import pyloxi @ 39ed7a3
diff --git a/src/python/loxi/pp.py b/src/python/loxi/pp.py
new file mode 100644
index 0000000..852215d
--- /dev/null
+++ b/src/python/loxi/pp.py
@@ -0,0 +1,248 @@
+"""
+pp - port of Ruby's PP library
+Also based on Lindig, C., & GbR, G. D. (2000). Strictly Pretty.
+
+Example usage:
+>>> import pp.pp as pp
+>>> print pp([[1, 2], [3, 4]], maxwidth=15)
+[
+ [ 1, 2 ],
+ [ 3, 4 ]
+]
+"""
+import unittest
+from contextlib import contextmanager
+
+def pp(obj, maxwidth=79):
+ """
+ Pretty-print the given object.
+ """
+ ctx = PrettyPrinter(maxwidth=maxwidth)
+ ctx.pp(obj)
+ return str(ctx)
+
+
+## Pretty-printers for builtin classes
+
+def pretty_print_list(pp, obj):
+ with pp.group():
+ pp.text('[')
+ with pp.indent(2):
+ for v in obj:
+ if not pp.first(): pp.text(',')
+ pp.breakable()
+ pp.pp(v)
+ pp.breakable()
+ pp.text(']')
+
+def pretty_print_dict(pp, obj):
+ with pp.group():
+ pp.text('{')
+ with pp.indent(2):
+ for (k, v) in sorted(obj.items()):
+ if not pp.first(): pp.text(',')
+ pp.breakable()
+ pp.pp(k)
+ pp.text(': ')
+ pp.pp(v)
+ pp.breakable()
+ pp.text('}')
+
+pretty_printers = {
+ list: pretty_print_list,
+ dict: pretty_print_dict,
+}
+
+
+## Implementation
+
+class PrettyPrinter(object):
+ def __init__(self, maxwidth):
+ self.maxwidth = maxwidth
+ self.cur_indent = 0
+ self.root_group = Group()
+ self.group_stack = [self.root_group]
+
+ def current_group(self):
+ return self.group_stack[-1]
+
+ def text(self, s):
+ self.current_group().append(str(s))
+
+ def breakable(self, sep=' '):
+ self.current_group().append(Breakable(sep, self.cur_indent))
+
+ def first(self):
+ return self.current_group().first()
+
+ @contextmanager
+ def indent(self, n):
+ self.cur_indent += n
+ yield
+ self.cur_indent -= n
+
+ @contextmanager
+ def group(self):
+ self.group_stack.append(Group())
+ yield
+ new_group = self.group_stack.pop()
+ self.current_group().append(new_group)
+
+ def pp(self, obj):
+ if hasattr(obj, "pretty_print"):
+ obj.pretty_print(self)
+ elif type(obj) in pretty_printers:
+ pretty_printers[type(obj)](self, obj)
+ else:
+ self.text(repr(obj))
+
+ def __str__(self):
+ return self.root_group.render(0, self.maxwidth)
+
+class Group(object):
+ __slots__ = ["fragments", "length", "_first"]
+
+ def __init__(self):
+ self.fragments = []
+ self.length = 0
+ self._first = True
+
+ def append(self, x):
+ self.fragments.append(x)
+ self.length += len(x)
+
+ def first(self):
+ if self._first:
+ self._first = False
+ return True
+ return False
+
+ def __len__(self):
+ return self.length
+
+ def render(self, curwidth, maxwidth):
+ dobreak = len(self) > (maxwidth - curwidth)
+
+ a = []
+ for x in self.fragments:
+ if isinstance(x, Breakable):
+ if dobreak:
+ a.append('\n')
+ a.append(' ' * x.indent)
+ curwidth = 0
+ else:
+ a.append(x.sep)
+ elif isinstance(x, Group):
+ a.append(x.render(curwidth, maxwidth))
+ else:
+ a.append(x)
+ curwidth += len(a[-1])
+ return ''.join(a)
+
+class Breakable(object):
+ __slots__ = ["sep", "indent"]
+
+ def __init__(self, sep, indent):
+ self.sep = sep
+ self.indent = indent
+
+ def __len__(self):
+ return len(self.sep)
+
+
+## Tests
+
+class TestPP(unittest.TestCase):
+ def test_scalars(self):
+ self.assertEquals(pp(1), "1")
+ self.assertEquals(pp("foo"), "'foo'")
+
+ def test_hash(self):
+ expected = """{ 1: 'a', 'b': 2 }"""
+ self.assertEquals(pp(eval(expected)), expected)
+ expected = """\
+{
+ 1: 'a',
+ 'b': 2
+}"""
+ self.assertEquals(pp(eval(expected), maxwidth=0), expected)
+
+ def test_array(self):
+ expected = """[ 1, 'a', 2 ]"""
+ self.assertEquals(pp(eval(expected)), expected)
+ expected = """\
+[
+ 1,
+ 'a',
+ 2
+]"""
+ self.assertEquals(pp(eval(expected), maxwidth=0), expected)
+
+ def test_nested(self):
+ expected = """[ [ 1, 2 ], [ 3, 4 ] ]"""
+ self.assertEquals(pp(eval(expected)), expected)
+ expected = """\
+[
+ [
+ 1,
+ 2
+ ],
+ [
+ 3,
+ 4
+ ]
+]"""
+ self.assertEquals(pp(eval(expected), maxwidth=0), expected)
+
+ def test_breaking(self):
+ expected = """\
+[
+ [ 1, 2 ],
+ 'abcdefghijklmnopqrstuvwxyz'
+]"""
+ self.assertEquals(pp(eval(expected), maxwidth=24), expected)
+ expected = """\
+[
+ [ 'abcd', 2 ],
+ [ '0123456789' ],
+ [
+ '0123456789',
+ 'abcdefghij'
+ ],
+ [ 'abcdefghijklmnop' ],
+ [
+ 'abcdefghijklmnopq'
+ ],
+ { 'k': 'v' },
+ {
+ 1: [ 2, [ 3, 4 ] ],
+ 'foo': 'abcdefghijklmnop'
+ }
+]"""
+ self.assertEquals(pp(eval(expected), maxwidth=24), expected)
+ expected = """\
+[
+ [ 1, 2 ],
+ [ 3, 4 ]
+]"""
+ self.assertEquals(pp(eval(expected), maxwidth=15), expected)
+
+ # This is an edge case where our simpler algorithm breaks down.
+ @unittest.expectedFailure
+ def test_greedy_breaking(self):
+ expected = """\
+abc def
+ghijklmnopqrstuvwxyz\
+"""
+ pp = PrettyPrinter(maxwidth=8)
+ pp.text("abc")
+ with pp.group():
+ pp.breakable()
+ pp.text("def")
+ with pp.group():
+ pp.breakable()
+ pp.text("ghijklmnopqrstuvwxyz")
+ self.assertEquals(str(pp), expected)
+
+if __name__ == '__main__':
+ unittest.main()