From 1bf642c6a1ef244131d37b9764a7493c8e1c5648 Mon Sep 17 00:00:00 2001 From: Michael Williamson Date: Mon, 1 May 2023 17:14:43 +0100 Subject: Update docs --- README.rst | 87 ++++++++++++++++++++++++++++++++++++++++++++++++++++---------- 1 file changed, 73 insertions(+), 14 deletions(-) (limited to 'README.rst') diff --git a/README.rst b/README.rst index ed1c287..aa8cf49 100644 --- a/README.rst +++ b/README.rst @@ -59,15 +59,53 @@ Once Homebrew is installed, you can install the remaining dependencies with: Usage ----- -Call ``jq.compile`` to compile a jq program. -Call ``.input()`` on the compiled program to supply an input value. -The input must either be: +Using jq requires three steps: -* a valid JSON value, such as the values returned from ``json.load`` -* unparsed JSON text passed as the keyword argument ``text``. +#. Call ``jq.compile()`` to compile a jq program. +#. Call an input method on the compiled program to supply the input. +#. Call an output method on the result to retrieve the output. -Calling ``first()`` on the result will run the program with the given input, -and return the first output element. +For instance: + +.. code-block:: python + + import jq + + assert jq.compile(".+5").input_value(42).first() == 47 + +Input methods +~~~~~~~~~~~~~ + +Call ``.input_value()`` to supply a valid JSON value, such as the values returned from ``json.load``: + +.. code-block:: python + + import jq + + assert jq.compile(".").input_value(None).first() == None + assert jq.compile(".").input_value(42).first() == 42 + assert jq.compile(".").input_value(0.42).first() == 0.42 + assert jq.compile(".").input_value(True).first() == True + assert jq.compile(".").input_value("hello").first() == "hello" + +Call ``.input_text()`` to supply unparsed JSON text: + +.. code-block:: python + + import jq + + assert jq.compile(".").input_text("null").first() == None + assert jq.compile(".").input_text("42").first() == 42 + assert jq.compile(".").input_text("0.42").first() == 0.42 + assert jq.compile(".").input_text("true").first() == True + assert jq.compile(".").input_text('"hello"').first() == "hello" + +You can also call the older ``input()`` method by passing: + +* a valid JSON value, such as the values returned from ``json.load``, as a positional argument +* unparsed JSON text passed as the keyword argument ``text`` + +For instance: .. code-block:: python @@ -75,43 +113,61 @@ and return the first output element. assert jq.compile(".").input("hello").first() == "hello" assert jq.compile(".").input(text='"hello"').first() == "hello" - assert jq.compile("[.[]+1]").input([1, 2, 3]).first() == [2, 3, 4] - assert jq.compile(".[]+1").input([1, 2, 3]).first() == 2 + +Return methods +~~~~~~~~~~~~~~ + +Calling ``first()`` on the result will run the program with the given input, +and return the first output element. + +.. code-block:: python + + import jq + + assert jq.compile(".").input_value("hello").first() == "hello" + assert jq.compile("[.[]+1]").input_value([1, 2, 3]).first() == [2, 3, 4] + assert jq.compile(".[]+1").input_value([1, 2, 3]).first() == 2 Call ``text()`` instead of ``first()`` to serialise the output into JSON text: .. code-block:: python - assert jq.compile(".").input("42").text() == '"42"' + assert jq.compile(".").input_value("42").text() == '"42"' When calling ``text()``, if there are multiple output elements, each element is represented by a separate line: .. code-block:: python - assert jq.compile(".[]").input([1, 2, 3]).text() == "1\n2\n3" + assert jq.compile(".[]").input_value([1, 2, 3]).text() == "1\n2\n3" Call ``all()`` to get all of the output elements in a list: .. code-block:: python - assert jq.compile(".[]+1").input([1, 2, 3]).all() == [2, 3, 4] + assert jq.compile(".[]+1").input_value([1, 2, 3]).all() == [2, 3, 4] Call ``iter()`` to get all of the output elements as an iterator: .. code-block:: python - iterator = iter(jq.compile(".[]+1").input([1, 2, 3])) + iterator = iter(jq.compile(".[]+1").input_value([1, 2, 3])) assert next(iterator, None) == 2 assert next(iterator, None) == 3 assert next(iterator, None) == 4 assert next(iterator, None) == None +Arguments +~~~~~~~~~ + Calling ``compile()`` with the ``args`` argument allows predefined variables to be used within the program: .. code-block:: python program = jq.compile("$a + $b + .", args={"a": 100, "b": 20}) - assert program.input(3).first() == 123 + assert program.input_value(3).first() == 123 + +Convenience functions +~~~~~~~~~~~~~~~~~~~~~ Convenience functions are available to get the output for a program and input in one call: @@ -123,6 +179,9 @@ Convenience functions are available to get the output for a program and input in assert jq.all(".[] + 1", [1, 2, 3]) == [2, 3, 4] assert list(jq.iter(".[] + 1", [1, 2, 3])) == [2, 3, 4] +Original program string +~~~~~~~~~~~~~~~~~~~~~~~ + The original program string is available on a compiled program as the ``program_string`` attribute: .. code-block:: python -- cgit v1.2.3