#
# svalue.py -- read/write MudOS "svalues"
#
# Written by Greg Stein sometime in early May, 1995.
#
import types
import regex

_regex_string = regex.symcomp('"\(<str>\([^"\\]\|\\\\.\)*\)"')
_regex_number = regex.compile('-?[-+.0-9e]+')

error = 'svalue error'

def read_svalue(str):
    if str[0] == '(':
	if str[1] == '{' or str[1] == '/':
	    array = []
	    str = str[2:]
	    while str[0] != '}' and str[0] != '/':
		value, str = read_svalue(str)
		array = array + [ value ]
		if str[0] != ',':
		    raise error, 'missing comma in array:'+str
		str = str[1:]
	    if str[1] != ')':
		raise error, 'bad termination of array:'+str
	    return array, str[2:]
	elif str[1] == '[':
	    mapping = {}
	    str = str[2:]
	    while str[0] != ']':
		key, str = read_svalue(str)
		if str[0] != ':':
		    raise error, 'missing colon in mapping:'+str
		value, str = read_svalue(str[1:])
		mapping[key] = value
		if str[0] != ',':
		    raise error, 'missing comma in mapping:'+str
		str = str[1:]
	    if str[1] != ')':
		raise error, 'bad termination of mapping:'+str
	    return mapping, str[2:]
	else:
	    raise error, 'bad character after opening paren:'+str
    elif str[0] == '"':
	mlen = _regex_string.match(str)
	if mlen < 0:
	    raise error, 'bad string format:'+str
	return _regex_string.group('str'), str[mlen:]
    elif (str[0] >= '0' and str[0] <= '9') or str[0] == '-':
	mlen = _regex_number.match(str)
	if mlen < 0:
	    raise error, 'bad number format:'+str
	return eval(str[:mlen]), str[mlen:]
    else:
	raise error, 'bad initial character:'+str

def write_svalue(value):
    if type(value) in [ types.IntType, types.FloatType ]:
	return repr(value)
    elif type(value) is types.StringType:
	return '"' + value + '"'
    elif type(value) is types.ListType:
	return '({'+reduce(lambda x,y: x+write_svalue(y)+',',
			   value,
			   '') + '})'
    elif type(value) is types.DictionaryType:
	return '(['+reduce(lambda x,y: (x+write_svalue(y[0])+':'+
                                        write_svalue(y[1])+','),
			   value.items(),
			   '') + '])'
    else:
	raise error, 'bad type: %s %s' % (type(value), value)