path: root/contrib/python/ipython/py2/IPython/utils/text.py

# encoding: utf-8 
""" 
Utilities for working with strings and text. 
 
Inheritance diagram: 
 
.. inheritance-diagram:: IPython.utils.text 
   :parts: 3 
""" 
from __future__ import absolute_import 
 
import os 
import re 
import sys 
import textwrap 
from string import Formatter 
try:
    from pathlib import Path
except ImportError:
    # Python 2 backport
    from pathlib2 import Path
 
from IPython.testing.skipdoctest import skip_doctest_py3, skip_doctest 
from IPython.utils import py3compat 
 
# datetime.strftime date format for ipython 
if sys.platform == 'win32': 
    date_format = "%B %d, %Y" 
else: 
    date_format = "%B %-d, %Y" 
 
class LSString(str): 
    """String derivative with a special access attributes. 
 
    These are normal strings, but with the special attributes: 
 
        .l (or .list) : value as list (split on newlines). 
        .n (or .nlstr): original value (the string itself). 
        .s (or .spstr): value as whitespace-separated string. 
        .p (or .paths): list of path objects (requires path.py package) 
 
    Any values which require transformations are computed only once and 
    cached. 
 
    Such strings are very useful to efficiently interact with the shell, which 
    typically only understands whitespace-separated options for commands.""" 
 
    def get_list(self): 
        try: 
            return self.__list 
        except AttributeError: 
            self.__list = self.split('\n') 
            return self.__list 
 
    l = list = property(get_list) 
 
    def get_spstr(self): 
        try: 
            return self.__spstr 
        except AttributeError: 
            self.__spstr = self.replace('\n',' ') 
            return self.__spstr 
 
    s = spstr = property(get_spstr) 
 
    def get_nlstr(self): 
        return self 
 
    n = nlstr = property(get_nlstr) 
 
    def get_paths(self): 
        try: 
            return self.__paths 
        except AttributeError: 
            self.__paths = [Path(p) for p in self.split('\n') if os.path.exists(p)]
            return self.__paths 
 
    p = paths = property(get_paths) 
 
# FIXME: We need to reimplement type specific displayhook and then add this 
# back as a custom printer. This should also be moved outside utils into the 
# core. 
 
# def print_lsstring(arg): 
#     """ Prettier (non-repr-like) and more informative printer for LSString """ 
#     print "LSString (.p, .n, .l, .s available). Value:" 
#     print arg 
# 
# 
# print_lsstring = result_display.when_type(LSString)(print_lsstring) 
 
 
class SList(list): 
    """List derivative with a special access attributes. 
 
    These are normal lists, but with the special attributes: 
 
    * .l (or .list) : value as list (the list itself). 
    * .n (or .nlstr): value as a string, joined on newlines. 
    * .s (or .spstr): value as a string, joined on spaces. 
    * .p (or .paths): list of path objects (requires path.py package) 
 
    Any values which require transformations are computed only once and 
    cached.""" 
 
    def get_list(self): 
        return self 
 
    l = list = property(get_list) 
 
    def get_spstr(self): 
        try: 
            return self.__spstr 
        except AttributeError: 
            self.__spstr = ' '.join(self) 
            return self.__spstr 
 
    s = spstr = property(get_spstr) 
 
    def get_nlstr(self): 
        try: 
            return self.__nlstr 
        except AttributeError: 
            self.__nlstr = '\n'.join(self) 
            return self.__nlstr 
 
    n = nlstr = property(get_nlstr) 
 
    def get_paths(self): 
        try: 
            return self.__paths 
        except AttributeError: 
            self.__paths = [Path(p) for p in self if os.path.exists(p)]
            return self.__paths 
 
    p = paths = property(get_paths) 
 
    def grep(self, pattern, prune = False, field = None): 
        """ Return all strings matching 'pattern' (a regex or callable) 
 
        This is case-insensitive. If prune is true, return all items 
        NOT matching the pattern. 
 
        If field is specified, the match must occur in the specified 
        whitespace-separated field. 
 
        Examples:: 
 
            a.grep( lambda x: x.startswith('C') ) 
            a.grep('Cha.*log', prune=1) 
            a.grep('chm', field=-1) 
        """ 
 
        def match_target(s): 
            if field is None: 
                return s 
            parts = s.split() 
            try: 
                tgt = parts[field] 
                return tgt 
            except IndexError: 
                return "" 
 
        if isinstance(pattern, py3compat.string_types): 
            pred = lambda x : re.search(pattern, x, re.IGNORECASE) 
        else: 
            pred = pattern 
        if not prune: 
            return SList([el for el in self if pred(match_target(el))]) 
        else: 
            return SList([el for el in self if not pred(match_target(el))]) 
 
    def fields(self, *fields): 
        """ Collect whitespace-separated fields from string list 
 
        Allows quick awk-like usage of string lists. 
 
        Example data (in var a, created by 'a = !ls -l'):: 
 
            -rwxrwxrwx  1 ville None      18 Dec 14  2006 ChangeLog 
            drwxrwxrwx+ 6 ville None       0 Oct 24 18:05 IPython 
 
        * ``a.fields(0)`` is ``['-rwxrwxrwx', 'drwxrwxrwx+']`` 
        * ``a.fields(1,0)`` is ``['1 -rwxrwxrwx', '6 drwxrwxrwx+']`` 
          (note the joining by space). 
        * ``a.fields(-1)`` is ``['ChangeLog', 'IPython']`` 
 
        IndexErrors are ignored. 
 
        Without args, fields() just split()'s the strings. 
        """ 
        if len(fields) == 0: 
            return [el.split() for el in self] 
 
        res = SList() 
        for el in [f.split() for f in self]: 
            lineparts = [] 
 
            for fd in fields: 
                try: 
                    lineparts.append(el[fd]) 
                except IndexError: 
                    pass 
            if lineparts: 
                res.append(" ".join(lineparts)) 
 
        return res 
 
    def sort(self,field= None,  nums = False): 
        """ sort by specified fields (see fields()) 
 
        Example:: 
 
            a.sort(1, nums = True) 
 
        Sorts a by second field, in numerical order (so that 21 > 3) 
 
        """ 
 
        #decorate, sort, undecorate 
        if field is not None: 
            dsu = [[SList([line]).fields(field),  line] for line in self] 
        else: 
            dsu = [[line,  line] for line in self] 
        if nums: 
            for i in range(len(dsu)): 
                numstr = "".join([ch for ch in dsu[i][0] if ch.isdigit()]) 
                try: 
                    n = int(numstr) 
                except ValueError: 
                    n = 0 
                dsu[i][0] = n 
 
 
        dsu.sort() 
        return SList([t[1] for t in dsu]) 
 
 
# FIXME: We need to reimplement type specific displayhook and then add this 
# back as a custom printer. This should also be moved outside utils into the 
# core. 
 
# def print_slist(arg): 
#     """ Prettier (non-repr-like) and more informative printer for SList """ 
#     print "SList (.p, .n, .l, .s, .grep(), .fields(), sort() available):" 
#     if hasattr(arg,  'hideonce') and arg.hideonce: 
#         arg.hideonce = False 
#         return 
# 
#     nlprint(arg)   # This was a nested list printer, now removed. 
# 
# print_slist = result_display.when_type(SList)(print_slist) 
 
 
def indent(instr,nspaces=4, ntabs=0, flatten=False): 
    """Indent a string a given number of spaces or tabstops. 
 
    indent(str,nspaces=4,ntabs=0) -> indent str by ntabs+nspaces. 
 
    Parameters 
    ---------- 
 
    instr : basestring 
        The string to be indented. 
    nspaces : int (default: 4) 
        The number of spaces to be indented. 
    ntabs : int (default: 0) 
        The number of tabs to be indented. 
    flatten : bool (default: False) 
        Whether to scrub existing indentation.  If True, all lines will be 
        aligned to the same indentation.  If False, existing indentation will 
        be strictly increased. 
 
    Returns 
    ------- 
 
    str|unicode : string indented by ntabs and nspaces. 
 
    """ 
    if instr is None: 
        return 
    ind = '\t'*ntabs+' '*nspaces 
    if flatten: 
        pat = re.compile(r'^\s*', re.MULTILINE) 
    else: 
        pat = re.compile(r'^', re.MULTILINE) 
    outstr = re.sub(pat, ind, instr) 
    if outstr.endswith(os.linesep+ind): 
        return outstr[:-len(ind)] 
    else: 
        return outstr 
 
 
def list_strings(arg): 
    """Always return a list of strings, given a string or list of strings 
    as input. 
 
    Examples 
    -------- 
    :: 
 
        In [7]: list_strings('A single string') 
        Out[7]: ['A single string'] 
 
        In [8]: list_strings(['A single string in a list']) 
        Out[8]: ['A single string in a list'] 
 
        In [9]: list_strings(['A','list','of','strings']) 
        Out[9]: ['A', 'list', 'of', 'strings'] 
    """ 
 
    if isinstance(arg, py3compat.string_types): return [arg] 
    else: return arg 
 
 
def marquee(txt='',width=78,mark='*'): 
    """Return the input string centered in a 'marquee'. 
 
    Examples 
    -------- 
    :: 
 
        In [16]: marquee('A test',40) 
        Out[16]: '**************** A test ****************' 
 
        In [17]: marquee('A test',40,'-') 
        Out[17]: '---------------- A test ----------------' 
 
        In [18]: marquee('A test',40,' ') 
        Out[18]: '                 A test                 ' 
 
    """ 
    if not txt: 
        return (mark*width)[:width] 
    nmark = (width-len(txt)-2)//len(mark)//2 
    if nmark < 0: nmark =0 
    marks = mark*nmark 
    return '%s %s %s' % (marks,txt,marks) 
 
 
ini_spaces_re = re.compile(r'^(\s+)') 
 
def num_ini_spaces(strng): 
    """Return the number of initial spaces in a string""" 
 
    ini_spaces = ini_spaces_re.match(strng) 
    if ini_spaces: 
        return ini_spaces.end() 
    else: 
        return 0 
 
 
def format_screen(strng): 
    """Format a string for screen printing. 
 
    This removes some latex-type format codes.""" 
    # Paragraph continue 
    par_re = re.compile(r'\\$',re.MULTILINE) 
    strng = par_re.sub('',strng) 
    return strng 
 
 
def dedent(text): 
    """Equivalent of textwrap.dedent that ignores unindented first line. 
 
    This means it will still dedent strings like: 
    '''foo 
    is a bar 
    ''' 
 
    For use in wrap_paragraphs. 
    """ 
 
    if text.startswith('\n'): 
        # text starts with blank line, don't ignore the first line 
        return textwrap.dedent(text) 
 
    # split first line 
    splits = text.split('\n',1) 
    if len(splits) == 1: 
        # only one line 
        return textwrap.dedent(text) 
 
    first, rest = splits 
    # dedent everything but the first line 
    rest = textwrap.dedent(rest) 
    return '\n'.join([first, rest]) 
 
 
def wrap_paragraphs(text, ncols=80): 
    """Wrap multiple paragraphs to fit a specified width. 
 
    This is equivalent to textwrap.wrap, but with support for multiple 
    paragraphs, as separated by empty lines. 
 
    Returns 
    ------- 
 
    list of complete paragraphs, wrapped to fill `ncols` columns. 
    """ 
    paragraph_re = re.compile(r'\n(\s*\n)+', re.MULTILINE) 
    text = dedent(text).strip() 
    paragraphs = paragraph_re.split(text)[::2] # every other entry is space 
    out_ps = [] 
    indent_re = re.compile(r'\n\s+', re.MULTILINE) 
    for p in paragraphs: 
        # presume indentation that survives dedent is meaningful formatting, 
        # so don't fill unless text is flush. 
        if indent_re.search(p) is None: 
            # wrap paragraph 
            p = textwrap.fill(p, ncols) 
        out_ps.append(p) 
    return out_ps 
 
 
def long_substr(data): 
    """Return the longest common substring in a list of strings. 
     
    Credit: http://stackoverflow.com/questions/2892931/longest-common-substring-from-more-than-two-strings-python 
    """ 
    substr = '' 
    if len(data) > 1 and len(data[0]) > 0: 
        for i in range(len(data[0])): 
            for j in range(len(data[0])-i+1): 
                if j > len(substr) and all(data[0][i:i+j] in x for x in data): 
                    substr = data[0][i:i+j] 
    elif len(data) == 1: 
        substr = data[0] 
    return substr 
 
 
def strip_email_quotes(text): 
    """Strip leading email quotation characters ('>'). 
 
    Removes any combination of leading '>' interspersed with whitespace that 
    appears *identically* in all lines of the input text. 
 
    Parameters 
    ---------- 
    text : str 
 
    Examples 
    -------- 
 
    Simple uses:: 
 
        In [2]: strip_email_quotes('> > text') 
        Out[2]: 'text' 
 
        In [3]: strip_email_quotes('> > text\\n> > more') 
        Out[3]: 'text\\nmore' 
 
    Note how only the common prefix that appears in all lines is stripped:: 
 
        In [4]: strip_email_quotes('> > text\\n> > more\\n> more...') 
        Out[4]: '> text\\n> more\\nmore...' 
 
    So if any line has no quote marks ('>') , then none are stripped from any 
    of them :: 
     
        In [5]: strip_email_quotes('> > text\\n> > more\\nlast different') 
        Out[5]: '> > text\\n> > more\\nlast different' 
    """ 
    lines = text.splitlines() 
    matches = set() 
    for line in lines: 
        prefix = re.match(r'^(\s*>[ >]*)', line) 
        if prefix: 
            matches.add(prefix.group(1)) 
        else: 
            break 
    else: 
        prefix = long_substr(list(matches)) 
        if prefix: 
            strip = len(prefix) 
            text = '\n'.join([ ln[strip:] for ln in lines]) 
    return text 
 
def strip_ansi(source): 
    """ 
    Remove ansi escape codes from text. 
     
    Parameters 
    ---------- 
    source : str 
        Source to remove the ansi from 
    """ 
    return re.sub(r'\033\[(\d|;)+?m', '', source) 
 
 
class EvalFormatter(Formatter): 
    """A String Formatter that allows evaluation of simple expressions. 
     
    Note that this version interprets a : as specifying a format string (as per 
    standard string formatting), so if slicing is required, you must explicitly 
    create a slice. 
     
    This is to be used in templating cases, such as the parallel batch 
    script templates, where simple arithmetic on arguments is useful. 
 
    Examples 
    -------- 
    :: 
 
        In [1]: f = EvalFormatter() 
        In [2]: f.format('{n//4}', n=8) 
        Out[2]: '2' 
 
        In [3]: f.format("{greeting[slice(2,4)]}", greeting="Hello") 
        Out[3]: 'll' 
    """ 
    def get_field(self, name, args, kwargs): 
        v = eval(name, kwargs) 
        return v, name 
 
#XXX: As of Python 3.4, the format string parsing no longer splits on a colon 
# inside [], so EvalFormatter can handle slicing. Once we only support 3.4 and 
# above, it should be possible to remove FullEvalFormatter. 
 
@skip_doctest_py3 
class FullEvalFormatter(Formatter): 
    """A String Formatter that allows evaluation of simple expressions. 
     
    Any time a format key is not found in the kwargs, 
    it will be tried as an expression in the kwargs namespace. 
     
    Note that this version allows slicing using [1:2], so you cannot specify 
    a format string. Use :class:`EvalFormatter` to permit format strings. 
     
    Examples 
    -------- 
    :: 
 
        In [1]: f = FullEvalFormatter() 
        In [2]: f.format('{n//4}', n=8) 
        Out[2]: u'2' 
 
        In [3]: f.format('{list(range(5))[2:4]}') 
        Out[3]: u'[2, 3]' 
 
        In [4]: f.format('{3*2}') 
        Out[4]: u'6' 
    """ 
    # copied from Formatter._vformat with minor changes to allow eval 
    # and replace the format_spec code with slicing 
    def vformat(self, format_string, args, kwargs): 
        result = [] 
        for literal_text, field_name, format_spec, conversion in \ 
                self.parse(format_string): 
 
            # output the literal text 
            if literal_text: 
                result.append(literal_text) 
 
            # if there's a field, output it 
            if field_name is not None: 
                # this is some markup, find the object and do 
                # the formatting 
 
                if format_spec: 
                    # override format spec, to allow slicing: 
                    field_name = ':'.join([field_name, format_spec]) 
 
                # eval the contents of the field for the object 
                # to be formatted 
                obj = eval(field_name, kwargs) 
 
                # do any conversion on the resulting object 
                obj = self.convert_field(obj, conversion) 
 
                # format the object and append to the result 
                result.append(self.format_field(obj, '')) 
 
        return u''.join(py3compat.cast_unicode(s) for s in result) 
 
 
@skip_doctest_py3 
class DollarFormatter(FullEvalFormatter): 
    """Formatter allowing Itpl style $foo replacement, for names and attribute 
    access only. Standard {foo} replacement also works, and allows full 
    evaluation of its arguments. 
 
    Examples 
    -------- 
    :: 
 
        In [1]: f = DollarFormatter() 
        In [2]: f.format('{n//4}', n=8) 
        Out[2]: u'2' 
 
        In [3]: f.format('23 * 76 is $result', result=23*76) 
        Out[3]: u'23 * 76 is 1748' 
 
        In [4]: f.format('$a or {b}', a=1, b=2) 
        Out[4]: u'1 or 2' 
    """ 
    _dollar_pattern = re.compile("(.*?)\$(\$?[\w\.]+)") 
    def parse(self, fmt_string): 
        for literal_txt, field_name, format_spec, conversion \ 
                    in Formatter.parse(self, fmt_string): 
             
            # Find $foo patterns in the literal text. 
            continue_from = 0 
            txt = "" 
            for m in self._dollar_pattern.finditer(literal_txt): 
                new_txt, new_field = m.group(1,2) 
                # $$foo --> $foo 
                if new_field.startswith("$"): 
                    txt += new_txt + new_field 
                else: 
                    yield (txt + new_txt, new_field, "", None) 
                    txt = "" 
                continue_from = m.end() 
             
            # Re-yield the {foo} style pattern 
            yield (txt + literal_txt[continue_from:], field_name, format_spec, conversion) 
 
#----------------------------------------------------------------------------- 
# Utils to columnize a list of string 
#----------------------------------------------------------------------------- 
 
def _col_chunks(l, max_rows, row_first=False): 
    """Yield successive max_rows-sized column chunks from l.""" 
    if row_first: 
        ncols = (len(l) // max_rows) + (len(l) % max_rows > 0) 
        for i in py3compat.xrange(ncols): 
            yield [l[j] for j in py3compat.xrange(i, len(l), ncols)] 
    else: 
        for i in py3compat.xrange(0, len(l), max_rows): 
            yield l[i:(i + max_rows)] 
 
 
def _find_optimal(rlist, row_first=False, separator_size=2, displaywidth=80): 
    """Calculate optimal info to columnize a list of string""" 
    for max_rows in range(1, len(rlist) + 1): 
        col_widths = list(map(max, _col_chunks(rlist, max_rows, row_first))) 
        sumlength = sum(col_widths) 
        ncols = len(col_widths) 
        if sumlength + separator_size * (ncols - 1) <= displaywidth: 
            break 
    return {'num_columns': ncols, 
            'optimal_separator_width': (displaywidth - sumlength) / (ncols - 1) if (ncols - 1) else 0, 
            'max_rows': max_rows, 
            'column_widths': col_widths 
            } 
 
 
def _get_or_default(mylist, i, default=None): 
    """return list item number, or default if don't exist""" 
    if i >= len(mylist): 
        return default 
    else : 
        return mylist[i] 
 
 
def compute_item_matrix(items, row_first=False, empty=None, *args, **kwargs) : 
    """Returns a nested list, and info to columnize items 
 
    Parameters 
    ---------- 
 
    items 
        list of strings to columize 
    row_first : (default False) 
        Whether to compute columns for a row-first matrix instead of 
        column-first (default). 
    empty : (default None) 
        default value to fill list if needed 
    separator_size : int (default=2) 
        How much caracters will be used as a separation between each columns. 
    displaywidth : int (default=80) 
        The width of the area onto wich the columns should enter 
 
    Returns 
    ------- 
 
    strings_matrix 
 
        nested list of string, the outer most list contains as many list as 
        rows, the innermost lists have each as many element as colums. If the 
        total number of elements in `items` does not equal the product of 
        rows*columns, the last element of some lists are filled with `None`. 
 
    dict_info 
        some info to make columnize easier: 
 
        num_columns 
          number of columns 
        max_rows 
          maximum number of rows (final number may be less) 
        column_widths 
          list of with of each columns 
        optimal_separator_width 
          best separator width between columns 
 
    Examples 
    -------- 
    :: 
 
        In [1]: l = ['aaa','b','cc','d','eeeee','f','g','h','i','j','k','l'] 
           ...: compute_item_matrix(l, displaywidth=12) 
        Out[1]: 
            ([['aaa', 'f', 'k'], 
            ['b', 'g', 'l'], 
            ['cc', 'h', None], 
            ['d', 'i', None], 
            ['eeeee', 'j', None]], 
            {'num_columns': 3, 
            'column_widths': [5, 1, 1], 
            'optimal_separator_width': 2, 
            'max_rows': 5}) 
    """ 
    info = _find_optimal(list(map(len, items)), row_first, *args, **kwargs) 
    nrow, ncol = info['max_rows'], info['num_columns'] 
    if row_first: 
        return ([[_get_or_default(items, r * ncol + c, default=empty) for c in range(ncol)] for r in range(nrow)], info) 
    else: 
        return ([[_get_or_default(items, c * nrow + r, default=empty) for c in range(ncol)] for r in range(nrow)], info) 
 
 
def columnize(items, row_first=False, separator='  ', displaywidth=80, spread=False): 
    """ Transform a list of strings into a single string with columns. 
 
    Parameters 
    ---------- 
    items : sequence of strings 
        The strings to process. 
 
    row_first : (default False) 
        Whether to compute columns for a row-first matrix instead of 
        column-first (default). 
 
    separator : str, optional [default is two spaces] 
        The string that separates columns. 
 
    displaywidth : int, optional [default is 80] 
        Width of the display in number of characters. 
 
    Returns 
    ------- 
    The formatted string. 
    """ 
    if not items: 
        return '\n' 
    matrix, info = compute_item_matrix(items, row_first=row_first, separator_size=len(separator), displaywidth=displaywidth) 
    if spread: 
        separator = separator.ljust(int(info['optimal_separator_width'])) 
    fmatrix = [filter(None, x) for x in matrix] 
    sjoin = lambda x : separator.join([ y.ljust(w, ' ') for y, w in zip(x, info['column_widths'])]) 
    return '\n'.join(map(sjoin, fmatrix))+'\n' 
 
 
def get_text_list(list_, last_sep=' and ', sep=", ", wrap_item_with=""): 
    """ 
    Return a string with a natural enumeration of items 
 
    >>> get_text_list(['a', 'b', 'c', 'd']) 
    'a, b, c and d' 
    >>> get_text_list(['a', 'b', 'c'], ' or ') 
    'a, b or c' 
    >>> get_text_list(['a', 'b', 'c'], ', ') 
    'a, b, c' 
    >>> get_text_list(['a', 'b'], ' or ') 
    'a or b' 
    >>> get_text_list(['a']) 
    'a' 
    >>> get_text_list([]) 
    '' 
    >>> get_text_list(['a', 'b'], wrap_item_with="`") 
    '`a` and `b`' 
    >>> get_text_list(['a', 'b', 'c', 'd'], " = ", sep=" + ") 
    'a + b + c = d' 
    """ 
    if len(list_) == 0: 
        return '' 
    if wrap_item_with: 
        list_ = ['%s%s%s' % (wrap_item_with, item, wrap_item_with) for 
                 item in list_] 
    if len(list_) == 1: 
        return list_[0] 
    return '%s%s%s' % ( 
        sep.join(i for i in list_[:-1]), 
        last_sep, list_[-1])