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special_vars [2006/08/29 20:18] (current)
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 +======Special Variables and Expandos======
 +
 +In addition to normal variables created with [[ASSIGN]], and
 +the built-in [[SET]] variables, EPIC also supports a number
 +of reserved, dynamic variables, sometimes referred to as expandos.  They
 +are special in that the client is constantly updating their values
 +automatically.  There are also numerous variable modifiers available.
 +
 +^     Modifier        Description                                           ^
 +|$variable         |A normal variable, expanding to the first match of: \\ 1) a variable created with [[ASSIGN]] or @ \\ 2) an internal [[SET]] variable \\ 3) an environment variable \\ 4) an empty string              |
 +|$[num]variable    |Expands to the variables value, with 'num' width.  If the number is negative, the value is right-aligned. The value is truncated or padded to meet the width.              |
 +|$#variable        |Expands to the number of words in $variable. If $variable is omitted, it assumes $*              |
 +|$@variable        |Expands to the number of characters in $variable. if $variable is omitted, it assumes $*              |
 +|$($subvariable)   |This is somewhat similar to a pointer, in that the value of $subvar is taken as the name of the variable to expand to.  Nesting is allowed.              |
 +|${expression}     |Expands to the return value of the expression.  In addition, ${} permits the value to be embedded in another string unambiguously.              |
 +|$!history!        |Expands to a matching entry in the client's command history, wildcards allowed.              |
 +|$"some text"      |Uses 'text' as an input prompt, and returns the next line of text the user types (up to a <return>             |
 +|$'some text'      |Uses 'text' as an input prompt, and returns the next key that the user presses.              |
 +
 +Whenever an alias is called, these expandos are set to the arguments passed
 +to it.  If none of these expandos are used in the alias, or the $() form
 +shown above, any arguments passed will automatically be appended to the last
 +command in the alias.
 +
 +^   Expando  ^     Description                                                  ^
 +|$*          |expands to all arguments passed to an alias                       |
 +|$n          |expands to argument 'n' passed to an alias (counting from zero)   |
 +|$n-m        |expands to arguments 'n' through 'm' passed to an alias           |
 +|$n-         |expands to all arguments from 'n' on passed to an alias           |
 +|$-m         |expands to all arguments up to 'm' passed to an alias             |
 +|$~          |expands to the last argument passed to an alias                   |
 +
 +These variables are set and updated dynamically by the client.  The case of
 +$A .. $Z is important.  Also note that $A .. $Z can be overridden by [[ASSIGN]],
 +so it is usually good practice to make variable names 2 or more characters
 +long.
 +
 +^   Variable    ^      Description                                               ^
 +|$,             |last person who sent you a [[MSG]]                 |
 +|$.             |last person to whom you sent a [[MSG]]                 |
 +|$:             |last person to join a channel you are on                 |
 +|$;             |last person to send a public message to a channel you are on                 |
 +|$A             |text of your [[AWAY]] message, if any                 |
 +|$B             |body of last [[MSG]] you sent                 |
 +|$C             |current channel                 |
 +|$D             |last person that [[notify command|NOTIFY]] detected a signon for                 |
 +|$E             |idle time                 |
 +|$F             |time client was started, $[[time function|time]]() format                 |
 +|$G             |value of [[set banner|BANNER]], expanded if [[set banner_expand|BANNER_EXPAND]] is on.                 |
 +|$H             |current server numeric being processed                 |
 +|$I             |channel you were last [[INVITE]]d to                 |
 +|$J             |client version text string                 |
 +|$K             |current value of [[set cmdchars|CMDCHARS]]                 |
 +|$L             |current contents of the input line                 |
 +|$M             |modes of current channel, if any                 |
 +|$N             |current nickname                 |
 +|$O             |value of [[set status oper|STATUS_OPER]] if you are an irc operator                 |
 +|$P             |if you are a channel operator in $C, expands to a '@'                 |
 +|$Q             |nickname of whomever you are [[QUERY]]ing                 |
 +|$R             |version of current server                 |
 +|$S             |current server name                 |
 +|$T             |target of current input (channel or [[QUERY]] nickname)                 |
 +|$U             |value of cutbuffer                 |
 +|$V             |client release date (numeric version string)                 |
 +|$W             |current working directory                 |
 +|$X             |your /[[userhost command|userhost]] $N address (user@host)                 |
 +|$Y             |value of REALNAME                 |
 +|$Z             |time of day (hh:mm)                 |
 +|$$             |a literal '$'                 |
 +
 +For example, assume you have the following alias:
 +
 +   alias blah { msg $D Hi there!  }
 +
 +If /blah is passed any arguments, they will automatically be appended to the
 +[[MSG]] text.  For example:
 +
 +   /blah oops                          /* command as entered */
 +   "Hi there! oops"                    /* text sent to $D */
 +
 +One of the more confusing expandos to look at is the $() form.  It evaluates
 +the variable or function inside the parenthesis, and whatever is returned is
 +used as the name of the variable to expand.  For example:
 +
 +   assign foo blah                     /* inside variable */
 +   assign blah 10                      /* real variable */
 +   /eval echo $($foo)                  /* $foo expands to "blah" */
 +   "10"                                /* $blah expands to "10" */
 +
 +Another useful form is ${}.  In general, variables can be embedded inside
 +strings without problems, assuming the surrounding text could not be
 +misinterpreted as part of the variable name.  This form guarantees that
 +surrounding text will not affect the expression's return value.
 +
 +   /eval echo foo$Nfoo                 /* breaks, looks for $nfoo */
 +   /eval echo foo${N}foo               /* ${N} returns current nickname */
 +   fooYourNickfoo                      /* returned by above command */
 +   /eval echo ${[foo]}bar              /* expression parser may be used */
 +   foobar                              /* returned by above command */
  
special_vars.txt ยท Last modified: 2006/08/29 20:18 (external edit)