AOLserver Wiki - User contributions [en]

Ns returnfile

2008-06-19T19:52:25Z

Jadeforrest: correct mistake

ns_returnfile 200 "application/zip" $filepath
ns_returnfile 200 [ns_guesstype $file] $filepath

For now, see [[ns_return]]

Want to name the file?

ns_set update [ns_conn outputheaders] content-disposition "attachment; filename=1.abc"

Ns returnfile

2008-06-19T19:14:50Z

Jadeforrest:

ns_returnfile 200 "application/zip" $filepath
ns_returnfile 200 [ns_guesstype $file] $filepath

For now, see [[ns_return]]

Want to name the file?

ns_set update [ns_conn headers] content-disposition "attachment; filename=1.abc"

Ns returnfile

2008-06-19T19:14:35Z

Jadeforrest: added content disposition hint

Languages

2008-04-14T15:23:03Z

Jadeforrest: add requirement for adding new languages.

One of AOLserver's greatest strengths is it's built in Tcl interpreter, but many other languages
are also available via loadable [[modules]].
* [[Java]], via [[nsjk2]], [[nsjava]], [[nstomcat]]
* Python, via [[PyWX]]
* [[PHP]]
* [[Perl]]
* OCaml, via [[nsocaml]]
* [[Scheme]]
* [[Ruby]]

In order to support a language in the core, the language runtime must
have these two non-negotiable properties:

1) Fully thread-safe
2) Embeddable

(Dossy)

Languages

2008-04-13T14:09:46Z

Jadeforrest: remove standard ML -- I believe this is an advertisement, as it links to SMLServer, which is not related to Aolserver in any way.

SMLserver

2008-04-13T14:08:59Z

Jadeforrest: remove content -- this does not seem to be related to Aolserver in any way -- it seems to be advertising.

Ruby

2007-12-12T16:49:29Z

Jadeforrest:

NsRuby is a module for serving Ruby on Aolserver. What is it's status?

It currently sits starving at: http://sourceforge.net/projects/nsruby

Talk:Ruby

2007-12-12T16:48:31Z

Jadeforrest: /* Ruby on Rails on AOLserver? */

== Ruby on Rails on AOLserver? ==

Any thoughts or ideas on whether [http://www.rubyonrails.org Ruby on Rails] would work with the nsruby module? --[[User:Caveman|Caveman]] 10:28, 9 December 2005 (EST)

* What would be the point? Rails already includes a Ruby-based HTTP listener that's closely integrated with Rails. You would get no performance benefit from putting AOLserver in front of Rails, as Rails is all single-threaded so requests get processed in serial, as I understand it. If you wanted to accelerate a Rails app, I'd front it with a load balancing switch and run a bunch of Rails listeners. But, that'd mean Rails couldn't keep in-memory state information unless you want to run the switch in sticky-session mode, which is lame. ''-- [[User:Dossy|Dossy]] 07:50, 10 December 2005 (EST)''

* Dossy is correct here, as far as I understand. It's amazing how long it has taken for other web servers to begin to approach Aolserver, and even now, the hottest thing around (Rails) faces such terrible scalability issues. The problem is most people won't notice until their web site really blows up -- [[User:Jadeforrest|Jadeforrest]]

== Ruby on Aolserver? ==

Yes, but Ruby on Aolserver would absolutely ROCK!

Talk:Ruby

2007-12-12T16:47:33Z

Jadeforrest: /* Ruby on Rails on AOLserver? */

== Ruby on Rails on AOLserver? ==

Any thoughts or ideas on whether [http://www.rubyonrails.org Ruby on Rails] would work with the nsruby module? --[[User:Caveman|Caveman]] 10:28, 9 December 2005 (EST)

* What would be the point? Rails already includes a Ruby-based HTTP listener that's closely integrated with Rails. You would get no performance benefit from putting AOLserver in front of Rails, as Rails is all single-threaded so requests get processed in serial, as I understand it. If you wanted to accelerate a Rails app, I'd front it with a load balancing switch and run a bunch of Rails listeners. But, that'd mean Rails couldn't keep in-memory state information unless you want to run the switch in sticky-session mode, which is lame. ''-- [[User:Dossy|Dossy]] 07:50, 10 December 2005 (EST)''

* Dossy is correct here, as far as I understand. It's amazing how long it has taken for other web servers to begin to approach Aolserver, and even now, the hot thing faces such scalability issues. Rails can only serve one request at a time. That is completely lame -- [[User:Jadeforrest|Jadeforrest]]

== Ruby on Aolserver? ==

Yes, but Ruby on Aolserver would absolutely ROCK!

Talk:Ruby

2007-12-12T16:45:36Z

Jadeforrest: /* Ruby on Rails on AOLserver? */

== Ruby on Rails on AOLserver? ==

Any thoughts or ideas on whether [http://www.rubyonrails.org Ruby on Rails] would work with the nsruby module? --[[User:Caveman|Caveman]] 10:28, 9 December 2005 (EST)

* What would be the point? Rails already includes a Ruby-based HTTP listener that's closely integrated with Rails. You would get no performance benefit from putting AOLserver in front of Rails, as Rails is all single-threaded so requests get processed in serial, as I understand it. If you wanted to accelerate a Rails app, I'd front it with a load balancing switch and run a bunch of Rails listeners. But, that'd mean Rails couldn't keep in-memory state information unless you want to run the switch in sticky-session mode, which is lame. ''-- [[User:Dossy|Dossy]] 07:50, 10 December 2005 (EST)''

== Ruby on Aolserver? ==

Yes, but Ruby on Aolserver would absolutely ROCK!

Ns returnfile

2006-12-12T00:26:47Z

Jadeforrest:

ns_returnfile 200 "application/zip" $filepath
ns_returnfile 200 [ns_guesstype $file] $filepath

For now, see [[ns_return]]

Ns returnfile

2006-12-12T00:04:21Z

Jadeforrest:

ns_returnfile 200 "application/zip" $filepath
ns_returnfile 200 [ns_ugesstype $file] $filepath

For now, see [[ns_return]]

Ns returnfile

2006-12-12T00:03:48Z

Jadeforrest:

ns_returnfile 200 "application/zip" $filepath
ns_returnfile 200 [ns_ugesstype $file] $filepath

For now, see [[ns_return]]

Ns set

2006-04-25T20:18:32Z

Jadeforrest: added example of running through ns_set

Man page: http://aolserver.com/docs/tcl/ns_set.html

----

'''NAME'''

: ns_set - Manipulate sets of key-value pairs

'''SYNOPSIS'''

: '''ns_set''' ''option ?arg arg ...?''

'''DESCRIPTION'''

: This command is used to manipulate sets of key-value pairs or "fields". The fields in the set are ordered by number. The field numbers start at zero and increase by one, up to the total number of fields. An '''ns_set''' is actually a multiset - in other words, the same key can appear multiple times in the same set. This data structure is particularly useful for things like HTTP headers which have this same property.

: The legal ''option''s (which may be abbreviated) are:
* '''ns_set array''' ''setId''

: Returns the contents of the ''setId'' in a string representation similar to Tcl's '''array get''' format. This is useful for converting an '''ns_set''' to an '''array''' or for iterating over the key-value pairs with '''foreach'''. Since '''ns_set'''s can contain the same key multiple times, converting an '''ns_set''' to an '''array''' can result in an array that is not exactly the same as the original '''ns_set''' as keys in an array are unique.
* '''ns_set cleanup'''

: Frees all sets in the current interp.
* '''ns_set copy''' ''?-persist? setId''

: Returns a new set that has the same name and contents as the set referenced in ''setId''. If ''-persist'' is specified, the new set will not be freed when the current transaction ends, and you can free it later with '''ns_set free'''. If ''-persist'' is not specified, the new set is automatically freed when the transaction ends.
* '''ns_set cput''' ''setId key value''

: Appends a new field to the set with ''key'' and ''value'', if the field does not already exist in the set. If the field already exists in the set, the set is unchanged. Returns the field number of the new field, or the field number of the existing field if it already exists in the set.
* '''ns_set create''' ''?-persist? ?name? ?key? ?value? ...''
* '''ns_set new''' ''?-persist? ?name? ?key? ?value? ...''

: Allocates memory for a new set and returns the setId for the new set. If ''-persist'' is specified, the new set will not be freed when the current transaction ends, and you can free it later with '''ns_set free'''. If ''-persist'' is not specified, the new set is automatically freed when the transaction ends.
* '''ns_set delete''' ''setId fieldNumber''

: Deletes the field in the set at field number ''fieldNumber''.
* '''ns_set delkey''' ''setId key''

: Removes the first field in the set whose key is ''key''. Note that there could be multiple fields in the set with this key; this command only removes the first occurrence.
* '''ns_set find''' ''setId key''

: Returns the index of the first field in the specified ''setId'' whose ''key'' matches the specified key. Indexing starts at zero. If no matching fields are found, '''ns_set find''' returns -1.
* '''ns_set free''' ''setId''

: Frees the specified set. Sets must be explicitly freed with '''ns_set free''' if the ''-persist'' option was used when creating the set. Otherwise, sets are automatically freed when the transaction ends.
* '''ns_set get''' ''setId key''

: Returns the first value associated with ''key''. If ''key'' isn't in the set, an empty string is returned.
* '''ns_set icput''' ''setId key value''

: Case-insensitive counterpart of '''ns_set cput'''.
* '''ns_set idelkey''' ''setId key''

: Case-insensitive counterpart of '''ns_set delkey'''.
* '''ns_set ifind''' ''setId key''

: Case-insensitive counterpart of '''ns_set find'''.
* '''ns_set iget''' ''setId key''

: Case-insensitive counterpart of '''ns_set get'''.
* '''ns_set isnull''' ''setId fieldNumber''

: Returns 1 if the value of the field specified by ''fieldNumber'' is null and 0 if it is not. Note that an empty string is not the same as a null. '''ns_set isnull''' will return 0 if the value is an empty string.
* '''ns_set iunique''' ''setId key''

: Case-insensitive counterpart of '''ns_set unique'''.
* '''ns_set key''' ''setId fieldNumber''

: Returns the key for the field numbered ''fieldNumber''. This command is useful when looping through all the key-value pairs in the set in order.
* '''ns_set list''' ''?-shared?''

: Returns the list of all non-persistent '''ns_set'''s. If ''-shared'' is specified, this command returns only the list of persistent '''ns_set'''s.
* '''ns_set merge''' ''high low''

: Merges two sets. Any fields in the ''low'' set are appended to the ''high'' set if a field with the same key name does not already exist in the ''high'' set.
* '''ns_set move''' ''to from''

: Moves all fields from the ''from'' set to the end of the ''to'' set, leaving the ''from'' set a valid, empty set.
* '''ns_set name''' ''setId''

: Returns the name of the set. Returns an empty string if no name has been set.
* '''ns_set print''' ''setId''

: Prints the specified set to stderr which should go to the server log. This is useful for debugging, but '''ns_set array''' may be more useful in actual code.
* '''ns_set put''' ''setId key value''

: Appends a new field to the set with ''key'' and ''value''. Note that the field is appended so if a previous field has the same key as the new field, the previous field will be returned by '''ns_set get'''. The field number of the new field is returned.
* '''ns_set size''' ''setId''

: Returns the number of fields in the set.
* '''ns_set split''' ''?-persist? setId ?splitChar?''

: Splits one set into multiple sets based on the ''splitChar'' as described below and returns a Tcl list of IDs for the newly-allocated sets. It assumes that the keys in the source ''setId'' contain a specific character (''splitChar'') that can be used to separate the name of a new set and the key in the new set. The default ''splitChar'' is a period ".".
* '''ns_set truncate''' ''setId fieldNumber''

: Removes any fields with index ''fieldNumber'' or greater and frees any memory allocated for them.
* '''ns_set unique''' ''setId key''

: Returns 1 if the specified key is unique in the specified set and 0 if it is not. For example, a web browser could send multiple "Accept:" headers which would end up in the header set for the connection. '''ns_set unique''' would return 0 for the "Accept:" key, because there are multiple fields with the key "Accept:". The test for uniqueness is performed case-sensitively.
* '''ns_set update''' ''setId key value''

: Updates the first field in the specified set whose key is ''key'' and replaces its value with ''value''. This is equivalent to '''ns_set delkey''' followed by '''ns_set put''' if there is only one field with the key of ''key''.
* '''ns_set value''' ''setId fieldNumber''

: Returns the value of the set at field number ''fieldNumber''. This command is useful when looping through all the key-value pairs in the set.

'''EXAMPLES'''

% set mySet [ns_set create mySetName a b c d e f A Joe B John C Jeff]
d0

% ns_set size $mySet
6

% ns_set name $mySet
mySetName

% ns_set array $mySet
a b c d e f A Joe B John C Jeff

% ns_set get $mySet A
Joe

% ns_set iget $mySet a
b

% ns_set unique $mySet a
1

% ns_set iunique $mySet a
0

% ns_set truncate $mySet 3

% ns_set print $mySet
mySetName:
a = b
c = d
e = f

% ns_set update $mySet c "Hello World!"
2

% ns_set print $mySet
mySetName:
a = b
e = f
c = Hello World!

% ns_set find $mySet c
2

% ns_set find $mySet nokey
-1

% ns_set delete $mySet 0

% ns_set array $mySet
e f c {Hello World!}

% set anotherSet [ns_set create]
d1

% ns_set list
d0 d1

% ns_set put $anotherSet dog.food "Yummy dog food!"
0

% ns_set put $anotherSet cat.food "Yummy cat food!"
1

% ns_set print $anotherSet
<Unamed set>:
dog.food = Yummy dog food!
cat.food = Yummy cat food!

% set newSets [ns_set split $anotherSet]
d2 d3

% foreach s $newSets { ns_set print $s }
dog:
food = Yummy dog food!
cat:
food = Yummy cat food!

% ns_set key $anotherSet 0
dog.food

% ns_set value $anotherSet 1
Yummy cat food!

% ns_set move $mySet $anotherSet
d0

% ns_set array $mySet
e f c {Hello World!} dog.food {Yummy dog food!} cat.food {Yummy cat food!}

% ns_set array $anotherSet

% set thirdSet [ns_set new]
d4

% ns_set move $thirdSet $mySet
d4

% ns_set array $thirdSet
e f c {Hello World!} dog.food {Yummy dog food!} cat.food {Yummy cat food!}

% array set testArray [ns_set array $thirdSet]

to run through an ns_set
for {set i 0} {$i < [ns_set size $myset]} {incr i} {
set key [ns_set key $myset $i]
set value [ns_set value $myset $i]
}

'''NOTES'''

: The ns_set command currently reports that it accepts two additional subcommands, idelete and purge. These are both noops (idelete may be a mistake as delete is already case-irrelevant).

: NULL values, distinct from the empty string, are useful when representing a database row as an ns_set. Currently, it is difficult to get a NULL value in an ns_set through the TCL API. You may get a NULL value in the set created by [[ns_parsequery]] or by omitting the last value when seeding the ns_set in the create/new subcommand, etc. It is possible to create NULL-valued fields through the C API.

: ns_set is intended for relatively ''small'' amounts of data. (Keys are found by a ''linear'' search through the whole underlying C array.) If you stuff very large amounts of data into an ns_set, performance will be very poor - use a Tcl Array instead for that.

'''SEE ALSO'''

: [[ns_findset]]

----

[[Category Documentation]] - [[Category Core Tcl API]]

Ns returnfile

2006-04-19T17:22:55Z

Jadeforrest:

For now, see [[ns_return]]

Ns return

2006-04-19T17:22:30Z

Jadeforrest: add internal links

Name
ns_connsendfp, ns_respond, ns_return, ns_returnadminnotice, ns_returnbadrequest, ns_returnerror, ns_returnfile, ns_returnforbidden, ns_returnfp, ns_returnnotfound, ns_returnnotice, ns_returnredirect, ns_returnunauthorized, ns_write - commands
Synopsis
[[ns_connsendfp]] fp len

[[ns_respond]]

ns_return status type string

[[ns_returnadminnotice]] status msg ?longmsg?

[[ns_returnbadrequest]] reason

[[ns_returnerror]] status msg

[[ns_returnfile]] status type filename

[[ns_returnforbidden]]

[[ns_returnfp]] status type fileid len

[[ns_returnnotfound]]

[[ns_returnnotice]] status msg ?longmsg?

[[ns_returnredirect]] location

[[ns_returnunauthorized]]

[[ns_write]] string

Description

These procedures provide a simple interface for returning information to the client. They build HTTP/1.0 headers and send the appropriate data out the socket to the client. The script does not end at the time ns_return* is invoked so you can continue processing data after the client has gotten the data and closed the socket.

type should be a MIME type (see ns_guesstype manual page for a list). status is a three-digit number fitting the pattern below:

1xx Informational - Not used, but reserved for future use.
2xx Success - The action was successfully received, understood, and accepted.
3xx Redirection - Further action must be taken in order to complete the request.
4xx Client Error - The request contains bad syntax or cannot be fulfilled.
5xx Server Error - The server failed to fulfill an apparently valid request.
Some common status values and their meanings are:

201 Created
202 Accepted
203 Provisional Information
204 No Content
300 Multiple Choices
301 Moved Permanently
302 Moved Temporarily
303 Method
304 Not Modified
401 Unauthorized
402 Payment Required
403 Forbidden
404 Not Found
405 Method Not Allowed
406 None Acceptable
407 Proxy Authentication Required
408 Request Time-out
409 Conflict
410 Gone
501 Not Implemented
502 Bad Gateway
503 Service Unavailable
504 Gateway Time-out
ns_connsendfp
This function writes len bytes of the specified channel or file to the conn.
ns_return
Sends back both the headers and the string.
ns_returnadminnotice
Wraps the text msg and longmsg in some html, appends a line with a link to "mailto:serveradministrator" based on the virtual server parameter "WebMaster".
ns_returnbadrequest
Returns a 400 status code and a formatted HTML message containing the reason text.
ns_returnerror
Wraps the text msg in some html and returns that to the client.
ns_returnfile
Sends back the headers and the contents of the file.
ns_returnforbidden
Returns a 403 status code.
ns_returnfp
First sends the appropriate headers. Next, it writes out the contents of file from the current file position until the end of the file.
ns_returnnotfound
Returns a 404 status code.
ns_returnnotice
Wraps teh text msg and longmsg in some html and returns that to the client.
ns_returnredirect
Returns a redirect to the passed in location
ns_returnunauthorized
Returns a 401 status code
ns_write
Writes the string out the connection. You can use it instead of the ns_return or ns_respond functions to build HTTP responses. AOLserver will not include the usual headers on the output data. The script does not end at the time ns_write* is invoked so you can continue processing data after the client has gotten the data and closed the socket.

See Also

ns_respond(n) , ns_writefp(n)

Ns return

2006-04-19T17:21:19Z

Jadeforrest:

Name
ns_connsendfp, ns_respond, ns_return, ns_returnadminnotice, ns_returnbadrequest, ns_returnerror, ns_returnfile, ns_returnforbidden, ns_returnfp, ns_returnnotfound, ns_returnnotice, ns_returnredirect, ns_returnunauthorized, ns_write - commands
Synopsis
ns_connsendfp fp len

ns_respond

ns_return status type string

ns_returnadminnotice status msg ?longmsg?

ns_returnbadrequest reason

ns_returnerror status msg

[ns_returnfile] status type filename

ns_returnforbidden

ns_returnfp status type fileid len

ns_returnnotfound

ns_returnnotice status msg ?longmsg?

ns_returnredirect location

ns_returnunauthorized

ns_write string

Description

These procedures provide a simple interface for returning information to the client. They build HTTP/1.0 headers and send the appropriate data out the socket to the client. The script does not end at the time ns_return* is invoked so you can continue processing data after the client has gotten the data and closed the socket.

type should be a MIME type (see ns_guesstype manual page for a list). status is a three-digit number fitting the pattern below:

1xx Informational - Not used, but reserved for future use.
2xx Success - The action was successfully received, understood, and accepted.
3xx Redirection - Further action must be taken in order to complete the request.
4xx Client Error - The request contains bad syntax or cannot be fulfilled.
5xx Server Error - The server failed to fulfill an apparently valid request.
Some common status values and their meanings are:

201 Created
202 Accepted
203 Provisional Information
204 No Content
300 Multiple Choices
301 Moved Permanently
302 Moved Temporarily
303 Method
304 Not Modified
401 Unauthorized
402 Payment Required
403 Forbidden
404 Not Found
405 Method Not Allowed
406 None Acceptable
407 Proxy Authentication Required
408 Request Time-out
409 Conflict
410 Gone
501 Not Implemented
502 Bad Gateway
503 Service Unavailable
504 Gateway Time-out
ns_connsendfp
This function writes len bytes of the specified channel or file to the conn.
ns_return
Sends back both the headers and the string.
ns_returnadminnotice
Wraps the text msg and longmsg in some html, appends a line with a link to "mailto:serveradministrator" based on the virtual server parameter "WebMaster".
ns_returnbadrequest
Returns a 400 status code and a formatted HTML message containing the reason text.
ns_returnerror
Wraps the text msg in some html and returns that to the client.
ns_returnfile
Sends back the headers and the contents of the file.
ns_returnforbidden
Returns a 403 status code.
ns_returnfp
First sends the appropriate headers. Next, it writes out the contents of file from the current file position until the end of the file.
ns_returnnotfound
Returns a 404 status code.
ns_returnnotice
Wraps teh text msg and longmsg in some html and returns that to the client.
ns_returnredirect
Returns a redirect to the passed in location
ns_returnunauthorized
Returns a 401 status code
ns_write
Writes the string out the connection. You can use it instead of the ns_return or ns_respond functions to build HTTP responses. AOLserver will not include the usual headers on the output data. The script does not end at the time ns_write* is invoked so you can continue processing data after the client has gotten the data and closed the socket.

See Also

ns_respond(n) , ns_writefp(n)

Ns return

2006-04-19T17:21:01Z

Jadeforrest: copy from man page

Name
ns_connsendfp, ns_respond, ns_return, ns_returnadminnotice, ns_returnbadrequest, ns_returnerror, ns_returnfile, ns_returnforbidden, ns_returnfp, ns_returnnotfound, ns_returnnotice, ns_returnredirect, ns_returnunauthorized, ns_write - commands
Synopsis
ns_connsendfp fp len

ns_respond

ns_return status type string

ns_returnadminnotice status msg ?longmsg?

ns_returnbadrequest reason

ns_returnerror status msg

ns_returnfile status type filename

ns_returnforbidden

ns_returnfp status type fileid len

ns_returnnotfound

ns_returnnotice status msg ?longmsg?

ns_returnredirect location

ns_returnunauthorized

ns_write string

Description

These procedures provide a simple interface for returning information to the client. They build HTTP/1.0 headers and send the appropriate data out the socket to the client. The script does not end at the time ns_return* is invoked so you can continue processing data after the client has gotten the data and closed the socket.

type should be a MIME type (see ns_guesstype manual page for a list). status is a three-digit number fitting the pattern below:

1xx Informational - Not used, but reserved for future use.
2xx Success - The action was successfully received, understood, and accepted.
3xx Redirection - Further action must be taken in order to complete the request.
4xx Client Error - The request contains bad syntax or cannot be fulfilled.
5xx Server Error - The server failed to fulfill an apparently valid request.
Some common status values and their meanings are:

201 Created
202 Accepted
203 Provisional Information
204 No Content
300 Multiple Choices
301 Moved Permanently
302 Moved Temporarily
303 Method
304 Not Modified
401 Unauthorized
402 Payment Required
403 Forbidden
404 Not Found
405 Method Not Allowed
406 None Acceptable
407 Proxy Authentication Required
408 Request Time-out
409 Conflict
410 Gone
501 Not Implemented
502 Bad Gateway
503 Service Unavailable
504 Gateway Time-out
ns_connsendfp
This function writes len bytes of the specified channel or file to the conn.
ns_return
Sends back both the headers and the string.
ns_returnadminnotice
Wraps the text msg and longmsg in some html, appends a line with a link to "mailto:serveradministrator" based on the virtual server parameter "WebMaster".
ns_returnbadrequest
Returns a 400 status code and a formatted HTML message containing the reason text.
ns_returnerror
Wraps the text msg in some html and returns that to the client.
ns_returnfile
Sends back the headers and the contents of the file.
ns_returnforbidden
Returns a 403 status code.
ns_returnfp
First sends the appropriate headers. Next, it writes out the contents of file from the current file position until the end of the file.
ns_returnnotfound
Returns a 404 status code.
ns_returnnotice
Wraps teh text msg and longmsg in some html and returns that to the client.
ns_returnredirect
Returns a redirect to the passed in location
ns_returnunauthorized
Returns a 401 status code
ns_write
Writes the string out the connection. You can use it instead of the ns_return or ns_respond functions to build HTTP responses. AOLserver will not include the usual headers on the output data. The script does not end at the time ns_write* is invoked so you can continue processing data after the client has gotten the data and closed the socket.

See Also

ns_respond(n) , ns_writefp(n)