"""Walk the knitting pattern."""
[docs]def walk(knitting_pattern):
"""Walk the knitting pattern in a right-to-left fashion.
:return: an iterable to walk the rows
:rtype: list
:param knittingpattern.KnittingPattern.KnittingPattern knitting_pattern: a
knitting pattern to take the rows from
"""
rows_before = {} # key consumes from values
free_rows = []
walk = []
for row in knitting_pattern.rows:
rows_before_ = row.rows_before[:]
if rows_before_:
rows_before[row] = rows_before_
else:
free_rows.append(row)
assert free_rows
while free_rows:
# print("free rows:", free_rows)
row = free_rows.pop(0)
walk.append(row)
assert row not in rows_before
for freed_row in reversed(row.rows_after):
todo = rows_before[freed_row]
# print(" freed:", freed_row, todo)
todo.remove(row)
if not todo:
del rows_before[freed_row]
free_rows.insert(0, freed_row)
assert not rows_before, "everything is walked"
return walk
__all__ = ["walk"]