evennia/evennia/commands/cmdparser.py

132 lines
5.3 KiB
Python

"""
The default command parser. Use your own by assigning
`settings.COMMAND_PARSER` to a Python path to a module containing the
replacing cmdparser function. The replacement parser must accept the
same inputs as the default one.
"""
from __future__ import division
import re
from django.conf import settings
from evennia.utils.logger import log_trace
_MULTIMATCH_SEPARATOR = settings.SEARCH_MULTIMATCH_SEPARATOR
_MULTIMATCH_REGEX = re.compile(r"([0-9]+)%s(.*)" % _MULTIMATCH_SEPARATOR, re.I + re.U)
def cmdparser(raw_string, cmdset, caller, match_index=None):
"""
This function is called by the cmdhandler once it has
gathered and merged all valid cmdsets valid for this particular parsing.
Args:
raw_string (str): The unparsed text entered by the caller.
cmdset (CmdSet): The merged, currently valid cmdset
caller (Session, Player or Object): The caller triggering this parsing.
match_index (int, optional): Index to pick a given match in a
list of same-named command matches. If this is given, it suggests
this is not the first time this function was called: normally
the first run resulted in a multimatch, and the index is given
to select between the results for the second run.
Notes:
The cmdparser understand the following command combinations (where
[] marks optional parts.
```
[cmdname[ cmdname2 cmdname3 ...] [the rest]
```
A command may consist of any number of space-separated words of any
length, and contain any character. It may also be empty.
The parser makes use of the cmdset to find command candidates. The
parser return a list of matches. Each match is a tuple with its
first three elements being the parsed cmdname (lower case),
the remaining arguments, and the matched cmdobject from the cmdset.
"""
def create_match(cmdname, string, cmdobj):
"""
Builds a command match by splitting the incoming string and
evaluating the quality of the match.
Args:
cmdname (str): Name of command to check for.
string (str): The string to match against.
cmdobj (str): The full Command instance.
Returns:
match (tuple): This is on the form (cmdname, args, cmdobj, cmdlen, mratio), where
`cmdname` is the command's name and `args` the rest of the incoming string,
without said command name. `cmdobj` is the Command instance, the cmdlen is
the same as len(cmdname) and mratio is a measure of how big a part of the
full input string the cmdname takes up - an exact match would be 1.0.
"""
cmdlen, strlen = len(unicode(cmdname)), len(unicode(string))
mratio = 1 - (strlen - cmdlen) / (1.0 * strlen)
args = string[cmdlen:]
return (cmdname, args, cmdobj, cmdlen, mratio)
if not raw_string:
return []
matches = []
# match everything that begins with a matching cmdname.
l_raw_string = raw_string.lower()
for cmd in cmdset:
try:
matches.extend([create_match(cmdname, raw_string, cmd)
for cmdname in [cmd.key] + cmd.aliases
if cmdname and l_raw_string.startswith(cmdname.lower())
and (not cmd.arg_regex or
cmd.arg_regex.match(l_raw_string[len(cmdname):]))])
except Exception:
log_trace("cmdhandler error. raw_input:%s" % raw_string)
if not matches:
# no matches found
num_ref_match = _MULTIMATCH_REGEX.match(raw_string)
if num_ref_match:
# the user might be trying to identify the command
# with a #num-command style syntax.
mindex, new_raw_string = num_ref_match.groups()
return cmdparser(new_raw_string, cmdset,
caller, match_index=int(mindex))
# only select command matches we are actually allowed to call.
matches = [match for match in matches if match[2].access(caller, 'cmd')]
if len(matches) > 1:
# See if it helps to analyze the match with preserved case but only if
# it leaves at least one match.
trimmed = [match for match in matches
if raw_string.startswith(match[0])]
if trimmed:
matches = trimmed
if len(matches) > 1:
# we still have multiple matches. Sort them by count quality.
matches = sorted(matches, key=lambda m: m[3])
# only pick the matches with highest count quality
quality = [mat[3] for mat in matches]
matches = matches[-quality.count(quality[-1]):]
if len(matches) > 1:
# still multiple matches. Fall back to ratio-based quality.
matches = sorted(matches, key=lambda m: m[4])
# only pick the highest rated ratio match
quality = [mat[4] for mat in matches]
matches = matches[-quality.count(quality[-1]):]
if len(matches) > 1 and match_index != None and 0 < match_index <= len(matches):
# We couldn't separate match by quality, but we have an
# index argument to tell us which match to use.
matches = [matches[match_index-1]]
# no matter what we have at this point, we have to return it.
return matches