Generator support for petl.fromdicts()

[arturponinski]

Minimal, reproducible code sample, a copy-pastable example if possible

import petl

data = [
    {"foo":"baz"},
    {"foo":"bar"}
]

table = petl.fromdicts(data)
print(petl.header(table))
print(petl.look(table))

def foo():
    yield {"foo": "baz"}
    yield {"foo": "bar"}

table = petl.fromdicts(foo())
print(petl.header(table))
print(petl.look(table))

Output:

('foo',)
+-------+
| foo   |
+=======+
| 'baz' |
+-------+
| 'bar' |
+-------+

('foo',)
+
|
+

Problem description

When passing a generator to petl.fromdicts() the generator is iterated only once, hence calling header(), previewing in debug or trying to iterate the table second time, returns empty result

Version and installation information

• Value of petl.__version__ 1.7.5.dev6+dirty
• Version of Python interpreter, tests on all supported versions