# -*- coding: utf-8; -*-
'''Utilities for building REPLs.'''

__all__ = ["doc", "sourcecode", "get_makemacro_sourcecode"]

import inspect

def doc(obj):
    """Print an object's docstring, non-interactively.

    If available, print also the filename and the starting line number
    of the definition of `obj`.
    """
    try:
        filename = inspect.getsourcefile(obj)
        source, firstlineno = inspect.getsourcelines(obj)
        print(f"{filename}:{firstlineno}")
    except (TypeError, OSError):
        pass
    if not hasattr(obj, "__doc__") or not obj.__doc__:
        print("<no docstring>")
        return
    print(inspect.cleandoc(obj.__doc__))

def sourcecode(obj):
    """Print an object's source code, non-interactively.

    If available, print also the filename and the starting line number
    of the definition of `obj`.
    """
    try:
        filename = inspect.getsourcefile(obj)
        source, firstlineno = inspect.getsourcelines(obj)
        print(f"{filename}:{firstlineno}")
        for line in source:
            print(line.rstrip("\n"))
    except (TypeError, OSError):
        print("<no source code available>")

def get_makemacro_sourcecode():
    """Return source code for the REPL's `macro` magic function.

    For injection by REPL into the session.

    We assume the expander instance has been bound to the global variable
    `__macro_expander__` inside the REPL session.
    """
    return """
    def macro(function):
        '''[mcpyrate] `macro(f)`: bind function `f` as a macro. Works also as a decorator. REPL only.'''
        if not callable(function):
            raise TypeError(f'`function` must be callable, got {type(function)} with value {repr(function)}')
        if function.__name__ == '<lambda>':
            raise TypeError('`function` must be a named function, got a lambda.')
        __macro_expander__.bindings[function.__name__] = function
        return function
    """