imacropy 0.1.0

Interactive MacroPy - IPython REPL, generic bootstrapper.

Imacropy is interactive macropy.

We provide some agile-development addons for MacroPy, namely a generic macro-enabling bootstrapper, and an IPython extension to macro-enable its REPL.

Bootstrapper:

The bootstrapper imports the specified file or module, pretending its __name__ is "__main__". This allows your main program to use macros.

For example, some_program.py:

from simplelet import macros, let

def main():
    x = let((y, 21))[2*y]
    assert x == 42
    print("All OK")

if __name__ == "__main__":
    main()

Start it as:

macropy3 some_program.py

or:

macropy3 -m some_program

The only command-line switch the bootstrapper supports is -m module_name. If you need to set other Python command-line options:

python3 <your options here> -m macropy3 -m some_program

The first -m goes to Python itself, the second to the macropy3 bootstrapper.

IPython extension:

The extension allows to use macros in the IPython REPL. (Defining macros in the REPL is currently not supported.)

For example:

In [1]: from simplelet import macros, let

In [2]: let((x, 21))[2*x]
Out[2]: 42

A from-import of macros from a given module clears from the REPL session all current macros loaded from that module, and loads the latest definitions of only the specified macros from disk. This allows interactive testing when editing macros.

The most recent definition of any given macro remains alive until the next macro from-import from the same module, or until the IPython session is terminated.

Macro docstrings and source code can be viewed using ? and ??, as usual.

To load the extension once, %load_ext imacropy.console.

To autoload it when IPython starts, add "imacropy.console" to the list c.InteractiveShellApp.extensions in your ipython_config.py. To find the config file, ipython profile locate.

When the extension loads, it imports macropy into the REPL session. You can use this to debug whether it is loaded, if necessary.

Currently no startup banner is printed, because extension loading occurs after IPython has already printed its own banner. We cannot manually print a banner, because some tools (notably importmagic.el for Emacs, included in Spacemacs) treat the situation as a fatal error in Python interpreter startup if anything is printed (and ipython3 --no-banner is rather convenient to have as the python-shell, to run IPython in Emacs’s inferior-shell mode).

For more details, see the docstring of imacropy.console.