==Array \
+          and @md.creator.author_detail.is_a?(Array) \
           and @md.creator.author_detail.length > 0
             txt=''
             @md.creator.author_detail.each do |h|
@@ -366,7 +366,7 @@ module SiSU_DbColumns
         end
         def tuple
           t=if defined? @md.creator.editor_detail \
-          and @md.creator.editor_detail.class==Array \
+          and @md.creator.editor_detail.is_a?(Array) \
           and @md.creator.editor_detail.length > 0
             txt=@md.creator.editor_detail #dc
             txt=''
@@ -394,7 +394,7 @@ module SiSU_DbColumns
         end
         def tuple
           t=if defined? @md.creator.contributor_detail \
-          and @md.creator.contributor_detail.class==Array \
+          and @md.creator.contributor_detail.is_a?(Array) \
           and @md.creator.contributor_detail.length > 0
             txt=@md.creator.contributor_detail #dc
             txt=''
@@ -422,7 +422,7 @@ module SiSU_DbColumns
         end
         def tuple
           t=if defined? @md.creator.illustrator_detail \
-          and @md.creator.illustrator_detail.class==Array \
+          and @md.creator.illustrator_detail.is_a?(Array) \
           and @md.creator.illustrator_detail.length > 0
             txt=@md.creator.illustrator_detail
             txt=''
@@ -450,7 +450,7 @@ module SiSU_DbColumns
         end
         def tuple
           t=if defined? @md.creator.photographer_detail \
-          and @md.creator.photographer_detail.class==Array \
+          and @md.creator.photographer_detail.is_a?(Array) \
           and @md.creator.photographer_detail.length > 0
             txt=@md.creator.photographer_detail
             txt=''
@@ -478,7 +478,7 @@ module SiSU_DbColumns
         end
         def tuple
           t=if defined? @md.creator.translator_detail \
-          and @md.creator.translator_detail.class==Array \
+          and @md.creator.translator_detail.is_a?(Array) \
           and @md.creator.translator_detail.length > 0
             txt=''
             @md.creator.translator_detail.each do |h|
@@ -505,7 +505,7 @@ module SiSU_DbColumns
         end
         def tuple
           t=if defined? @md.creator.prepared_by_detail \
-          and @md.creator.prepared_by_detail.class==Array \
+          and @md.creator.prepared_by_detail.is_a?(Array) \
           and @md.creator.prepared_by_detail.length > 0
             txt=@md.creator.prepared_by_detail
             txt=''
@@ -533,7 +533,7 @@ module SiSU_DbColumns
         end
         def tuple
           t=if defined? @md.creator.digitized_by_detail \
-          and @md.creator.digitized_by_detail.class==Array \
+          and @md.creator.digitized_by_detail.is_a?(Array) \
           and @md.creator.digitized_by_detail.length > 0
             txt=@md.creator.digitized_by_detail
             txt=''
@@ -561,7 +561,7 @@ module SiSU_DbColumns
         end
         def tuple
           t=if defined? @md.creator.audio_detail \
-          and @md.creator.audio_detail.class==Array \
+          and @md.creator.audio_detail.is_a?(Array) \
           and @md.creator.audio_detail.length > 0
             txt=@md.creator.audio_detail
             txt=''
@@ -589,7 +589,7 @@ module SiSU_DbColumns
         end
         def tuple
           t=if defined? @md.creator.video_detail \
-          and @md.creator.video_detail.class==Array \
+          and @md.creator.video_detail.is_a?(Array) \
           and @md.creator.video_detail.length > 0
             txt=''
             @md.creator.video_detail.each do |h|
@@ -1891,7 +1891,7 @@ module SiSU_DbColumns
         end
         def tuple
           t=if defined? @md.dgst \
-          and @md.dgst.class==Array \
+          and @md.dgst.is_a?(Array) \
           and @md.dgst[1]=~/\S+/
             txt=@md.dgst[1]
             ["#{name}, ","'#{txt}', "]
@@ -2025,7 +2025,7 @@ module SiSU_DbColumns
         end
         def tuple
           t=if defined? @md.dgst_skin \
-          and @md.dgst_skin.class==Array \
+          and @md.dgst_skin.is_a?(Array) \
           and @md.dgst_skin[1]=~/\S+/
             txt=@md.dgst_skin[1]
             txt=special_character_escape(txt)
diff --git a/lib/sisu/v3/db_select.rb b/lib/sisu/v3/db_select.rb
index b2773b97..a013c00b 100644
--- a/lib/sisu/v3/db_select.rb
+++ b/lib/sisu/v3/db_select.rb
@@ -78,7 +78,7 @@ module SiSU_DbSelect
         puts %{no connection with #{@sql_type} database established, createdb "#{@db.sqlite.db}"?}
         exit
       end
-      if @conn.class==NilClass
+      if @conn.is_a?(NilClass)
         db=@sql_type=='sqlite' \
         ? @db.sqlite.db
         : @db.psql.db
diff --git a/lib/sisu/v3/db_sqltxt.rb b/lib/sisu/v3/db_sqltxt.rb
index f6651724..53c15ed3 100644
--- a/lib/sisu/v3/db_sqltxt.rb
+++ b/lib/sisu/v3/db_sqltxt.rb
@@ -68,7 +68,7 @@ module SiSU_DbText
     end
     def clean_searchable_text(arr) #produce clean, searchable, plaintext from document source
       txt_arr,en=[],[]
-      arr=arr.class==String ? arr.split(/\n+/m) : arr
+      arr=(arr.is_a?(String)) ? arr.split(/\n+/m) : arr
       arr.each do |s|
         s=s.gsub(/([*\/_-])\{(.+?)\}\1/m,'\2').
           gsub(/^(?:block|group|poem|code)\{/m,'').gsub(/^\}(?:block|group|poem|code)/m,'').
diff --git a/lib/sisu/v3/dbi_discreet.rb b/lib/sisu/v3/dbi_discreet.rb
index fc10fd71..07814a1a 100644
--- a/lib/sisu/v3/dbi_discreet.rb
+++ b/lib/sisu/v3/dbi_discreet.rb
@@ -106,7 +106,7 @@ module  SiSU_DBI_Discreet                               #% database building
         puts msg
         exit
       end
-      if conn.class==NilClass
+      if conn.is_a?(NilClass)
         puts msg
         exit
       end
diff --git a/lib/sisu/v3/epub_format.rb b/lib/sisu/v3/epub_format.rb
index 06a6d623..cc98219c 100644
--- a/lib/sisu/v3/epub_format.rb
+++ b/lib/sisu/v3/epub_format.rb
@@ -1838,7 +1838,7 @@ WOK
     attr_accessor :md,:t_o,:txt,:ocn,:format,:table,:link,:linkname,:paranum,:p_num,:headname,:banner,:url
     def initialize(md,t_o)
       @md,@t_o=md,t_o
-      if t_o.class==Hash
+      if t_o.is_a?(Hash)
         @txt            =t_o[:txt]            || nil
         @ocn            =t_o[:ocn]            || nil
         @ocn_display    =t_o[:ocn_display]    || nil
diff --git a/lib/sisu/v3/epub_segments.rb b/lib/sisu/v3/epub_segments.rb
index 896ed152..5a3f3092 100644
--- a/lib/sisu/v3/epub_segments.rb
+++ b/lib/sisu/v3/epub_segments.rb
@@ -271,9 +271,9 @@ WOK
             @@get_hash_to=dob.name
             @@get_hash_fn=dob.name
           end
-          if dob.obj.class==String
+          if dob.obj.is_a?(String)
             markup(dob)
-          elsif dob.obj.class==Array
+          elsif dob.obj.is_a?(Array)
             dob.obj.each do |pg|
               markup(pg)
             end
diff --git a/lib/sisu/v3/epub_tune.rb b/lib/sisu/v3/epub_tune.rb
index a9bf31b0..1362815e 100644
--- a/lib/sisu/v3/epub_tune.rb
+++ b/lib/sisu/v3/epub_tune.rb
@@ -96,7 +96,7 @@ module SiSU_EPUB_Tune
     end
     def clean
       html=@html
-      str=if html.class==String
+      str=if html.is_a?(String)
         html
       else html.obj
       end
diff --git a/lib/sisu/v3/harvest_authors.rb b/lib/sisu/v3/harvest_authors.rb
index 6036816d..7c044425 100644
--- a/lib/sisu/v3/harvest_authors.rb
+++ b/lib/sisu/v3/harvest_authors.rb
@@ -157,7 +157,7 @@ module SiSU_HarvestAuthors
         idx_array.each do |idx|
           idx[:author][:last_first_format_a].each do |author|
             author=author.strip
-            if @@the_idx_authors[lang][author].class==NilClass
+            if @@the_idx_authors[lang][author].is_a?(NilClass)
               @@the_idx_authors[lang][author]={ md: [] }
             end
             @@the_idx_authors[lang][author][:md] << { filename: idx[:filename], file: idx[:file], author: idx[:author], title: idx[:title], date: idx[:date], page: idx[:page], lang: idx[:lang] }
@@ -201,7 +201,7 @@ module SiSU_HarvestAuthors
     def html_file_close
       @the_idx.keys.each do |lng|
         @output[lng][:html].close
-        @output[lng][:html_mnt].close if @output[lng][:html_mnt].class==File
+        @output[lng][:html_mnt].close if @output[lng][:html_mnt].is_a?(File)
       end
     end
     def html_print
@@ -305,12 +305,12 @@ WOK
 </html>
 WOK
         @the_idx.keys.each do |lng|
-          @output[lng][:html_mnt] << a if @output[lng][:html_mnt].class==File
+          @output[lng][:html_mnt] << a if @output[lng][:html_mnt].is_a?(File)
           @output[lng][:html] << a
         end
       end
       def do_html(lng,html)
-        @output[lng][:html_mnt] << html if @output[lng][:html_mnt].class==File
+        @output[lng][:html_mnt] << html if @output[lng][:html_mnt].is_a?(File)
         @output[lng][:html] << html
       end
       def do_string_name(lng,attrib,string)
@@ -324,7 +324,7 @@ WOK
           while @letter < f
             if @alph.length > 0
               @letter=@alph.shift
-              if @output[lng][:html_mnt].class==File
+              if @output[lng][:html_mnt].is_a?(File)
                 @output[lng][:html_mnt] << %{\n<p class="letter"><a name="#{@letter}"></p>#{@letter}</a><p class="book_index_lev1"><a name="#{@letter.downcase}"></a></p>}
               end
               @output[lng][:html] << %{\n<p class="letter"><a name="#{@letter}">#{@letter}</a></p><p class="book_index_lev1"><a name="#{@letter.downcase}"></a></p>}
@@ -340,7 +340,7 @@ WOK
             do_string_name(lng,'',a)
             name=a[0].sub(/(.+?)(?:,.+|$)/,'\1').gsub(/\s+/,'_')
             x = %{<p class="author"><a name="#{name}">#{a[0]}</a></p>}
-            if @output[lng][:html_mnt].class==File
+            if @output[lng][:html_mnt].is_a?(File)
               @output[lng][:html_mnt] << x
             end
             @output[lng][:html] << x
@@ -356,13 +356,13 @@ WOK
                 "../#{x[:file]}/#{x[:page]}"
               end
               work=[ "#{x[:date]} #{x[:title]}", %{<p class="publication">#{x[:date]} <a href="#{manifest_at}">#{x[:title]}</a>, #{x[:author][:authors_s]}</p>} ]
-              works<<=(@output[lng][:html_mnt].class==File) \
+              works<<=(@output[lng][:html_mnt].is_a?(File)) \
               ? (work.concat([%{<p class="publication">[<a href="#{x[:file]}.sst">src</a>]&nbsp;&nbsp;#{x[:date]} <a href="file://#{manifest_at}">#{x[:title]}</a>, #{x[:author][:authors_s]} -- [<a href="#{x[:file]}.sst">#{x[:file]}.sst</a>]</p>}]))
               : work
             end
             works.sort_by {|x| x[0]}.each do |x|
               @output[lng][:html] << x[1]
-              @output[lng][:html_mnt] << x[2] if @output[lng][:html_mnt].class==File
+              @output[lng][:html_mnt] << x[2] if @output[lng][:html_mnt].is_a?(File)
             end
           end
         end
diff --git a/lib/sisu/v3/harvest_topics.rb b/lib/sisu/v3/harvest_topics.rb
index 3487ab6b..952f1411 100644
--- a/lib/sisu/v3/harvest_topics.rb
+++ b/lib/sisu/v3/harvest_topics.rb
@@ -233,8 +233,8 @@ module SiSU_HarvestTopics
       end
       @idx_a.each do |c|
         if c.length > 1 \
-        and c.class == Array
-          if c[2].class == Hash
+        and c.is_a?(Array)
+          if c[2].is_a?(Hash)
             c[1].each do |alt|
               v=key_create(c,alt)
               @the_a << [v, c[2]] if v
@@ -242,8 +242,8 @@ module SiSU_HarvestTopics
           end
         end
         if c.length > 2 \
-        and c.class == Array
-          if c[3].class == Hash
+        and c.is_a?(Array)
+          if c[3].is_a?(Hash)
             c[2].each do |alt|
               v=key_create(c,alt)
               @the_a << [v, c[3]] if v
@@ -251,8 +251,8 @@ module SiSU_HarvestTopics
           end
         end
         if c.length > 3 \
-        and c.class == Array
-          if c[4].class == Hash
+        and c.is_a?(Array)
+          if c[4].is_a?(Hash)
             c[3].each do |alt|
               v=key_create(c,alt)
               @the_a << [v, c[4]] if v
@@ -260,8 +260,8 @@ module SiSU_HarvestTopics
           end
         end
         if c.length > 4 \
-        and c.class == Array
-          if c[5].class == Hash
+        and c.is_a?(Array)
+          if c[5].is_a?(Hash)
             c[4].each do |alt|
               v=key_create(c,alt)
               @the_a << [v, c[5]] if v
@@ -269,8 +269,8 @@ module SiSU_HarvestTopics
           end
         end
         if c.length > 5 \
-        and c.class == Array
-          if c[6].class == Hash
+        and c.is_a?(Array)
+          if c[6].is_a?(Hash)
             c[5].each do |alt|
               v=key_create(c,alt)
               @the_a << [v, c[6]] if v
@@ -278,8 +278,7 @@ module SiSU_HarvestTopics
           end
         end
       end
-      y=@the_a.sort_by { |x| x[0] }
-      #y.each {|z| puts z}
+      y=@the_a.sort_by { |x| x[0] } #; y.each {|z| puts z}
     end
     def construct_book_topic_hash(y)
       @the_h={}
@@ -369,22 +368,22 @@ module SiSU_HarvestTopics
     end
     def traverse_base
       @the_h.each_pair do |x0,y|
-        puts '  '*0 + x0 if x0.class == String
-        if y.class == Hash
+        puts '  '*0 + x0 if x0.is_a?(String)
+        if y.is_a?(Hash)
           y.each_pair do |x1,y|
-            puts '  '*1 + x1 if x1.class == String
-            if y.class == Hash
+            puts '  '*1 + x1 if x1.is_a?(String)
+            if y.is_a?(Hash)
               y.each_pair do |x2,y|
-                puts '  '*2 + x2 if x2.class == String
-                if y.class == Hash
+                puts '  '*2 + x2 if x2.is_a?(String)
+                if y.is_a?(Hash)
                   y.each_pair do |x3,y|
-                    puts '  '*3 + x3 if x3.class == String
-                    if y.class == Hash
+                    puts '  '*3 + x3 if x3.is_a?(String)
+                    if y.is_a?(Hash)
                       y.each_pair do |x4,y|
-                        puts '  '*4 + x4 if x4.class == String
-                        if y.class == Hash
+                        puts '  '*4 + x4 if x4.is_a?(String)
+                        if y.is_a?(Hash)
                           y.each_pair do |x5,y|
-                            puts '  '*5 + x5 if x5.class == String
+                            puts '  '*5 + x5 if x5.is_a?(String)
                           end
                         end
                       end
@@ -399,37 +398,37 @@ module SiSU_HarvestTopics
     end
     def traverse
       @the_h.each_pair do |x0,y|
-        puts '  '*0 + x0 if x0.class == String
-        if y.class == Hash
+        puts '  '*0 + x0 if x0.is_a?(String)
+        if y.is_a?(Hash)
           if y.has_key?(:md)
             y[:md].each { |x| puts '  '*5 + x[:title] }
           end
           y.each_pair do |x1,y|
-            puts '  '*1 + x1 if x1.class == String
-            if y.class == Hash
+            puts '  '*1 + x1 if x1.is_a?(String)
+            if y.is_a?(Hash)
               if y.has_key?(:md)
                 y[:md].each { |x| puts '  '*5 + x[:title] }
               end
               y.each_pair do |x2,y|
-                puts '  '*2 + x2 if x2.class == String
-                if y.class == Hash
+                puts '  '*2 + x2 if x2.is_a?(String)
+                if y.is_a?(Hash)
                   if y.has_key?(:md)
                     y[:md].each { |x| puts '  '*5 + x[:title] }
                   end
                   y.each_pair do |x3,y|
-                    puts '  '*3 + x3 if x3.class == String
-                    if y.class == Hash
+                    puts '  '*3 + x3 if x3.is_a?(String)
+                    if y.is_a?(Hash)
                       if y.has_key?(:md)
                         y[:md].each { |x| puts '  '*5 + x[:title] }
                       end
                       y.each_pair do |x4,y|
-                        puts '  '*4 + x4 if x4.class == String
-                        if y.class == Hash
+                        puts '  '*4 + x4 if x4.is_a?(String)
+                        if y.is_a?(Hash)
                           if y.has_key?(:md)
                             y[:md].each { |x| puts '  '*5 + x[:title] }
                           end
                           y.each_pair do |x5,y|
-                            puts '  '*5 + x4 if x4.class == String
+                            puts '  '*5 + x4 if x4.is_a?(String)
                           end
                         end
                       end
@@ -480,7 +479,7 @@ module SiSU_HarvestTopics
     def html_file_close
       @the_idx.keys.each do |lng|
         @output[lng][:html].close
-        @output[lng][:html_mnt].close if @output[lng][:html_mnt].class==File
+        @output[lng][:html_mnt].close if @output[lng][:html_mnt].is_a?(File)
       end
     end
     def html_print
@@ -496,11 +495,11 @@ module SiSU_HarvestTopics
       def html_body_traverse
         @the_idx.each_pair do |x0,y|
           lng=x0
-          if x0.class == String
+          if x0.is_a?(String)
             #do_string_name(lng,'lev0',x0)
             #puts '  '*0 + x0
           end
-          if y.class == Hash
+          if y.is_a?(Hash)
             if y.has_key?(:md)
               y[:md].each do |x|
                 #do_hash(lng,attrib,x) #lv==0 ? 
@@ -508,11 +507,11 @@ module SiSU_HarvestTopics
               end
             end
             y.each_pair do |x1,y|
-              if x1.class == String
+              if x1.is_a?(String)
                 do_string_name(lng,'lev0',x1)
                 #puts '  '*1 + x1
               end
-              if y.class == Hash
+              if y.is_a?(Hash)
                 if y.has_key?(:md)
                   y[:md].each do |x|
                     do_hash(lng,0,x)
@@ -520,11 +519,11 @@ module SiSU_HarvestTopics
                   end
                 end
                 y.each_pair do |x2,y|
-                  if x2.class == String
+                  if x2.is_a?(String)
                     do_string(lng,'lev1',x2)
                     #puts '  '*2 + x2
                   end
-                  if y.class == Hash
+                  if y.is_a?(Hash)
                     if y.has_key?(:md)
                       y[:md].each do |x|
                         do_hash(lng,1,x)
@@ -532,11 +531,11 @@ module SiSU_HarvestTopics
                       end
                     end
                     y.each_pair do |x3,y|
-                      if x3.class == String
+                      if x3.is_a?(String)
                         do_string(lng,'lev2',x3)
                         #puts '  '*3 + x3
                       end
-                      if y.class == Hash
+                      if y.is_a?(Hash)
                         if y.has_key?(:md)
                           y[:md].each do |x|
                             do_hash(lng,2,x)
@@ -544,11 +543,11 @@ module SiSU_HarvestTopics
                           end
                         end
                         y.each_pair do |x4,y|
-                          if x4.class == String
+                          if x4.is_a?(String)
                             do_string(lng,'lev3',x4)
                             #puts '  '*4 + x4
                           end
-                          if y.class == Hash
+                          if y.is_a?(Hash)
                             if y.has_key?(:md)
                               y[:md].each do |x|
                                 do_hash(lng,3,x)
@@ -556,7 +555,7 @@ module SiSU_HarvestTopics
                               end
                             end
                             y.each_pair do |x5,y|
-                              if x5.class == String
+                              if x5.is_a?(String)
                                 do_string(lng,'lev4',x5)
                                 #puts '  '*5 + x5
                               end
@@ -667,7 +666,7 @@ WOK
 </html>
 WOK
         @the_idx.keys.each do |lng|
-          @output[lng][:html_mnt] << a if @output[lng][:html_mnt].class==File
+          @output[lng][:html_mnt] << a if @output[lng][:html_mnt].is_a?(File)
           @output[lng][:html] << a
         end
       end
@@ -675,12 +674,12 @@ WOK
         @output[lng][:html] << html
       end
       def do_html_maintenance(lng,html)
-        @output[lng][:html_mnt] << html if @output[lng][:html_mnt].class==File
+        @output[lng][:html_mnt] << html if @output[lng][:html_mnt].is_a?(File)
       end
       def do_string(lng,attrib,string)
         html=%{<p class="#{attrib}">#{string}</p>}
         do_html(lng,html)
-        do_html_maintenance(lng,html) if @output[lng][:html_mnt].class==File
+        do_html_maintenance(lng,html) if @output[lng][:html_mnt].is_a?(File)
       end
       def do_string_default(lng,attrib,string)
         html=%{<p class="#{attrib}">#{string}</p>}
@@ -688,7 +687,7 @@ WOK
       end
       def do_string_maintenance(lng,attrib,string)
         html=%{<p class="#{attrib}">#{string}</p>}
-        do_html_maintenance(lng,html) if @output[lng][:html_mnt].class==File
+        do_html_maintenance(lng,html) if @output[lng][:html_mnt].is_a?(File)
       end
       def do_string_name(lng,attrib,string)
         f=/^(\S)/.match(string)[1]
@@ -701,7 +700,7 @@ WOK
           while @letter < f
             if @alph.length > 0
               @letter=@alph.shift
-              if @output[lng][:html_mnt].class==File
+              if @output[lng][:html_mnt].is_a?(File)
                 @output[lng][:html_mnt] << %{\n<p class="letter"><a name="#{@letter}">#{@letter}</a></p><p class="book_index_lev1"><a name="#{@letter.downcase}"></a></p>}
               end
               @output[lng][:html] << %{\n<p class="letter"><a name="#{@letter}">#{@letter}</a></p><p class="book_index_lev1"><a name="#{@letter.downcase}"></a></p>}
@@ -712,7 +711,7 @@ WOK
         name=string.strip.gsub(/\s+/,'_')
         html=%{<p class="#{attrib}"><a name="#{name}">#{string}</a></p>}
         do_html(lng,html)
-        do_html_maintenance(lng,html) if @output[lng][:html_mnt].class==File
+        do_html_maintenance(lng,html) if @output[lng][:html_mnt].is_a?(File)
       end
       def do_array(lng,lv,array)
         lv+=1
@@ -733,7 +732,7 @@ WOK
         do_string_default(lng,attrib,html)
       end
       def do_hash_md_maintenance(lng,attrib,hash)
-        if @output[lng][:html_mnt].class==File #should not be run for presentation output
+        if @output[lng][:html_mnt].is_a?(File) #should not be run for presentation output
           html=%{[<a href="#{hash[:file]}.sst">src</a>]&nbsp;&nbsp;<a href="file://#{@env.path.output}/#{hash[:file]}/#{hash[:page]}">#{hash[:title]}</a> - #{hash[:author]}}
           do_string_maintenance(lng,attrib,html)
         end
@@ -765,16 +764,15 @@ WOK
         end
       end
       def do_case(lng,lv,a)
-        y = a.class
-        case
-        when y==String
+        case a
+        when String
           attrib="lev#{lv}"
           if a=~/S/
             lv==0 ? do_string_name(lng,attrib,a) : do_string(lng,attrib,a)
           end
-        when y==Array
+        when Array
           do_array(lng,lv,a)
-        when y==Hash
+        when Hash
           do_hash(lng,lv,a)
         end
       end
diff --git a/lib/sisu/v3/html_format.rb b/lib/sisu/v3/html_format.rb
index 1b950358..e16cbc5d 100644
--- a/lib/sisu/v3/html_format.rb
+++ b/lib/sisu/v3/html_format.rb
@@ -903,7 +903,7 @@ WOK
     attr_accessor :md,:t_o,:txt,:ocn,:format,:table,:link,:linkname,:paranum,:p_num,:headname,:banner,:url
     def initialize(md,t_o)
       @md,@t_o=md,t_o
-      if t_o.class==Hash
+      if t_o.is_a?(Hash)
         @txt            =t_o[:txt]            || nil
         @ocn            =t_o[:ocn]            || nil
         @ocn_display    =t_o[:ocn_display]    || nil
diff --git a/lib/sisu/v3/html_promo.rb b/lib/sisu/v3/html_promo.rb
index a2edea47..387da244 100644
--- a/lib/sisu/v3/html_promo.rb
+++ b/lib/sisu/v3/html_promo.rb
@@ -98,7 +98,7 @@ module SiSU_HTML_Promo
         elsif @flag[:sk]                                   #promo set in associated skin
           promo_array=@vz.widget_promo
         elsif @flag[:rc]                                   #promo set in rc file
-          promo_array=if @rc['html']['promo'].class==String
+          promo_array=if @rc['html']['promo'].is_a?(String)
             @rc['html']['promo'].split(/[,;]\s*/)
           else @rc['html']['promo']
           end
@@ -406,7 +406,7 @@ WOK
                 adverts << output_form_select(type,id)
               else
                 if defined? @ad[:promo][category][type][id] \
-                and @ad[:promo][category][type][id].class==Array \
+                and @ad[:promo][category][type][id].is_a?(Array) \
                 and @ad[:promo][category][type][id].length > 0
                   adverts << @ad[:promo][category][type][id].join("\n")
                 end
diff --git a/lib/sisu/v3/html_segments.rb b/lib/sisu/v3/html_segments.rb
index bb77cb36..14c13d36 100644
--- a/lib/sisu/v3/html_segments.rb
+++ b/lib/sisu/v3/html_segments.rb
@@ -312,9 +312,9 @@ module SiSU_HTML_Seg
             @@get_hash_to=dob.name
             @@get_hash_fn=dob.name
           end
-          if dob.obj.class==String
+          if dob.obj.is_a?(String)
             markup(dob)
-          elsif dob.obj.class==Array
+          elsif dob.obj.is_a?(Array)
             dob.obj.each do |pg|
               markup(pg)
             end
diff --git a/lib/sisu/v3/html_tune.rb b/lib/sisu/v3/html_tune.rb
index f7b60cff..05126ede 100644
--- a/lib/sisu/v3/html_tune.rb
+++ b/lib/sisu/v3/html_tune.rb
@@ -101,7 +101,7 @@ module SiSU_HTML_Tune
     end
     def clean
       html=@html
-      str=if html.class==String
+      str=if html.is_a?(String)
         html
       else html.obj
       end
diff --git a/lib/sisu/v3/hub.rb b/lib/sisu/v3/hub.rb
index 2ab95052..8a67ce10 100644
--- a/lib/sisu/v3/hub.rb
+++ b/lib/sisu/v3/hub.rb
@@ -141,7 +141,7 @@ module SiSU
       number_of_files={}
       @opt.files.each_with_index do |fns,i|
         fn=fns.gsub(/(?:~(?:#{@r}))?\.ss[tm]$/,'')
-        if number_of_files[fn].class == Array
+        if number_of_files[fn].is_a?(Array)
           number_of_files[fn] << i
         else
           number_of_files.store(fn,[i])
diff --git a/lib/sisu/v3/manifest.rb b/lib/sisu/v3/manifest.rb
index 743bc090..fdacf164 100644
--- a/lib/sisu/v3/manifest.rb
+++ b/lib/sisu/v3/manifest.rb
@@ -697,7 +697,7 @@ WOK
           @manifest[:html] << %{<tr><th class="left"><p class="bold_left">#{@translate.topic_register}:</p></th><td>\n}
           @md.topic_register_array.each do |t|
             t.each_with_index do |st,i|
-              if st.class==Array
+              if st.is_a?(Array)
                 st.each do |v|
                   @manifest[:html] << %{<p class="it#{i}">#{v}</p>\n}
                 end
diff --git a/lib/sisu/v3/manpage.rb b/lib/sisu/v3/manpage.rb
index 31a64a57..81f2ed2c 100644
--- a/lib/sisu/v3/manpage.rb
+++ b/lib/sisu/v3/manpage.rb
@@ -415,7 +415,7 @@ WOK
         filename_manpage=SiSU_Env::FileOp.new(@md).write_file.manpage
         @sisu=[]
         @content.each do |para|                                                # this is a hack
-          if para.class==Array \
+          if para.is_a?(Array) \
           and para.length > 0
             para.each do |line|
               line=line.gsub(/\s+$/m,'')
diff --git a/lib/sisu/v3/odf.rb b/lib/sisu/v3/odf.rb
index d4d16b1d..807d2832 100644
--- a/lib/sisu/v3/odf.rb
+++ b/lib/sisu/v3/odf.rb
@@ -386,7 +386,7 @@ module SiSU_ODF
       end
       def footnote(t_o)
         str=if defined? t_o.obj then t_o.obj
-        elsif t_o.class==String then t_o
+        elsif t_o.is_a?(String) then t_o
         end
         if str
           @astx||=10000
@@ -421,7 +421,7 @@ module SiSU_ODF
           end
         end
         if defined? t_o.obj     then t_o.obj=str
-        elsif t_o.class==String then t_o=str
+        elsif t_o.is_a?(String) then t_o=str
         end
         t_o
       end
diff --git a/lib/sisu/v3/odf_format.rb b/lib/sisu/v3/odf_format.rb
index 62eae47a..adfcf684 100644
--- a/lib/sisu/v3/odf_format.rb
+++ b/lib/sisu/v3/odf_format.rb
@@ -127,7 +127,7 @@ module SiSU_ODF_Format
   class FormatTextObject
     def initialize(md,t_o)
       @md,@t_o=md,t_o
-      if t_o.class==Hash
+      if t_o.is_a?(Hash)
         @txt =t_o[:txt]            || nil
       else
         p t_o.class
diff --git a/lib/sisu/v3/param.rb b/lib/sisu/v3/param.rb
index 7a416bd9..64baf271 100644
--- a/lib/sisu/v3/param.rb
+++ b/lib/sisu/v3/param.rb
@@ -165,10 +165,10 @@ module SiSU_Param
       end
       def validate_length(s,l,n)
         #s=(s.length <= l) ? s : nil
-        s=if s.class==String \
+        s=if s.is_a?(String) \
         and s.length <= l
           s
-        elsif s.class==NilClass
+        elsif s.is_a?(NilClass)
           nil
         elsif s.class !=String
           STDERR.puts "#{n} is #{s.class}: programming error, String expected #{__FILE__}:#{__LINE__}"
@@ -308,7 +308,7 @@ module SiSU_Param
           names=@h['editor'] \
           ? name_format(@h['editor'])
           : nil
-          s=(names.class==Hash) \
+          s=(names.is_a?(Hash)) \
           ? names[:name_str]
           : nil
           s=if s
@@ -321,7 +321,7 @@ module SiSU_Param
           names=@h['editor'] \
           ? name_format(@h['editor'])
           : nil
-          (names.class==Hash) \
+          (names.is_a?(Hash)) \
           ? names[:name_a_h]
           : nil
         end
@@ -329,7 +329,7 @@ module SiSU_Param
           names=@h['contributor'] \
           ? name_format(@h['contributor'])
           : nil
-          s=(names.class==Hash) \
+          s=(names.is_a?(Hash)) \
           ? names[:name_str]
           : nil
           s=if s
@@ -342,7 +342,7 @@ module SiSU_Param
           names=@h['contributor'] \
           ? name_format(@h['contributor'])
           : nil
-          (names.class==Hash) \
+          (names.is_a?(Hash)) \
           ? names[:name_a_h]
           : nil
         end
@@ -350,7 +350,7 @@ module SiSU_Param
           names=@h['illustrator'] \
           ? name_format(@h['illustrator'])
           : nil
-          s=(names.class==Hash) \
+          s=(names.is_a?(Hash)) \
           ? names[:name_str]
           : nil
           s=if s
@@ -363,7 +363,7 @@ module SiSU_Param
           names=@h['illustrator'] \
           ? name_format(@h['illustrator'])
           : nil
-          (names.class==Hash) \
+          (names.is_a?(Hash)) \
           ? names[:name_a_h]
           : nil
         end
@@ -371,7 +371,7 @@ module SiSU_Param
           names=@h['photographer'] \
           ? name_format(@h['photographer'])
           : nil
-          s=(names.class==Hash) \
+          s=(names.is_a?(Hash)) \
           ? names[:name_str]
           : nil
           s=if s
@@ -384,7 +384,7 @@ module SiSU_Param
           names=@h['photographer'] \
           ? name_format(@h['photographer'])
           : nil
-          (names.class==Hash) \
+          (names.is_a?(Hash)) \
           ? names[:name_a_h]
           : nil
         end
@@ -392,7 +392,7 @@ module SiSU_Param
           names=@h['translator'] \
           ? name_format(@h['translator'])
           : nil
-          s=(names.class==Hash) \
+          s=(names.is_a?(Hash)) \
           ? names[:name_str]
           : nil
           s=if s
@@ -405,7 +405,7 @@ module SiSU_Param
           names=@h['translator'] \
           ? name_format(@h['translator'])
           : nil
-          (names.class==Hash) \
+          (names.is_a?(Hash)) \
           ? names[:name_a_h]
           : nil
         end
@@ -413,7 +413,7 @@ module SiSU_Param
           names=@h['audio'] \
           ? name_format(@h['audio'])
           : nil
-          s=(names.class==Hash) \
+          s=(names.is_a?(Hash)) \
           ? names[:name_str]
           : nil
           s=if s
@@ -426,7 +426,7 @@ module SiSU_Param
           names=@h['audio'] \
           ? name_format(@h['audio'])
           : nil
-          (names.class==Hash) \
+          (names.is_a?(Hash)) \
           ? names[:name_a_h]
           : nil
         end
@@ -434,7 +434,7 @@ module SiSU_Param
           names=@h['digitized_by'] \
           ? name_format(@h['digitized_by'])
           : nil
-          s=(names.class==Hash) \
+          s=(names.is_a?(Hash)) \
           ? names[:name_str]
           : nil
           s=if s
@@ -447,7 +447,7 @@ module SiSU_Param
           names=@h['digitized_by'] \
           ? name_format(@h['digitized_by'])
           : nil
-          (names.class==Hash) \
+          (names.is_a?(Hash)) \
           ? names[:name_a_h]
           : nil
         end
@@ -455,7 +455,7 @@ module SiSU_Param
           names=@h['prepared_by'] \
           ? name_format(@h['prepared_by'])
           : nil
-          s=(names.class==Hash) \
+          s=(names.is_a?(Hash)) \
           ? names[:name_str]
           : nil
           s=if s
@@ -469,7 +469,7 @@ module SiSU_Param
           ? name_format(@h['prepared_by'])
           : nil
           names=name_format(@h['prepared_by'])
-          (names.class==Hash) \
+          (names.is_a?(Hash)) \
           ? names[:name_a_h]
           : nil
         end
@@ -1186,7 +1186,7 @@ module SiSU_Param
             SiSU_Screen::Ansi.new(@opt.cmd,'No SiSU markup version provided').warn if @opt.cmd =~/[VM]/
           end
         else
-          mv=if defined? @markup_version.determined and not @markup_version.determined.nil?
+          mv=if @markup_version.determined.is_a?(Float)
             x=@markup_version.determined
             "markup version determined #{x}"
           else ''
@@ -1406,17 +1406,17 @@ module SiSU_Param
         @ec[:multimedia]=@ec[:multimedia].uniq.flatten.sort
         unless @rights
           if defined? @creator.author \
-          and @creator.author \
+          and @creator.author.is_a?(String) \
           and defined? @date.published \
-          and @date.published
+          and @date.published.is_a?(String)
             @rights=SiSU_Param::Parameters::MdDefault.new.rights(@creator.author,@date.published)
           elsif defined? @creator.author \
-          and @creator.author
+          and @creator.author.is_a?(String)
             @rights=SiSU_Param::Parameters::MdDefault.new.rights("[#{@creator.author}]",'')
           end
         end
         if defined? @classify.topic_register \
-        and not @classify.topic_register.nil? \
+        and @classify.topic_register.is_a?(String) \
         and @classify.topic_register.length >3
            topic_register=@classify.topic_register
            u=topic_register.scan(/[^;]+/)
diff --git a/lib/sisu/v3/plaintext.rb b/lib/sisu/v3/plaintext.rb
index 2fa98883..c86fddb9 100644
--- a/lib/sisu/v3/plaintext.rb
+++ b/lib/sisu/v3/plaintext.rb
@@ -350,7 +350,7 @@ WOK
             p_num=''
             if @env.plaintext_ocn?
               if defined? dob.ocn \
-              and not dob.ocn.nil?
+              and dob.ocn.is_a?(Fixnum)
                 p_num=SiSU_PlaintextFormat::ParagraphNumber.new(dob.ocn).display
               end
             end
@@ -409,7 +409,7 @@ WOK
         @sisu=[]
         emptyline=0
         @content.each do |para|                                                # this is a hack
-          if para.class==Array \
+          if para.is_a?(Array) \
           and para.length > 0
             para.each do |line|
               if line
diff --git a/lib/sisu/v3/plaintext_format.rb b/lib/sisu/v3/plaintext_format.rb
index 445d8c66..fe24112d 100644
--- a/lib/sisu/v3/plaintext_format.rb
+++ b/lib/sisu/v3/plaintext_format.rb
@@ -76,7 +76,7 @@ module SiSU_PlaintextFormat
   class FormatTextObject
     def initialize(md,t_o)
       @md,@t_o=md,t_o
-      if t_o.class==Hash
+      if t_o.is_a?(Hash)
         @txt =t_o[:txt]            || nil
         @lnk_url =t_o[:lnk_url]    || nil
         @lnk_txt =t_o[:lnk_txt]    || nil
diff --git a/lib/sisu/v3/po4a.rb b/lib/sisu/v3/po4a.rb
index 7ce825ee..53bab960 100644
--- a/lib/sisu/v3/po4a.rb
+++ b/lib/sisu/v3/po4a.rb
@@ -214,7 +214,7 @@ module SiSU_Po4a
           end
           desc="#{d}#{s_mark}#{instruct}"
           orig=(orig_notes[i].to_s =~/^\^~[\d*+]+/) ? (orig_notes[i].to_s.gsub(/^\^~[\d*+]+/,'^~')) : orig_notes[i].to_s
-          trans=if trn_notes.class==Array \
+          trans=if trn_notes.is_a?(Array) \
           and trn_notes.length==orig_notes.length
             (trn_notes[i].to_s =~/^\^~[\d*+]+/) ? (trn_notes[i].to_s.gsub(/^\^~[\d*+]+/,'^~')) : trn_notes[i].to_s
           else ''
@@ -749,12 +749,12 @@ GSUB
                 #next if data_trn[t].is == :comment
               end
             end
-            if (defined? data_src[s].ocn and data_src[s].ocn.class == Fixnum) \
-            and (defined? data_trn[t].ocn and data_trn[t].ocn.class == Fixnum) \
+            if (defined? data_src[s].ocn and data_src[s].ocn.is_a?(Fixnum)) \
+            and (defined? data_trn[t].ocn and data_trn[t].ocn.is_a?(Fixnum)) \
             and (data_src[s].ocn == data_trn[t].ocn)
               @m_s,@m_t=s,t
-            elsif (defined? data_src[s].ocn and data_src[s].ocn.class == Fixnum) \
-            and (defined? data_trn[t].ocn and data_trn[t].ocn.class == Fixnum) \
+            elsif (defined? data_src[s].ocn and data_src[s].ocn.is_a?(Fixnum)) \
+            and (defined? data_trn[t].ocn and data_trn[t].ocn.is_a?(Fixnum)) \
             and (data_src[s].ocn != data_trn[t].ocn)
               p '--- OCN ---'
               p 'mis-match'
@@ -934,7 +934,7 @@ GSUB
         @sisu=[]
         emptyline=0
         @content.each do |para|                                                # this is a hack
-          if para.class==Array \
+          if para.is_a?(Array) \
           and para.length > 0
             para.each do |line|
               if line
diff --git a/lib/sisu/v3/po4a_set.rb b/lib/sisu/v3/po4a_set.rb
index af6fba88..0dcc25a9 100644
--- a/lib/sisu/v3/po4a_set.rb
+++ b/lib/sisu/v3/po4a_set.rb
@@ -162,7 +162,7 @@ WOK
       line_wrap
     end
     def array_wrap
-      if @orig.class==Array
+      if @orig.is_a?(Array)
         @arr=[]
         @orig.each do |line|
           @arr << SiSU_TextUtils::Wrap.new(line,@n_char_max,@n_indent,@n_hang).line_wrap
diff --git a/lib/sisu/v3/qrcode.rb b/lib/sisu/v3/qrcode.rb
index dfd253d8..3908a1d4 100644
--- a/lib/sisu/v3/qrcode.rb
+++ b/lib/sisu/v3/qrcode.rb
@@ -668,7 +668,7 @@ WOK
 @sp='  '
           @md.topic_register_array.each do |t|
             t.each_with_index do |st,i|
-              if st.class==Array
+              if st.is_a?(Array)
                 st.each do |v|
                   @manifest[:txt] << %{#{@sp*i}#{v}\n}
                 end
diff --git a/lib/sisu/v3/shared_markup_alt.rb b/lib/sisu/v3/shared_markup_alt.rb
index 98c55e66..4efedff1 100644
--- a/lib/sisu/v3/shared_markup_alt.rb
+++ b/lib/sisu/v3/shared_markup_alt.rb
@@ -58,7 +58,7 @@
 module SiSU_TextRepresentation
   class Alter
     def initialize(x)
-      if x.class==String
+      if x.is_a?(String)
         @t_o,@s=nil,x
       else
         @t_o,@s=x,x.obj.dup
@@ -196,7 +196,7 @@ module SiSU_TextRepresentation
   class ModifiedTextPlusHashDigest
     def initialize(md,x)
       @md=md
-      if x.class==String
+      if x.is_a?(String)
         @t_o,@s=nil,x
       else
         @t_o,@s=x,x.obj.dup
diff --git a/lib/sisu/v3/shared_metadata.rb b/lib/sisu/v3/shared_metadata.rb
index a8698fd7..cd1e97db 100644
--- a/lib/sisu/v3/shared_metadata.rb
+++ b/lib/sisu/v3/shared_metadata.rb
@@ -259,12 +259,12 @@ module SiSU_Metadata
         meta << self.meta_para
       end
       if defined? @md.dgst \
-      and @md.dgst.class==Array
+      and @md.dgst.is_a?(Array)
         @tag,@inf,@class='Source Digest',"#{@md.dgst[0]} #{@md.dgst[1]}",'src'
         meta << self.meta_para
       end
       if defined? @md.dgst_skin \
-      and @md.dgst_skin.class==Array
+      and @md.dgst_skin.is_a?(Array)
         @tag,@inf,@class='Skin Digest',"#{@md.dgst_skin[0]} #{@md.dgst_skin[1]}",'src'
         meta << self.meta_para
       end
@@ -288,7 +288,7 @@ module SiSU_Metadata
         meta << self.meta_para
       end
       if defined? @md.generated \
-      and @md.generated.class==Time
+      and @md.generated.is_a?(Time)
         @tag,@inf,@class=tr.last_generated,@md.generated,'date'
         meta << self.meta_para
       end
@@ -734,7 +734,7 @@ module SiSU_Metadata
       @s=str
       def utf8
         if @s \
-        and @s.class==String
+        and @s.is_a?(String)
           @s=@s.gsub(/<br(?: \/)?>/u,Mx[:br_paragraph]).
             gsub(/</um,'&#60;'). # '&lt;'   # &#060;
             gsub(/</um,'&#60;'). # '&lt;'   # &#060;
@@ -908,7 +908,7 @@ WOK
     def odf
       def meta_para
         url_brace=SiSU_Viz::Skin.new.url_decoration
-        if @inf.class==String
+        if @inf.is_a?(String)
           @inf=@inf.gsub(/</,'&lt;').gsub(/>/,'&gt;').
             gsub(/&lt;br(?: \/)?&gt;/,'<br />')
           if @inf =~/&/
@@ -979,7 +979,7 @@ WOK
       @br="\\\\\n"
     end
     def meta_para(tag,inf,sc=true)
-      inf=((inf.class==String && sc) ? spec_char(inf) : inf)
+      inf=((inf.is_a?(String) && sc) ? spec_char(inf) : inf)
       %{\\begin\{bfseries\}#{tag}:\\end\{bfseries\} #{inf}
 }
     end
@@ -1193,7 +1193,7 @@ WOK
         meta << meta_para(tag,inf)
       end
       if defined? @md.dgst \
-      and @md.dgst.class==Array
+      and @md.dgst.is_a?(Array)
         hash_of=spec_char(@md.dgst[0])
         hash_of=word_break_points(hash_of)
         dgst=number_break_points(@md.dgst[1])
@@ -1201,7 +1201,7 @@ WOK
         meta << meta_para(tag,inf,false)
       end
       if defined? @md.dgst_skin \
-      and @md.dgst_skin.class==Array
+      and @md.dgst_skin.is_a?(Array)
         hash_of=spec_char(@md.dgst_skin[0])
         hash_of=word_break_points(hash_of)
         dgst=number_break_points(@md.dgst_skin[1])
@@ -1210,7 +1210,7 @@ WOK
       end
       meta << %{#{@br}\\begin\{bfseries\}Generated \\end\{bfseries\}}
       if defined? @md.generated \
-      and @md.generated.class==Time
+      and @md.generated.is_a?(Time)
         tag,inf=tr.last_generated,@md.generated
         meta << meta_para(tag,inf)
       end
diff --git a/lib/sisu/v3/shared_txt.rb b/lib/sisu/v3/shared_txt.rb
index 39363fcf..228109c1 100644
--- a/lib/sisu/v3/shared_txt.rb
+++ b/lib/sisu/v3/shared_txt.rb
@@ -114,7 +114,7 @@ module SiSU_TextUtils
       line_wrap
     end
     def array_wrap
-      if @para.class==Array
+      if @para.is_a?(Array)
         @arr=[]
         @para.each do |line|
           @arr << SiSU_TextUtils::Wrap.new(line,@n_char_max,@n_indent,@n_hang).line_wrap
diff --git a/lib/sisu/v3/shared_xml.rb b/lib/sisu/v3/shared_xml.rb
index 959170b6..6860d80c 100644
--- a/lib/sisu/v3/shared_xml.rb
+++ b/lib/sisu/v3/shared_xml.rb
@@ -110,7 +110,7 @@ module SiSU_XML_Munge
       def utf8(dob='')
         if @sys.locale =~/utf-?8/i # instead ucs for utf8 # String#encode Iñtërnâtiônàlizætiøn
           str=if defined? dob.obj then dob.obj
-          elsif dob.class==String then dob
+          elsif dob.is_a?(String) then dob
           end
           if str
             #¿ÀÁÂÃÄÅÆÇÈÉÊËÌÍÎÏÐÑÒÓÔÕÖØÙÚÛÜÞßàáâãäåæçèéêëìíîïðñòóôõöøùúûü
@@ -217,7 +217,7 @@ module SiSU_XML_Munge
           dob=if defined? dob.obj
             dob.obj=str
             dob
-          elsif dob.class==String
+          elsif dob.is_a?(String)
             str
           end
           dob
diff --git a/lib/sisu/v3/sst_to_s_xml_sax.rb b/lib/sisu/v3/sst_to_s_xml_sax.rb
index 20f68aca..cc08be70 100644
--- a/lib/sisu/v3/sst_to_s_xml_sax.rb
+++ b/lib/sisu/v3/sst_to_s_xml_sax.rb
@@ -427,7 +427,7 @@ WOK
         @sisu=new_file_data.scan(/.+/)
         SiSU_Env::FileOp.new(@md).mkdir
         filename_sxm=SiSU_Env::FileOp.new(@md,@md.fn[:sxs]).mkfile_pwd
-        if filename_sxm.class==File
+        if filename_sxm.is_a?(File)
           @sisu.each {|para| filename_sxm.puts para}
           filename_sxm.close
         else puts 'file not created, is directory writable?'
diff --git a/lib/sisu/v3/sysenv.rb b/lib/sisu/v3/sysenv.rb
index a9df7b2a..1c813fd8 100644
--- a/lib/sisu/v3/sysenv.rb
+++ b/lib/sisu/v3/sysenv.rb
@@ -467,8 +467,8 @@ module SiSU_Env
       filename=(@fns =~/\.ssm\.sst$/) \
       ? @fns.gsub(/\.ssm\.sst$/,'.ssm')
       : @fns
-      unless (filename.nil? \
-      or filename.empty?)
+      if filename.is_a?(String) \
+      and not filename.empty?
         if output_dir_structure.by_language_code?
           m=/((.+?)(?:\~\w{2,3})?)\.(sst|ssm)$/
           @fn[:b],@fn[:m],@fn[:t]=filename[m,1],filename[m,2],filename[m,3]
@@ -988,7 +988,7 @@ module SiSU_Env
       elsif defined? @env.fnb \
       and @env.fnb
         @env.fnb
-      elsif not @fns.nil? \
+      elsif @fns.is_a?(String) \
       and not @fns.empty?
         m=/(.+)?\.(?:(?:-|ssm\.)?sst|ssm)$/m
         @fns[m,1] if not @fns.empty?
@@ -1191,25 +1191,25 @@ module SiSU_Env
     end
     def html_minitoc?
       flag=if defined? @rc['html']['minitoc'] \
-      and not @rc['html']['minitoc'].nil?
+      and @rc['html']['minitoc'].is_a?(String)
         @rc['html']['minitoc']
       else false
       end
     end
     def manifest_minitoc?
-      flag=if (defined? @rc['manifest']['minitoc'] \
-      and not @rc['manifest']['minitoc'].nil?)
+      flag=if defined? @rc['manifest']['minitoc'] \
+      and @rc['manifest']['minitoc'].is_a?(String)
         @rc['manifest']['minitoc']
       else false
       end
     end
     def build
       def omit_list
-        @off_list ||=if (defined? @rc['omit_list'] \
-        and not @rc['omit_list'].nil?)
+        @off_list ||=if defined? @rc['omit_list'] \
+        and @rc['omit_list'].is_a?(String)
           @rc['omit_list']
-        elsif (defined? @rc['omit']['list'] \
-        and not @rc['omit']['list'].nil?)
+        elsif defined? @rc['omit']['list'] \
+        and @rc['omit']['list'].is_a?(String)
           @rc['omit']['list']
         else
           nil
@@ -1388,7 +1388,7 @@ module SiSU_Env
           true
         elsif defined? @vz.widget_promo \
         and not @vz.widget_promo.nil? \
-        and @vz.widget_promo.class==Array \
+        and @vz.widget_promo.is_a?(Array) \
         and @vz.widget_promo.length > 0
           @flag[:sk]=true
           true
@@ -2075,8 +2075,7 @@ WOK
       end
       def dal
         pth=if defined? @rc['processing']['dal'] \
-          and not @rc['processing']['dal'].nil? \
-          and not @rc['processing']['dal'].empty?
+          and @rc['processing']['dal'].is_a?(String)
           "#{processing}/#{@rc['processing']['dal']}"
         else "#{processing}/#{defaults[:processing_dal]}"
         end
@@ -2085,8 +2084,7 @@ WOK
       end
       def tune
         pth=if defined? @rc['processing']['tune'] \
-          and not @rc['processing']['tune'].nil? \
-          and not @rc['processing']['tune'].empty?
+          and @rc['processing']['tune'].is_a?(String)
           "#{processing}/#{@rc['processing']['tune']}"
         else "#{processing}/#{defaults[:processing_tune]}"
         end
@@ -2100,8 +2098,7 @@ WOK
       end
       def git
         pth=if defined? @rc['git']['dir'] \
-        and not @rc['git']['dir'].nil? \
-        and not @rc['git']['dir'].empty?
+        and @rc['git']['dir'].is_a?(String)
           x=(@rc['git']['dir'] =~/^(?:~|home)$/) \
           ? home + '/' + Gt[:git]
           : @rc['git']['dir'] + '/' + Gt[:git]
@@ -2166,8 +2163,7 @@ WOK
       end
       def tex
         pth=if defined? @rc['processing']['latex'] \
-          and not @rc['processing']['latex'].nil? \
-          and not @rc['processing']['latex'].empty?
+        and @rc['processing']['latex'].is_a?(String)
           "#{processing}/#{@rc['processing']['latex']}"
         else "#{processing}/#{defaults[:processing_latex]}"
         end
@@ -2176,8 +2172,7 @@ WOK
       end
       def texi
         pth=if defined? @rc['processing']['texinfo'] \
-          and not @rc['processing']['texinfo'].nil? \
-          and not @rc['processing']['texinfo'].empty?
+        and @rc['processing']['texinfo'].is_a?(String)
           "#{processing}/#{@rc['processing']['texinfo']}"
         else "#{processing}/#{defaults[:processing_texinfo]}"
         end
@@ -2192,8 +2187,7 @@ WOK
       end
       def lout
         pth=if defined? @rc['processing']['lout'] \
-          and not @rc['processing']['lout'].nil? \
-          and not @rc['processing']['lout'].empty?
+        and @rc['processing']['lout'].is_a?(String)
           "#{processing}/#{@rc['processing']['lout']}"
         else "#{processing}/#{defaults[:processing_lout]}"
         end
@@ -2207,8 +2201,7 @@ WOK
       end
       def sqlite
         pth=if defined? @rc['processing']['sqlite'] \
-          and not @rc['processing']['sqlite'].nil? \
-          and not @rc['processing']['sqlite'].empty?
+        and @rc['processing']['sqlite'].is_a?(String)
           "#{processing}/#{@rc['processing']['sqlite']}"
         else "#{processing}/#{defaults[:processing_sqlite]}"
         end
@@ -2217,8 +2210,7 @@ WOK
       end
       def postgresql
         pth=if defined? @rc['processing']['postgresql'] \
-          and not @rc['processing']['postgresql'].nil? \
-          and not @rc['processing']['postgresql'].empty?
+        and @rc['processing']['postgresql'].is_a?(String)
           "#{processing}/#{@rc['processing']['postgresql']}"
         else "#{processing}/#{defaults[:processing_postgresql]}"
         end
@@ -2333,7 +2325,7 @@ WOK
       end
       def webserv_cgi                                                          #web url for local webserv (localhost, or hostname)
         if defined? @rc['webserv_cgi']['host'] \
-        and not @rc['webserv_cgi']['host'].nil?
+        and @rc['webserv_cgi']['host'].is_a?(String)
           http=((@rc['webserv_cgi']['host'] =~ /https?:\/\//) ? '' : 'http://') #check https? missing
           if webserv_port_cgi
             "#{http}#{@rc['webserv_cgi']['host']}:#{webserv_port_cgi}/#{@stub_pwd}"
@@ -2349,7 +2341,7 @@ WOK
       end
       def webserv_base_cgi                                                     #web url for local webserv (localhost, or hostname)
         if defined? @rc['webserv_cgi']['host'] \
-        and not @rc['webserv_cgi']['host'].nil?
+        and @rc['webserv_cgi']['host'].is_a?(String)
           http=((@rc['webserv_cgi']['host'] =~ /https?:\/\//) ? '' : 'http://')
           if webserv_port_cgi
             "#{http}#{@rc['webserv_cgi']['host']}:#{webserv_port_cgi}"
@@ -2365,7 +2357,7 @@ WOK
       end
       def webrick #must have a port #REMOVE
         if defined? @rc['webserv_cgi']['host'] \
-        and not @rc['webserv_cgi']['host'].nil?
+        and @rc['webserv_cgi']['host'].is_a?(String)
           http=if @rc['webserv_cgi']['host'] =~/http:\/\//
             'http://'
           elsif @rc['webserv_cgi']['host'] =~/https:\/\//
@@ -2374,7 +2366,7 @@ WOK
           end
           "#{http}#{@rc['webserv_cgi']['host']}"
         elsif webserv_host_base \
-        and not webserv_host_base.nil?
+        and webserv_host_base.is_a?(String)
           "#{http}#{webserv_host_base}"
         else "#{http}localhost" end
       end
@@ -2743,48 +2735,42 @@ WOK
     end
     def cf_0                                                                   #processing flag shortcuts
       if defined? @rc['flag']['default'] \
-      and not (@rc['flag']['default'].nil? \
-      or @rc['flag']['default'].empty?)
+      and @rc['flag']['default'].is_a?(String)
         @rc['flag']['default']
       else                               '-NQhewpotbxXdyYv'
       end
     end
     def cf_1                                                                   #processing flag shortcuts
       if defined? @rc['flag']['i'] \
-      and not (@rc['flag']['i'].nil? \
-      or @rc['flag']['i'].empty?)
+      and @rc['flag']['i'].is_a?(String)
         @rc['flag']['i']
       else                               '-Qhewpoty'
       end
     end
     def cf_2                                                                   #processing flag shortcuts
       if defined? @rc['flag']['ii'] \
-      and not (@rc['flag']['ii'].nil? \
-      or @rc['flag']['ii'].empty?)
+      and @rc['flag']['ii'].is_a?(String)
         @rc['flag']['ii']
       else                               '-NQhewpotbxXdy'
       end
     end
     def cf_3                                                                   #processing flag shortcuts
       if defined? @rc['flag']['iii'] \
-      and not (@rc['flag']['iii'].nil? \
-      or @rc['flag']['iii'].empty?)
+      and @rc['flag']['iii'].is_a?(String)
         @rc['flag']['iii']
       else                               '-NQhewpotbxXdyY'
       end
     end
     def cf_4                                                                   #processing flag shortcuts
       if defined? @rc['flag']['iv'] \
-      and not (@rc['flag']['iv'].nil? \
-      or @rc['flag']['iv'].empty?)
+      and @rc['flag']['iv'].is_a?(String)
         @rc['flag']['iv']
       else                               '-NQhewpotbxXdDyY --update'
       end
     end
     def cf_5                                                                   #processing flag shortcuts
       if defined? @rc['flag']['v'] \
-      and not (@rc['flag']['v'].nil? \
-      or @rc['flag']['v'].empty?)
+      and @rc['flag']['v'].is_a?(String)
         @rc['flag']['v']
       else                               '-NQhewpotbxXdDyYv --update'
       end
@@ -2982,7 +2968,7 @@ WOK
     def remote_host #see InfoRemote remote_host_base_general
       r=[]
       r=if (defined? @rc['remote'] \
-      and @rc['remote'].class==Array)
+      and @rc['remote'].is_a?(Array))
         r_array=@rc['remote']
         r_array.each_with_index do |renv,i|
           r[i]={}
@@ -2999,7 +2985,7 @@ WOK
         end
         r
       elsif (defined? @rc['remote'] \
-      and @rc['remote'].class==Hash \
+      and @rc['remote'].is_a?(Hash) \
       and defined? @rc['remote']['user'] \
       and defined? @rc['remote']['host'])
         r[0]={}
@@ -3877,7 +3863,7 @@ WOK
       def port #PGPORT
         ((defined? @rc['db']['postgresql']['port']) \
         && ( @rc['db']['postgresql']['port'] =~/\d+/ \
-        || @rc['db']['postgresql']['port'].class==Fixnum)) \
+        || @rc['db']['postgresql']['port'].is_a?(Fixnum))) \
         ? @rc['db']['postgresql']['port']
         : (@defaults[:postgresql_port])
       end
@@ -5641,7 +5627,7 @@ WOK
   class InfoSkin
     def initialize(md=nil,skin=nil)
       @md=md
-      @d_sk=if skin.class==String
+      @d_sk=if skin.is_a?(String)
         skin
       elsif defined? md.doc_skin \
       and md.doc_skin
diff --git a/lib/sisu/v3/texinfo_format.rb b/lib/sisu/v3/texinfo_format.rb
index 7374d01e..78f2a188 100644
--- a/lib/sisu/v3/texinfo_format.rb
+++ b/lib/sisu/v3/texinfo_format.rb
@@ -66,10 +66,10 @@ module SiSU_TexInfoFormat
     @@tex_pattern_margin_number="\\\\marginpar.+?\s+"
     def initialize(md,dob=nil)
       @md,@dob=md,dob
-      if dob.class==Hash
+      if dob.is_a?(Hash)
         p dob.class
         p caller
-      elsif dob.class==String
+      elsif dob.is_a?(String)
         p dob.class
         p caller
       end
diff --git a/lib/sisu/v3/texpdf.rb b/lib/sisu/v3/texpdf.rb
index fc007a4f..0665c9b4 100644
--- a/lib/sisu/v3/texpdf.rb
+++ b/lib/sisu/v3/texpdf.rb
@@ -401,8 +401,8 @@ module SiSU_TeX
       def tables(data)
         @tex_file=[]
         data.each do |dob|
-          @tex_file << if dob.class==String \
-          or dob.class==Hash
+          @tex_file << if dob.is_a?(String) \
+          or dob.is_a?(Hash)
             dob
           elsif dob.is==:table
             tables_hash(@md,dob) #Hash result
@@ -538,12 +538,12 @@ module SiSU_TeX
               idx_arr=[]
               idx=SiSU_Particulars::CombinedSingleton.instance.get_idx_raw(@md.opt).raw_idx
               idx.each do |x|
-                x=if x.class==String
+                x=if x.is_a?(String)
                   x=SiSU_TeX_Pdf::SpecialCharacters.new(@md,x).special_characters
                   x=SiSU_TeX_Pdf::FormatTextObject.new(@md,x).url_str_internal(x,true)
                 else x=nil
                 end
-                idx_arr << x.sub(/,$/,'') if x.class==String
+                idx_arr << x.sub(/,$/,'') if x.is_a?(String)
               end
               idx_str=idx_arr.join(br)
               l=heading + br + idx_str
@@ -582,7 +582,7 @@ module SiSU_TeX
             dob.tmp=dob.tmp.strip unless dob.is==:code
             dob=enclose(dob) unless dob.tmp =~/^$/
           end
-          if dob.class==String
+          if dob.is_a?(String)
             dob.tmp=dob.tmp.gsub(/\s*(?:#{Mx[:br_line]}|#{Mx[:br_nl]})\s*/,' \newline ').   #% tread with care
               gsub(/(\.#{Tex[:tilde]}\S*\s*|<:\S+>|#{Mx[:fa_o]}.*?#{Mx[:fa_c]}|#{Mx[:gr_o]}.*?#{Mx[:gr_c]}|<!.*?!>|<!>)/,' ')   #% tread with care
           end
@@ -776,7 +776,7 @@ WOK
         @tex_file << x
         x=nil
         data.each do |dob|                                                      #% case follows with levels 1-6 indents & graphics
-          if dob.class==Hash
+          if dob.is_a?(Hash)
           elsif dob.of==:para \
           || dob.of==:block #GATEWAY FIX FIX stuff
             dob=markup_common(dob)
@@ -797,7 +797,7 @@ WOK
                   end
                 end
               end
-            elsif dob.tmp.class==Hash \
+            elsif dob.tmp.is_a?(Hash) \
             and (dob.tmp[:p] and dob.tmp[:l])
               dob = {
                 p: markup_common(dob.tmp[:p]),
@@ -844,7 +844,7 @@ WOK
       def number_paras(data)
         tex_file=[]
         data.each do |dob|
-          dob=if dob.class==Hash
+          dob=if dob.is_a?(Hash)
             if ( dob['a4'] \
             or dob['a5'] \
             or dob['b5'] \
@@ -932,7 +932,7 @@ WOK
           file[:portrait] << @@tex_head[ps][:p]
           file[:landscape] << @@tex_head[ps][:l]
           array.each do |morph|
-            if morph.class==String
+            if morph.is_a?(String)
               #morph.gsub!(/^\s+/,'')
               if morph !~/\A\s*\Z/
                 file[:portrait].puts morph,"\n"
@@ -940,7 +940,7 @@ WOK
               end
             elsif morph.class.inspect =~ /SiSU_DAL_DocumentStructure/ \
             and morph.tmp \
-            and morph.tmp.class==String
+            and morph.tmp.is_a?(String)
               if morph.is !=:code \
               && morph.of !=:block
                 morph.tmp=morph.tmp.gsub(/^\s+/,'')
@@ -951,10 +951,10 @@ WOK
                 file[:portrait].puts morph.tmp,"\n"
                 file[:landscape].puts morph.tmp,"\n"
               end
-            elsif morph.class==Hash            #inserted headers and the like, only
+            elsif morph.is_a?(Hash)            #inserted headers and the like, only
               h={ ps: ps, h: morph, filename: file }
               output_morph_hash(h)
-            elsif morph.tmp.class==Hash       #tables & images?
+            elsif morph.tmp.is_a?(Hash)       #tables & images?
               h={ ps: ps, h: morph.tmp, filename: file }
               output_morph_hash(h)
             end
diff --git a/lib/sisu/v3/texpdf_format.rb b/lib/sisu/v3/texpdf_format.rb
index 43763157..a7331447 100644
--- a/lib/sisu/v3/texpdf_format.rb
+++ b/lib/sisu/v3/texpdf_format.rb
@@ -719,7 +719,7 @@ module SiSU_TeX_Pdf
     def initialize(md,t_o)
       @md,@t_o=md,t_o
       @env=SiSU_Env::InfoEnv.new(@md.fns)
-      if t_o.class==Hash
+      if t_o.is_a?(Hash)
         @txt =t_o[:txt]            || nil
         @subtitle=t_o[:subtitle]   || nil
         @ps=t_o[:paper_size]       || nil
diff --git a/lib/sisu/v3/xhtml_table.rb b/lib/sisu/v3/xhtml_table.rb
index 753b0242..30701433 100644
--- a/lib/sisu/v3/xhtml_table.rb
+++ b/lib/sisu/v3/xhtml_table.rb
@@ -84,7 +84,7 @@ module SiSU_XHTML_Table
           end
           nc+=1
         end
-        trc=trc.class==Array ? trc.flatten.join : trc
+        trc=(trc.is_a?(Array)) ? trc.flatten.join : trc
         trc="      <tr>#{trc}</tr>\n"
         nr+=1
         table_rows << trc
diff --git a/lib/sisu/v3/xml_format.rb b/lib/sisu/v3/xml_format.rb
index a9f6fb01..54d889cd 100644
--- a/lib/sisu/v3/xml_format.rb
+++ b/lib/sisu/v3/xml_format.rb
@@ -999,7 +999,7 @@ WOK
     attr_accessor :md,:dob,:txt,:ocn,:format,:table,:link,:linkname,:paranum,:p_num,:headname,:banner,:url
     def initialize(md,t_o)
       @md,@t_o=md,t_o
-      if t_o.class==Hash
+      if t_o.is_a?(Hash)
         @txt            =t_o[:txt]            || nil
         @ocn            =t_o[:ocn]            || nil
         @ocn_display    =t_o[:ocn_display]    || nil