RiveScript - Rendering Intelligence Very Easily

- NAME
- SYNOPSIS
- DESCRIPTION
- METHODS

- GENERAL
- LOADING AND PARSING
- CONFIGURATION
- INTERACTION
- INTERNAL

- RIVESCRIPT
- ERROR MESSAGES

- ERR: Deep Recursion Detected!
- ERR: No Reply Matched
- ERR: No Reply Found
- [ERR: Can't Modify Non-Numeric Variable $var]
- [ERR: Math Can't "add" Non-Numeric Value $value]
- [ERR: Can't Divide By Zero]
- [ERR: Object Not Found]

- SEE ALSO
- CHANGES
- AUTHOR
- KEYWORDS
- COPYRIGHT AND LICENSE

# NAME

RiveScript - Rendering Intelligence Very Easily

# SYNOPSIS

      use RiveScript;

      # Create a new RiveScript interpreter.
      my $rs = new RiveScript;

      # Load a directory of replies.
      $rs->loadDirectory ("./replies");

      # Load another file.
      $rs->loadFile ("./more_replies.rs");

      # Stream in some RiveScript code.
      $rs->stream (q~
        + hello bot
        - Hello, human.
      ~);

      # Sort all the loaded replies.
      $rs->sortReplies;

      # Chat with the bot.
      while (1) {
        print "You> ";
        chomp (my $msg = <STDIN>);
        my $reply = $rs->reply ('localuser',$msg);
        print "Bot> $reply\n";
      }

# DESCRIPTION

RiveScript is a simple trigger/response language primarily used for the creation of chatting robots. It's designed to have an easy-to-learn syntax but provide a lot of power and flexibility. For more information, visit http://www.rivescript.com/

# METHODS

## GENERAL

new (ARGS)

  Create a new instance of a RiveScript interpreter. The instance will become its own "chatterbot," with its own set of responses and user variables. You can pass in any global variables here. The two standard variables are:

        debug     - Turns on debug mode (a LOT of information will be printed to the
                    terminal!). Default is 0 (disabled).
        verbose   - When debug mode is on, all debug output will be printed to the
                    terminal if 'verbose' is also true. The default value is 1.
        debugfile - Optional: paired with debug mode, all debug output is also written
                    to this file name. Since debug mode prints such a large amount of
                    data, it is often more practical to have the output go to an
                    external file for later review. Default is '' (no file).
        depth     - Determines the recursion depth limit when following a trail of replies
                    that point to other replies. Default is 50.
        strict    - If this has a true value, any syntax errors detected while parsing
                    a RiveScript document will result in a fatal error. Set it to a
                    false value and only a warning will result. Default is 1.

  It's recommended that if you set any other global variables that you do so by calling `setGlobal` or defining it within the RiveScript code. This will avoid the possibility of overriding reserved globals. Currently, these variable names are reserved:

        topics   sorted  sortsthat  sortedthat  thats
        arrays   subs    person     client      bot
        objects  syntax  sortlist   reserved    debugopts
        frozen   globals handlers   objlangs

  Note: the options "verbose" and "debugfile", when provided, are noted and then deleted from the root object space, so that if your RiveScript code uses variables by the same values it won't conflict with the values that you passed here.

## LOADING AND PARSING

loadDirectory ($PATH[,@EXTS])

  Load a directory full of RiveScript documents. `$PATH` must be a path to a directory. `@EXTS` is optionally an array containing file extensions, including the dot. By default `@EXTS` is `('.rs')`.

  Returns true on success, false on failure.

loadFile ($PATH)

  Load a single RiveScript document. `$PATH` should be the path to a valid RiveScript file. Returns true on success; false otherwise.

stream ($CODE)

  Stream RiveScript code directly into the module. This is for providing RS code from within the Perl script instead of from an external file. Returns true on success.

checkSyntax ($COMMAND, $LINE)

  Check the syntax of a line of RiveScript code. This is called automatically for each line parsed by the module. `$COMMAND` is the command part of the line, and `$LINE` is the rest of the line following the command (and excluding inline comments).

  If there is no problem with the line, this method returns `undef`. Otherwise it returns the text of the syntax error.

  If `strict` mode is enabled in the constructor (which is on by default), a syntax error will result in a fatal error. If it's not enabled, the error is only sent via `warn` and the file currently being processed is aborted.

sortReplies

  Call this method after loading replies to create an internal sort buffer. This is necessary for trigger matching purposes. If you fail to call this method yourself, RiveScript will call it once when you request a reply. However, it will complain loudly about it.

## CONFIGURATION

setHandler ($LANGUAGE => $CODEREF, ...)

  Define some code to handle objects of a particular programming language. If the coderef is `undef`, it will delete the handler.

  The code receives the variables `$rs, $action, $name,` and `$data`. These variables are described here:

        $rs     = Reference to Perl RiveScript object.
        $action = "load" during the parsing phase when an >object is found.
                  "call" when provoked via a <call> tag for a reply
        $name   = The name of the object.
        $data   = The source of the object during the parsing phase, or an array
                  reference of arguments when provoked via a <call> tag.

  There is a default handler set up that handles Perl objects.

  If you want to block Perl objects from being loaded, you can just set it to be undef, and its handler will be deleted and Perl objects will be skipped over:

        $rs->setHandler (perl => undef);

  The rationale behind this "pluggable" object interface is that it makes RiveScript more flexible given certain environments. For instance, if you use RiveScript on the web where the user chats with your bot using CGI, you might define a handler so that JavaScript objects can be loaded and called. Perl itself can't execute JavaScript, but the user's web browser can.

  See the JavaScript example in the `docs` directory in this distribution.

setSubroutine ($NAME, $CODEREF)

  Manually create a RiveScript object (a dynamic bit of Perl code that can be provoked in a RiveScript response). `$NAME` should be a single-word, alphanumeric string. `$CODEREF` should be a pointer to a subroutine or an anonymous sub.

setGlobal (%DATA)

  Set one or more global variables, in hash form, where the keys are the variable names and the values are their value. This subroutine will make sure that you don't override any reserved global variables, and warn if that happens.

  This is equivalent to `! global` in RiveScript code.

  To delete a global, set its value to `undef` or "`<undef>`". This is true for variables, substitutions, person, and uservars.

setVariable (%DATA)

  Set one or more bot variables (things that describe your bot's personality).

  This is equivalent to `! var` in RiveScript code.

setSubstitution (%DATA)

  Set one or more substitution patterns. The keys should be the original word, and the value should be the word to substitute with it.

        $rs->setSubstitution (
          q{what's}  => 'what is',
          q{what're} => 'what are',
        );

  This is equivalent to `! sub` in RiveScript code.

setPerson (%DATA)

  Set a person substitution. This is equivalent to `! person` in RiveScript code.

setUservar ($USER,%DATA)

  Set a variable for a user. `$USER` should be their User ID, and `%DATA` is a hash containing variable/value pairs.

  This is like `<set>` for a specific user.

getUservar ($USER, $VAR)

  This is an alias for getUservars, and is here because it makes more grammatical sense.

getUservars ([$USER][, $VAR])

  Get all the variables about a user. If a username is provided, returns a hash reference containing that user's information. Else, a hash reference of all the users and their information is returned.

  You can optionally pass a second argument, `$VAR`, to get a specific variable that belongs to the user. For instance, `getUservars ("soandso", "age")`.

  This is like `<get>` for a specific user or for all users.

clearUservars ([$USER])

  Clears all variables about `$USER`. If no `$USER` is provided, clears all variables about all users.

freezeUservars ($USER)

  Freeze the current state of variables for user `$USER`. This will back up the user's current state (their variables and reply history). This won't statically prevent the user's state from changing; it merely saves its current state. Then use `thawUservars()` to revert back to this previous state.

thawUservars ($USER[, %OPTIONS])

  If the variables for `$USER` were previously frozen, this method will restore them to the state they were in when they were last frozen. It will then delete the stored cache by default. The following options are accepted as an additional hash of parameters (these options are mutually exclusive and you shouldn't use both of them at the same time. If you do, "discard" will win.):

        discard: Don't restore the user's state from the frozen copy, just delete the
                 frozen copy.
        keep:    Keep the frozen copy even after restoring the user's state. With this
                 you can repeatedly thawUservars on the same user to revert their state
                 without having to keep freezing them again. On the next freeze, the
                 last frozen state will be replaced with the new current state.

  Examples:

        # Delete the frozen cache but don't modify the user's variables.
        $rs->thawUservars ("soandso", discard => 1);

        # Restore the user's state from cache, but don't delete the cache.
        $rs->thawUservars ("soandso", keep => 1);

lastMatch ($USER)

  After fetching a reply for user `$USER`, the `lastMatch` method will return the raw text of the trigger that the user has matched with their reply. This function may return undef in the event that the user did not match any trigger at all (likely the last reply was "`ERR: No Reply Matched`" as well).

## INTERACTION

reply ($USER,$MESSAGE)

  Fetch a response to `$MESSAGE` from user `$USER`. RiveScript will take care of lowercasing, running substitutions, and removing punctuation from the message.

  Returns a response from the RiveScript brain.

## INTERNAL

debug ($MESSAGE) *Internal

  Prints a debug message to the terminal. Called from within in debug mode.

issue ($MESSAGE) *Internal

  Called internally to report an issue (similar to a warning). If debug mode is active, it will print the issue to STDOUT with a # sign prepended. Otherwise, the issue is sent to STDERR via `warn`.

parse ($FILENAME, $CODE) *Internal

  This method is called internally to parse a file or streamed RiveScript code. `$FILENAME` is only there so it can keep internal track of files and line numbers, in case syntax errors appear.

sortThatTriggers *Internal

  This method sorts all the `+Trigger` lines that are paired with a common `%Previous` line. This is necessary for when one question by the bot could have multiple replies. I found a bug with the following RS code:

        + how [are] you [doing]
        - I'm doing great, how are you?
        - Good -- how are you?
        - Fine, how are you?

        + [*] @good [*]
        % * how are you
        - That's good. :-)

        + [*] @bad [*]
        % * how are you
        - Aww. :-( What's the matter?

        + *
        % * how are you
        - I see...

  The effective trigger order was "`[*] @good [*]`", "`*`", "`[*] @bad [*]`", because there was no sort buffer and it was relying on Perl's hash sorting. This method was introduced to fix that problem and sort these triggers too.

  You don't need to call this method yourself; it is called automatically on a `sortReplies()` request.

sortList ($NAME,@LIST) *Internal

  This is used internally to sort arrays (namely, person and substitution pattern arrays). Sets `$rs-`{sortlist}->{$NAME}> to an array reference of the sorted values in `@LIST`. The values are sorted by number of words from greatest to smallest, with each group of same-word-count items sorted by length amongst themselves.

_getreply ($USER,$MSG,%TAGS) *Internal

  Do NOT call this method yourself. This method assumes a few things about the user's input that is taken care of by `reply()`. There is no reason to call this method manually.

_reply_regexp ($USER,$TRIGGER) *Internal

  This method takes a raw trigger `$TRIGGER` and formats it for a matching attempt in a regular expression. It removes `{weight}` tags, processes arrays, processes bot variables and other tags, and returns something ready for the regular expression engine.

processTags ($USER,$MSG,$REPLY,$STARS,$BOTSTARS) *Internal

  Process tags in the bot's response. `$USER` and `$MSG` are the values originally passed to the reply engine. `$REPLY` is the bot's raw response. `$STARS` and `$BOTSTARS` are array references containing any wildcards matched in a trigger or `%Previous` command, respectively. Returns a reply with all the tags processed.

_formatMessage ($STRING) *Internal

  Formats a message to prepare it for reply matching. Lowercases the string, runs substitutions, and sanitizes what's left.

_stringUtil ($TYPE,$STRING) *Internal

  Runs string modifiers on `$STRING` (uppercase, lowercase, sentence, formal).

_personSub ($STRING) *Internal

  Runs person substitutions on `$STRING`.

# RIVESCRIPT

This interpreter tries its best to follow RiveScript standards. Currently it supports RiveScript 2.0 documents. A current copy of the RiveScript working draft is included with this package: see the RiveScript::WD manpage.

# ERROR MESSAGES

Most of the Perl warnings that the module will emit are self-explanatory, and when parsing RiveScript files, file names and line numbers will be given. This section of the manpage instead outlines error strings that may turn up in responses to the bot's queries.

## ERR: Deep Recursion Detected!

The deep recursion depth limit has been reached (a response redirected to a different trigger, which redirected somewhere else, etc.).

How to fix: override the global variable `depth`. This can be done via `setGlobal` or in the RiveScript code:

      ! global depth = 100

## ERR: No Reply Matched

No match was found for the client's message.

How to fix: create a catch-all trigger of just `*`.

      + *
      - I don't know how to reply to that.

## ERR: No Reply Found

A match to the client's message was found, but no response to it was found. This might mean you had a set of conditionals after it, and no `-Reply` to fall back on, and every conditional returned false.

How to fix: make sure you have at least one `-Reply` to every `+Trigger`, even if you don't expect that the `-Reply` will ever be used.

## [ERR: Can't Modify Non-Numeric Variable $var]

You called a math tag on a variable, and the current value of the variable contains something that isn't a number.

How to fix: verify that the variable you're working with is a number. If necessary, reset the variable via `<set>`.

## [ERR: Math Can't "add" Non-Numeric Value $value]

("add" may also be sub, mult, or div). You tried to run a math function on a variable, but the value you used wasn't a number.

How to fix: verify that you're adding, subtracting, multiplying, or dividing using numbers.

## [ERR: Can't Divide By Zero]

A `<div>` tag was found that attempted to divide a variable by zero.

How to fix: make sure your division isn't dividing by zero. If you're using a variable to provide the divisor, validate that the variable isn't zero by using a conditional.

      * <get divisor> == 0 => The divisor is zero so I can't do that.
      - <div myvar=<get divisor>>I divided the variable by <get divisor>.

## [ERR: Object Not Found]

RiveScript attempted to call an object that doesn't exist. This may be because a syntax error in the object prevented Perl from evaluating it, or the object was written in a different programming language.

How to fix: verify that the called object was loaded properly. You will receive notifications on the terminal if the object failed to load for any reason.

# SEE ALSO

the RiveScript::WD manpage - A current snapshot of the Working Draft that defines the standards of RiveScript.

http://www.rivescript.com/ - The official homepage of RiveScript.

# CHANGES

      1.22  Sep 22 2011
      - Cleaned up the documentation of RiveScript; moved the JavaScript object
        example to a separate document in the `docs' directory.
      - Obsoleted the `rsdemo` command that used to ship with the distribution. In
        its place is `rivescript`, which can also be used non-interactively so that a
        third party, non-Perl application could still make use of RiveScript.
      - RiveScript.pm is now dual licensed. It uses the GPLv2 for open source
        applications as before, but you can contact the author for details if you
        want to use RiveScript.pm in a closed source commercial application.

      1.20  Jul 30 2009
      - Added automatic syntax checking when parsing RiveScript code. Also added
        'strict mode' - if true (default), a syntax error is a fatal error. If false,
        a syntax error is a warning, and RiveScript aborts processing the file any
        further.
      - Changed the behavior of "inherits" a bit: a new type has been added called
        "includes" which does what the old "inherits" does (mixes the trigger list
        of both topics together into the same pool). The new "inherits" option though
        causes the trigger list from the source topic to be higher in matching priority
        than the trigger list of the inherited topic.
      - Moving to a new versioning scheme: development releases will have odd
        version numbers, stable (CPAN) versions will have even numbers.
      - Fixed the Eliza brain; in many places a <star2> was used when there was only one
        star in the trigger. Fixes lots of issues with Eliza.
      - Bugfix: recursion depth limits weren't taken into account when the {@} tag
        was responsible for a redirection. Fixed.
      - Bugfix: there was a problem in the regular expression that counts real words
        while sorting triggers, so that triggers with *'s in them weren't sorted
        properly and would therefore cause matching issues.
      - Bugfix: when the internal _getreply is called because of a recursive
        redirection (@, {@}), the %previous tags should be ignored. They weren't.
        since "lastreply" is always the same no matter how deeply recursive _getreply
        is going, it could result in some infinite recursion in rare cases. Fixed.
      - Bugfix: using a reserved name as a global variable wasn't working properly
        and would crash RiveScript. Fixed.

      1.19  Apr 12 2009
      - Added support for defining custom object handlers for non-Perl programming
        languages.
      - All the methods like setGlobal, setVariable, setUservar, etc. will now
        accept undef or "<undef>" as values - this will delete the variables.
      - There are no reserved global variable names anymore. Now, if a variable name
        would conflict with a reserved name, it is put into a "protected" space
        elsewhere in the object. Still take note of which names are reserved though.

      1.18  Dec 31 2008
      - Added support for topics to inherit their triggers from other topics.
        e.g. > topic alpha inherits beta
      - Fixed some bugs related to !array with ^continue's, and expanded its
        functionality therein.
      - Updated the getUservars() function to optionally be able to get just a specific
        variable from the user's data. Added getUservar() as a grammatically correct
        alias to this new functionality.
      - Added the functions freezeUservars() and thawUservars() to back up and
        restore a user's variables.
      - Added the function lastMatch(), which returns the text of the trigger that
        matched the user's last message.
      - The # command for RiveScript comments has been deprecated in revision 7 of
        the RiveScript Working Draft. The Perl module will now emit warnings each
        time the # comments are processed.
      - Modified a couple of triggers in the default Eliza brain to improve matching
        issues therein.
      - +Triggers can contain user <get> tags now.
      - Updated the RiveScript Working Draft.

      1.17  Sep 15 2008
      - Updated the rsdemo tool to be more flexible as a general debugging and
        developing program. Also updated rsdemo and rsup to include POD documentation
        that can be read via `perldoc`.
      - Added a global variable $RiveScript::basedir which is the the path to your
        Perl lib/RiveScript folder. This is used by `rsdemo` as its default location
        to search for replies.
      - Tweak: Triggers of only # and _ can exist now alongside the old single-wildcard
        trigger of *.
      - Bugfix: The lookahead code would throw Perl warnings if the following line
        had a single space in it, but was otherwise empty.
      - Bugfix: Inline comment removing has been fixed.
      - Bugfix: In conditionals, any blank side of the equality will get a default
        value of "undefined". This way you can use a matching array inside an optional
        and check if that <star> tag is defined.
        + i am wearing a [(@colors)] shirt
        * <star> ne undefined => Why are you wearing a <star> shirt?
        - What color is it?
      - Updated the RiveScript Working Draft.

      1.16  Jul 22 2008
      - New options to the constructor: 'verbose' and 'debugfile'. See the new()
        constructor for details.
      - Added new wildcard variants:
        * matches anything (previous behavior)
        # matches only numbers
        _ matches only letters
        So you can have a trigger like "+ i am # years old" and "+ i am * years old",
        with the latter trigger telling them to try that again and use a NUMBER this
        time. :)
      - Bugfix: when there were multiple +trigger's that had a common %previous,
        there was no internal sort buffer for those +trigger's. As a result, matching
        wasn't very efficient. Added the method sortThatTriggers() to fix this.
      - Bugfix: tags weren't being processed in @Redirects when they really
        should've!
      - Bugfix: The ^Continue lookahead code wouldn't work if the next line began
        with a tab. Fixed!
      - Updated the RiveScript Working Draft.

      1.15  Jun 19 2008
      - Person substitutions support multiple-word patterns now.
      - Message substititons also support multiple-word patterns now.
      - Added syntax tracking, so Deep Recursion errors can give you a filename and
        line number where the problem occurred.
      - Added a handler for detecting when a user was put into an empty topic.
      - Rearranged tag priority.
      - Updated the RiveScript Working Draft.

      1.14  Apr  2 2008
      - Bugfix: If a BEGIN/request trigger didn't exist, RiveScript would not fetch
        any replies for the client's message. Fixed.
      - Bugfix: Tags weren't being re-processed for the text of the BEGIN statement,
        so i.e. {uppercase}{ok}{/uppercase} wasn't working as expected. Fixed.
      - Bugfix: RiveScript wasn't parsing out inline comments properly.
      - Rearranged tag priorities.
      - Optimization: When substituting <star>s in, an added bit of code will insert
        '' (nothing) if the variable is undefined. This prevents Perl warnings that
        occurred frequently with the Eliza brain.
      - Updated the RiveScript Working Draft.

      1.13  Mar 18 2008
      - Included an "rsup" script for upgrading old RiveScript code.
      - Attempted to fix the package for CPAN (1.12 was a broken upload).
      - Bugfix: <bot> didn't have higher priority than <set>, so
        i.e. <set name=<bot name>> wouldn't work as expected. Fixed.

      1.12  Mar 16 2008
      - Initial beta release for a RiveScript 2.00 parser.

# AUTHOR

      Noah Petherbridge, http://www.kirsle.net

# KEYWORDS

bot, chatbot, chatterbot, chatter bot, reply, replies, script, aiml, alpha

# COPYRIGHT AND LICENSE

The Perl RiveScript interpreter is dual licensed as of version 1.22. For open source applications the module is using the GNU General Public License. If you'd like to use the RiveScript module in a closed source or commercial application, contact the author for more information.

      RiveScript - Rendering Intelligence Very Easily
      Copyright (C) 2011 Noah Petherbridge

      This program is free software; you can redistribute it and/or modify
      it under the terms of the GNU General Public License as published by
      the Free Software Foundation; either version 2 of the License, or
      (at your option) any later version.

      This program is distributed in the hope that it will be useful,
      but WITHOUT ANY WARRANTY; without even the implied warranty of
      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
      GNU General Public License for more details.

      You should have received a copy of the GNU General Public License
      along with this program; if not, write to the Free Software
      Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA