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Diffstat (limited to 'ruby_1_9_3/lib/prettyprint.rb')
| -rw-r--r-- | ruby_1_9_3/lib/prettyprint.rb | 395 |
1 files changed, 0 insertions, 395 deletions
diff --git a/ruby_1_9_3/lib/prettyprint.rb b/ruby_1_9_3/lib/prettyprint.rb deleted file mode 100644 index 9a90713a4d..0000000000 --- a/ruby_1_9_3/lib/prettyprint.rb +++ /dev/null @@ -1,395 +0,0 @@ -# This class implements a pretty printing algorithm. It finds line breaks and -# nice indentations for grouped structure. -# -# By default, the class assumes that primitive elements are strings and each -# byte in the strings have single column in width. But it can be used for -# other situations by giving suitable arguments for some methods: -# * newline object and space generation block for PrettyPrint.new -# * optional width argument for PrettyPrint#text -# * PrettyPrint#breakable -# -# There are several candidate uses: -# * text formatting using proportional fonts -# * multibyte characters which has columns different to number of bytes -# * non-string formatting -# -# == Bugs -# * Box based formatting? -# * Other (better) model/algorithm? -# -# == References -# Christian Lindig, Strictly Pretty, March 2000, -# http://www.st.cs.uni-sb.de/~lindig/papers/#pretty -# -# Philip Wadler, A prettier printer, March 1998, -# http://homepages.inf.ed.ac.uk/wadler/topics/language-design.html#prettier -# -# == Author -# Tanaka Akira <akr@m17n.org> -# -class PrettyPrint - - # This is a convenience method which is same as follows: - # - # begin - # q = PrettyPrint.new(output, maxwidth, newline, &genspace) - # ... - # q.flush - # output - # end - # - def PrettyPrint.format(output='', maxwidth=79, newline="\n", genspace=lambda {|n| ' ' * n}) - q = PrettyPrint.new(output, maxwidth, newline, &genspace) - yield q - q.flush - output - end - - # This is similar to PrettyPrint::format but the result has no breaks. - # - # +maxwidth+, +newline+ and +genspace+ are ignored. - # - # The invocation of +breakable+ in the block doesn't break a line and is - # treated as just an invocation of +text+. - # - def PrettyPrint.singleline_format(output='', maxwidth=nil, newline=nil, genspace=nil) - q = SingleLine.new(output) - yield q - output - end - - # Creates a buffer for pretty printing. - # - # +output+ is an output target. If it is not specified, '' is assumed. It - # should have a << method which accepts the first argument +obj+ of - # PrettyPrint#text, the first argument +sep+ of PrettyPrint#breakable, the - # first argument +newline+ of PrettyPrint.new, and the result of a given - # block for PrettyPrint.new. - # - # +maxwidth+ specifies maximum line length. If it is not specified, 79 is - # assumed. However actual outputs may overflow +maxwidth+ if long - # non-breakable texts are provided. - # - # +newline+ is used for line breaks. "\n" is used if it is not specified. - # - # The block is used to generate spaces. {|width| ' ' * width} is used if it - # is not given. - # - def initialize(output='', maxwidth=79, newline="\n", &genspace) - @output = output - @maxwidth = maxwidth - @newline = newline - @genspace = genspace || lambda {|n| ' ' * n} - - @output_width = 0 - @buffer_width = 0 - @buffer = [] - - root_group = Group.new(0) - @group_stack = [root_group] - @group_queue = GroupQueue.new(root_group) - @indent = 0 - end - attr_reader :output, :maxwidth, :newline, :genspace - attr_reader :indent, :group_queue - - # Returns the group most recently added to the stack. - def current_group - @group_stack.last - end - - # first? is a predicate to test the call is a first call to first? with - # current group. - # - # It is useful to format comma separated values as: - # - # q.group(1, '[', ']') { - # xxx.each {|yyy| - # unless q.first? - # q.text ',' - # q.breakable - # end - # ... pretty printing yyy ... - # } - # } - # - # first? is obsoleted in 1.8.2. - # - def first? - warn "PrettyPrint#first? is obsoleted at 1.8.2." - current_group.first? - end - - # Breaks the buffer into lines that are shorter than #maxwidth - def break_outmost_groups - while @maxwidth < @output_width + @buffer_width - return unless group = @group_queue.deq - until group.breakables.empty? - data = @buffer.shift - @output_width = data.output(@output, @output_width) - @buffer_width -= data.width - end - while !@buffer.empty? && Text === @buffer.first - text = @buffer.shift - @output_width = text.output(@output, @output_width) - @buffer_width -= text.width - end - end - end - - # This adds +obj+ as a text of +width+ columns in width. - # - # If +width+ is not specified, obj.length is used. - # - def text(obj, width=obj.length) - if @buffer.empty? - @output << obj - @output_width += width - else - text = @buffer.last - unless Text === text - text = Text.new - @buffer << text - end - text.add(obj, width) - @buffer_width += width - break_outmost_groups - end - end - - # This is similar to #breakable except - # the decision to break or not is determined individually. - # - # Two #fill_breakable under a group may cause 4 results: - # (break,break), (break,non-break), (non-break,break), (non-break,non-break). - # This is different to #breakable because two #breakable under a group - # may cause 2 results: - # (break,break), (non-break,non-break). - # - # The text sep+ is inserted if a line is not broken at this point. - # - # If +sep+ is not specified, " " is used. - # - # If +width+ is not specified, +sep.length+ is used. You will have to - # specify this when +sep+ is a multibyte character, for example. - # - def fill_breakable(sep=' ', width=sep.length) - group { breakable sep, width } - end - - # This says "you can break a line here if necessary", and a +width+\-column - # text +sep+ is inserted if a line is not broken at the point. - # - # If +sep+ is not specified, " " is used. - # - # If +width+ is not specified, +sep.length+ is used. You will have to - # specify this when +sep+ is a multibyte character, for example. - # - def breakable(sep=' ', width=sep.length) - group = @group_stack.last - if group.break? - flush - @output << @newline - @output << @genspace.call(@indent) - @output_width = @indent - @buffer_width = 0 - else - @buffer << Breakable.new(sep, width, self) - @buffer_width += width - break_outmost_groups - end - end - - # Groups line break hints added in the block. The line break hints are all - # to be used or not. - # - # If +indent+ is specified, the method call is regarded as nested by - # nest(indent) { ... }. - # - # If +open_obj+ is specified, <tt>text open_obj, open_width</tt> is called - # before grouping. If +close_obj+ is specified, <tt>text close_obj, - # close_width</tt> is called after grouping. - # - def group(indent=0, open_obj='', close_obj='', open_width=open_obj.length, close_width=close_obj.length) - text open_obj, open_width - group_sub { - nest(indent) { - yield - } - } - text close_obj, close_width - end - - def group_sub - group = Group.new(@group_stack.last.depth + 1) - @group_stack.push group - @group_queue.enq group - begin - yield - ensure - @group_stack.pop - if group.breakables.empty? - @group_queue.delete group - end - end - end - - # Increases left margin after newline with +indent+ for line breaks added in - # the block. - # - def nest(indent) - @indent += indent - begin - yield - ensure - @indent -= indent - end - end - - # outputs buffered data. - # - def flush - @buffer.each {|data| - @output_width = data.output(@output, @output_width) - } - @buffer.clear - @buffer_width = 0 - end - - class Text - def initialize - @objs = [] - @width = 0 - end - attr_reader :width - - def output(out, output_width) - @objs.each {|obj| out << obj} - output_width + @width - end - - def add(obj, width) - @objs << obj - @width += width - end - end - - class Breakable - def initialize(sep, width, q) - @obj = sep - @width = width - @pp = q - @indent = q.indent - @group = q.current_group - @group.breakables.push self - end - attr_reader :obj, :width, :indent - - def output(out, output_width) - @group.breakables.shift - if @group.break? - out << @pp.newline - out << @pp.genspace.call(@indent) - @indent - else - @pp.group_queue.delete @group if @group.breakables.empty? - out << @obj - output_width + @width - end - end - end - - class Group - def initialize(depth) - @depth = depth - @breakables = [] - @break = false - end - attr_reader :depth, :breakables - - def break - @break = true - end - - def break? - @break - end - - def first? - if defined? @first - false - else - @first = false - true - end - end - end - - class GroupQueue - def initialize(*groups) - @queue = [] - groups.each {|g| enq g} - end - - def enq(group) - depth = group.depth - @queue << [] until depth < @queue.length - @queue[depth] << group - end - - def deq - @queue.each {|gs| - (gs.length-1).downto(0) {|i| - unless gs[i].breakables.empty? - group = gs.slice!(i, 1).first - group.break - return group - end - } - gs.each {|group| group.break} - gs.clear - } - return nil - end - - def delete(group) - @queue[group.depth].delete(group) - end - end - - class SingleLine - def initialize(output, maxwidth=nil, newline=nil) - @output = output - @first = [true] - end - - def text(obj, width=nil) - @output << obj - end - - def breakable(sep=' ', width=nil) - @output << sep - end - - def nest(indent) - yield - end - - def group(indent=nil, open_obj='', close_obj='', open_width=nil, close_width=nil) - @first.push true - @output << open_obj - yield - @output << close_obj - @first.pop - end - - def flush - end - - def first? - result = @first[-1] - @first[-1] = false - result - end - end -end |