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git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@1936 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
681 lines
13 KiB
Ruby
681 lines
13 KiB
Ruby
# $Id$
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=begin
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= PrettyPrint
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The class implements pretty printing algorithm.
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It finds line breaks and nice indentations for grouped structure.
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By default, the class assumes that primitive elements are strings and
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each byte in the strings have single column in width.
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But it can be used for other situasions
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by giving suitable arguments for some methods:
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newline object and space generation block for (({PrettyPrint.new})),
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optional width argument for (({PrettyPrint#text})),
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(({PrettyPrint#breakable})), etc.
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There are several candidates to use them:
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text formatting using proportional fonts,
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multibyte characters which has columns diffrent to number of bytes,
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non-string formatting, etc.
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== class methods
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--- PrettyPrint.new([newline]) [{|width| ...}]
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creates a buffer for pretty printing.
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((|newline|)) is used for line breaks.
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(({"\n"})) is used if it is not specified.
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The block is used to generate spaces.
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(({{|width| ' ' * width}})) is used if it is not given.
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== methods
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--- text(obj[, width])
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adds ((|obj|)) as a text of ((|width|)) columns in width.
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If ((|width|)) is not specified, (({((|obj|)).length})) is used.
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--- breakable([sep[, width]])
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tells "you can break a line here if necessary", and a
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((|width|))-column text ((|sep|)) is inserted if a line is not
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broken at the point.
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If ((|sep|)) is not specified, (({" "})) is used.
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If ((|width|)) is not specified, (({((|sep|)).length})) is used.
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You will have to specify this when ((|sep|)) is a multibyte
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character, for example.
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--- nest(indent) {...}
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increases left margin after newline with ((|indent|)) for line breaks added in the block.
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--- group {...}
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groups line break hints added in the block.
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--- format(out[, width])
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outputs buffered data to ((|out|)).
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It tries to restrict the line length to ((|width|)) but it may
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overflow.
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If ((|width|)) is not specified, 79 is assumed.
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((|out|)) must have a method named (({<<})) which accepts
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a first argument ((|obj|)) of (({PrettyPrint#text})),
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a first argument ((|sep|)) of (({PrettyPrint#breakable})),
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a first argument ((|newline|)) of (({PrettyPrint.new})),
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and
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a result of a given block for (({PrettyPrint.new})).
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== Bugs
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* Line breaks in a group is constrained to whether all line break hints are
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to be breaked or not. Maybe, non-constrained version of
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PrettyPrint#group should be provided to filling multi lines.
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* Box based formatting?
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== References
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Strictly Pretty, Christian Lindig, March 2000,
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((<URL:http://www.gaertner.de/~lindig/papers/strictly-pretty.html>))
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A prettier printer, Philip Wadler, March 1998,
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((<URL:http://cm.bell-labs.com/cm/cs/who/wadler/topics/recent.html#prettier>))
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=end
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class PrettyPrint
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def initialize(newline="\n", &genspace)
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@newline = newline
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@genspace = genspace || lambda {|n| ' ' * n}
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@buf = Group.new
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@nest = [0]
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@stack = []
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end
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def text(obj, width=obj.length)
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@buf << Text.new(obj, width)
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end
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def breakable(sep=' ', width=sep.length)
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@buf << Breakable.new(sep, width, @nest.last, @newline, @genspace)
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end
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def nest(indent)
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nest_enter(indent)
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begin
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yield
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ensure
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nest_leave
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end
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end
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def nest_enter(indent)
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@nest << @nest.last + indent
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end
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def nest_leave
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@nest.pop
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end
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def group
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group_enter
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begin
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yield
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ensure
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group_leave
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end
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end
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def group_enter
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g = Group.new
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@buf << g
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@stack << @buf
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@buf = g
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end
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def group_leave
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@buf = @stack.pop
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end
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def format(out, width=79)
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tails = [[-1, 0]]
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@buf.update_tails(tails, 0)
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@buf.multiline_output(out, 0, 0, width)
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end
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class Text
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def initialize(text, width)
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@text = text
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@width = width
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end
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def update_tails(tails, group)
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tails[-1][1] += @width
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end
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def singleline_width
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return @width
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end
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def singleline_output(out)
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out << @text
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end
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def multiline_output(out, group, margin, width)
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singleline_output(out)
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return margin + singleline_width
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end
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end
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class Breakable
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def initialize(sep, width, indent, newline, genspace)
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@sep = sep
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@width = width
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@indent = indent
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@newline = newline
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@genspace = genspace
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end
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def update_tails(tails, group)
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if group == tails[-1][0]
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tails[-2][1] += @width + tails[-1][1]
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tails[-1][1] = 0
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else
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tails[-1][1] += @width
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tails << [group, 0]
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end
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end
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def singleline_width
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return @width
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end
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def singleline_output(out)
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out << @sep
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end
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def multiline_output(out, group, margin, width)
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out << @newline
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out << @genspace.call(@indent)
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return @indent
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end
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end
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class Group
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def initialize
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@buf = []
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@singleline_width = nil
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end
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def <<(obj)
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@buf << obj
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end
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def update_tails(tails, group)
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@tail = tails.empty? ? 0 : tails[-1][1]
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len = 0
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@buf.reverse_each {|obj|
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obj.update_tails(tails, group + 1)
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len += obj.singleline_width
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}
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@singleline_width = len
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while !tails.empty? && group <= tails[-1][0]
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tails[-2][1] += tails[-1][1]
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tails.pop
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end
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end
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def singleline_width
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return @singleline_width
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end
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def singleline_output(out)
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@buf.each {|obj| obj.singleline_output(out)}
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end
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def multiline_output(out, group, margin, width)
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if margin + singleline_width + @tail <= width
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singleline_output(out)
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margin += singleline_width
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else
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@buf.each {|obj|
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margin = obj.multiline_output(out, group + 1, margin, width)
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}
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end
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return margin
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end
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end
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end
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if __FILE__ == $0
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require 'runit/testcase'
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require 'runit/cui/testrunner'
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class WadlerExample < RUNIT::TestCase
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def setup
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@hello = PrettyPrint.new
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@hello.group {
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@hello.group {
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@hello.group {
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@hello.group {
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@hello.text 'hello'; @hello.breakable; @hello.text 'a'
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}
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@hello.breakable; @hello.text 'b'
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}
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@hello.breakable; @hello.text 'c'
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}
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@hello.breakable; @hello.text 'd'
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}
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@tree = Tree.new("aaaa", Tree.new("bbbbb", Tree.new("ccc"),
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Tree.new("dd")),
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Tree.new("eee"),
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Tree.new("ffff", Tree.new("gg"),
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Tree.new("hhh"),
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Tree.new("ii")))
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end
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def test_hello_00_06
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expected = <<'End'.chomp
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hello
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a
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b
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c
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d
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End
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@hello.format(out='', 0); assert_equal(expected, out)
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@hello.format(out='', 6); assert_equal(expected, out)
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end
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def test_hello_07_08
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expected = <<'End'.chomp
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hello a
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b
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c
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d
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End
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@hello.format(out='', 7); assert_equal(expected, out)
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@hello.format(out='', 8); assert_equal(expected, out)
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end
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def test_hello_09_10
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expected = <<'End'.chomp
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hello a b
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c
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d
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End
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@hello.format(out='', 9); assert_equal(expected, out)
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@hello.format(out='', 10); assert_equal(expected, out)
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end
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def test_hello_11_12
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expected = <<'End'.chomp
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hello a b c
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d
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End
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@hello.format(out='', 11); assert_equal(expected, out)
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@hello.format(out='', 12); assert_equal(expected, out)
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end
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def test_hello_13
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expected = <<'End'.chomp
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hello a b c d
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End
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@hello.format(out='', 13); assert_equal(expected, out)
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end
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def test_tree_00_19
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pp = PrettyPrint.new
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@tree.show(pp)
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expected = <<'End'.chomp
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aaaa[bbbbb[ccc,
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dd],
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eee,
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ffff[gg,
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hhh,
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ii]]
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End
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pp.format(out='', 0); assert_equal(expected, out)
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pp.format(out='', 19); assert_equal(expected, out)
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end
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def test_tree_20_22
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pp = PrettyPrint.new
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@tree.show(pp)
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expected = <<'End'.chomp
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aaaa[bbbbb[ccc, dd],
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eee,
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ffff[gg,
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hhh,
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ii]]
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End
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pp.format(out='', 20); assert_equal(expected, out)
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pp.format(out='', 22); assert_equal(expected, out)
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end
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def test_tree_23_43
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pp = PrettyPrint.new
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@tree.show(pp)
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expected = <<'End'.chomp
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aaaa[bbbbb[ccc, dd],
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eee,
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ffff[gg, hhh, ii]]
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End
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pp.format(out='', 23); assert_equal(expected, out)
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pp.format(out='', 43); assert_equal(expected, out)
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end
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def test_tree_44
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pp = PrettyPrint.new
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@tree.show(pp)
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pp.format(out='', 44)
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assert_equal(<<'End'.chomp, out)
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aaaa[bbbbb[ccc, dd], eee, ffff[gg, hhh, ii]]
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End
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end
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def test_tree_alt_00_18
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pp = PrettyPrint.new
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@tree.altshow(pp)
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expected = <<'End'.chomp
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aaaa[
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bbbbb[
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ccc,
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dd
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],
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eee,
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ffff[
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gg,
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hhh,
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ii
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]
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]
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End
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pp.format(out='', 0); assert_equal(expected, out)
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pp.format(out='', 18); assert_equal(expected, out)
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end
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def test_tree_alt_19_20
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pp = PrettyPrint.new
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@tree.altshow(pp)
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expected = <<'End'.chomp
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aaaa[
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bbbbb[ ccc, dd ],
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eee,
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ffff[
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gg,
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hhh,
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ii
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]
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]
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End
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pp.format(out='', 19); assert_equal(expected, out)
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pp.format(out='', 20); assert_equal(expected, out)
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end
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def test_tree_alt_20_49
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pp = PrettyPrint.new
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@tree.altshow(pp)
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expected = <<'End'.chomp
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aaaa[
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bbbbb[ ccc, dd ],
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eee,
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ffff[ gg, hhh, ii ]
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]
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End
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pp.format(out='', 21); assert_equal(expected, out)
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pp.format(out='', 49); assert_equal(expected, out)
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end
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def test_tree_alt_50
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pp = PrettyPrint.new
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@tree.altshow(pp)
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expected = <<'End'.chomp
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aaaa[ bbbbb[ ccc, dd ], eee, ffff[ gg, hhh, ii ] ]
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End
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pp.format(out='', 50); assert_equal(expected, out)
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end
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class Tree
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def initialize(string, *children)
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@string = string
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@children = children
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end
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def show(pp)
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pp.group {
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pp.text @string
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pp.nest(@string.length) {
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unless @children.empty?
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pp.text '['
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pp.nest(1) {
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first = true
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@children.each {|t|
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if first
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first = false
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else
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pp.text ','
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pp.breakable
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end
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t.show(pp)
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}
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}
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pp.text ']'
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end
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}
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}
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end
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def altshow(pp)
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pp.group {
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pp.text @string
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unless @children.empty?
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pp.text '['
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pp.nest(2) {
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pp.breakable
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first = true
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@children.each {|t|
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if first
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first = false
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else
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pp.text ','
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pp.breakable
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end
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t.altshow(pp)
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}
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}
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pp.breakable
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pp.text ']'
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end
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}
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end
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end
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end
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class StrictPrettyExample < RUNIT::TestCase
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def setup
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@pp = PrettyPrint.new
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@pp.group {
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@pp.group {@pp.nest(2) {
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@pp.text "if"; @pp.breakable;
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@pp.group {
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@pp.nest(2) {
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@pp.group {@pp.text "a"; @pp.breakable; @pp.text "=="}
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@pp.breakable; @pp.text "b"}}}}
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@pp.breakable
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@pp.group {@pp.nest(2) {
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@pp.text "then"; @pp.breakable;
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@pp.group {
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@pp.nest(2) {
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@pp.group {@pp.text "a"; @pp.breakable; @pp.text "<<"}
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@pp.breakable; @pp.text "2"}}}}
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@pp.breakable
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@pp.group {@pp.nest(2) {
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@pp.text "else"; @pp.breakable;
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@pp.group {
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@pp.nest(2) {
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@pp.group {@pp.text "a"; @pp.breakable; @pp.text "+"}
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@pp.breakable; @pp.text "b"}}}}}
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end
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def test_00_04
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expected = <<'End'.chomp
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if
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a
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==
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b
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then
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a
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<<
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2
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else
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a
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+
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b
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End
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@pp.format(out='', 0); assert_equal(expected, out)
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@pp.format(out='', 4); assert_equal(expected, out)
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end
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def test_05
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expected = <<'End'.chomp
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if
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a
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==
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b
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then
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a
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<<
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2
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else
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a +
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b
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End
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@pp.format(out='', 5); assert_equal(expected, out)
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end
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def test_06
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expected = <<'End'.chomp
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if
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a ==
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b
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then
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a <<
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2
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else
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a +
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b
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End
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@pp.format(out='', 6); assert_equal(expected, out)
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end
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def test_07
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expected = <<'End'.chomp
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if
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a ==
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b
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then
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a <<
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2
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else
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a + b
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End
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@pp.format(out='', 7); assert_equal(expected, out)
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end
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def test_08
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expected = <<'End'.chomp
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if
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a == b
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then
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a << 2
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else
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a + b
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End
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@pp.format(out='', 8); assert_equal(expected, out)
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end
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def test_09
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expected = <<'End'.chomp
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if a == b
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then
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a << 2
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else
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a + b
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End
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@pp.format(out='', 9); assert_equal(expected, out)
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end
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def test_10
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expected = <<'End'.chomp
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if a == b
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|
then
|
|
a << 2
|
|
else a + b
|
|
End
|
|
@pp.format(out='', 10); assert_equal(expected, out)
|
|
end
|
|
|
|
def test_11_31
|
|
expected = <<'End'.chomp
|
|
if a == b
|
|
then a << 2
|
|
else a + b
|
|
End
|
|
@pp.format(out='', 11); assert_equal(expected, out)
|
|
@pp.format(out='', 15); assert_equal(expected, out)
|
|
@pp.format(out='', 31); assert_equal(expected, out)
|
|
end
|
|
|
|
def test_32
|
|
expected = <<'End'.chomp
|
|
if a == b then a << 2 else a + b
|
|
End
|
|
@pp.format(out='', 32); assert_equal(expected, out)
|
|
end
|
|
|
|
end
|
|
|
|
class TailGroup < RUNIT::TestCase
|
|
def test_1
|
|
pp = PrettyPrint.new
|
|
pp.group {
|
|
pp.group {
|
|
pp.text "abc"
|
|
pp.breakable
|
|
pp.text "def"
|
|
}
|
|
pp.group {
|
|
pp.text "ghi"
|
|
pp.breakable
|
|
pp.text "jkl"
|
|
}
|
|
}
|
|
pp.format(out='', 10)
|
|
assert_equal("abc\ndefghi jkl", out)
|
|
end
|
|
end
|
|
|
|
class NonString < RUNIT::TestCase
|
|
def setup
|
|
@pp = PrettyPrint.new('newline') {|n| "#{n} spaces"}
|
|
@pp.text(3, 3)
|
|
@pp.breakable(1, 1)
|
|
@pp.text(3, 3)
|
|
end
|
|
|
|
def test_6
|
|
@pp.format(out=[], 6)
|
|
assert_equal([3, "newline", "0 spaces", 3], out)
|
|
end
|
|
|
|
def test_7
|
|
@pp.format(out=[], 7)
|
|
assert_equal([3, 1, 3], out)
|
|
end
|
|
|
|
end
|
|
|
|
RUNIT::CUI::TestRunner.run(WadlerExample.suite)
|
|
RUNIT::CUI::TestRunner.run(StrictPrettyExample.suite)
|
|
RUNIT::CUI::TestRunner.run(TailGroup.suite)
|
|
RUNIT::CUI::TestRunner.run(NonString.suite)
|
|
end
|