import re MODIFIERS = ( "[._-]?" r"((?!post)(?:beta|b|c|pre|RC|alpha|a|patch|pl|p|dev)(?:(?:[.-]?\d+)*)?)?" r"([+-]?([0-9A-Za-z-]+(\.[0-9A-Za-z-]+)*))?" ) _COMPLETE_VERSION = r"v?(\d+)(?:\.(\d+))?(?:\.(\d+))?(?:\.(\d+))?{}(?:\+[^\s]+)?".format(MODIFIERS) COMPLETE_VERSION = re.compile("(?i)" + _COMPLETE_VERSION) CARET_CONSTRAINT = re.compile(r"(?i)^\^({})$".format(_COMPLETE_VERSION)) TILDE_CONSTRAINT = re.compile("(?i)^~(?!=)({})$".format(_COMPLETE_VERSION)) TILDE_PEP440_CONSTRAINT = re.compile("(?i)^~=({})$".format(_COMPLETE_VERSION)) X_CONSTRAINT = re.compile(r"^(!=|==)?\s*v?(\d+)(?:\.(\d+))?(?:\.(\d+))?(?:\.[xX*])+$") BASIC_CONSTRAINT = re.compile(r"(?i)^(<>|!=|>=?|<=?|==?)?\s*({}|dev)".format(_COMPLETE_VERSION))