General Operations Applicable to all Values

Function: int typeof (value)

Takes any MOO value and returns an integer representing the type of value. The result is the same as the initial value of one of these built-in variables: INT, FLOAT, STR, LIST, OBJ, or ERR. Thus, one usually writes code like this:

if (typeof(x) == LIST) ...

and not like this:

if (typeof(x) == 3) ...

because the former is much more readable than the latter.

Function: str tostr (value, ...)

Converts all of the given MOO values into strings and returns the concatenation of the results.

tostr(17)                  =>   "17"
tostr(1.0/3.0)             =>   "0.333333333333333"
tostr(#17)                 =>   "#17"
tostr("foo")               =>   "foo"
tostr({1, 2})              =>   "{list}"
tostr(E_PERM)              =>   "Permission denied"
tostr("3 + 4 = ", 3 + 4)   =>   "3 + 4 = 7"

Note that tostr() does not do a good job of converting lists into strings; all lists, including the empty list, are converted into the string "{list}". The function toliteral(), below, is better for this purpose.

Function: str toliteral (value)

Returns a string containing a MOO literal expression that, when evaluated, would be equal to value.

toliteral(17)         =>   "17"
toliteral(1.0/3.0)    =>   "0.333333333333333"
toliteral(#17)        =>   "#17"
toliteral("foo")      =>   "\"foo\""
toliteral({1, 2})     =>   "{1, 2}"
toliteral(E_PERM)     =>   "E_PERM"

Function: int toint (value)

Function: int tonum (value)

Converts the given MOO value into an integer and returns that integer. Floating-point numbers are rounded toward zero, truncating their fractional parts. Object numbers are converted into the equivalent integers. Strings are parsed as the decimal encoding of a real number which is then converted to an integer. Errors are converted into integers obeying the same ordering (with respect to <= as the errors themselves. Toint() raises E_TYPE if value is a list. If value is a string but the string does not contain a syntactically-correct number, then toint() returns 0.

toint(34.7)        =>   34
toint(-34.7)       =>   -34
toint(#34)         =>   34
toint("34")        =>   34
toint("34.7")      =>   34
toint(" - 34  ")   =>   -34
toint(E_TYPE)      =>   1

Function: obj toobj (value)

Converts the given MOO value into an object number and returns that object number. The conversions are very similar to those for toint() except that for strings, the number may be preceded by `#'.

toobj("34")       =>   #34
toobj("#34")      =>   #34
toobj("foo")      =>   #0
toobj({1, 2})     error-->   E_TYPE

Function: float tofloat (value)

Converts the given MOO value into a floating-point number and returns that number. Integers and object numbers are converted into the corresponding integral floating-point numbers. Strings are parsed as the decimal encoding of a real number which is then represented as closely as possible as a floating-point number. Errors are first converted to integers as in toint() and then converted as integers are. Tofloat() raises E_TYPE if value is a list. If value is a string but the string does not contain a syntactically-correct number, then tofloat() returns 0.

tofloat(34)          =>   34.0
tofloat(#34)         =>   34.0
tofloat("34")        =>   34.0
tofloat("34.7")      =>   34.7
tofloat(E_TYPE)      =>   1.0

Function: int equal (value1, value2)

Returns true if value1 is completely indistinguishable from value2. This is much the same operation as "value1 == value2" except that, unlike ==, the equal() function does not treat upper- and lower-case characters in strings as equal.

"Foo" == "foo"         =>   1
equal("Foo", "foo")    =>   0
equal("Foo", "Foo")    =>   1

Function: int value_bytes (value)

Returns the number of bytes of the server's memory required to store the given value.

Function: str value_hash (value)

Returns the same string as string_hash(toliteral(value)); see the description of string_hash() for details.