MetaKernel Echo Demo¶

The kernel running this notebook is MetaKernel Echo — a MetaKernel subclass that purely echoes its input back as output. It is useful as a minimal reference implementation for building new kernels on top of MetaKernel.

Despite its simplicity, it inherits the full MetaKernel magic system.

Installation¶

Install the echo kernel by running pip install . from that directory. Then run ipython notebook from this directory. Select "Echo" from the top right dropdown list of kernels.

In [1]:

Hello, world!

Hello, world!

Out[1]:

'Hello, world!'

Magics¶

Like all of the Metakernels, the echo kernel comes with a base set of magics.

In [2]:

%magic

%magic

Line magics:

    %activity FILENAME - run a widget-based activity
    %blockly - show visual code
    %cd PATH - change current directory of session
    %connect_info - show connection information
    %conversation ID - insert conversation by ID
    %dot CODE - render code as Graphviz image
    %download URL [-f FILENAME] - download file from URL
    %edit FILENAME - load code from filename into next cell for editing
    %get VARIABLE - get a variable from the kernel in a Python-type.
    %help TEXT - get help on the given text
    %html CODE - display code as HTML
    %include FILENAME ... - include code from filename into this code
    %install PACKAGE - install package
    %install_magic URL - download and install magic from URL
    %javascript CODE - send code as JavaScript
    %jigsaw LANGUAGE - show visual code editor/generator
    %kernel MODULE CLASS [-k NAME] - construct a kernel for sending code.
    %kx CODE [-k NAME] - send the code to the kernel.
    %latex TEXT - display text as LaTeX
    %load FILENAME - load code from filename into next cell
    %ls PATH - list files and directories under PATH
    %lsmagic - list the current line and cell magics
    %macro NAME - execute a macro
    %magic - show installed magics
    %matplotlib BACKEND - set the matplotlib backend to BACKEND
    %parallel MODULE CLASS [-k NAME] [-i [...]] - construct an interface to the cluster.
    %plot [options] backend - configure plotting for the session.
    %pmap FUNCTION [ARGS1,ARGS2,...] - ("parallel map") call a FUNCTION on args
    %px EXPRESSION - send EXPRESSION to the cluster.
    %python CODE - evaluate code as Python
    %reload_magics - reload the magics from the installed files
    %restart - restart session
    %run [--language LANG] FILENAME - run code in filename by
    %scheme CODE - evaluate code as Scheme
    %set VARIABLE VALUE - set a variable in the kernel.
    %shell COMMAND - run the line as a shell command

Cell magics:

     %%shell - run the contents of the cell as shell commands
    %%activity FILENAME - make an activity from
    %%brain - run a cell as brain control code
    %%debug - step through the code expression by expression
    %%dot - render contents of cell as Graphviz image
    %%file [--append|-a] FILENAME - write contents of cell to file
    %%help TEXT - get detailed help on the given text
    %%html - display contents of cell as HTML
    %%javascript - send contents of cell as JavaScript
    %%kx [-k NAME] - send the cell code to the kernel.
    %%latex - display contents of cell as LaTeX
    %%macro NAME - learn a new macro
    %%pipe FUNCTION1 | FUNCTION2 ...
    %%processing - run the cell in the language Processing
    %%px - send cell to the cluster.
    %%python - evaluate contents of cell as Python
    %%scheme - evaluate contents of cell as Scheme
    %%show [-o]- show cell contents or results in system pager
    %%time - show time to run cell
    %%tutor [--language=LANGUAGE] - show cell with
    %conversation ID - insert conversation by ID

Shell shortcut:

    ! COMMAND ... - execute command in shell

Any cell magic can be made persistent for rest of session by using %%% prefix.

Help on items:

    ??item - get detailed, technical information on item

    ?item  - get help on item

    item?  - get help on item

    item?? - get detailed, technical information on item

In [3]:

%python print('hello, world!')

%python print('hello, world!')

hello, world!

You can get help on a magic by typing ?

In [4]:

%%html?

%%html?

You can also get help by pressing SHIFT+TAB at the end of the word.

In [5]:

%lsmagic

%lsmagic

Available line magics:
%activity  %blockly  %cd  %connect_info  %conversation  %dot  %download  %edit  %get  %help  %html  %include  %install  %install_magic  %javascript  %jigsaw  %kernel  %kx  %latex  %load  %ls  %lsmagic  %macro  %magic  %matplotlib  %parallel  %plot  %pmap  %px  %python  %reload_magics  %restart  %run  %scheme  %set  %shell

Available cell magics:
%%activity  %%brain  %%conversation  %%debug  %%dot  %%file  %%help  %%html  %%javascript  %%kx  %%latex  %%macro  %%pipe  %%processing  %%px  %%python  %%scheme  %%shell  %%show  %%time  %%tutor

Code completion works for magics. Press tab below to see the completion (when not viewing through nbviewer).

In [6]:

%javas

%javas

Out[6]:

'%javas'

Completion also works for path names (local, absolute, or from the home ~ directory). Press TAB below for completion.

In [7]:

echo_kernel.ip

echo_kernel.ip

Out[7]:

'echo_kernel.ip'

In [8]:

%%file  temp.txt
This concludes our example.
Goodbye, world!

%%file temp.txt This concludes our example. Goodbye, world!

Created file '/Users/stevensilvester/workspace/metakernel/examples/temp.txt'.

In [ ]: