Show More
@@ -1,56 +1,71 b'' | |||||
1 | How IPython Works |
|
1 | How IPython Works | |
2 | ================= |
|
2 | ================= | |
3 |
|
3 | |||
4 | Terminal IPython |
|
4 | Terminal IPython | |
5 | ---------------- |
|
5 | ---------------- | |
6 |
|
6 | |||
7 | When you type ``ipython``, you get the original IPython interface, running in |
|
7 | When you type ``ipython``, you get the original IPython interface, running in | |
8 | the terminal. It does something like this:: |
|
8 | the terminal. It does something like this:: | |
9 |
|
9 | |||
10 | while True: |
|
10 | while True: | |
11 | code = input(">>> ") |
|
11 | code = input(">>> ") | |
12 | exec(code) |
|
12 | exec(code) | |
13 |
|
13 | |||
14 | Of course, it's much more complicated, because it has to deal with multi-line |
|
14 | Of course, it's much more complicated, because it has to deal with multi-line | |
15 | code, tab completion using :mod:`readline`, magic commands, and so on. But the |
|
15 | code, tab completion using :mod:`readline`, magic commands, and so on. But the | |
16 | model is like that: prompt the user for some code, and when they've entered it, |
|
16 | model is like that: prompt the user for some code, and when they've entered it, | |
17 | exec it in the same process. |
|
17 | exec it in the same process. | |
18 |
|
18 | |||
19 | The IPython Kernel |
|
19 | The IPython Kernel | |
20 | ------------------ |
|
20 | ------------------ | |
21 |
|
21 | |||
22 | All the other interfaces—the Notebook, the Qt console, ``ipython console`` in |
|
22 | All the other interfaces—the Notebook, the Qt console, ``ipython console`` in | |
23 | the terminal, and third party interfaces—use the IPython Kernel. This is a |
|
23 | the terminal, and third party interfaces—use the IPython Kernel. This is a | |
24 | separate process which is responsible for running user code, and things like |
|
24 | separate process which is responsible for running user code, and things like | |
25 | computing possible completions. Frontends communicate with it using JSON |
|
25 | computing possible completions. Frontends communicate with it using JSON | |
26 | messages sent over ZeroMQ sockets; the protocol they use is described in |
|
26 | messages sent over ZeroMQ sockets; the protocol they use is described in | |
27 | :doc:`messaging`. |
|
27 | :doc:`messaging`. | |
28 |
|
28 | |||
29 | The core execution machinery for the kernel is shared with terminal IPython: |
|
29 | The core execution machinery for the kernel is shared with terminal IPython: | |
30 |
|
30 | |||
31 | .. image:: figs/ipy_kernel_and_terminal.png |
|
31 | .. image:: figs/ipy_kernel_and_terminal.png | |
32 |
|
32 | |||
33 | A kernel process can be connected to more than one frontend simultaneously. In |
|
33 | A kernel process can be connected to more than one frontend simultaneously. In | |
34 | this case, the different frontends will have access to the same variables. |
|
34 | this case, the different frontends will have access to the same variables. | |
35 |
|
35 | |||
36 | .. TODO: Diagram illustrating this? |
|
36 | .. TODO: Diagram illustrating this? | |
37 |
|
37 | |||
38 | This design was intended to allow easy development of different frontends based |
|
38 | This design was intended to allow easy development of different frontends based | |
39 | on the same kernel, but it also made it possible to support new languages in the |
|
39 | on the same kernel, but it also made it possible to support new languages in the | |
40 | same frontends, by developing kernels in those languages, and we are refining |
|
40 | same frontends, by developing kernels in those languages, and we are refining | |
41 | IPython to make that more practical. |
|
41 | IPython to make that more practical. | |
42 |
|
42 | |||
43 | Today, there are two ways to develop a kernel for another language. Wrapper |
|
43 | Today, there are two ways to develop a kernel for another language. Wrapper | |
44 | kernels reuse the communications machinery from IPython, and implement only the |
|
44 | kernels reuse the communications machinery from IPython, and implement only the | |
45 | core execution part. Native kernels implement execution and communications in |
|
45 | core execution part. Native kernels implement execution and communications in | |
46 | the target language: |
|
46 | the target language: | |
47 |
|
47 | |||
48 | .. image:: figs/other_kernels.png |
|
48 | .. image:: figs/other_kernels.png | |
49 |
|
49 | |||
50 | .. seealso:: |
|
50 | .. seealso:: | |
51 |
|
51 | |||
52 | :doc:`kernels` |
|
52 | :doc:`kernels` | |
53 |
|
53 | |||
54 | :doc:`wrapperkernels` |
|
54 | :doc:`wrapperkernels` | |
55 |
|
55 | |||
56 |
|
56 | Notebooks | ||
|
57 | --------- | |||
|
58 | ||||
|
59 | The Notebook frontend does something extra. In addition to running your code, it | |||
|
60 | stores code and output, together with markdown notes, in an editable document | |||
|
61 | called a notebook. When you save it, this is sent from your browser to the | |||
|
62 | notebook server, which saves it on disk as a JSON file with a ``.ipynb`` | |||
|
63 | extension. | |||
|
64 | ||||
|
65 | .. TODO: Diagram of how these pieces fit together. | |||
|
66 | ||||
|
67 | The notebook server, not the kernel, is responsible for saving and loading | |||
|
68 | notebooks, so you can edit notebooks even if you don't have the kernel for that | |||
|
69 | language—you just won't be able to run code. The kernel doesn't know anything | |||
|
70 | about the notebook document: it just gets sent cells of code to execute when the | |||
|
71 | user runs them. |
General Comments 0
You need to be logged in to leave comments.
Login now