Type:
Class

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:

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, www.st.cs.uni-sb.de/~lindig/papers/#pretty

Philip Wadler, A prettier printer, March 1998, homepages.inf.ed.ac.uk/wadler/topics/language-design.html#prettier

Author

Tanaka Akira <akr@m17n.org>

format

format(output='', maxwidth=79, newline="\n", genspace=lambda {|n| ' ' * n}) Class Public methods

2015-04-28 09:56:33
new

new(output='', maxwidth=79, newline="\n", &genspace) Class Public methods Creates

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singleline_format

singleline_format(output='', maxwidth=nil, newline=nil, genspace=nil) Class Public methods

2015-04-28 10:06:21
fill_breakable

fill_breakable(sep=' ', width=sep.length) Instance Public methods This is similar

2015-04-28 10:17:58
flush

flush() Instance Public methods outputs buffered data.

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first?

first?() Instance Public methods first? is a predicate to test the call is a

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current_group

current_group() Instance Public methods Returns the group most recently added

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group

group(indent=0, open_obj='', close_obj='', open_width=open_obj.length, close_width=close_obj.length) Instance Public

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break_outmost_groups

break_outmost_groups() Instance Public methods Breaks the buffer into lines

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text

text(obj, width=obj.length) Instance Public methods This adds obj

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