This procedure returns the product of its arguments.

This procedure returns the product of its arguments.

This procedure returns the sum of its arguments.

This procedure returns the sum of its arguments.

With two or more arguments, this procedure returns the difference of its arguments, associating to the left. With one argument, however, it returns the additive inverse of its argument.

(
->char-set
[
string?
x
]
)
⟹
char-set?
(
->char-set
[
char?
x
]
)
⟹
char-set?
(
->char-set
[
char-set?
x
]
)
⟹
char-set?

Coerces x into a char-set. X may be a string, character or char-set. A string is converted to the set of its constituent characters; a character is converted to a singleton set; a char-set is returned as-is. This procedure is intended for use by other procedures that want to provide "user-friendly", wide-spectrum interfaces to their clients.

(
->char-set
[
string?
x
]
)
⟹
char-set?
(
->char-set
[
char?
x
]
)
⟹
char-set?
(
->char-set
[
char-set?
x
]
)
⟹
char-set?

With two or more arguments, this procedure returns the quotient of its arguments, associating to the left. With one argument, however, it returns multiplicative inverse of its argument. It is an error if any argument of / other than the first is an exact zero. If the first argument is an exact zero, an implementation may return an exact zero unless one of the other arguments is a NaN.

With two or more arguments, this procedure returns the quotient of its arguments, associating to the left. With one argument, however, it returns the multiplicative inverse of its argument.

This procedure returns #t if its arguments are monotonically increasing, and #f otherwise. If any of the arguments are +nan.0, predicate returns #f. It does not distinguish between inexact zero and inexact negative zero. The predicate is transitive. Note: While it is not an error to compare inexact numbers using this predicate, the results are unreliable because a small inaccuracy can affect the result. When in doubt, consult a numerical analyst.

This procedure returns #t if its arguments are monotonically increasing.

This procedure returns #t if its arguments are monotonically non-decreasing.

This procedure returns #t if its arguments are monotonically non-decreasing, and #f otherwise. If any of the arguments are +nan.0, predicate returns #f. It does not distinguish between inexact zero and inexact negative zero. The predicate is transitive. Note: While it is not an error to compare inexact numbers using this predicate, the results are unreliable because a small inaccuracy can affect the result. When in doubt, consult a numerical analyst.

(
<=?
[
comparator?
comparator
]
object1
object2
object3
...
)
⟹
boolean?

=?, <?, >?, <=?, >=? These procedures are analogous to the number, character, and string comparison predicates of Scheme. They allow the convenient use of comparators to handle variable data types.
These procedures apply the equality and ordering predicates of comparator to the objects as follows. If the specified relation returns #t for all objecti and objectj where n is the number of objects and 1 <= i < j <= n, then the procedures return #t, but otherwise #f. Because the relations are transitive, it suffices to compare each object with its successor. The order in which the values are compared is unspecified.

(
<=?
[
comparator?
comparator
]
object1
object2
object3
...
)
⟹
boolean?

(
<?
[
comparator?
comparator
]
object1
object2
object3
...
)
⟹
boolean?

(
<?
[
comparator?
comparator
]
object1
object2
object3
...
)
⟹
boolean?

This procedure returns #t if its arguments are equal.

This procedure returns #t if its arguments are equal, and #f otherwise. If any of the arguments are +nan.0, the predicate return #f. It does not distinguish between inexact zero and inexact negative zero. This predicate is transitive. Note: While it is not an error to compare inexact numbers using this predicate, the results are unreliable because a small inaccuracy can affect the result; this is especially true of =. When in doubt, consult a numerical analyst.

(
=?
[
comparator?
comparator
]
object1
object2
object3
...
)
⟹
boolean?

(
=?
[
comparator?
comparator
]
object1
object2
object3
...
)
⟹
boolean?

This procedure returns #t if its arguments are monotonically decreasing.

This procedure returns #t if its arguments are monotonically decreasing, and #f otherwise. If any of the arguments are +nan.0, predicate returns #f. It does not distinguish between inexact zero and inexact negative zero. The predicate is transitive. Note: While it is not an error to compare inexact numbers using this predicate, the results are unreliable because a small inaccuracy can affect the result. When in doubt, consult a numerical analyst.

This procedure returns #t if its arguments are monotonically non-increasing.

This procedure returns #t if its arguments are monotonically non-increasing, and #f otherwise. If any of the arguments are +nan.0, predicate returns #f. It does not distinguish between inexact zero and inexact negative zero. The predicate is transitive. Note: While it is not an error to compare inexact numbers using this predicate, the results are unreliable because a small inaccuracy can affect the result. When in doubt, consult a numerical analyst.

(
>=?
[
comparator?
comparator
]
object1
object2
object3
...
)
⟹
boolean?

(
>=?
[
comparator?
comparator
]
object1
object2
object3
...
)
⟹
boolean?

(
>?
[
comparator?
comparator
]
object1
object2
object3
...
)
⟹
boolean?

(
>?
[
comparator?
comparator
]
object1
object2
object3
...
)
⟹
boolean?

(
abandoned-mutex-exception?
obj
)
⟹
boolean?

Abs returns the absolute value of its argument.

The abs procedure returns the absolute value of its argument.

(
alist->bag
[
comparator?
comparator
]
[
list?
alist
]
)
⟹
bag?

(
alist->bag
[
comparator?
comparator
]
[
list?
alist
]
)
⟹
bag?

(
alist->hash-table
[
list?
alist
]
[
comparator?
comparator
]
arg
...
)
⟹
hash-table?
(
alist->hash-table
[
list?
alist
]
[
procedure?
equality-predicate
]
arg
...
)
⟹
hash-table?
(
alist->hash-table
[
list?
alist
]
[
procedure?
equality-predicate
]
[
procedure?
hash-function
]
arg
...
)
⟹
hash-table?

equality-predicate
⟹
(
λ
a
b
)
⟹
boolean?

hash-function
⟹
(
λ
obj
)
⟹
integer?

Returns a newly allocated hash-table as if by make-hash-table using comparator and the args. It is then initialized from the associations of alist. Associations earlier in the list take precedence over those that come later. The second form is for compatibility with SRFI 69, and is deprecated.

(
alist->hash-table
[
list?
alist
]
[
comparator?
comparator
]
arg
...
)
⟹
hash-table?

(
alist->hash-table
[
list?
alist
]
[
comparator?
comparator
]
arg
...
)
⟹
hash-table?
(
alist->hash-table
[
list?
alist
]
[
procedure?
equality-predicate
]
arg
...
)
⟹
hash-table?
(
alist->hash-table
[
list?
alist
]
[
procedure?
equality-predicate
]
[
procedure?
hash-function
]
arg
...
)
⟹
hash-table?

equality-predicate
⟹
(
λ
a
b
)
⟹
boolean?

hash-function
⟹
(
λ
obj
)
⟹
integer?

Returns a newly allocated hash-table as if by make-hash-table using comparator and the args. It is then initialized from the associations of alist. Associations earlier in the list take precedence over those that come later. The second form is for compatibility with SRFI 69, and is deprecated.