141226.9 · 5bfb9781f7e5ba2ad99b71150bccc559d53b928f

Add Streaming parser (--stream)

Streaming means that outputs are produced as soon as possible. With the `foreach` syntax one can write programs which reduce portions of the streaming parse of a large input (reduce into proper JSON values, for example), and discard the rest, processing incrementally.

This:

$ jq -c --stream .

should produce the same output as this:

$ jq -c '. as $dot | path(..) as $p | $dot | getpath($p) | [$p,.]'

The output of `jq --stream .` should be a sequence of`[[<path>],<leaf>]` and `[[<path>]]` values. The latter indicate that the array/object at that path ended.

Scalars and empty arrays and objects are leaf values for this purpose.

For example, a truncated input produces a path as soon as possible, then later the error:

$ printf '[0,\n'|./jq -c --stream .
[[0],0]
parse error: Unfinished JSON term at EOF at line 3, column 0
$

new file mode 100644@@ -0,0 +1,7 @@+0 12 true false null [] {} [{}] [[]]+[0,01,[12,22,[34,[45,56],7]],[]]+{"a":[1]}+{"a":[{}]}+{"a":[{},[],[[]]]}+{"a":[{"b":[]}]}+{"a":[{"b":[]},{},[2]]}