Add option for minifying standalone modules (which will be called by other code)

[fiatjaf]

Using regular --rename option, everything gets renamed, including top level functions and variables. This breaks the file if it is used as a module by other files.

There should be an option for preserving global functions/variables for these use cases.

[gareth-rees]

There's the --preserve command-line option, or you can make use of the __all__ list.

[fiatjaf]

I wrote a patch, but, knowing you'll find it dirty, I'll just paste here as a suggestion (or for discussion) for later development after your commentary:

def toplevel_names(tree):
    """
    Search tree for FunctionDef and Assign statements with indentation 
    level 0. Return the names of these variables and functions.
    """
    names = set()
    for elem in walk(tree):
        if type(elem) is Global:
            names.update(elem.names)
        if type(elem) is Assign and elem.col_offset == 0:
            names.update([target.id for target in elem.targets\
                                     if hasattr(target, 'id')])
        if type(elem) is FunctionDef and elem.col_offset == 0:
            names.add(elem.name)
    return names

This function is called when this option is selected:

p.add_option('--preservetoplevel', '-m',
             action='store_true', default=False,
             help="preserve top level object names (for use as imported module)"
                  "(implies --rename)")

Like this:

    if opts['rename'] or opts['preservetoplevel']:
        r = reserved_names_in_ast(tree)
        if opts['preserve']:
            r.update(opts['preserve'].split(','))
        if opts['preservetoplevel']:
            toplevel = toplevel_names(tree)
            r.update(toplevel)

[fiatjaf]

Whoa, I didn't thought of this simple solution!
How do I use the __all__ list? Can I do this without modifying the code?

[gareth-rees]

No, you need to explicitly set up an __all__ list.

[fiatjaf]

Oh, so it isn't that simple.