gmel - gnu make extension library

Based on gnu make Loaded Object API
Required make >= 4.0. Currently tested only under linux.

The most interesting part of gmel is the embedded python interpreter. After initialization, execution of an arbitrary python code in the context of the main module is available. See py_eval and py_call for details.

Arguments: 1. python_code
Returns: None
Action: evaluates given python_code in embedded interpreter.
Example:

define py_cmd :=
import os
def test(a, b):
    return os.path.normpath(os.path.join(a, b))
endef
$(py_eval $(py_cmd))

Arguments: 1. callable_name 2+ [optional arguments]
Returns: result of gmel_pycall_wrapper(callable_name(*arguments))
Action: try to call python callable_name in context of main module
Details: gmel python engine formats arguments as unicode for python3 and as bytes for python2. As result of function call it expects None or bytes. For convenience, there is an automatically applied built-in gmel_pycall_wrapper: str/bytes -> bytes, int -> str(int), and so on. See gmel_py2/gmel_py3 in source code for concrete rules.
Example:

$(py_call test,/home/test,../user) # returns /home/user

Arguments: 1. target_name 2. bind_name 3+ [optional command arguments]
Returns: None
Action: creates function bind. Optional command arguments adds as first arguments of binded function.
Example:

_func = $(if $(3),$(1) $(2),$(2))
$(bind func,_func,ARG1)
# nowtime it is possible to call func without $(call)
$(func 10, 20) # returns ARG1 10

Arguments: 1. bind_name 2. target_name 3+ [optional command arguments]
Returns: None
Action: like bind, except of order of two first arguments.
Example:

$(bind popen_bind,bind_r,popen)
# with bind_r
$(popen_bind python,/usr/bin/python,-c)
# the same without bind_r:
$(bind python,popen,/usr/bin/python,-c)

Arguments: 1. cmd_bin 2+ [optional command arguments]
Returns: result of cmd
Action: call $(error) in case of non-zero exit-code
Example:

$(popen seq,-w,9,10) # returns 09 10

Arguments: 1. command
Returns: result of /bin/bash -e -o pipefail -c command
Action: call $(error) in case of non-zero exit-code
Todo: use SHELL/.SHELLFLAGS instead of hard-coded /bin/bash.
Example:

$(sshell echo 1; false) # fails

Arguments: 1. date_format 2. date_str
Returns: unix time (timestamp) in seconds
Example:

$(strptime %Y-%m-%d,2014-01-11) # returns 1389384000

Arguments: 1. date_format 2. unix_timestamp
Returns: date_str
Example:

$(strftime %Y%m%d,1389384000) # returns 20140111

Arguments: 1. new_date_format 2. old_date_format 3. date_str
Returns: date_str in new format
Example:

$(strfptime %Y%m%d,%Y-%m-%d %H,2014-01-11 23) # returns 20140111