I want to use the yy_scan_bytes() as I have null characters defining a rule. My problem is that my string can match more than one rule. I want to get hold of all the rules matched. I want to feed the yylex() function one character at a time and check if something matched. I tried the following code for testing but this doesnt work.
for(int i=0;i<length;i++)
{
yy_scan_bytes(&temp[i],1 );
index=TomsonTalkslex();
}
For simplicity I just return the index of the rule matched from scanner. temp is a char buffer. I tried to use the yy_switch_to_buffer(yy_scan_bytes(&temp[i],1 )); but this didnt work.
How can I tell the scanner not to reset its state and continue processing subsequent buffers with the same state.
Ok, This is just a misunderstanding of how lex/flex works. By default, yylex hooks into stdin, reading until it receives EOF, and matching each rule. That's why it's a tokenizer. So, the sample program below will read from stdin until you enter -c to send an EOF.
%option 8bit outfile="scanner.c"
%option nounput nomain noyywrap
%option warn
%%
ab { fprintf(yyout, "We ran the ab rule.\n"); }
cd { fprintf(yyout, "We ran the cd rule.\n"); }
// echo everything else we find to yyout
. { ECHO; }
\n { ECHO; }
%%
To compile the above, use:
flex -Cf scanner.l
gcc -O -o flexer.exe scanner.c
Save the source file as scanner.l when you do this. Once you compile, you will get a file called flexer.exe in the same directory. Run it from a terminal, and you will get a blank prompt waiting for input. Everything you type will try and match against the rules, until you find only one match. It will then execute the code associated with the rule.
Therefore, if you type abcd, then you will match both the ab and cd rules.
I suggest reading lex and yacc for a more detailed introduction.
Related
I basically want to check the incoming 'From' in the email received and then either
Keep it and make it deliver to the intended mailbox if the email matches a Specified MySQL/PostgreSQL
Database User (eg. select email from users where exists ('from email address') )
If the 'From' address is blank or it is not found in the database, the email should be discarded
Any way I can achieve this before the e-mail is delivered to the intended mailbox?
I am using Procmail + Virtualmin + Webmin + PostgreSQL
PS: I want to apply this filter not to the wole server but to some specified mailboxes/users (i'm assuming 1 user = 1 mailbox here)
Procmail can easily run an external command in a condition and react to its exit status. How exactly to make your particular SQL client set its exit code will depend on which one you are using; perhaps its man page will reveal an option to make it exit with an error when a query produces an empty result set, for example? Or else write a shell wrapper to look for empty output.
A complication is that Procmail (or rather, the companion utility formail) can easily extract a string from e.g. the From: header; but you want to reduce this to just the email terminus. This is a common enough task that it's easy to find a canned solution - generate a reply and then extract the To: address (sic!) from that.
FROM=`formail -rtzxTo:`
:0
* FROM ?? ^(one#example\.com|two#site\.example\.net|third#example\.org)$
{
:0
* ? yoursql --no-headers --fail-if-empty-result \
--batch --query databasename \
--eval "select yada yada where address = '$FROM'"
{ }
:0E
/dev/null
}
The first condition examines the variable and succeeds if it contains one of the addresses (my original answer simply had the regex . which matches if the string contains at least one character, any character; I'm not convinced this is actually necessary or useful; there should be no way for From: to be empty). If it is true, Procmail enters the braces; if not, they will be skipped.
The first recipe inside the braces runs an external command and examines its exit code. I'm imagining your SQL client is called yoursql and that it has options to turn off human-friendly formatting (table headers etc) and for running a query directly from the command line on a specific database. We use double quotes so that the shell will interpolate the variable FROM before running this command (maybe there is a safer way to pass string variables which might contain SQL injection attempts with something like --variable from="$FROM" and then use that variable in the query? See below.)
If there is no option to directly set the exit code, but you can make sure standard output is completely empty in the case of no result, piping the command to grep -q . will produce the correct exit code. In a more complex case, maybe write a simple Awk script to identify an empty result set and set its exit status accordingly.
Scraping together information from
https://www.postgresql.org/docs/current/app-psql.html,
How do you use script variables in psql?,
Making an empty output from psql,
and from your question, I end up with the following attempt to implement this in psql; but as I don't have a Postgres instance to test with, or any information about your database schema, this is still approximate at best.
* ? psql --no-align --tuples-only --quiet \
--dbname=databasename --username=something --no-password \
--variable=from="$FROM" \
--command="select email from users where email = :'from'" \
| grep -q .
(We still can't use single quotes around the SQL query, to completely protect it from the shell, because Postgres insists on single quotes around :'from', and the shell offers no facility for embedding literal single quotes inside single quotes.)
The surrounding Procmail code should be reasonably self-explanatory, but here goes anyway. In the first recipe inside the braces, if the condition is true, the empty braces in its action line are a no-op; the E flag on the next recipe is a condition which is true only if any of the conditions on the previous recipe failed. This is a common idiom to avoid having to use a lot of negations; perhaps look up "de Morgan's law". The net result is that we discard the message by delivering it to /dev/null if either condition in the first recipe failed; and otherwise, we simply pass it through, and Procmail will eventually deliver it to its default destination.
The recipe was refactored in response to updates to your question; perhaps now it would make more sense to just negate the exit code from psql with a ! in front:
FROM=`formail -rtzxTo:`
:0
* FROM ?? ^(one#example\.com|two#site\.example\.net|third#example\.org)$
* ! ? psql --no-align --tuples-only --quiet \
--dbname=databasename --username=something --no-password \
--variable=from="$FROM" \
--command="select email from users where email = :'from'" \
| grep -q .
/dev/null
Tangentially, perhaps notice how Procmail's syntax exploits the fact that a leading ? or a doubled ?? are not valid in regular expressions. So the parser can unambiguously tell that these conditions are not regular expressions; they compare a variable to the regex after ??, or examine the exit status of an external command, respectively. There are a few other special conditions like this in Procmail; arguably, all of them are rather obscure.
Newcomers to shell scripting should also notice that each shell command pipeline has two distinct results: whatever is being printed on standard output, and, completely separate from that, an exit code which reveals whether or not the command completed successfully. (Conventionally, a zero exit status signals success, and anything else is an error. For example, the exit status from grep is 0 if it finds at least one match, 1 if it doesn't, and usually some other nonzero exit code if you passed in an invalid regular expression, or you don't have permission to read the input file, etc.)
For further details, perhaps see also http://www.iki.fi/era/procmail/ which has an old "mini-FAQ" which covers several of the topics here, and a "quick reference" for looking up details of the syntax.
I'm not familiar with Virtualmin but https://docs.virtualmin.com/Webmin/PostgreSQL_Database_Server shows how to set up Postgres and as per https://docs.virtualmin.com/Webmin/Procmail_Mail_Filter I guess you will want to use the option to put this code in an include file.
in my MIRC script, it is set up to read a text file, in these text files there is the symbol " | " followed by a space on both ends, it seems to read everything before " | " just fine, but cuts it off right at the first space. Any help is appreciated.
I am using
msg $nick $read(test.txt, n, 1)
to read the text file.
EDIT:: I have tried all switches which result in the same thing.
EDIT:: It also tells me in the server window "Unknown Command"
EDIT:: After making a new pastebin uploading script, it still seems to get that issue? It will completely just cut off the rest of the text after a "&" or " | "
The symptoms is matching to a scenario which $read was evaluated to a command and the result will take the separators as set of commands to be executed.
This can be due to aliases or events.
Try the first /play command, which will play the file from the 3rd line to see if it behaving as the line we expect it to be or instead each line as a set of commands, separated by /
Then perform the 2nd /play command to view how it should been send to the server.
This is design to see where the problem lie.
/play -axl3 echo test.txt
/play -exl3 test.txt
The output should be the same and as we expect it with the line being displayed including |.
This will make sure the problem is to blame upon other corrupt aliases or events.
We will perform the following and after each step you will test you code to see if it was solved.
Test to see if it an alias named msg hurt you, by converting your script command to /!msg $nick$read(test.txt, n, 1).
Check for dangerous events such as the infamous INPUT or the rising bandit PARSELINE by disabling them.If the problem solved then return the events one by one the find the problematic event and fix it.
Due to the lack of a responses/answers, I was unable to solve it, I have made a makeshift fix for this issue by using
play -xl# $nick test.txt
rather than
msg $nick $read(test.txt, n, 1)
I had almost the same problem and was able to solve it, using the same solution, try this:
Your previous script was: msg $nick $read(test.txt, n, 1)
Now remove the 'msg $nick' and add that to the beginning of every line in the text.txt file with a space between 'msg $nick' and the rest of the line, i.e : msg $nick Hey I see you are back | msg $nick Missed You!
Then your script becomes: $read(test.txt, p)
^^ Hope that makes sense, but I found the original issues was Double Evaluation hence why sometimes you would see the error: Unknown Command or something along those lines.
Below I have wrote my basic goal and the code I already have, any help is much appreciated as I am learning myself how IRC Scripting works, thanks guys!
on $*:text:*test*:#: {
if ($date isin $read(test1.txt, 1)) {
if ($nick isin $read(test1.txt, 1)) { write test.txt "entire line $nick was found on in test1.txt" $1- }
}
}
In the future, you should make your question clearer.
Your question looks like this one mIRC Search for multiple words in text file, you can read my answer there for more information, it's mostly the same so I'm copying and pasting it here with edits for your case.
To read a .txt file line by line you need a loop. To use this loop type: /findNick <NICK>
alias findNick {
var %nick = $1
while ($read(test1.txt, nw, $+(*,$date,*), $calc($readn + 1))) {
var %line = $v1
if (%nick isin %line) {
echo -a %nick found on the line: %line
; do your stuff here
}
}
}
$readn is an identifier that returns the line that $read() matched. It is used to start searching for the pattern on the next line. Which is in this case $date. The asteriks means a wildcard, so anything that contains that date.
In the code above, $readn starts at 0. We use $calc() to start at line 1. Every match $read() will start searching on the next line. When no more matches are after the line specified $read will return $null - terminating the loop.
The w switch is used to use a wildcard in your search
The n switch prevents evaluating the text it reads as if it was mSL code. In almost EVERY case you must use the n switch. Except if you really need it. Improper use of the $read() identifier without the 'n' switch could leave your script highly vulnerable.
The result is stored in a variable named %line to use it again to check wheter $nick is in the found line. If the $nick was found, it will echo the result in your active window.
And again, if there's anything unclear, I will try to explain it better.
I wrote a script analyzing perl-files (totally without PPI, because it will be used on Servers where the admins don't want PPI to be installed and so on and so forth, but let's not talk about that).
Now, let's say I have this code:
my $object = MySQL->new();
my $ob2 = $object;
$ob2->
(Where MySQL is one of our modules).
My script correctly identifies that $ob2 is a MySQL-Object and sees where it came from, and then returns a list of found subs in that module.
My idea was, that, since I use vim for editing, this could be a really cool way for "CTRL-n"-Completetion.
So, when...
$ob2->[CTRL-n]
It shows the CTRL-n-Box which opens my Perl-Script and gives it a few parameters (I would need: The line that I am actually on, the cursor position and the whole file as it is in vim).
I already found things like vim-perl, which allows me to write something like
if has('perl')
function DefPerl()
perl << EOF
use MyModule;
return call_to_my_function(); # returns all the methods from the object for example
EOF
endfunction
call DefPerl()
endif
But somehow this does not get executed (I tried writing something to a file with a system call just for the sake of testing)...
So, in short:
Does anyone here know how to achieve that? Calling a perl-function from vim by pressing CTRL-n with the full file-code and the line vim is actually in and the position, and then opening a completetion-menu with the results it got from the perl-script?
I hope someone knows what I mean here. Any help would be appreciated.
The details and tips for invoking embedded Perl code from Vim can be found in this Vim Tips Wiki article. Your attempts are already pretty close, but to return stuff from Perl, you need to use Vim's Perl API:
VIM::DoCommand "let retVal=". aMeaningfullThingToReturn
For the completion menu, your Perl code needs to return a List of Vim objects that adhere to the format as described by :help complete-items. And :help complete-functions shows how to trigger the completion. Basically, you define an insert-mode mapping that sets 'completefunc' and then trigger your function via <C-x><C-u>. Here's a skeleton to get your started:
function! ExampleComplete( findstart, base )
if a:findstart
" Locate the start of the keyword.
let l:startCol = searchpos('\k*\%#', 'bn', line('.'))[1]
if l:startCol == 0
let l:startCol = col('.')
endif
return l:startCol - 1 " Return byte index, not column.
else
" Find matches starting with a:base.
let l:matches = [{'word': 'example1'}, {'word': 'example2'}]
" TODO: Invoke your Perl function here, input: a:base, output: l:matches
return l:matches
endif
endfunction
function! ExampleCompleteExpr()
set completefunc=ExampleComplete
return "\<C-x>\<C-u>"
endfunction
inoremap <script> <expr> <Plug>(ExampleComplete) ExampleCompleteExpr()
if ! hasmapto('<Plug>(ExampleComplete)', 'i')
imap <C-x><C-z> <Plug>(ExampleComplete)
endif
I've noticed a big lack in documentation from mIRC scripting abilities so I apologize if I've missed something but I've been searching everwhere.
Basically, I have an on event when someone says something, I need to get there entire message, how is this possible? I've managed to discover $1- however this only grabs the text from what the event triggered from to the end, I need the entire message, is this possible?
This is actually pretty simple, although maybe you're on an earlier version of mirc, if the documentation is lacking:
on *:TEXT:*I need help with*:#channel: {
msg $chan $1-
}
$1- will always contain the full message. $# are space-delimited identifiers, so if your message is john: I need help with etc, $1 will contain john:, and $2 will contain I, and so on and so-forth. Adding the dash means 'this and everything onwards'. Since your match text is 'everything before I need help with and everything after, this code will always contain the full text.
The code above, in case it is not obvious, will message the channel the event triggered on with the full message text. Whatever you do with the text is up to you; it's just an example.
/dbg
alias dbg {
if !$debug { debug -i d dbg }
if $regex($1-,/.+!.+#.+.PRIVMSG.#.+:.+/g) {
echo 4 -s $*
}
}
$1- or $1