r7rs-extras

Augmentations to R7RS-small standard libraries.

Import (r7rs-extras all) to get all of the following.

I/O

(r7rs-extras io)

• (call-with-input-string string proc): Applies proc to an input port fed with string.

• (call-with-output-string proc): Applies proc to a port feeding a string which is then returned.

• (with-input-port port thunk): Closes port after calling thunk with it as the current-input-port.

• (with-output-port port thunk): Closes port after calling thunk with it as the current-output-port.

• (with-error-port port thunk): Closes port after calling thunk with it as the current-error-port.

• (with-input-from-port port thunk): Calls thunk with port as the current-input-port. Doesn't close port.

• (with-output-to-port port thunk): Calls thunk with port as the current-output-port. Doesn't close port.

• (with-error-to-port port thunk): Calls thunk with port as the current-error-port. Doesn't close port.

• (with-error-to-file file thunk): Calls thunk with current-error-port bound to file.

• (with-input-from-string string thunk): Calls thunk with current-input-port bound to a port fed with string.

• (with-output-to-string thunk): Calls thunk with current-output-port bound to a port feeding a string which is then returned.

• (with-error-to-string thunk): Calls thunk with current-error-port bound to a port feeding a string which is then returned.

higher-order

(r7rs-extras higher-order)

• (const value): Make a nullary procedure always returning value.

• (negate proc): Make a procedure negating the application of proc to its arguments.

• (compose proc . rest): Functional composition; e.g. ((compose x y) a) = (x (y a)).

• (pipeline proc . rest): Reverse functional composition; e.g. ((pipeline x y) a) = (y (x a)).

• (identity . x): Returns values given to it as-is.

• (and=> value proc): If value is true, call proc on it, else return false.

partition

(r7rs-extras partition)

• (partition* list . procs): Partitions list via procs, returning procs + 1 many lists; the last list containing elements that didn't match any procedure. The ordering of each list obeys that of list. If there are elements matching multiple procs, it's unspecified in which one of the matching lists they appear.

• (partition+ list . procs): This is like the partition* procedure, but elements matching multiple procedures appear in every corresponding list.

arithmetic

(r7rs-extras arithmetic)

• (euclidean/ x y): Return q and r in x = q*y + r where 0 <= r < |y|.

• (euclidean-quotient x y): Return q in x = q*y + r where 0 <= R < |y|.

• (euclidean-remainder x y): Return r in x = q*y + r where 0 <= r < |y|.

• (ceiling/ x y): Return q and r in x = q*y + r where q = ceiling(x/y).

• (ceiling-quotient x y): Return q in x = q*y + r where q = ceiling(x/y).

• (ceiling-remainder x y): Return r in x = q*y + r where q = ceiling(x/y).

• (centered/ x y): Return q and r in x = q*y + r where -|y/2| <= r < |y/2|.

• (centered-quotient x y): Return q in x = q*y + r where -|y/2| <= r < |y/2|.

• (centered-remainder x y): Return r in x = q*y + r where -|y/2| <= r < |y/2|.

• (round/ x y): Return q and r in x = q*y + r where q = round(x/y).

• (round-quotient x y): Return q in x = q*y + r where q = round(x/y).

• (round-remainder x y): Return r in x = q*y + r where q = round(x/y).

push! and pop!

(r7rs-extras pushpop)

• (push! pair value): (set! pair (cons value pair))

• (pop! pair): (let ((value (car pair))) (set! pair (cdr pair)) value)