<A NAME="IDX183"></A>
<A NAME="IDX184"></A>
<A NAME="IDX185"></A>
<H1><A NAME="SEC36" HREF="coldmud_toc.html#SEC36">Function Descriptions</A></H1>
<P>
The function descriptions are arranged by category, and alphabetically
within their category. You can use the function index to look up the
description of a function by name.
<P>
Every function can throw a <CODE>~numargs</CODE> error if passed the wrong
number of arguments, and most can throw a <CODE>~type</CODE> error if passed
arguments of the wrong type. If a function can throw any other type of
error, it will be documented in the function's description.
<P>
<A NAME="IDX186"></A>
<A NAME="IDX187"></A>
<A NAME="IDX188"></A>
<H2><A NAME="SEC37" HREF="coldmud_toc.html#SEC37">Data functions</A></H2>
<P>
The functions described in this section allow you to perform various
operations on data. Operations specific to strings or lists are grouped
in their own sections.
<P>
<A NAME="IDX189"></A>
<H3><A NAME="SEC38" HREF="coldmud_toc.html#SEC38">class</A></H3>
<P>
<PRE>
class(<VAR>frob</VAR>)
</PRE>
<P>
This function returns the class of a frob. See section <A HREF="coldmud.html#SEC23">Frobs</A> for details
on frobs.
<P>
<A NAME="IDX190"></A>
<H3><A NAME="SEC39" HREF="coldmud_toc.html#SEC39">todbref</A></H3>
<P>
<PRE>
todbref(<VAR>number</VAR>)
</PRE>
<P>
This function converts <EM>number</EM> to a dbref.
<P>
Examples:
<P>
<PRE>
todbref(0)
=> #0
</PRE>
<P>
<A NAME="IDX191"></A>
<H3><A NAME="SEC40" HREF="coldmud_toc.html#SEC40">toerr</A></H3>
<P>
<PRE>
toerr(<VAR>string</VAR>)
</PRE>
<P>
This function converts <EM>string</EM> to an error code. <EM>string</EM>
can be any string; it does not have to be a valid identifier.
<P>
Examples:
<P>
<PRE>
toerr("foo")
=> ~foo
</PRE>
<P>
<A NAME="IDX192"></A>
<H3><A NAME="SEC41" HREF="coldmud_toc.html#SEC41">toint</A></H3>
<P>
<PRE>
toint(<VAR>string</VAR>)
</PRE>
<P>
This function converts <EM>string</EM> to an integer. If <EM>string</EM> is
not a number, the resulting integer will be <CODE>0</CODE>.
<P>
Examples:
<P>
<PRE>
toint("67")
=> 67
toint("foo")
=> 0
</PRE>
<P>
<A NAME="IDX193"></A>
<H3><A NAME="SEC42" HREF="coldmud_toc.html#SEC42">toliteral</A></H3>
<P>
<PRE>
toliteral(<VAR>data</VAR>)
</PRE>
<P>
This function converts any data to a <CODE>C--</CODE> literal or constructor
expression which, when read by the interpreter, will result in the same
data object.
<P>
Examples:
<P>
<PRE>
toliteral([3, "foo", 'bar, #60, ~none])
=> "[3, \"foo\", 'bar, #60, ~none]"
toliteral(tosym("foo-" + tostr(3 + 4)))
=> "tosym(\"foo-7\")"
toliteral(<#56, #[['type, 'obj], ['obj, #22]]>)
=> "<#56, #[['type, 'obj], ['obj, #22]]>"
</PRE>
<P>
<A NAME="IDX194"></A>
<H3><A NAME="SEC43" HREF="coldmud_toc.html#SEC43">tostr</A></H3>
<P>
<PRE>
tostr(<VAR>data</VAR>)
</PRE>
<P>
This function converts any data to a string representation of it. For
strings, the string representation is the string itself; for symbols and
error codes, the string representation is the identifier part of the
data object converted to a string value; for lists and frobs, the string
representations are <CODE>"<list>"</CODE> and <CODE>"<frob>"</CODE> respectively;
for integers and dbrefs, <CODE>tostr()</CODE> is equivalent to
<CODE>toliteral()</CODE>.
<P>
Examples:
<P>
<PRE>
tostr(3)
=> "3"
tostr("foo")
=> "foo"
tostr(#0)
=> "#0"
tostr([2, 3, 4])
=> "<list>"
tostr('foo)
=> "foo"
tostr(~methodnf)
=> "methodnf"
tostr(<#66, #[['type, 'obj], ['obj, #40]]>)
=> "<frob>"
</PRE>
<P>
<A NAME="IDX195"></A>
<H3><A NAME="SEC44" HREF="coldmud_toc.html#SEC44">tosym</A></H3>
<P>
<PRE>
tosym(<VAR>string</VAR>)
</PRE>
<P>
This function converts <EM>string</EM> into a symbol. <EM>string</EM> can
be any string; it does not have to be a valid identifier.
<P>
Examples:
<P>
<PRE>
tosym("foo")
=> 'foo
</PRE>
<P>
<A NAME="IDX196"></A>
<H3><A NAME="SEC45" HREF="coldmud_toc.html#SEC45">type</A></H3>
<P>
<PRE>
type(<VAR>data</VAR>)
</PRE>
<P>
This function returns a symbol giving the type of <VAR>data</VAR>. The
return value is one of <CODE>'integer</CODE>, <CODE>'string</CODE>, <CODE>'dbref</CODE>,
<CODE>'list</CODE>, <CODE>'symbol</CODE>, or <CODE>'error</CODE>.
<P>
Examples:
<P>
<PRE>
type(5)
=> 'integer
type([6, 'foo, "bar"])
=> 'list
type(<#44, #[['type, 'obj], ['obj, #20]]>)
=> 'frob
</PRE>
<P>
<A NAME="IDX197"></A>
<H3><A NAME="SEC46" HREF="coldmud_toc.html#SEC46">valid</A></H3>
<P>
<PRE>
valid(<VAR>data</VAR>)
</PRE>
<P>
This function returns <CODE>1</CODE> if <VAR>data</VAR> is a dbref and is valid, or
<CODE>0</CODE> otherwise. A dbref is valid if it refers to an object that
exists in the database.
<P>
Examples:
<P>
<PRE>
valid(#0)
=> 1
valid('foo)
=> 0
</PRE>
<P>
<A NAME="IDX198"></A>
<A NAME="IDX199"></A>
<A NAME="IDX200"></A>
<H2><A NAME="SEC47" HREF="coldmud_toc.html#SEC47">String Functions</A></H2>
<P>
The functions described in this section allow you to perform operations
on strings. All of the functions described in this section are
case-insensitive except for <CODE>strcmp()</CODE> and, if specified,
<CODE>match_regexp()</CODE>.
<P>
<A NAME="IDX201"></A>
<H3><A NAME="SEC48" HREF="coldmud_toc.html#SEC48">crypt</A></H3>
<P>
<PRE>
crypt(<VAR>string</VAR>)
crypt(<VAR>string</VAR>, <VAR>salt</VAR>)
</PRE>
<P>
This function performs one-way encryption on <VAR>string</VAR>, using the
host system's <CODE>crypt()</CODE> library routine. If <VAR>salt</VAR> is
specified, then it must be a two-character string; otherwise, a salt is
chosen randomly. The return value of <CODE>crypt()</CODE> is the encrypted
string; the first two characters of the encrypted string are the salt
used.
<P>
The encryption performed by this function has the property that it is
very difficult to find a string which will produce a given result;
however, a given string and a given salt will always yield the same
encrypted string.
<P>
Examples:
<P>
<PRE>
crypt("foo", "ab")
=> "abQ9KY.KfrYrc"
</PRE>
<P>
<A NAME="IDX202"></A>
<H3><A NAME="SEC49" HREF="coldmud_toc.html#SEC49">explode</A></H3>
<P>
<PRE>
explode(<VAR>string</VAR>)
explode(<VAR>string</VAR>, <VAR>separator</VAR>, [<VAR>want-blanks</VAR>])
</PRE>
<P>
This function returns a list of the words in <VAR>string</VAR>. If the
string <VAR>separator</VAR> is specified, then it is used as the word
separator; otherwise a space (<CODE>" "</CODE>) is used. If the optional
argument <VAR>want-blanks</VAR> is specified and is true, <CODE>explode()</CODE>
will include zero-length words in the returned list; otherwise, it will
not.
<P>
Examples:
<P>
<PRE>
explode(" foo bar baz")
=> ["foo", "bar", "baz"]
explode("foo:bar:baz", ":")
=> ["foo", "bar", "baz"]
</PRE>
<P>
<A NAME="IDX203"></A>
<H3><A NAME="SEC50" HREF="coldmud_toc.html#SEC50">lowercase</A></H3>
<P>
<PRE>
lowercase(<VAR>string</VAR>)
</PRE>
<P>
This function returns the result of changing each uppercase character in
<VAR>string</VAR> to lowercase.
<P>
<PRE>
lowercase("fOOBAr 23")
=> "foobar 23"
</PRE>
<P>
<A NAME="IDX204"></A>
<H3><A NAME="SEC51" HREF="coldmud_toc.html#SEC51">match_begin</A></H3>
<P>
<PRE>
match_begin(<VAR>string</VAR>, <VAR>search</VAR>)
match_begin(<VAR>string</VAR>, <VAR>search</VAR>, <VAR>separator</VAR>)
</PRE>
<P>
This function looks for the string <VAR>search</VAR> at the beginning of each
word in <VAR>string</VAR>. The word separator is given by the string
<VAR>separator</VAR> if it is specified; otherwise, a space (<CODE>" "</CODE>) is
used. The return value of <CODE>match_begin()</CODE> is <CODE>1</CODE> if
<VAR>search</VAR> was found at the beginning of a word in <VAR>string</VAR>, or
<CODE>0</CODE> if not.
<P>
Examples:
<P>
<PRE>
match_begin("foo:bar:baz", "fo", ":")
=> 1
match_begin("foo bar baz", "ar")
=> 0
</PRE>
<P>
<A NAME="IDX205"></A>
<H3><A NAME="SEC52" HREF="coldmud_toc.html#SEC52">match_pattern</A></H3>
<P>
<PRE>
match_pattern(<VAR>pattern</VAR>, <VAR>string</VAR>)
</PRE>
<P>
This function matches the wildcard pattern <VAR>pattern</VAR> against
<VAR>string</VAR>. A wildcard pattern is a string with asterixes (<SAMP>`*'</SAMP>)
signifying wildcards. A regular character matches itself, while a
wildcard matches any number of arbitrary characters. The return value
of <CODE>match_pattern()</CODE> is a list of the substrings of <VAR>string</VAR>
which matched the wildcards in <VAR>pattern</VAR>, or <CODE>0</CODE> if the match
fails.
<P>
<CODE>match_pattern()</CODE> allows you to do simple character-based matching.
For matching against command formats, however, you should use the
<CODE>match_template()</CODE> function.
<P>
Examples:
<P>
<PRE>
match_pattern("*", "foobar")
=> ["foobar"]
match_pattern("foo * bar * baz", "foo quux bar quuux baz")
=> ["quux", "quuux"]
match_pattern("foo * bar", "baz")
=> 0
</PRE>
<P>
<A NAME="IDX206"></A>
<H3><A NAME="SEC53" HREF="coldmud_toc.html#SEC53">match_regexp</A></H3>
<P>
<PRE>
match_regexp(<VAR>regexp</VAR>, <VAR>string</VAR>, [<VAR>case_matters</VAR>])
</PRE>
<P>
This function matches the regular expression <VAR>regexp</VAR>, a
string,against the string <VAR>string</VAR>. If <VAR>case_matters</VAR> is
specified and is true, the match is case-sensitive; otherwise, it is
case-insensitive. If the match succeeds, <CODE>match_regexp()</CODE> returns
a ten-element list giving the substitutions for the match (see below);
otherwise, <CODE>match_regexp()</CODE> returns 0.
<P>
Coldmud uses a regular expression matcher written by Henry Spencer. Its
syntax is very similar to the regular expression syntax used by Unix
utilities like <CODE>ed</CODE> or <CODE>egrep</CODE>. Here is Spencer's description
of his regular expression syntax:
<P>
<BLOCKQUOTE>
A regular expression is zero or more branches, separated by <SAMP>`|'</SAMP>.
It matches anything that matches one of the branches.
<P>
A branch is zero or more pieces, concatenated. It matches a match for
the first, followed by a match for the second, etc.
<P>
A piece is an atom possibly followed by <SAMP>`*'</SAMP>, <SAMP>`+'</SAMP>, or <SAMP>`?'</SAMP>.
An atom followed by <SAMP>`*'</SAMP> matches a sequence of 0 or more matches of
the atom. An atom followed by <SAMP>`+'</SAMP> matches a sequence of 1 or more
matches of the atom. An atom followed by <SAMP>`?'</SAMP> matches a match of
the atom, or the null string.
<P>
An atom is a regular expression in parentheses (matching a match for the
regular expression), a range (see below), <SAMP>`.'</SAMP> (matching any single
character), <SAMP>`^'</SAMP> (matching the null string at the beginning of the
input string), <SAMP>`$'</SAMP> (matching the null string at the end of the
input string), a <SAMP>`\'</SAMP> followed by a single character (matching that
character), or a single character with no other significance (matching
that character).
<P>
A range is a sequence of characters enclosed in <SAMP>`[]'</SAMP>. It normally
matches any single character from the sequence. If the sequence begins
with <SAMP>`^'</SAMP>, it matches any single character not from the rest of the
sequence. If two characters in the sequence are separated by <SAMP>`-'</SAMP>,
this is shorthand for the full list of ASCII characters between them
(e.g. <CODE>[0-9]</CODE> matches any decimal digit). To include a literal
<SAMP>`]'</SAMP> in the sequence, make it the first character (following a
possible <SAMP>`^'</SAMP>). To include a literal <SAMP>`-'</SAMP>, make it the first or
last character.
</BLOCKQUOTE>
<P>
The substitutions are the text in <VAR>string</VAR> which matches the
parenthesized subexpressions in <VAR>regexp</VAR>. The first substitution is
the text in <VAR>string</VAR> which matches the whole regexp. Thus, a
regular expression can contain no more than nine parenthesized
subexpressions. Substitutions are returned as two-element lists
<CODE>[<VAR>start</VAR>, <VAR>len</VAR>]</CODE> giving the index of the matching text in
<VAR>string</VAR> and the length of the text. When the substitutions are
ambiguous, leftmost <SAMP>`*'</SAMP> matches are always as long as possible.
<P>
If <VAR>regexp</VAR> is not a valid regular expression, <CODE>match_regexp()</CODE>
throws a <CODE>~regexp</CODE> error.
<P>
Examples:
<P>
<PRE>
match_regexp("bar", "fooBAR")
=> [[4, 3], [0, 0], [0, 0], [0, 0], [0, 0],
[0, 0], [0, 0], [0, 0], [0, 0], [0, 0]]
match_regexp("^([^ ]+) says, \"(.*)\"$", "Greg says, \"Hello.\"")
=> [[1, 19], [1, 4], [13, 6], [0, 0], [0, 0],
[0, 0], [0, 0], [0, 0], [0, 0], [0, 0]]
match_regexp("[0-9]+", " 300 100 200 ")
=> [[2, 3], [0, 0], [0, 0], [0, 0], [0, 0],
[0, 0], [0, 0], [0, 0], [0, 0], [0, 0]]
match_regexp("foo", "bar")
=> 0
match_regexp("foo", "Foo", 1)
=> 0
</PRE>
<P>
<A NAME="IDX207"></A>
<H3><A NAME="SEC54" HREF="coldmud_toc.html#SEC54">match_template</A></H3>
<P>
<PRE>
match_template(<VAR>template</VAR>, <VAR>string</VAR>)
</PRE>
<P>
This function matches the template <VAR>template</VAR> against the command
<VAR>string</VAR>. The return value of <CODE>match_template()</CODE> is a list of
fields resulting from the template match, or <CODE>0</CODE> if the match fails
or if <VAR>template</VAR> is an invalid template.
<P>
A <EM>template</EM> is a sequence of word-patterns and wildcards separated
by spaces, with wildcards never occurring more than one at a time. A
<EM>word-pattern</EM> is a sequence of words separated by pipe characters
(<SAMP>`|'</SAMP>). A word is a sequence of alphanumeric characters, with an
optional question mark (<SAMP>`?'</SAMP>) indicating the beginning of an allowed
partial match. A <EM>wildcard</EM> is either a simple wildcard,
represented by an asterix (<SAMP>`*'</SAMP>) or a <EM>coupled wildcard</EM>,
represented by the three-character sequence <SAMP>`*=*'</SAMP>.
<P>
That definition of a template is confusing, so we will now go back and
explain each component of a template in more detail.
<P>
A <EM>word-pattern</EM> is a list of words separated by pipe characters.
A word-pattern matches any of the words contained in it. The
word-pattern <CODE>"look|examine"</CODE> matches either of the words
<CODE>"look"</CODE> or <CODE>"examine"</CODE>. The word separator for template
matching is always a space.
<P>
A word can include a question mark (<SAMP>`?'</SAMP>) to indicate that partial
matches that extend at least as far as the question mark are okay. The
word pattern <CODE>"look|ex?amine"</CODE> matches any of the words
<CODE>"look"</CODE>, <CODE>"ex"</CODE>, <CODE>"exa"</CODE>, <CODE>"exam"</CODE>, <CODE>"exami"</CODE>,
<CODE>"examin"</CODE>, and <CODE>"examine"</CODE>.
<P>
When a word-pattern successfully matches a word in <VAR>string</VAR>, it
results in a <EM>field</EM>, or string in the returned list. This field
contains the word which matched the word-pattern.
<P>
A <EM>simple wildcard</EM> is represented by an asterix (<SAMP>`*'</SAMP>). A
simple wildcard matches any number of words in <EM>string</EM>. If the
wildcard is followed by a word-pattern in <EM>template</EM>, then it can
also match a <EM>quoted wildcard match</EM>.
<P>
A quoted wildcard match is just like a <CODE>C--</CODE> string literal: it
begins and ends with a double quote (<SAMP>`"'</SAMP>), and can include a
literal double quote or backslash by preceding the character with a
backslash (<SAMP>`\'</SAMP>). If the simple wildcard is followed by a
word-pattern, and the words in <VAR>string</VAR> that the wildcard would
match begin with a double quote, then the match must be a quoted
wildcard match or the match fails, even if the match would have
succeeded if the words were not treated as a quoted wildcard match.
However, if the words that the wildcard would match begin with a
backslash followed by a double quote, then the backslash is ignored and
the double quote and the text following it are treated as regular words.
<P>
The template <CODE>"* bar"</CODE> matches any of the following strings:
<P>
<PRE>
foo bar
foo baz bar
"foo bar \\ \" baz" bar
\"foo baz bar
</PRE>
<P>
Matching against a simple wildcard produces one field, the words that
the simple wildcard matched. If the wildcard matches a quoted wildcard
match, then the beginning and ending double quotes are stripped out of
the resulting field, as well as any backslashes used to escape
characters inside the double quotes.
<P>
A <EM>coupled wildcard</EM> is represented by the three-character sequence
<SAMP>`*=*'</SAMP>. It matches any sequence of words containing an equal sign
(<SAMP>`='</SAMP>), and results in two fields, the text before the equal sign
and the text after it. Any spaces surrounding the equal sign are
ignored and do not show up in the resulting fields. The text before the
equal sign can be a quoted wildcard match (as before, if it begins with
a double quote, then it must be a quoted wildcard match or the match
fails, unless the initial double quote is escaped by a backslash). If
the coupled wildcard is followed by a word pattern, then the text after
the equal sign can also be a quoted wildcard match.
<P>
The coupled wildcard is a special feature intended for parsing
TinyMUD command formats. If possible, its use should be avoided.
<P>
If <VAR>template</VAR> is invalid, then the match usually fails, although
this is not guaranteed.
<P>
Examples:
<P>
<PRE>
match_template("@desc?ribe * as *", "@descr me as foobar")
=> ["@descr", "me", "as", "foobar"]
match_template("@desc?ribe * as *", "@desc \"as is\" as foobar")
=> ["@desc", "as is", "as", "foobar"]
match_template("@desc?ribe * as *", "@desc \"as\" is as foobar")
=> 0
match_template("@desc?ribe * as *", "@desc \\\"as\" is as foobar")
=> ["@desc", "\"as\" is", "as", "foobar"]
match_template("@desc?ribe *=*", "@descr me =foobar")
=> ["@descr", "me", "foobar"]
match_template("@desc?ribe *=*", "@desc \"2+2=4\"= an equation")
=> ["@desc", "2+2=4", "an equation"]
match_template("l?ook|ex?amine *", "look at rose")
=> ["look", "at rose"]
</PRE>
<P>
<A NAME="IDX208"></A>
<H3><A NAME="SEC55" HREF="coldmud_toc.html#SEC55">pad</A></H3>
<P>
<PRE>
pad(<VAR>string</VAR>, <VAR>length</VAR>)
pad(<VAR>string</VAR>, <VAR>length</VAR>, <VAR>filler</VAR>)
</PRE>
<P>
This function pads or truncates <VAR>string</VAR> to the length <VAR>length</VAR>.
If <VAR>filler</VAR> is specified, then it must be a single-character string
to use as the filler character; otherwise, a space is used. If
<VAR>length</VAR> is greater than the length of <VAR>string</VAR>, then <VAR>pad</VAR>
adds filler characters on the right; however, you can force <VAR>pad</VAR> to
add filler on the left by specifying <VAR>length</VAR> as a negative number.
<P>
Examples:
<P>
<PRE>
pad("foo", 6)
=> "foo "
pad("foobar", 3)
=> "foo"
pad(tostr(29), -4, "0")
=> "0029"
</PRE>
<P>
<A NAME="IDX209"></A>
<H3><A NAME="SEC56" HREF="coldmud_toc.html#SEC56">strcmp</A></H3>
<P>
<PRE>
strcmp(<VAR>string1</VAR>, <VAR>string2</VAR>)
</PRE>
<P>
This function compares <VAR>string1</VAR> against <VAR>string2</VAR> and returns
zero if they are equal, greater than zero if <VAR>string1</VAR> is lexically
greater than <VAR>string2</VAR>, and less than zero if <VAR>string1</VAR> is
lexically less than <VAR>string2</VAR>. The comparison performed by
<CODE>strcmp()</CODE> is case-sensitive.
<P>
<PRE>
strcmp("Foo", "bar")
=> -28
strcmp("cashmir", "cashmiR")
=> 32
strcmp("foo", "foo")
=> 0
</PRE>
<P>
<A NAME="IDX210"></A>
<H3><A NAME="SEC57" HREF="coldmud_toc.html#SEC57">strlen</A></H3>
<P>
<PRE>
strlen(<VAR>string</VAR>)
</PRE>
<P>
This function returns the length of <VAR>string</VAR>.
<P>
Examples:
<P>
<PRE>
length("foo")
=> 3
</PRE>
<P>
<A NAME="IDX211"></A>
<H3><A NAME="SEC58" HREF="coldmud_toc.html#SEC58">strsub</A></H3>
<P>
<PRE>
strsub(<VAR>string</VAR>, <VAR>search</VAR>, <VAR>replace</VAR>)
</PRE>
<P>
This function returns the result of replacing each occurrence of the
string <VAR>search</VAR> in <VAR>string</VAR> with the string <VAR>replace</VAR>.
<P>
Examples:
<P>
<PRE>
strsub("foobar", "bar", "baz")
=> "foobaz"
</PRE>
<P>
<A NAME="IDX212"></A>
<H3><A NAME="SEC59" HREF="coldmud_toc.html#SEC59">substr</A></H3>
<P>
<PRE>
substr(<VAR>string</VAR>, <VAR>start</VAR>)
substr(<VAR>string</VAR>, <VAR>start</VAR>, <VAR>length</VAR>)
</PRE>
<P>
This function returns a substring of <VAR>string</VAR> beginning at the
character numbered by <VAR>start</VAR>. If <VAR>length</VAR> is specified, then
the substring has that length; otherwise, the length is given by
<CODE>(length(<VAR>string</VAR>) - (<VAR>start</VAR> - 1))</CODE>. If <VAR>start</VAR> is
less than <CODE>1</CODE>, if the length of the substring is negative, or if
the sum of <VAR>start</VAR> and <VAR>length</VAR> is greater than one more than
the length of the string, then <CODE>substr()</CODE> throws a <CODE>~range</CODE>
error.
<P>
Examples:
<P>
<PRE>
substr("foobar", 2, 3)
=> "oob"
substr("foobar", 3)
=> "obar"
substr("foobar", 7)
=> ""
</PRE>
<P>
<A NAME="IDX213"></A>
<H3><A NAME="SEC60" HREF="coldmud_toc.html#SEC60">uppercase</A></H3>
<P>
<PRE>
uppercase(<VAR>string</VAR>)
</PRE>
<P>
This function returns the result of changing each lowercase character in
<VAR>string</VAR> to uppercase.
<P>
<PRE>
uppercase("fOOBAr 23")
=> "FOOBAR 23"
</PRE>
<P>
<A NAME="IDX214"></A>
<A NAME="IDX215"></A>
<A NAME="IDX216"></A>
<H2><A NAME="SEC61" HREF="coldmud_toc.html#SEC61">List Functions</A></H2>
<P>
The functions described in this section allow you to perform operations
on list. None of these functions actually modify the lists passed as
arguments; instead, they return modified lists.
<P>
<A NAME="IDX217"></A>
<H3><A NAME="SEC62" HREF="coldmud_toc.html#SEC62">delete</A></H3>
<P>
<PRE>
delete(<VAR>list</VAR>, <VAR>position</VAR>)
</PRE>
<P>
This function returns the result of deleting the element of <VAR>list</VAR>
numbered by the integer <VAR>position</VAR>. If <VAR>position</VAR> is less than
<CODE>1</CODE> or is greater than the length of <VAR>list</VAR>, then
<CODE>delete()</CODE> throws a <CODE>~range</CODE> error.
<P>
Examples:
<P>
<PRE>
delete([2, 3, 4], 2)
=> [2, 4]
</PRE>
<P>
<A NAME="IDX218"></A>
<H3><A NAME="SEC63" HREF="coldmud_toc.html#SEC63">insert</A></H3>
<P>
<PRE>
insert(<VAR>list</VAR>, <VAR>position</VAR>, <VAR>data</VAR>)
</PRE>
<P>
This function returns the result of inserting <VAR>data</VAR> into <VAR>list</VAR>
before the element numbered by the integer <VAR>position</VAR>. If
<VAR>position</VAR> is less than one or is more than one more than the length
of <VAR>list</VAR>, then <CODE>insert()</CODE> throws a <CODE>~range</CODE> error.
<P>
Examples:
<P>
<PRE>
insert([2, 3, 4], 3, 'foo)
=> [2, 3, 'foo, 4]
insert(["foo", 'bar, ~none], 4, 'baz)
=> ["foo", 'bar, ~none, 'baz]
</PRE>
<P>
<A NAME="IDX219"></A>
<H3><A NAME="SEC64" HREF="coldmud_toc.html#SEC64">listlen</A></H3>
<P>
<PRE>
listlen(<VAR>list</VAR>)
</PRE>
<P>
This function returns the length of <VAR>list</VAR>.
<P>
Examples:
<P>
<PRE>
length([2, "foo", 'bar])
=> 3
</PRE>
<P>
<A NAME="IDX220"></A>
<H3><A NAME="SEC65" HREF="coldmud_toc.html#SEC65">replace</A></H3>
<P>
<PRE>
replace(<VAR>list</VAR>, <VAR>position</VAR>, <VAR>data</VAR>)
</PRE>
<P>
This function returns the result of replacing the element of <VAR>list</VAR>
numbered by <VAR>position</VAR> with <VAR>data</VAR>. If <VAR>position</VAR> is less
than one or is greater than the length of <VAR>list</VAR>, then
<CODE>replace()</CODE> throws a <CODE>~range</CODE> error.
<P>
Examples:
<P>
<PRE>
replace([2, 3, 4], 2, 'foo)
=> [2, 'foo, 4]
</PRE>
<P>
<A NAME="IDX221"></A>
<H3><A NAME="SEC66" HREF="coldmud_toc.html#SEC66">setadd</A></H3>
<P>
<PRE>
setadd(<VAR>list</VAR>, <VAR>data</VAR>)
</PRE>
<P>
This function returns the result of adding <VAR>data</VAR> to the end of
<VAR>list</VAR> if it was not already somewhere in <VAR>list</VAR>. If <VAR>data</VAR>
was already in <VAR>list</VAR>, then <CODE>setadd()</CODE> returns <VAR>list</VAR>
unmodified.
<P>
Examples:
<P>
<PRE>
setadd([2, 3, 4], 'foo)
=> [2, 3, 4, 'foo]
setadd([2, 3, 4], 3)
=> [2, 3, 4]
</PRE>
<P>
<A NAME="IDX222"></A>
<H3><A NAME="SEC67" HREF="coldmud_toc.html#SEC67">setremove</A></H3>
<P>
<PRE>
setremove(<VAR>list</VAR>, <VAR>data</VAR>)
</PRE>
<P>
This function returns the result of removing the first occurrence of
<VAR>data</VAR> from <VAR>list</VAR> if <VAR>data</VAR> exists in <VAR>list</VAR>. If
<VAR>data</VAR> does not exist in <VAR>list</VAR>, then <CODE>setremove()</CODE> returns
<VAR>list</VAR> unmodified.
<P>
Examples:
<P>
<PRE>
setremove([2, 3, 4, 'foo], 'foo)
=> [2, 3, 4]
setremove([2, 3, 4], 5)
=> [2, 3, 4]
setremove([2, 3, 2, 4], 2)
=> [3, 2, 4]
</PRE>
<P>
<A NAME="IDX223"></A>
<H3><A NAME="SEC68" HREF="coldmud_toc.html#SEC68">sublist</A></H3>
<P>
<PRE>
sublist(<VAR>list</VAR>, <VAR>start</VAR>)
sublist(<VAR>list</VAR>, <VAR>start</VAR>, <VAR>length</VAR>)
</PRE>
<P>
This function returns a sublist of <VAR>list</VAR> beginning at the element
numbered by <VAR>start</VAR>. If <VAR>length</VAR> is specified, then the sublist
has that length; otherwise, the length is given by
<CODE>(length(<VAR>list</VAR>) - (<VAR>start</VAR> - 1))</CODE>. If <VAR>start</VAR> is less
than <CODE>1</CODE>, if the length of the sublist is negative, or if the sum
of <VAR>start</VAR> and <VAR>length</VAR> is greater than one more than the length
of the list, then <CODE>sublist()</CODE> throws a <CODE>~range</CODE> error.
<P>
Examples:
<P>
<PRE>
sublist([2, 3, 4, 5, 6, 7], 2, 3)
=> [3, 4, 5]
sublist([2, 3, 4, 5, 6, 7], 3)
=> [4, 5, 6, 7]
sublist([2, 3, 4, 5, 6, 7], 7)
=> []
</PRE>
<P>
<A NAME="IDX224"></A>
<H3><A NAME="SEC69" HREF="coldmud_toc.html#SEC69">union</A></H3>
<P>
<PRE>
union(<VAR>list1</VAR>, <VAR>list2</VAR>)
</PRE>
<P>
This function returns the result of adding each element of <VAR>list2</VAR>
which does not already exist in <VAR>list1</VAR> to the elements of
<VAR>list1</VAR>. Elements which exist in <VAR>list2</VAR> more than once will
only be added once, but duplicate elements in <VAR>list1</VAR> will remain.
<P>
<PRE>
union([2, 3, 4], [4, 5, 4, 6])
=> [2, 3, 4, 5, 6]
union([2, 2, 4, 5], [4, 5, 6, 6, 7])
=> [2, 2, 4, 5, 6, 7])
</PRE>
<P>
<A NAME="IDX225"></A>
<A NAME="IDX226"></A>
<H2><A NAME="SEC70" HREF="coldmud_toc.html#SEC70">Dictionary Functions</A></H2>
<P>
The functions described in this section perform operations on
dictionaries. These options do not actually modify the dictionaries
they accept as arguments; instead, they return the modified dictionaries
as their return values.
<P>
<A NAME="IDX227"></A>
<H3><A NAME="SEC71" HREF="coldmud_toc.html#SEC71">dict_add</A></H3>
<P>
<PRE>
dict_add(<VAR>dictionary</VAR>, <VAR>key</VAR>, <VAR>value</VAR>)
</PRE>
<P>
This function returns the result of adding the association
<CODE>[<VAR>key</VAR>, <VAR>value</VAR>]</CODE> to the dictionary <VAR>dictionary</VAR>. If
<VAR>key</VAR> already exists in <VAR>dictionary</VAR>, then <CODE>dict_add()</CODE>
replaces the value of that key with <VAR>value</VAR>.
<P>
Examples:
<P>
<PRE>
dict_add(#[["foo", "bar"]], 3, 'quux)
=> #[["foo", "bar"], [3, 'quux]]
dict_add(#[["foo", 1], ["bar", 2], ["baz", 3]], "bar", 4)
=> #[["foo", 1], ["bar", 4], ["baz", 3]]
</PRE>
<P>
<A NAME="IDX228"></A>
<H3><A NAME="SEC72" HREF="coldmud_toc.html#SEC72">dict_add_elem</A></H3>
<P>
<PRE>
dict_add_elem(<VAR>dictionary</VAR>, <VAR>key</VAR>, <VAR>element</VAR>)
</PRE>
<P>
This function returns the result of adding <VAR>element</VAR> to the list
value <VAR>key</VAR> in <VAR>dictionary</VAR>. If <VAR>dictionary</VAR> has no
association with key <VAR>key</VAR>, then <CODE>dict_add_elem()</CODE> adds an
association <CODE>[<VAR>key</VAR>, [<VAR>element</VAR>]]</CODE> to <VAR>dictionary</VAR>. If
<VAR>dictionary</VAR> has an association with key <VAR>key</VAR>, and the value
part of the association is a list, then <CODE>dict_add_elem()</CODE> adds
<VAR>element</VAR> to the end of that list. If <VAR>dictionary</VAR> has an
association with key <VAR>key</VAR>, but the value part of the association is
not a list, then <CODE>dict_add_elem()</CODE> throws a <CODE>~type</CODE> error.
<P>
Examples:
<P>
<PRE>
dict_add_elem(#[["foo", ["bar"]]], "foo", "baz")
=> #[["foo", ["bar", "baz"]]]
dict_add_elem(#[], "foo", "bar")
=> #[["foo", ["bar"]]]
</PRE>
<P>
<A NAME="IDX229"></A>
<H3><A NAME="SEC73" HREF="coldmud_toc.html#SEC73">dict_contains</A></H3>
<P>
<PRE>
dict_contains(<VAR>dictionary</VAR>, <VAR>key</VAR>)
</PRE>
<P>
This function returns 1 if there is an association in <VAR>dictionary</VAR>
with the key <VAR>key</VAR>, or 0 otherwise.
<P>
Examples:
<P>
<PRE>
dict_contains(#[["foo", "bar"]], "foo")
=> 1
dict_contains(#[["foo", "bar"]], "bar")
=> 0
</PRE>
<P>
<A NAME="IDX230"></A>
<H3><A NAME="SEC74" HREF="coldmud_toc.html#SEC74">dict_del</A></H3>
<P>
<PRE>
dict_del(<VAR>dictionary</VAR>, <VAR>key</VAR>)
</PRE>
<P>
This function returns the result of removing the association in
<VAR>dictionary</VAR> which has the key <VAR>key</VAR>. If there is no such
association, then <CODE>dict_del()</CODE> raises a <CODE>~keynf</CODE> exception.
<P>
<PRE>
dict_del(#[["foo", 1], ["bar", 2]], "foo")
=> #[["bar", 2]]
</PRE>
<P>
<A NAME="IDX231"></A>
<H3><A NAME="SEC75" HREF="coldmud_toc.html#SEC75">dict_del_elem</A></H3>
<P>
<PRE>
dict_del_elem(<VAR>dictionary</VAR>, <VAR>key</VAR>, <VAR>element</VAR>)
</PRE>
<P>
This function returns the result of removing <VAR>element</VAR> from the list
value of <VAR>key</VAR> in <VAR>dictionary</VAR>. If <VAR>dictionary</VAR> contains no
association with key <VAR>key</VAR>, then <CODE>dict_del_elem()</CODE> throws a
<CODE>~keynf</CODE> error. If <VAR>dictionary</VAR> contains an association with
key <VAR>key</VAR>, and it is not a list, then <CODE>dict_del_elem()</CODE> throws
a <CODE>~type</CODE> error.
<P>
Assuming that <VAR>dictionary</VAR> contains an association with key
<VAR>key</VAR>, and it is a list, <CODE>dict_del_elem()</CODE> removes the first
occurrence of <VAR>element</VAR> in the list if <VAR>element</VAR> occurs in the
list. If the resulting list is an empty list, then
<CODE>dict_del_elem()</CODE> removes the association from <VAR>dictionary</VAR>
altogether. If <VAR>element</VAR> does not occur in the list, then
<CODE>dict_del_elem()</CODE> returns <VAR>dictionary</VAR> unchanged.
<P>
Examples:
<P>
<PRE>
dict_del_elem(#[["foo", ["bar", "baz"]]], "foo", "bar")
=> #[["foo", ["baz"]]]
dict_del_elem(#[["foo", ["baz"]]], "foo", "baz")
=> #[]
</PRE>
<P>
<A NAME="IDX232"></A>
<H3><A NAME="SEC76" HREF="coldmud_toc.html#SEC76">dict_keys</A></H3>
<P>
<PRE>
dict_keys(<VAR>dictionary</VAR>)
</PRE>
<P>
This function returns a list of the keys of the associations in
<VAR>dictionary</VAR>.
<P>
<PRE>
dict_keys(#[["foo", 1"], ["bar", 2], ['baz, 3]])
=> ["foo", "bar", 'baz]
</PRE>
<P>
<A NAME="IDX233"></A>
<A NAME="IDX234"></A>
<H2><A NAME="SEC77" HREF="coldmud_toc.html#SEC77">Buffer Functions</A></H2>
<P>
The functions described in this section apply to buffers. As with
strings and lists, these functions will not actually modify any buffers
passed as arguments, but will instead return the results of performing
modifications on the buffers.
<P>
<A NAME="IDX235"></A>
<H3><A NAME="SEC78" HREF="coldmud_toc.html#SEC78">buffer_add</A></H3>
<P>
<PRE>
buffer_add(<VAR>buffer</VAR>, <VAR>byte</VAR>)
</PRE>
<P>
This function returns the result of adding <VAR>byte</VAR>, an integer, to
the end of <VAR>buffer</VAR>. If <VAR>byte</VAR> is not between <CODE>0</CODE> and
<CODE>255</CODE>, the value appended to <VAR>buffer</VAR> will be the lower-order
eight bits of <VAR>byte</VAR>.
<P>
Examples:
<P>
<PRE>
buffer_add(%[65, 66, 67], 10)
=> %[65, 66, 67, 10]
</PRE>
<P>
<A NAME="IDX236"></A>
<H3><A NAME="SEC79" HREF="coldmud_toc.html#SEC79">buffer_append</A></H3>
<P>
<PRE>
buffer_append(<VAR>buffer1</VAR>, <VAR>buffer2</VAR>)
</PRE>
<P>
This function returns the result of appending <VAR>buffer2</VAR> to the end
of <VAR>buffer1</VAR>.
<P>
Examples:
<P>
<PRE>
buffer_append(%[65, 66, 67, 10], %[67, 66, 65, 10])
=> %[65, 66, 67, 10, 67, 66, 65, 10]
</PRE>
<P>
<A NAME="IDX237"></A>
<H3><A NAME="SEC80" HREF="coldmud_toc.html#SEC80">buffer_from_strings</A></H3>
<P>
<PRE>
buffer_from_strings(<VAR>list-of-strings</VAR>, [<VAR>terminator</VAR>])
</PRE>
<P>
This function returns a buffer constructed by appending the strings in
<VAR>list-of-strings</VAR> together, treating the strings as sequences of
ASCII values, with each string followed by <VAR>terminator</VAR>, a buffer.
If <VAR>terminator</VAR> is not specified, then <CODE>buffer_from_strings()</CODE>
uses the buffer <CODE>%[13, 10]</CODE>, a two-byte buffer containing the ASCII
codes for a carriage return and a newline.
<P>
Examples:
<P>
<PRE>
buffer_from_strings(["foo", "bar"])
=> <CODE>%[102, 111, 111, 13, 10, 98, 97, 4, 13, 10]</CODE>
buffer_from_strings(["foo", "bar"], %[10])
=> <CODE>%[102, 111, 111, 10, 98, 97, 4, 10]</CODE>
</PRE>
<P>
<A NAME="IDX238"></A>
<H3><A NAME="SEC81" HREF="coldmud_toc.html#SEC81">buffer_len</A></H3>
<P>
<PRE>
buffer_len(<VAR>buffer</VAR>)
</PRE>
<P>
This function returns the length of the buffer <VAR>buffer</VAR>.
<P>
Examples:
<P>
<PRE>
buffer_len(%[65, 66, 67, 10])
=> 4
</PRE>
<P>
<A NAME="IDX239"></A>
<H3><A NAME="SEC82" HREF="coldmud_toc.html#SEC82">buffer_replace</A></H3>
<P>
<PRE>
buffer_replace(<VAR>buffer</VAR>, <VAR>pos</VAR>, <VAR>value</VAR>)
</PRE>
<P>
This function returns the result of replacing the byte numbered
<VAR>pos</VAR> in <VAR>buffer</VAR> with the value <VAR>value</VAR>, with the first
byte of <VAR>buffer</VAR> is numbered <CODE>1</CODE>. If <VAR>pos</VAR> is less than
<CODE>1</CODE>, or greater than the length of <VAR>buffer</VAR>, then
<CODE>buffer_replace()</CODE> throws a <CODE>~range</CODE> error.
<P>
Examples:
<P>
<PRE>
buffer_replace(%[65, 66, 67, 10], 3, 15)
=> %[65, 66, 15, 10]
</PRE>
<P>
<A NAME="IDX240"></A>
<H3><A NAME="SEC83" HREF="coldmud_toc.html#SEC83">buffer_retrieve</A></H3>
<P>
<PRE>
buffer_retrieve(<VAR>buffer</VAR>, <VAR>pos</VAR>)
</PRE>
<P>
This function returns the byte numbered <VAR>pos</VAR> in <VAR>buffer</VAR>, with
the first byte of <VAR>buffer</VAR> is numbered <CODE>1</CODE>. If <VAR>pos</VAR> is
less than <CODE>1</CODE>, or greater than the length of <VAR>buffer</VAR>, then
<CODE>buffer_replace()</CODE> throws a <CODE>~range</CODE> error.
<P>
Examples:
<P>
<PRE>
buffer_retrieve(%[65, 66, 67, 10], 3)
=> 67
</PRE>
<P>
<A NAME="IDX241"></A>
<H3><A NAME="SEC84" HREF="coldmud_toc.html#SEC84">buffer_to_strings</A></H3>
<P>
<PRE>
buffer_to_strings(<VAR>buffer</VAR>, [<VAR>separator</VAR>])
</PRE>
<P>
This function returns a list of strings constructed from <VAR>buffer</VAR> by
splitting it around the bytes given by the buffer <VAR>separator</VAR>. If
<VAR>separator</VAR> is not specified, <CODE>buffer_to_strings()</CODE> uses the
buffer <CODE>%[10]</CODE>, a single-byte buffer containing the ASCII code for
a newline. <CODE>buffer_to_strings()</CODE> treats the bytes in <VAR>buffer</VAR>
not accounted for by the separator as ASCII values; unprintable ASCII
values are stripped. The last element of the returned list is a buffer
containing the bytes in the buffer after the last separator found; no
string is included in the returned list for these bytes.
<P>
Examples:
<P>
<PRE>
buffer_to_strings(%[65, 66, 67, 13, 10, 67, 66, 65, 13, 10, 66])
=> ["ABC", "CBA", %[66]]
buffer_to_strings(%[66, 10, 10, 65, 10])
=> ["B", "", "A", %[]]
buffer_to_strings(%[65, 66, 67, 13, 10, 67, 66, 65, 10, 66], %[66])
=> ["A", "CC", "A", %[]]
</PRE>
<P>
<A NAME="IDX242"></A>
<H3><A NAME="SEC85" HREF="coldmud_toc.html#SEC85">buffer_truncate</A></H3>
<P>
<PRE>
buffer_truncate(<VAR>buffer</VAR>, <VAR>length</VAR>)
</PRE>
<P>
This function returns the result of truncating <VAR>buffer</VAR> to the
length <VAR>length</VAR>. If <VAR>length</VAR> is less than <CODE>0</CODE> or greater
than the length of <VAR>buffer</VAR>, then <CODE>buffer_truncate()</CODE> throws a
<CODE>~range</CODE> error.
<P>
Examples:
<P>
<PRE>
buffer_truncate(%[65, 66, 67, 10], 2)
=> %[65, 66]
</PRE>
<P>
<A NAME="IDX243"></A>
<A NAME="IDX244"></A>
<A NAME="IDX245"></A>
<A NAME="IDX246"></A>
<H2><A NAME="SEC86" HREF="coldmud_toc.html#SEC86">Method Functions</A></H2>
<P>
The functions described in this section return information about the
objects involved in the call to the current method: the caller, the
definer, the sender, and the current object. If a method defined by
object A, processing a message for object B, sends a message to object
C, which results in a call to a method defined by object D, then A is
the caller, B is the sender, C is the current object, and D is the
definer.
<P>
<A NAME="IDX247"></A>
<H3><A NAME="SEC87" HREF="coldmud_toc.html#SEC87">caller</A></H3>
<P>
<PRE>
caller()
</PRE>
<P>
This function returns the dbref of the object which defines the method
which called the current method, or <CODE>0</CODE> if the current method was
called by the server.
<P>
<A NAME="IDX248"></A>
<H3><A NAME="SEC88" HREF="coldmud_toc.html#SEC88">definer</A></H3>
<P>
<PRE>
definer()
</PRE>
<P>
This function returns the dbref of the object which defines the current
method.
<P>
<A NAME="IDX249"></A>
<H3><A NAME="SEC89" HREF="coldmud_toc.html#SEC89">sender</A></H3>
<P>
<PRE>
sender()
</PRE>
<P>
This function returns the dbref of the object which sent the current
message, or <CODE>0</CODE> if the current method was called by the server.
<P>
<A NAME="IDX250"></A>
<H3><A NAME="SEC90" HREF="coldmud_toc.html#SEC90">task_id</A></H3>
<P>
<PRE>
task_id()
</PRE>
<P>
This function returns the ID of the current task. The task ID is an
integer which begins at <CODE>0</CODE> for the first task and increases by
<CODE>1</CODE> each time a task runs.
<P>
<A NAME="IDX251"></A>
<H3><A NAME="SEC91" HREF="coldmud_toc.html#SEC91">this</A></H3>
<P>
<PRE>
this()
</PRE>
<P>
This function returns the dbref of the current object.
<P>
<A NAME="IDX252"></A>
<A NAME="IDX253"></A>
<A NAME="IDX254"></A>
<A NAME="IDX255"></A>
<H2><A NAME="SEC92" HREF="coldmud_toc.html#SEC92">Error Functions</A></H2>
<P>
The functions described in this section perform operations related to
handling error conditions.
<P>
<A NAME="IDX256"></A>
<H3><A NAME="SEC93" HREF="coldmud_toc.html#SEC93">error</A></H3>
<P>
<PRE>
error()
</PRE>
<P>
This function, which you should only call inside an error handler for a
catch statement (see section <A HREF="coldmud.html#SEC16">Error-Handling Statements</A>), returns the error
code for the error which triggered the error handler. If you are not in
an error handler, this function throws an <CODE>~error</CODE> error.
<P>
<A NAME="IDX257"></A>
<H3><A NAME="SEC94" HREF="coldmud_toc.html#SEC94">error_arg</A></H3>
<P>
<PRE>
error_arg()
</PRE>
<P>
This function, which you should only call inside an error handler for a
catch statement (see section <A HREF="coldmud.html#SEC16">Error-Handling Statements</A>), returns the error
argument specified in the <CODE>throw()</CODE> call which caused the error
which triggered the error handler, or <CODE>0</CODE> if the no error argument
was specified in the <CODE>throw()</CODE> caller or if the error was thrown by
the interpreter. If you are not in an error handler, this function
throws an <CODE>~error</CODE> error.
<P>
<A NAME="IDX258"></A>
<H3><A NAME="SEC95" HREF="coldmud_toc.html#SEC95">error_str</A></H3>
<P>
<PRE>
error_str()
</PRE>
<P>
This function, which you should only call inside an error handler for a
catch statement (see section <A HREF="coldmud.html#SEC16">Error-Handling Statements</A>), returns the string
argument specified in the <CODE>throw()</CODE> call which caused the error
which triggered the error handler, or the interpreter's explanation of
the error if the error was thrown by the interpreter. If you are not in
an error handler, this function throws an <CODE>~error</CODE> error.
<P>
<A NAME="IDX259"></A>
<H3><A NAME="SEC96" HREF="coldmud_toc.html#SEC96">rethrow</A></H3>
<P>
<PRE>
rethrow(<VAR>error-code</VAR>)
</PRE>
<P>
This function, which you should only call inside an error handler for a
catch statement (see section <A HREF="coldmud.html#SEC16">Error-Handling Statements</A>), continues
propagating an error condition. The interpreter will abort the current
method and throw an error of type <VAR>error-code</VAR> in the calling
method. If you are not in an error handler, this function throws an
<CODE>~error</CODE> error.
<P>
Examples:
<P>
<PRE>
rethrow(~perm);
</PRE>
<P>
<A NAME="IDX260"></A>
<H3><A NAME="SEC97" HREF="coldmud_toc.html#SEC97">throw</A></H3>
<P>
<PRE>
throw(<VAR>error-code</VAR>, <VAR>explanation</VAR>, [<VAR>arg</VAR>])
</PRE>
<P>
This function throws an error in the method which called the current
method. The interpreter will abort the current method and throw an
error of type <VAR>error-code</VAR> in the calling method. The string
<VAR>explanation</VAR> will appear in the traceback. If <VAR>arg</VAR> is
specified, then it can be retrieved in an error handler by
<CODE>error_arg()</CODE>.
<P>
Examples:
<P>
<PRE>
throw(~perm, "Sender is not the system object.");
</PRE>
<P>
<A NAME="IDX261"></A>
<H3><A NAME="SEC98" HREF="coldmud_toc.html#SEC98">traceback</A></H3>
<P>
<PRE>
traceback()
</PRE>
<P>
This function, which you should only call inside an eror handler for a
catch statement (see section <A HREF="coldmud.html#SEC16">Error-Handling Statements</A>), returns the
traceback for the error which triggered the error handler. If you are
not in an error handler, this function throws an <CODE>~error</CODE>
error.
<P>
<A NAME="IDX262"></A>
<A NAME="IDX263"></A>
<A NAME="IDX264"></A>
<A NAME="IDX265"></A>
<A NAME="IDX266"></A>
<A NAME="IDX267"></A>
<A NAME="IDX268"></A>
<H2><A NAME="SEC99" HREF="coldmud_toc.html#SEC99">Communication Functions</A></H2>
<P>
The functions described in this section allow you to perform input
and output to connections. All of these functions apply to all
connections associated with the current object; you can never refer
to a particular connection directly using these functions.
<P>
<A NAME="IDX269"></A>
<H3><A NAME="SEC100" HREF="coldmud_toc.html#SEC100">disconnect</A></H3>
<P>
<PRE>
disconnect()
</PRE>
<P>
This function closes all connections associated with the current object,
and returns the number of connections closed.
<P>
<A NAME="IDX270"></A>
<H3><A NAME="SEC101" HREF="coldmud_toc.html#SEC101">echo</A></H3>
<P>
<PRE>
echo(<VAR>buffer</VAR>)
</PRE>
<P>
This function sends the bytes in <VAR>buffer</VAR> to all connections
associated with the current object, and returns <CODE>1</CODE>.
<P>
Examples:
<P>
<PRE>
echo(%[65, 66, 67, 13, 10])
=> 1
</PRE>
<P>
<A NAME="IDX271"></A>
<H3><A NAME="SEC102" HREF="coldmud_toc.html#SEC102">echo_file</A></H3>
<P>
<PRE>
echo_file(<VAR>name</VAR>)
</PRE>
<P>
This function sends the contents of the file named by the string
<VAR>name</VAR> to all connections associated with the current object. The
filename <VAR>name</VAR> must not contain the sequence <SAMP>`../'</SAMP>.
<CODE>echo_file()</CODE> returns <CODE>1</CODE> if <VAR>name</VAR> exists in the
subdirectory "text" of the current directory; otherwise, the result of
<CODE>echo_file()</CODE> is a <CODE>~file</CODE> error.
<P>
<A NAME="IDX272"></A>
<A NAME="IDX273"></A>
<A NAME="IDX274"></A>
<H2><A NAME="SEC103" HREF="coldmud_toc.html#SEC103">Object Functions</A></H2>
<P>
The functions described in this section allow you to modify or retrieve
information from the current object.
<P>
<A NAME="IDX275"></A>
<H3><A NAME="SEC104" HREF="coldmud_toc.html#SEC104">add_parameter</A></H3>
<P>
<PRE>
add_parameter(<VAR>name</VAR>)
</PRE>
<P>
This function adds a parameter named <VAR>name</VAR> to the current object.
<VAR>name</VAR> must be a symbol. If <VAR>name</VAR> is already a parameter on
the current object, then <CODE>add_parameter</CODE> throws a
<CODE>~paramexists</CODE> error. Otherwise, <CODE>add_parameter()</CODE> returns 1.
<P>
<A NAME="IDX276"></A>
<H3><A NAME="SEC105" HREF="coldmud_toc.html#SEC105">ancestors</A></H3>
<P>
<PRE>
ancestors()
</PRE>
<P>
This function returns a list of the dbrefs of the ancestors of the
current object, in the order that they would normally be searched for
methods. The dbref of the current object will be the first element of
the list.
<P>
<A NAME="IDX277"></A>
<H3><A NAME="SEC106" HREF="coldmud_toc.html#SEC106">children</A></H3>
<P>
<PRE>
children()
</PRE>
<P>
This function returns a list of the dbrefs of the children of the
current object, in no particular order.
<P>
<A NAME="IDX278"></A>
<H3><A NAME="SEC107" HREF="coldmud_toc.html#SEC107">compile</A></H3>
<P>
<PRE>
compile(<VAR>code</VAR>, <VAR>name</VAR>)
</PRE>
<P>
This function compiles the list of strings <VAR>code</VAR> and uses the
result as the definition of the method named by the symbol <VAR>name</VAR>.
If there were errors in compiling <VAR>code</VAR>, then <CODE>compile()</CODE>
returns a list of strings describing the errors; otherwise
<CODE>compile()</CODE> returns an empty list.
<P>
Examples:
<P>
<PRE>
compile(["echo(\"foo\");"], 'foo)
=> []
compile(["echo(\"foo\")"], 'foo)
=> ["Line 2: parse error"]
</PRE>
<P>
<A NAME="IDX279"></A>
<H3><A NAME="SEC108" HREF="coldmud_toc.html#SEC108">del_method</A></H3>
<P>
<PRE>
del_method(<VAR>name</VAR>)
</PRE>
<P>
This function removes the method named by the symbol <VAR>name</VAR> from the
current object. <CODE>del_method()</CODE> returns <CODE>1</CODE> if there was a
method named <VAR>name</VAR> on the current object; otherwise, it throws a
<CODE>~methodnf</CODE> error.
<P>
<A NAME="IDX280"></A>
<H3><A NAME="SEC109" HREF="coldmud_toc.html#SEC109">del_parameter</A></H3>
<P>
<PRE>
del_parameter(<VAR>name</VAR>)
</PRE>
<P>
This function removes the parameter named by the symbol <VAR>name</VAR> from
the current object. <CODE>del_parameter()</CODE> returns <CODE>1</CODE> if there
was a parameter named <VAR>name</VAR> on the current object; otherwise, it
throws a <CODE>~paramnf</CODE> error.
<P>
<A NAME="IDX281"></A>
<H3><A NAME="SEC110" HREF="coldmud_toc.html#SEC110">find_method</A></H3>
<P>
<PRE>
find_method(<VAR>name</VAR>)
</PRE>
<P>
This function returns the object which contains the method definition
which would be used if a message <VAR>name</VAR> were sent to the current
object. If none of the ancestors of the current object define a method
<VAR>name</VAR>, then <CODE>find_method()</CODE> throws a <CODE>~methodnf</CODE>
exception.
<P>
<A NAME="IDX282"></A>
<H3><A NAME="SEC111" HREF="coldmud_toc.html#SEC111">find_method</A></H3>
<P>
<PRE>
find_next_method(<VAR>name</VAR>, <VAR>after</VAR>)
</PRE>
<P>
This function returns the ancestor of the current object which contains
the method definition which would be used if a method <VAR>name</VAR> defined
by the object <VAR>after</VAR> executed an inspecific <CODE>pass()</CODE>. If no
method would be found, then <CODE>find_method()</CODE> throws a
<CODE>~methodnf</CODE> exception.
<P>
<A NAME="IDX283"></A>
<H3><A NAME="SEC112" HREF="coldmud_toc.html#SEC112">get_var</A></H3>
<P>
<PRE>
get_var(<VAR>name</VAR>)
</PRE>
<P>
This function returns the value of the object variable on the current
object referred to by the parameter <VAR>name</VAR> (a symbol) on the
current method's defining object. If the current method's defining
object does not have a parameter <VAR>name</VAR>, then <CODE>get_var()</CODE>
throws a <CODE>~paramnf</CODE> error.
<P>
<A NAME="IDX284"></A>
<H3><A NAME="SEC113" HREF="coldmud_toc.html#SEC113">list_method</A></H3>
<P>
<PRE>
list_method(<VAR>name</VAR>)
list_method(<VAR>name</VAR>, <VAR>indentation</VAR>)
list_method(<VAR>name</VAR>, <VAR>indentation</VAR>, <VAR>parenthesization</VAR>)
</PRE>
<P>
This function returns a list of strings containing a decompiled version
of the method named by the symbol <VAR>name</VAR>. If the method <VAR>name</VAR>
is not defined on the current object, then <CODE>list_method()</CODE> results
in a <CODE>~methodnf</CODE> error. Note that <VAR>name</VAR> must be defined on
the current object, not on its ancestors.
<P>
The decompiled code may not look exactly like the code that was compiled
to produce the method. The only guarantee is that it will compile to a
method with the same behavior.
<P>
If you specify the integer <VAR>indentation</VAR>, then the decompiler will
use that number of spaces for indenting. The default is 4 spaces. If
you specify the integer <VAR>parenthesization</VAR> and it is non-zero, then
the decompiler will put parentheses around every subexpression.
Otherwise, the compiler will only use parentheses when needed.
<P>
<A NAME="IDX285"></A>
<H3><A NAME="SEC114" HREF="coldmud_toc.html#SEC114">methods</A></H3>
<P>
<PRE>
methods()
</PRE>
<P>
This function returns a list of symbols giving the names of the methods
defined on the current object.
<P>
<A NAME="IDX286"></A>
<H3><A NAME="SEC115" HREF="coldmud_toc.html#SEC115">parameters</A></H3>
<P>
<PRE>
parameters()
</PRE>
<P>
This function returns a list of symbols giving the names of the
parameters defined on the current object.
<P>
<A NAME="IDX287"></A>
<H3><A NAME="SEC116" HREF="coldmud_toc.html#SEC116">parents</A></H3>
<P>
<PRE>
parents()
</PRE>
<P>
This function returns a list of the dbrefs of the parents of the current
object.
<P>
<A NAME="IDX288"></A>
<H3><A NAME="SEC117" HREF="coldmud_toc.html#SEC117">set_var</A></H3>
<P>
<PRE>
set_var(<VAR>name</VAR>, <VAR>data</VAR>)
</PRE>
<P>
This function assigns the value <VAR>data</VAR> to the object variable on
the current object referred to by the parameter <VAR>name</VAR> (a symbol)
on the current method's defining object. If the current method's
defining object does not have a parameter <VAR>name</VAR>, then
<CODE>get_var()</CODE> throws a <CODE>~paramnf</CODE> error.
<P>
<A NAME="IDX289"></A>
<A NAME="IDX290"></A>
<A NAME="IDX291"></A>
<H2><A NAME="SEC118" HREF="coldmud_toc.html#SEC118">Administrative Functions</A></H2>
<P>
The functions in this section allow you to perform privileged
operations. These functions can only be called from the system object.
For any other object, the result of any of these functions is an
<CODE>~perm</CODE> error.
<P>
<A NAME="IDX292"></A>
<H3><A NAME="SEC119" HREF="coldmud_toc.html#SEC119">binary_dump</A></H3>
<P>
<PRE>
binary_dump()
</PRE>
<P>
This function writes out all modified objects in the object cache to the
disk database. This guarantees that the disk database files <TT>`db'</TT>,
<TT>`db.dir'</TT>, and <TT>`db.pag'</TT> are consistent.
<P>
<A NAME="IDX293"></A>
<H3><A NAME="SEC120" HREF="coldmud_toc.html#SEC120">bind</A></H3>
<P>
<PRE>
bind(<VAR>port</VAR>, <VAR>receiver</VAR>)
</PRE>
<P>
This function instructs the server to begin listening on the port
numbered <VAR>port</VAR>, with the receiver object <VAR>receiver</VAR>. If the
server is already listening on that port, then the receiver object is
changed, with no other effect. If the socket cannot be created, then
<CODE>bind()</CODE> throws a <CODE>~socket</CODE> error. If the server cannot
bind to the port <VAR>port</VAR>, then <CODE>bind()</CODE> throws a <CODE>~bind</CODE>
error. Otherwise, <CODE>bind()</CODE> returns 1.
<P>
<A NAME="IDX294"></A>
<H3><A NAME="SEC121" HREF="coldmud_toc.html#SEC121">chparents</A></H3>
<P>
<PRE>
chparents(<VAR>dbref</VAR>, <VAR>parents</VAR>)
</PRE>
<P>
This function changes the parents of the object referred to by
<VAR>dbref</VAR> to the list of dbrefs in <VAR>parents</VAR>. If any of the
dbrefs in <VAR>parents</VAR> do not refer to an existing object, then
<CODE>chparents()</CODE> throws an <CODE>~objnf</CODE> error. If any of the parents
have <VAR>dbref</VAR> as an ancestor, or are <VAR>dbref</VAR> themselves, then
<CODE>chparents()</CODE> throws a <CODE>~parent</CODE> error. If <VAR>dbref</VAR> refers
to the root object, or <VAR>parents</VAR> is an empty list, then then
<CODE>chparents()</CODE> throws a <CODE>~perm</CODE> error. Otherwise,
<CODE>chparents()</CODE> returns <CODE>1</CODE>.
<P>
<A NAME="IDX295"></A>
<H3><A NAME="SEC122" HREF="coldmud_toc.html#SEC122">conn_assign</A></H3>
<P>
<PRE>
conn_assign(<VAR>dbref</VAR>)
</PRE>
<P>
This function sets the handler object of the current connection to
<VAR>dbref</VAR>. <CODE>conn_assign()</CODE> always returns <CODE>1</CODE>.
<P>
Examples:
<P>
<PRE>
conn_assign(#76)
=> 1
</PRE>
<P>
<A NAME="IDX296"></A>
<H3><A NAME="SEC123" HREF="coldmud_toc.html#SEC123">connect</A></H3>
<P>
<PRE>
connect(<VAR>address</VAR>, <VAR>port</VAR>, <VAR>receiver</VAR>)
</PRE>
<P>
This function establishes a connection to the remote Internet host named
by <VAR>address</VAR> (a string giving the IP address of the remote host) at
the port <VAR>port</VAR>.
<P>
If <VAR>address</VAR> is not a valid IP address, then <CODE>connect()</CODE> throw
an <CODE>~address</CODE> error. If a socket cannot be created for the
connection, then <CODE>connect()</CODE> throws a <CODE>~socket</CODE> error.
Otherwise, <CODE>connect()</CODE> attemptes to connect to the remote host and
returns 1 immediately; it does not wait to see if the connection attempt
succeeded.
<P>
If the connection succeeds, then the server will send the object
<VAR>receiver</VAR> a <CODE>connect</CODE> message, with one argument the task ID
of the task which called <CODE>connect()</CODE> (see section <A HREF="coldmud.html#SEC90">task_id</A>).
<VAR>receiver</VAR> then becomes the handler object for the connection, and
receives <CODE>parse</CODE> messages when lines arrive from the connection, as
well as a <CODE>disconnect</CODE> message when the connection terminates.
<P>
If the connection fails, then the object <VAR>receiver</VAR> will receive a
<CODE>failed</CODE> message with two arguments, the task ID of the task which
called <CODE>connect()</CODE>, and an error code: <CODE>~refused</CODE> indicates
that the connection was refused, <CODE>~net</CODE> indicates that the network
of the remote host could not be reached, <CODE>~timeout</CODE> indicates that
the connection attempt timed out, and <CODE>~other</CODE> indicates that some
other error occurred.
<P>
<A NAME="IDX297"></A>
<H3><A NAME="SEC124" HREF="coldmud_toc.html#SEC124">create</A></H3>
<P>
<PRE>
create(<VAR>dbref</VAR>, <VAR>parents</VAR>)
</PRE>
<P>
This function creates an object with the dbref <VAR>dbref</VAR> and the
parents <VAR>parents</VAR>, which should be a list of dbrefs referring to
existing objects. If any of the parent dbrefs do not refer to
existing objects, then <CODE>create()</CODE> throws a <CODE>~objnf</CODE> error.
If an object with the dbref <VAR>dbref</VAR> already exists,
<CODE>create()</CODE> throws a <CODE>~perm</CODE> error. Otherwise,
<CODE>create()</CODE> returns <VAR>dbref</VAR>.
<P>
<A NAME="IDX298"></A>
<H3><A NAME="SEC125" HREF="coldmud_toc.html#SEC125">data</A></H3>
<P>
<PRE>
data(<VAR>dbref</VAR>)
</PRE>
<P>
This function retrieves all the variables on the object given by the
dbref <VAR>dbref</VAR>. The return value is a dictionary whose associations
are between ancestors of the object and subdictionaries giving the
variable values for each ancestor's parameters. Each subdictionary's
associations are between parameters (expressed as symbols) of the
ancestor in question (as symbols) and the values of the variables
corresponding to those parameters. Thus, if the object given by
<VAR>dbref</VAR> defines a variable corresponding to a parameter
<VAR>parameter</VAR> on an ancestor <VAR>ancestor</VAR>, then
<CODE>data(<VAR>dbref</VAR>)[<VAR>ancestor</VAR>][<VAR>parameter</VAR>])</CODE> is the value
of that variable.
<P>
The subdictionaries in the dictionary returned by <CODE>data()</CODE> only
contains <CODE>[<VAR>parameter</VAR>, <VAR>value</VAR>]</CODE> associations for
variables which have been assigned values on the object given by
<VAR>dbref</VAR>, not variables which have never been assigned values and
which still have the default value <CODE>0</CODE>. Also, if no variables have
been assigned values for any parameters on an ancestor of the object
given by <VAR>dbref</VAR> (as is the case when the ancestor has no
parameters), then there will not be an association for that ancestor in
the dictionary returned by <CODE>data()</CODE>. Neither the keys in the
dictionary returned by <CODE>data()</CODE> nor the parameters in the
subdictionaries have any particular ordering.
<P>
If <VAR>dbref</VAR> is not the dbref of an object, then <CODE>data()</CODE> throws
an <CODE>~objnf</CODE> error.
<P>
<A NAME="IDX299"></A>
<H3><A NAME="SEC126" HREF="coldmud_toc.html#SEC126">destroy</A></H3>
<P>
<PRE>
destroy(<VAR>dbref</VAR>)
</PRE>
<P>
This function destroys the object given by the dbref <VAR>dbref</VAR>. If
any methods are currently executing on that object, or any methods are
executing which are defined by that object, then it will not be
destroyed immediately. If no object exists with the dbref
<VAR>dbref</VAR>, then <CODE>destroy()</CODE> throws a <CODE>~objnf</CODE> error.
<P>
Objects left orphaned by the destruction of their only parent are
reparented to the parents of the parent which was destroyed.
<P>
<CODE>destroy()</CODE> throws a <CODE>~perm</CODE> error if you attempt to destroy
the root object or system object, which is not allowed. Otherwise,
<CODE>destroy()</CODE> returns <CODE>1</CODE>.
<P>
<A NAME="IDX300"></A>
<H3><A NAME="SEC127" HREF="coldmud_toc.html#SEC127">log</A></H3>
<P>
<PRE>
log(<VAR>string</VAR>)
</PRE>
<P>
This function sends <VAR>string</VAR> to the standard error string, prefixed
by the date. <CODE>log()</CODE> always returns <CODE>1</CODE>.
<P>
Examples:
<P>
<PRE>
log("foo")
=> 1
</PRE>
<P>
<A NAME="IDX301"></A>
<H3><A NAME="SEC128" HREF="coldmud_toc.html#SEC128">run_script</A></H3>
<P>
<PRE>
run_script(<VAR>name</VAR>, <VAR>arguments</VAR>)
run_script(<VAR>name</VAR>, <VAR>arguments</VAR>, <VAR>background-flag</VAR>)
</PRE>
<P>
This function executes the script named by string <VAR>name</VAR>, passing it
the arguments in the list <VAR>arguments</VAR>. Each element of
<VAR>arguments</VAR> must be a string. Coldmud looks for the script named by
<VAR>name</VAR> in the directory <TT>`scripts'</TT> in the current directory.
<VAR>name</VAR> cannot contain a <SAMP>`../'</SAMP> sequence; that is, it cannot walk
back down the directory hierarchy.
<P>
If <VAR>background-flag</VAR> is specified, it must be an integer. If it is
non-zero, then <VAR>script</VAR> is run in the background. Otherwise,
Coldmud waits for the script to execute.
<P>
If <VAR>background-flag</VAR> is not specified, <CODE>run_script()</CODE> returns
the return status of the script, or <CODE>-1</CODE> if it does not
successfully execute the script. If <VAR>background-flag</VAR> is specified,
then <CODE>run_script()</CODE> might return <CODE>-1</CODE> if the script is not
successfully executed, and it may even return the return status of the
script if the script executes extremely quickly, but it will usually
return <CODE>0</CODE>.
<P>
<A NAME="IDX302"></A>
<H3><A NAME="SEC129" HREF="coldmud_toc.html#SEC129">set_heartbeat_freq</A></H3>
<P>
<PRE>
set_heartbeat_freq(<VAR>seconds</VAR>)
</PRE>
<P>
This function sets the frequency of the server heartbeat to
<VAR>seconds</VAR> seconds. If <VAR>seconds</VAR> is less than or equal to zero,
then the heartbeat is turned off; otherwise, the system object will
receive a <CODE>heartbeat</CODE> message approximately every <VAR>seconds</VAR>
seconds.
<P>
<A NAME="IDX303"></A>
<H3><A NAME="SEC130" HREF="coldmud_toc.html#SEC130">shutdown</A></H3>
<P>
<PRE>
shutdown()
</PRE>
<P>
This function updates the binary database in the same manner as
<CODE>binary_dump()</CODE>, and causes the server to shut down at the next
cycle of the main loop.
<P>
<A NAME="IDX304"></A>
<H3><A NAME="SEC131" HREF="coldmud_toc.html#SEC131">text_dump</A></H3>
<P>
<PRE>
text_dump()
</PRE>
<P>
This function writes a text database dump to the file <TT>`textdump'</TT>.
<CODE>text_dump()</CODE> returns <CODE>1</CODE> if it is successful, or <CODE>0</CODE> if
it cannot write the text dump. <CODE>text_dump()</CODE> uses a temporary file
<TT>`textdump.new'</TT> to avoid overwriting the old <TT>`textdump'</TT> until
it has finished; thus, if there is a server or machine crash while the
text dump is in progress, the partial text dump will be in
<TT>`textdump.new'</TT>, and the old <TT>`textdump'</TT> will be unmodified.
<P>
<A NAME="IDX305"></A>
<H3><A NAME="SEC132" HREF="coldmud_toc.html#SEC132">unbind</A></H3>
<P>
<PRE>
unbind(<VAR>port</VAR>)
</PRE>
<P>
This function instructs the server to stop listening on the port
numbered <VAR>port</VAR>. If the server was not already listening on that
port, then <CODE>unbind()</CODE> throws a <CODE>~servnf</CODE> error; otherwise,
<CODE>unbind()</CODE> returns 1.
<P>
<A NAME="IDX306"></A>
<H2><A NAME="SEC133" HREF="coldmud_toc.html#SEC133">Miscellaneous Functions</A></H2>
<P>
The functions in this section perform operations which do not fit into
any other category.
<P>
<A NAME="IDX307"></A>
<H3><A NAME="SEC134" HREF="coldmud_toc.html#SEC134">abs</A></H3>
<P>
<PRE>
abs(<VAR>number</VAR>)
</PRE>
<P>
This function returns the absolute value of <VAR>number</VAR>.
<P>
Examples:
<P>
<PRE>
abs(-6)
=> 6
abs(7)
=> 7
</PRE>
<P>
<A NAME="IDX308"></A>
<H3><A NAME="SEC135" HREF="coldmud_toc.html#SEC135">ctime</A></H3>
<P>
<PRE>
ctime()
ctime(<VAR>time</VAR>)
</PRE>
<P>
This function converts the integer <VAR>time</VAR> into a string format.
If <VAR>time</VAR> is not specified, then <CODE>ctime()</CODE> uses the current
time.
<P>
Examples:
<P>
<PRE>
ctime(739180536)
=> "Fri Jun 4 03:55:36 1993\n"
</PRE>
<P>
<A NAME="IDX309"></A>
<H3><A NAME="SEC136" HREF="coldmud_toc.html#SEC136">max</A></H3>
<P>
<PRE>
max(<VAR>value1</VAR>, <VAR>value2</VAR>, <VAR>...</VAR>)
</PRE>
<P>
This function returns the maximum of its arguments. All of the
arguments must be of the same type, and must be integers or strings.
<P>
<PRE>
max(3, 7, 9, 5)
=> 9
max("Foo", "aardvark", "bar", "Quux")
=> "Quux"
</PRE>
<P>
<A NAME="IDX310"></A>
<H3><A NAME="SEC137" HREF="coldmud_toc.html#SEC137">min</A></H3>
<P>
<PRE>
min(<VAR>value1</VAR>, <VAR>value2</VAR>, <VAR>...</VAR>)
</PRE>
<P>
This function returns the minimum of its arguments. All of the
arguments must be of the same type, and must be integers or strings.
<P>
<PRE>
min(3, 7, 9, 5)
=> 3
min("Foo", "aardvark", "bar", "Quux")
=> "aardvark"
</PRE>
<P>
<A NAME="IDX311"></A>
<H3><A NAME="SEC138" HREF="coldmud_toc.html#SEC138">random</A></H3>
<P>
<PRE>
random(<VAR>max</VAR>)
</PRE>
<P>
This function returns a random integer between one and <VAR>max</VAR>.
<P>
<A NAME="IDX312"></A>
<H3><A NAME="SEC139" HREF="coldmud_toc.html#SEC139">time</A></H3>
<P>
<PRE>
time()
</PRE>
<P>
This function returns the system time in seconds since midnight GMT,
January 1, 1970. You can use <CODE>ctime()</CODE> to turn this number into a
string.
<P>
<A NAME="IDX313"></A>
<H3><A NAME="SEC140" HREF="coldmud_toc.html#SEC140">version</A></H3>
<P>
<PRE>
version()
</PRE>
<P>
This function returns the version number of the Coldmud server as a
list of three numbers. The first two numbers are the major and minor
release numbers; the third number is a bug-fix release number.
<P>
Examples:
<P>
<PRE>
version()
=> [0, 10, 0]
</PRE>
<P>
<H1><A NAME="SEC141" HREF="coldmud_toc.html#SEC141">Running and Maintaining Coldmud</A></H1>
<P>
This chapter is intended for Coldmud adminstrators. It documents
Coldmud's behavior on startup, how Coldmud databases should be
maintained, and how Coldmud manages network connections. All of the
functions referred to in this chapter are administrative functions, and
only work if called by the system object (see section <A HREF="coldmud.html#SEC7">The System Object</A>).
<P>
<A NAME="IDX314"></A>
<A NAME="IDX315"></A>
<A NAME="IDX316"></A>
<A NAME="IDX317"></A>
<H2><A NAME="SEC142" HREF="coldmud_toc.html#SEC142">Starting the Server</A></H2>
<P>
Coldmud has the following usage:
<P>
<PRE>
coldmud <VAR>directory</VAR> [<VAR>other arguments</VAR>]
</PRE>
<P>
The first argument specifies the database directory, which can be
relative to the current directory. You can specify any number of
arguments after <VAR>directory</VAR>; these will be visible to the
<CODE>startup</CODE> method on the system object.
<P>
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<H2><A NAME="SEC143" HREF="coldmud_toc.html#SEC143">Disk Database</A></H2>
<P>
Coldmud normally operates using a binary disk-based database, storing
only a small number of objects in memory at any given time. This number
is usually no more than the product of the cache width and the cache
depth (fixed at 7 and 23 in this version).
<P>
Coldmud's database is normally stored in binary format in the file
<TT>`binary/objects'</TT> (relative to the database directory) and in an
ndbm database with the prefix <TT>`binary/index'</TT>. The file
<TT>`binary/clean'</TT> exists when the database is consistent. The
functions <CODE>binary_dump()</CODE> and <CODE>shutdown()</CODE> force binary
database consistency.
<P>
Because ndbm databases are usually byte-order-dependent, a binary
database generated by a Coldmud process on one machine cannot be
guaranteed to work with a process on another machine. Binary databases
are also heavily version-dependent; small changes in the internal format
of an object in a new version of the server will invalidate old binary
databases, even if the <CODE>C--</CODE> language and the conceptual structure
of a Coldmud object remain the same in the new version.
<P>
Coldmud also supports a text format for databases. The
<CODE>text_dump()</CODE> function stores a text database dump in the file
<TT>`textdump'</TT>. Text dumps specify the database in terms of the
<CODE>C--</CODE> language and a few simple directives, so they are compatible
with any version of Coldmud which can understand the <CODE>C--</CODE> code
contained in it. Text dumps are also simple enough to be written and
edited by humans, so they provide a good mechanism for distribution of
core databases.
<P>
At startup time, Coldmud looks for the file <TT>`binary/clean'</TT> to
determine if a consistent binary database exists and was generated by
the same version of Coldmud as the running process. If a clean binary
database exists, Coldmud will start up very quickly, pausing only to
read in the root object and system object. Otherwise, Coldmud tries to
read in a text dump from the file <TT>`textdump'</TT>. You can force the
use of a text dump by simple removing the file <TT>`binary/clean'</TT>.
Coldmud will fail to start if it cannot find a consistent binary
database or a text dump.
<P>
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<H2><A NAME="SEC144" HREF="coldmud_toc.html#SEC144">Connections</A></H2>
<P>
As a network server, Coldmud has the ability to listen for Internet
connections on ports. The <CODE>bind()</CODE> function instructs Coldmud to
listen on a port, with some object acting as a <EM>receiver object</EM>
for that port.
<P>
Network connections have associated with them a <EM>handler object</EM>.
When a connection occurs on a port, Coldmud initially uses the receiver
object for the port as the handler object for the connection, and sends
a <CODE>connect</CODE> message to the handler object, with two arguments: a
string giving the IP address of the remote host, and an integer giving
the port of the connection on the remote host. Because there is no way
to distinguish between connections with the same handler object, the
<CODE>connect</CODE> method on the handler object should arrange to have the
system object change either the receiver object for the port (using
<CODE>bind()</CODE>) or the handler object for the connection (using
<CODE>conn_assign()</CODE>).
<P>
When text arrives from a network connection, Coldmud sends a
<CODE>parse</CODE> message to the handler object for that connection, with the
text as a buffer argument. The <CODE>parse</CODE> method can then use
<CODE>buffer_to_strings()</CODE> to convert the buffer to a list of text
lines, if that is the usual form of input.
<P>
When a network connection is terminated, Coldmud sends a
<CODE>disconnect</CODE> message to the handler object for that connection.
<P>
Coldmud can also make make connections actively, using the
<CODE>connect()</CODE> function. The third argument to <CODE>connect()</CODE>
specifies a receiver object for the new connection; the server sends a
<CODE>connect</CODE> message to the receiver object upon success, or a
<CODE>failed</CODE> message to the receiver object upon failure, as described
in section <A HREF="coldmud.html#SEC123">connect</A>.
<P>