def _eval(text=None, filename=None, _larch=None,
          new_module=None, interactive=False,
          printall=False):
    """evaluate a string of larch text
    """
    if _larch is None:
        raise Warning("cannot eval string. larch broken?")

    if text is None:
        return None

    symtable = _larch.symtable
    lineno = 0
    output = None
    fname = filename

    inptext = inputText.InputText(interactive=interactive, _larch=_larch)
    is_complete = inptext.put(text, filename=filename)
    # print 'eval complete? ', is_complete, inptext.keys
    if not is_complete:
        inptext.input_buff.reverse()
        lline, lineno = 'unknown line', 0
        for tline, complete, eos, fname, lineno in inptext.input_buff:
            if complete: break
            lline = tline
        _larch.raise_exception(None, expr=lline, fname=fname, lineno=lineno+1,
                               exc=SyntaxError, msg= 'input is incomplete')

    if len(inptext.keys) > 0 and filename is not None:
        msg = "file ends with un-terminated '%s' block"
        _larch.raise_exception(None, expr="run('%s')" % filename,
                               fname=filename, lineno=inptext.lineno,
                               exc=IOError, msg=msg % inptext.keys[0])

    if new_module is not None:
        # save current module group
        #  create new group, set as moduleGroup and localGroup
        symtable.save_frame()
        thismod = symtable.create_group(name=new_module)
        symtable._sys.modules[new_module] = thismod
        symtable.set_frame((thismod, thismod))

    output = []
    # print 'eval %i lines of text ' % len(inptext)
    if len(_larch.error) > 0:
        inptext.clear()
        return output

    while len(inptext) > 0:
        block, fname, lineno = inptext.get()
        b = block.strip()
        if len(b) <= 0:
            continue
        ret = _larch.eval(block, fname=fname, lineno=lineno)
        if hasattr(ret, '__call__') and not isinstance(ret, type):
            try:
                if 1 == len(block.split()):
                    ret = ret()
            except:
                pass
        if len(_larch.error) > 0:
            break
        #
    if len(_larch.error) > 0:
        inptext.clear()
    elif printall or ret is not None:
        output.append("%s" % ret)

    # for a "newly created module" (as on import),
    # the module group is the return value
    # print 'eval End ', new_module, output
    if new_module is not None:
        symtable.restore_frame()
        output = thismod
    elif len(output) > 0:
        output = "\n".join(output)
    else:
        output = None
    return output
dataset/ETHPy150Open xraypy/xraylarch/lib/builtins.py/_eval/operator `and` -> `or`