deb-python-lesscpy/lesscpy/lessc/utility.py

# -*- coding: utf8 -*-
"""
.. module:: lesscpy.lessc.utility
    :synopsis: various utility functions
    
    Copyright (c)
    See LICENSE for details.
.. moduleauthor:: Johann T. Mariusson <jtm@robot.is>
"""
import collections
import re

def flatten(lst):
    """Flatten list.
    Args:
        lst (list): List to flatten
    Returns: 
        generator
    """
    for elm in lst:
        if isinstance(elm, collections.Iterable) and not isinstance(elm, str):
            for sub in flatten(elm):
                yield sub
        else:
            yield elm
            
def pairwise(lst):
    """ yield item i and item i+1 in lst. e.g.
        (lst[0], lst[1]), (lst[1], lst[2]), ..., (lst[-1], None)
    Args:
        lst (list): List to process
    Returns:
        list
    """
    if not lst: 
        return
    length = len(lst)
    for i in range(length-1):
        yield lst[i], lst[i+1]
    yield lst[-1], None
    
def rename(blocks, scope, stype):
    """ Rename all sub-blocks moved under another 
        block. (mixins)
    Args:
        lst (list): block list
        scope (object): Scope object
    """
    for p in blocks:
        if type(p) is stype:
            p.tokens[0].parse(scope)
            if p.tokens[1]: 
                scope.push()
                scope.current = p.tokens[0]
                rename(p.tokens[1], scope, stype)
                scope.pop()
            
def blocksearch(block, name):
    """ Recursive search for name in block (inner blocks)
    Args:
        name (str): search term
    Returns:
        Block OR False
    """
    if hasattr(block, 'tokens'):
        for b in block.tokens[1]:
            b = (b if hasattr(b, 'raw') and b.raw() == name 
                 else blocksearch(b, name))
            if b: return b
    return False

def reverse_guard(lst):
    """ Reverse guard expression. not 
        (@a > 5) ->  (@a <= 5)
    Args:
        lst (list): Expression
    returns:
        list
    """
    rev = {
        '<': '>=',
        '>': '<=',
        '=': '!=',
        '!=': '=',
        '>=': '<',
        '<=': '>'
    }
    return [rev[l] if l in rev else l for l in lst]

def debug_print(lst, lvl=0):
    """ Print scope tree
    args:
        lst (list): parse result
        lvl (int): current nesting level
    """
    pad = ''.join(['\t.'] * lvl)
    t = type(lst)
    if t is list:
        for p in lst:
            debug_print(p, lvl)
    elif hasattr(lst, 'tokens'):
        print(pad, t) 
        debug_print(list(flatten(lst.tokens)), lvl+1)

def destring(value):
    """ Strip quotes from string
    args:
        value (str)
    returns:
        str
    """
    return value.strip('"\'')

def analyze_number(var, err=''):
    """ Analyse number for type and split from unit
        1px -> (q, 'px')
    args:
        var (str): number string
    kwargs:
        err (str): Error message
    raises:
        SyntaxError
    returns:
        tuple
    """
    n, u = split_unit(var)
    if type(var) is not str:
        return (var, u)
    if is_color(var):
        return (var, 'color')
    if is_int(n):
        n = int(n)
    elif is_float(n):
        n = float(n)
    else:
        raise SyntaxError('%s ´%s´' % (err, var))
    return (n, u)

def with_unit(number, unit=None):
    """ Return number with unit
    args:
        number (mixed): Number
        unit (str): Unit
    returns:
        str
    """
    if type(number) is tuple:
        number, unit = number
    if number == 0: 
        return '0'
    if unit:
        number = str(number)
        if number.startswith('.'):
            number = '0' + number
        return "%s%s" % (number, unit)
    return number if type(number) is str else str(number)
            
def is_color(value):
    """ Is string CSS color
    args:
        value (str): string
    returns:
        bool
    """
    if not value or type(value) is not str: 
        return False
    if value[0] == '#' and len(value) in [4, 5, 7, 9]:
        try:
            int(value[1:], 16)
            return True
        except ValueError:
            pass
    return False
            
def is_variable(value):
    """ Check if string is LESS variable
    args:
        value (str): string
    returns:
        bool
    """
    if type(value) is str:
        return (value.startswith('@') or value.startswith('-@'))
    elif type(value) is tuple:
        value = ''.join(value)
        return (value.startswith('@') or value.startswith('-@'))
    return False

def is_int(value):
    """ Is value integer
    args:
        value (str): string
    returns:
        bool
    """
    try:
        int(str(value))
        return True
    except (ValueError, TypeError):
        pass
    return False

def is_float(value):
    """ Is value float
    args:
        value (str): string
    returns:
        bool
    """
    if not is_int(value):
        try:
            float(str(value))
            return True
        except (ValueError, TypeError):
            pass
    return False

def split_unit(value):
    """ Split a number from its unit
        1px -> (q, 'px')
    Args:
        value (str): input
    returns:
        tuple
    """
    r = re.search('^(\-?[\d\.]+)(.*)$', str(value))
    return r.groups() if r else ('','')