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diff --git a/slib.info-5 b/slib.info-5 deleted file mode 100644 index 04d1b28..0000000 --- a/slib.info-5 +++ /dev/null @@ -1,1536 +0,0 @@ -This is Info file slib.info, produced by Makeinfo-1.64 from the input -file slib.texi. - - This file documents SLIB, the portable Scheme library. - - Copyright (C) 1993 Todd R. Eigenschink Copyright (C) 1993, 1994, 1995 -Aubrey Jaffer - - Permission is granted to make and distribute verbatim copies of this -manual provided the copyright notice and this permission notice are -preserved on all copies. - - Permission is granted to copy and distribute modified versions of this -manual under the conditions for verbatim copying, provided that the -entire resulting derived work is distributed under the terms of a -permission notice identical to this one. - - Permission is granted to copy and distribute translations of this -manual into another language, under the above conditions for modified -versions, except that this permission notice may be stated in a -translation approved by the author. - - -File: slib.info, Node: Cyclic Checksum, Next: Plotting, Prev: Random Numbers, Up: Numerics - -Cyclic Checksum -=============== - - `(require 'make-crc)' - - - Function: make-port-crc - - Function: make-port-crc DEGREE - - Function: make-port-crc DEGREE GENERATOR - Returns an expression for a procedure of one argument, a port. - This procedure reads characters from the port until the end of - file and returns the integer checksum of the bytes read. - - The integer DEGREE, if given, specifies the degree of the - polynomial being computed - which is also the number of bits - computed in the checksums. The default value is 32. - - The integer GENERATOR specifies the polynomial being computed. - The power of 2 generating each 1 bit is the exponent of a term of - the polynomial. The bit at position DEGREE is implicit and should - not be part of GENERATOR. This allows systems with numbers - limited to 32 bits to calculate 32 bit checksums. The default - value of GENERATOR when DEGREE is 32 (its default) is: - - (make-port-crc 32 #b00000100110000010001110110110111) - - Creates a procedure to calculate the P1003.2/D11.2 (POSIX.2) 32-bit - checksum from the polynomial: - - 32 26 23 22 16 12 11 - ( x + x + x + x + x + x + x + - - 10 8 7 5 4 2 1 - x + x + x + x + x + x + x + 1 ) mod 2 - - (require 'make-crc) - (define crc32 (slib:eval (make-port-crc))) - (define (file-check-sum file) (call-with-input-file file crc32)) - (file-check-sum (in-vicinity (library-vicinity) "ratize.scm")) - - => 3553047446 - - -File: slib.info, Node: Plotting, Next: Root Finding, Prev: Cyclic Checksum, Up: Numerics - -Plotting on Character Devices -============================= - - `(require 'charplot)' - - The plotting procedure is made available through the use of the -`charplot' package. `charplot' is loaded by inserting `(require -'charplot)' before the code that uses this procedure. - - - Variable: charplot:height - The number of rows to make the plot vertically. - - - Variable: charplot:width - The number of columns to make the plot horizontally. - - - Procedure: plot! COORDS X-LABEL Y-LABEL - COORDS is a list of pairs of x and y coordinates. X-LABEL and - Y-LABEL are strings with which to label the x and y axes. - - Example: - (require 'charplot) - (set! charplot:height 19) - (set! charplot:width 45) - - (define (make-points n) - (if (zero? n) - '() - (cons (cons (/ n 6) (sin (/ n 6))) (make-points (1- n))))) - - (plot! (make-points 37) "x" "Sin(x)") - -| - Sin(x) ______________________________________________ - 1.25|- | - | | - 1|- **** | - | ** ** | - 750.0e-3|- * * | - | * * | - 500.0e-3|- * * | - | * | - 250.0e-3|- * | - | * * | - 0|-------------------*--------------------------| - | * | - -250.0e-3|- * * | - | * * | - -500.0e-3|- * | - | * * | - -750.0e-3|- * * | - | ** ** | - -1|- **** | - |____________:_____._____:_____._____:_________| - x 2 4 - - -File: slib.info, Node: Root Finding, Prev: Plotting, Up: Numerics - -Root Finding -============ - - `(require 'root)' - - - Function: newtown:find-integer-root F DF/DX X0 - Given integer valued procedure F, its derivative (with respect to - its argument) DF/DX, and initial integer value X0 for which - DF/DX(X0) is non-zero, returns an integer X for which F(X) is - closer to zero than either of the integers adjacent to X; or - returns `#f' if such an integer can't be found. - - To find the closest integer to a given integers square root: - - (define (integer-sqrt y) - (newton:find-integer-root - (lambda (x) (- (* x x) y)) - (lambda (x) (* 2 x)) - (ash 1 (quotient (integer-length y) 2)))) - - (integer-sqrt 15) => 4 - - - Function: integer-sqrt Y - Given a non-negative integer Y, returns the rounded square-root of - Y. - - - Function: newton:find-root F DF/DX X0 PREC - Given real valued procedures F, DF/DX of one (real) argument, - initial real value X0 for which DF/DX(X0) is non-zero, and - positive real number PREC, returns a real X for which `abs'(F(X)) - is less than PREC; or returns `#f' if such a real can't be found. - - If `prec' is instead a negative integer, `newton:find-root' - returns the result of -PREC iterations. - -H. J. Orchard, `The Laguerre Method for Finding the Zeros of -Polynomials', IEEE Transactions on Circuits and Systems, Vol. 36, No. -11, November 1989, pp 1377-1381. - - There are 2 errors in Orchard's Table II. Line k=2 for starting - value of 1000+j0 should have Z_k of 1.0475 + j4.1036 and line k=2 - for starting value of 0+j1000 should have Z_k of 1.0988 + j4.0833. - - - Function: laguerre:find-root F DF/DZ DDF/DZ^2 Z0 PREC - Given complex valued procedure F of one (complex) argument, its - derivative (with respect to its argument) DF/DX, its second - derivative DDF/DZ^2, initial complex value Z0, and positive real - number PREC, returns a complex number Z for which - `magnitude'(F(Z)) is less than PREC; or returns `#f' if such a - number can't be found. - - If `prec' is instead a negative integer, `laguerre:find-root' - returns the result of -PREC iterations. - - - Function: laguerre:find-polynomial-root DEG F DF/DZ DDF/DZ^2 Z0 PREC - Given polynomial procedure F of integer degree DEG of one - argument, its derivative (with respect to its argument) DF/DX, its - second derivative DDF/DZ^2, initial complex value Z0, and positive - real number PREC, returns a complex number Z for which - `magnitude'(F(Z)) is less than PREC; or returns `#f' if such a - number can't be found. - - If `prec' is instead a negative integer, - `laguerre:find-polynomial-root' returns the result of -PREC - iterations. - - -File: slib.info, Node: Procedures, Next: Standards Support, Prev: Numerics, Up: Top - -Procedures -********** - - Anything that doesn't fall neatly into any of the other categories -winds up here. - -* Menu: - -* Batch:: 'batch -* Common List Functions:: 'common-list-functions -* Format:: 'format -* Generic-Write:: 'generic-write -* Line I/O:: 'line-i/o -* Multi-Processing:: 'process -* Object-To-String:: 'object->string -* Pretty-Print:: 'pretty-print, 'pprint-file -* Sorting:: 'sort -* Topological Sort:: -* Standard Formatted I/O:: 'printf, 'scanf -* String-Case:: 'string-case -* String Ports:: 'string-port -* String Search:: -* Tektronix Graphics Support:: -* Tree Operations:: 'tree - - -File: slib.info, Node: Batch, Next: Common List Functions, Prev: Procedures, Up: Procedures - -Batch -===== - - `(require 'batch)' - -The batch procedures provide a way to write and execute portable scripts -for a variety of operating systems. Each `batch:' procedure takes as -its first argument a parameter-list (*note Parameter lists::.). This -parameter-list argument PARMS contains named associations. Batch -currently uses 2 of these: - -`batch-port' - The port on which to write lines of the batch file. - -`batch-dialect' - The syntax of batch file to generate. Currently supported are: - * unix - - * dos - - * vms - - * system - - * *unknown* - -`batch.scm' uses 2 enhanced relational tables (*note Database -Utilities::.) to store information linking the names of -`operating-system's to `batch-dialect'es. - - - Function: batch:initialize! DATABASE - Defines `operating-system' and `batch-dialect' tables and adds the - domain `operating-system' to the enhanced relational database - DATABASE. - - - Variable: batch:platform - Is batch's best guess as to which operating-system it is running - under. `batch:platform' is set to `(software-type)' (*note - Configuration::.) unless `(software-type)' is `unix', in which - case finer distinctions are made. - - - Function: batch:call-with-output-script PARMS FILE PROC - PROC should be a procedure of one argument. If FILE is an - output-port, `batch:call-with-output-script' writes an appropriate - header to FILE and then calls PROC with FILE as the only argument. - If FILE is a string, `batch:call-with-output-script' opens a - output-file of name FILE, writes an appropriate header to FILE, - and then calls PROC with the newly opened port as the only - argument. Otherwise, `batch:call-with-output-script' acts as if - it was called with the result of `(current-output-port)' as its - third argument. - - - Function: batch:apply-chop-to-fit PROC ARG1 ARG2 ... LIST - The procedure PROC must accept at least one argument and return - `#t' if successful, `#f' if not. `batch:apply-chop-to-fit' calls - PROC with ARG1, ARG2, ..., and CHUNK, where CHUNK is a subset of - LIST. `batch:apply-chop-to-fit' tries PROC with successively - smaller subsets of LIST until either PROC returns non-false, or - the CHUNKs become empty. - -The rest of the `batch:' procedures write (or execute if -`batch-dialect' is `system') commands to the batch port which has been -added to PARMS or `(copy-tree PARMS)' by the code: - - (adjoin-parameters! PARMS (list 'batch-port PORT)) - - - Function: batch:system PARMS STRING1 STRING2 ... - Calls `batch:try-system' (below) with arguments, but signals an - error if `batch:try-system' returns `#f'. - -These functions return a non-false value if the command was successfully -translated into the batch dialect and `#f' if not. In the case of the -`system' dialect, the value is non-false if the operation suceeded. - - - Function: batch:try-system PARMS STRING1 STRING2 ... - Writes a command to the `batch-port' in PARMS which executes the - program named STRING1 with arguments STRING2 .... - - - Function: batch:run-script PARMS STRING1 STRING2 ... - Writes a command to the `batch-port' in PARMS which executes the - batch script named STRING1 with arguments STRING2 .... - - *Note:* `batch:run-script' and `batch:try-system' are not the same - for some operating systems (VMS). - - - Function: batch:comment PARMS LINE1 ... - Writes comment lines LINE1 ... to the `batch-port' in PARMS. - - - Function: batch:lines->file PARMS FILE LINE1 ... - Writes commands to the `batch-port' in PARMS which create a file - named FILE with contents LINE1 .... - - - Function: batch:delete-file PARMS FILE - Writes a command to the `batch-port' in PARMS which deletes the - file named FILE. - - - Function: batch:rename-file PARMS OLD-NAME NEW-NAME - Writes a command to the `batch-port' in PARMS which renames the - file OLD-NAME to NEW-NAME. - -In addition, batch provides some small utilities very useful for writing -scripts: - - - Function: replace-suffix STR OLD NEW - Returns a new string similar to `str' but with the suffix string - OLD removed and the suffix string NEW appended. If the end of STR - does not match OLD, an error is signaled. - - - Function: string-join JOINER STRING1 ... - Returns a new string consisting of all the strings STRING1 ... in - order appended together with the string JOINER between each - adjacent pair. - - - Function: must-be-first LIST1 LIST2 - Returns a new list consisting of the elements of LIST2 ordered so - that if some elements of LIST1 are `equal?' to elements of LIST2, - then those elements will appear first and in the order of LIST1. - - - Function: must-be-last LIST1 LIST2 - Returns a new list consisting of the elements of LIST1 ordered so - that if some elements of LIST2 are `equal?' to elements of LIST1, - then those elements will appear last and in the order of LIST2. - - - Function: os->batch-dialect OSNAME - Returns its best guess for the `batch-dialect' to be used for the - operating-system named OSNAME. `os->batch-dialect' uses the - tables added to DATABASE by `batch:initialize!'. - -Here is an example of the use of most of batch's procedures: - - (require 'database-utilities) - (require 'parameters) - (require 'batch) - - (define batch (create-database #f 'alist-table)) - (batch:initialize! batch) - - (define my-parameters - (list (list 'batch-dialect (os->batch-dialect batch:platform)) - (list 'platform batch:platform) - (list 'batch-port (current-output-port)))) ;gets filled in later - - (batch:call-with-output-script - my-parameters - "my-batch" - (lambda (batch-port) - (adjoin-parameters! my-parameters (list 'batch-port batch-port)) - (and - (batch:comment my-parameters - "================ Write file with C program.") - (batch:rename-file my-parameters "hello.c" "hello.c~") - (batch:lines->file my-parameters "hello.c" - "#include <stdio.h>" - "int main(int argc, char **argv)" - "{" - " printf(\"hello world\\n\");" - " return 0;" - "}" ) - (batch:system my-parameters "cc" "-c" "hello.c") - (batch:system my-parameters "cc" "-o" "hello" - (replace-suffix "hello.c" ".c" ".o")) - (batch:system my-parameters "hello") - (batch:delete-file my-parameters "hello") - (batch:delete-file my-parameters "hello.c") - (batch:delete-file my-parameters "hello.o") - (batch:delete-file my-parameters "my-batch") - ))) - -Produces the file `my-batch': - - #!/bin/sh - # "my-batch" build script created Sat Jun 10 21:20:37 1995 - # ================ Write file with C program. - mv -f hello.c hello.c~ - rm -f hello.c - echo '#include <stdio.h>'>>hello.c - echo 'int main(int argc, char **argv)'>>hello.c - echo '{'>>hello.c - echo ' printf("hello world\n");'>>hello.c - echo ' return 0;'>>hello.c - echo '}'>>hello.c - cc -c hello.c - cc -o hello hello.o - hello - rm -f hello - rm -f hello.c - rm -f hello.o - rm -f my-batch - -When run, `my-batch' prints: - - bash$ my-batch - mv: hello.c: No such file or directory - hello world - - -File: slib.info, Node: Common List Functions, Next: Format, Prev: Batch, Up: Procedures - -Common List Functions -===================== - - `(require 'common-list-functions)' - - The procedures below follow the Common LISP equivalents apart from -optional arguments in some cases. - -* Menu: - -* List construction:: -* Lists as sets:: -* Lists as sequences:: -* Destructive list operations:: -* Non-List functions:: - - -File: slib.info, Node: List construction, Next: Lists as sets, Prev: Common List Functions, Up: Common List Functions - -List construction ------------------ - - - Function: make-list K . INIT - `make-list' creates and returns a list of K elements. If INIT is - included, all elements in the list are initialized to INIT. - - Example: - (make-list 3) - => (#<unspecified> #<unspecified> #<unspecified>) - (make-list 5 'foo) - => (foo foo foo foo foo) - - - Function: list* X . Y - Works like `list' except that the cdr of the last pair is the last - argument unless there is only one argument, when the result is - just that argument. Sometimes called `cons*'. E.g.: - (list* 1) - => 1 - (list* 1 2 3) - => (1 2 . 3) - (list* 1 2 '(3 4)) - => (1 2 3 4) - (list* ARGS '()) - == (list ARGS) - - - Function: copy-list LST - `copy-list' makes a copy of LST using new pairs and returns it. - Only the top level of the list is copied, i.e., pairs forming - elements of the copied list remain `eq?' to the corresponding - elements of the original; the copy is, however, not `eq?' to the - original, but is `equal?' to it. - - Example: - (copy-list '(foo foo foo)) - => (foo foo foo) - (define q '(foo bar baz bang)) - (define p q) - (eq? p q) - => #t - (define r (copy-list q)) - (eq? q r) - => #f - (equal? q r) - => #t - (define bar '(bar)) - (eq? bar (car (copy-list (list bar 'foo)))) - => #t - - -File: slib.info, Node: Lists as sets, Next: Lists as sequences, Prev: List construction, Up: Common List Functions - -Lists as sets -------------- - - `eq?' is used to test for membership by all the procedures below -which treat lists as sets. - - - Function: adjoin E L - `adjoin' returns the adjoint of the element E and the list L. - That is, if E is in L, `adjoin' returns L, otherwise, it returns - `(cons E L)'. - - Example: - (adjoin 'baz '(bar baz bang)) - => (bar baz bang) - (adjoin 'foo '(bar baz bang)) - => (foo bar baz bang) - - - Function: union L1 L2 - `union' returns the combination of L1 and L2. Duplicates between - L1 and L2 are culled. Duplicates within L1 or within L2 may or - may not be removed. - - Example: - (union '(1 2 3 4) '(5 6 7 8)) - => (4 3 2 1 5 6 7 8) - (union '(1 2 3 4) '(3 4 5 6)) - => (2 1 3 4 5 6) - - - Function: intersection L1 L2 - `intersection' returns all elements that are in both L1 and L2. - - Example: - (intersection '(1 2 3 4) '(3 4 5 6)) - => (3 4) - (intersection '(1 2 3 4) '(5 6 7 8)) - => () - - - Function: set-difference L1 L2 - `set-difference' returns the union of all elements that are in L1 - but not in L2. - - Example: - (set-difference '(1 2 3 4) '(3 4 5 6)) - => (1 2) - (set-difference '(1 2 3 4) '(1 2 3 4 5 6)) - => () - - - Function: member-if PRED LST - `member-if' returns LST if `(PRED ELEMENT)' is `#t' for any - ELEMENT in LST. Returns `#f' if PRED does not apply to any - ELEMENT in LST. - - Example: - (member-if vector? '(1 2 3 4)) - => #f - (member-if number? '(1 2 3 4)) - => (1 2 3 4) - - - Function: some PRED LST . MORE-LSTS - PRED is a boolean function of as many arguments as there are list - arguments to `some' i.e., LST plus any optional arguments. PRED - is applied to successive elements of the list arguments in order. - `some' returns `#t' as soon as one of these applications returns - `#t', and is `#f' if none returns `#t'. All the lists should have - the same length. - - Example: - (some odd? '(1 2 3 4)) - => #t - - (some odd? '(2 4 6 8)) - => #f - - (some > '(2 3) '(1 4)) - => #f - - - Function: every PRED LST . MORE-LSTS - `every' is analogous to `some' except it returns `#t' if every - application of PRED is `#t' and `#f' otherwise. - - Example: - (every even? '(1 2 3 4)) - => #f - - (every even? '(2 4 6 8)) - => #t - - (every > '(2 3) '(1 4)) - => #f - - - Function: notany PRED . LST - `notany' is analogous to `some' but returns `#t' if no application - of PRED returns `#t' or `#f' as soon as any one does. - - - Function: notevery PRED . LST - `notevery' is analogous to `some' but returns `#t' as soon as an - application of PRED returns `#f', and `#f' otherwise. - - Example: - (notevery even? '(1 2 3 4)) - => #t - - (notevery even? '(2 4 6 8)) - => #f - - - Function: find-if PRED LST - `find-if' searches for the first ELEMENT in LST such that `(PRED - ELEMENT)' returns `#t'. If it finds any such ELEMENT in LST, - ELEMENT is returned. Otherwise, `#f' is returned. - - Example: - (find-if number? '(foo 1 bar 2)) - => 1 - - (find-if number? '(foo bar baz bang)) - => #f - - (find-if symbol? '(1 2 foo bar)) - => foo - - - Function: remove ELT LST - `remove' removes all occurrences of ELT from LST using `eqv?' to - test for equality and returns everything that's left. N.B.: other - implementations (Chez, Scheme->C and T, at least) use `equal?' as - the equality test. - - Example: - (remove 1 '(1 2 1 3 1 4 1 5)) - => (2 3 4 5) - - (remove 'foo '(bar baz bang)) - => (bar baz bang) - - - Function: remove-if PRED LST - `remove-if' removes all ELEMENTs from LST where `(PRED ELEMENT)' - is `#t' and returns everything that's left. - - Example: - (remove-if number? '(1 2 3 4)) - => () - - (remove-if even? '(1 2 3 4 5 6 7 8)) - => (1 3 5 7) - - - Function: remove-if-not PRED LST - `remove-if-not' removes all ELEMENTs from LST for which `(PRED - ELEMENT)' is `#f' and returns everything that's left. - - Example: - (remove-if-not number? '(foo bar baz)) - => () - (remove-if-not odd? '(1 2 3 4 5 6 7 8)) - => (1 3 5 7) - - - Function: has-duplicates? LST - returns `#t' if 2 members of LST are `equal?', `#f' otherwise. - Example: - (has-duplicates? '(1 2 3 4)) - => #f - - (has-duplicates? '(2 4 3 4)) - => #t - - -File: slib.info, Node: Lists as sequences, Next: Destructive list operations, Prev: Lists as sets, Up: Common List Functions - -Lists as sequences ------------------- - - - Function: position OBJ LST - `position' returns the 0-based position of OBJ in LST, or `#f' if - OBJ does not occur in LST. - - Example: - (position 'foo '(foo bar baz bang)) - => 0 - (position 'baz '(foo bar baz bang)) - => 2 - (position 'oops '(foo bar baz bang)) - => #f - - - Function: reduce P LST - `reduce' combines all the elements of a sequence using a binary - operation (the combination is left-associative). For example, - using `+', one can add up all the elements. `reduce' allows you to - apply a function which accepts only two arguments to more than 2 - objects. Functional programmers usually refer to this as "foldl". - `collect:reduce' (*Note Collections::) provides a version of - `collect' generalized to collections. - - Example: - (reduce + '(1 2 3 4)) - => 10 - (define (bad-sum . l) (reduce + l)) - (bad-sum 1 2 3 4) - == (reduce + (1 2 3 4)) - == (+ (+ (+ 1 2) 3) 4) - => 10 - (bad-sum) - == (reduce + ()) - => () - (reduce string-append '("hello" "cruel" "world")) - == (string-append (string-append "hello" "cruel") "world") - => "hellocruelworld" - (reduce anything '()) - => () - (reduce anything '(x)) - => x - - What follows is a rather non-standard implementation of `reverse' - in terms of `reduce' and a combinator elsewhere called "C". - - ;;; Contributed by Jussi Piitulainen (jpiitula@ling.helsinki.fi) - - (define commute - (lambda (f) - (lambda (x y) - (f y x)))) - - (define reverse - (lambda (args) - (reduce-init (commute cons) args))) - - - Function: reduce-init P INIT LST - `reduce-init' is the same as reduce, except that it implicitly - inserts INIT at the start of the list. `reduce-init' is preferred - if you want to handle the null list, the one-element, and lists - with two or more elements consistently. It is common to use the - operator's idempotent as the initializer. Functional programmers - usually call this "foldl". - - Example: - (define (sum . l) (reduce-init + 0 l)) - (sum 1 2 3 4) - == (reduce-init + 0 (1 2 3 4)) - == (+ (+ (+ (+ 0 1) 2) 3) 4) - => 10 - (sum) - == (reduce-init + 0 '()) - => 0 - - (reduce-init string-append "@" '("hello" "cruel" "world")) - == - (string-append (string-append (string-append "@" "hello") - "cruel") - "world") - => "@hellocruelworld" - - Given a differentiation of 2 arguments, `diff', the following will - differentiate by any number of variables. - (define (diff* exp . vars) - (reduce-init diff exp vars)) - - Example: - ;;; Real-world example: Insertion sort using reduce-init. - - (define (insert l item) - (if (null? l) - (list item) - (if (< (car l) item) - (cons (car l) (insert (cdr l) item)) - (cons item l)))) - (define (insertion-sort l) (reduce-init insert '() l)) - - (insertion-sort '(3 1 4 1 5) - == (reduce-init insert () (3 1 4 1 5)) - == (insert (insert (insert (insert (insert () 3) 1) 4) 1) 5) - == (insert (insert (insert (insert (3)) 1) 4) 1) 5) - == (insert (insert (insert (1 3) 4) 1) 5) - == (insert (insert (1 3 4) 1) 5) - == (insert (1 1 3 4) 5) - => (1 1 3 4 5) - - - Function: butlast LST N - `butlast' returns all but the last N elements of LST. - - Example: - (butlast '(1 2 3 4) 3) - => (1) - (butlast '(1 2 3 4) 4) - => () - - - Function: nthcdr N LST - `nthcdr' takes N `cdr's of LST and returns the result. Thus - `(nthcdr 3 LST)' == `(cdddr LST)' - - Example: - (nthcdr 2 '(1 2 3 4)) - => (3 4) - (nthcdr 0 '(1 2 3 4)) - => (1 2 3 4) - - - Function: last LST N - `last' returns the last N elements of LST. N must be a - non-negative integer. - - Example: - (last '(foo bar baz bang) 2) - => (baz bang) - (last '(1 2 3) 0) - => 0 - - -File: slib.info, Node: Destructive list operations, Next: Non-List functions, Prev: Lists as sequences, Up: Common List Functions - -Destructive list operations ---------------------------- - - These procedures may mutate the list they operate on, but any such -mutation is undefined. - - - Procedure: nconc ARGS - `nconc' destructively concatenates its arguments. (Compare this - with `append', which copies arguments rather than destroying them.) - Sometimes called `append!' (*Note Rev2 Procedures::). - - Example: You want to find the subsets of a set. Here's the - obvious way: - - (define (subsets set) - (if (null? set) - '(()) - (append (mapcar (lambda (sub) (cons (car set) sub)) - (subsets (cdr set))) - (subsets (cdr set))))) - But that does way more consing than you need. Instead, you could - replace the `append' with `nconc', since you don't have any need - for all the intermediate results. - - Example: - (define x '(a b c)) - (define y '(d e f)) - (nconc x y) - => (a b c d e f) - x - => (a b c d e f) - - `nconc' is the same as `append!' in `sc2.scm'. - - - Procedure: nreverse LST - `nreverse' reverses the order of elements in LST by mutating - `cdr's of the list. Sometimes called `reverse!'. - - Example: - (define foo '(a b c)) - (nreverse foo) - => (c b a) - foo - => (a) - - Some people have been confused about how to use `nreverse', - thinking that it doesn't return a value. It needs to be pointed - out that - (set! lst (nreverse lst)) - - is the proper usage, not - (nreverse lst) - The example should suffice to show why this is the case. - - - Procedure: delete ELT LST - - Procedure: delete-if PRED LST - - Procedure: delete-if-not PRED LST - Destructive versions of `remove' `remove-if', and `remove-if-not'. - - Example: - (define lst '(foo bar baz bang)) - (delete 'foo lst) - => (bar baz bang) - lst - => (foo bar baz bang) - - (define lst '(1 2 3 4 5 6 7 8 9)) - (delete-if odd? lst) - => (2 4 6 8) - lst - => (1 2 4 6 8) - - Some people have been confused about how to use `delete', - `delete-if', and `delete-if', thinking that they dont' return a - value. It needs to be pointed out that - (set! lst (delete el lst)) - - is the proper usage, not - (delete el lst) - The examples should suffice to show why this is the case. - - -File: slib.info, Node: Non-List functions, Prev: Destructive list operations, Up: Common List Functions - -Non-List functions ------------------- - - - Function: and? . ARGS - `and?' checks to see if all its arguments are true. If they are, - `and?' returns `#t', otherwise, `#f'. (In contrast to `and', this - is a function, so all arguments are always evaluated and in an - unspecified order.) - - Example: - (and? 1 2 3) - => #t - (and #f 1 2) - => #f - - - Function: or? . ARGS - `or?' checks to see if any of its arguments are true. If any is - true, `or?' returns `#t', and `#f' otherwise. (To `or' as `and?' - is to `and'.) - - Example: - (or? 1 2 #f) - => #t - (or? #f #f #f) - => #f - - - Function: atom? OBJECT - Returns `#t' if OBJECT is not a pair and `#f' if it is pair. - (Called `atom' in Common LISP.) - (atom? 1) - => #t - (atom? '(1 2)) - => #f - (atom? #(1 2)) ; dubious! - => #t - - - Function: type-of OBJECT - Returns a symbol name for the type of OBJECT. - - - Function: coerce OBJECT RESULT-TYPE - Converts and returns OBJECT of type `char', `number', `string', - `symbol', `list', or `vector' to RESULT-TYPE (which must be one of - these symbols). - - -File: slib.info, Node: Format, Next: Generic-Write, Prev: Common List Functions, Up: Procedures - -Format -====== - - `(require 'format)' - -* Menu: - -* Format Interface:: -* Format Specification:: - - -File: slib.info, Node: Format Interface, Next: Format Specification, Prev: Format, Up: Format - -Format Interface ----------------- - - - Function: format DESTINATION FORMAT-STRING . ARGUMENTS - An almost complete implementation of Common LISP format description - according to the CL reference book `Common LISP' from Guy L. - Steele, Digital Press. Backward compatible to most of the - available Scheme format implementations. - - Returns `#t', `#f' or a string; has side effect of printing - according to FORMAT-STRING. If DESTINATION is `#t', the output is - to the current output port and `#t' is returned. If DESTINATION - is `#f', a formatted string is returned as the result of the call. - NEW: If DESTINATION is a string, DESTINATION is regarded as the - format string; FORMAT-STRING is then the first argument and the - output is returned as a string. If DESTINATION is a number, the - output is to the current error port if available by the - implementation. Otherwise DESTINATION must be an output port and - `#t' is returned. - - FORMAT-STRING must be a string. In case of a formatting error - format returns `#f' and prints a message on the current output or - error port. Characters are output as if the string were output by - the `display' function with the exception of those prefixed by a - tilde (~). For a detailed description of the FORMAT-STRING syntax - please consult a Common LISP format reference manual. For a test - suite to verify this format implementation load `formatst.scm'. - Please send bug reports to `lutzeb@cs.tu-berlin.de'. - - Note: `format' is not reentrant, i.e. only one `format'-call may - be executed at a time. - - - -File: slib.info, Node: Format Specification, Prev: Format Interface, Up: Format - -Format Specification (Format version 3.0) ------------------------------------------ - - Please consult a Common LISP format reference manual for a detailed -description of the format string syntax. For a demonstration of the -implemented directives see `formatst.scm'. - - This implementation supports directive parameters and modifiers (`:' -and `@' characters). Multiple parameters must be separated by a comma -(`,'). Parameters can be numerical parameters (positive or negative), -character parameters (prefixed by a quote character (`''), variable -parameters (`v'), number of rest arguments parameter (`#'), empty and -default parameters. Directive characters are case independent. The -general form of a directive is: - -DIRECTIVE ::= ~{DIRECTIVE-PARAMETER,}[:][@]DIRECTIVE-CHARACTER - -DIRECTIVE-PARAMETER ::= [ [-|+]{0-9}+ | 'CHARACTER | v | # ] - -Implemented CL Format Control Directives -........................................ - - Documentation syntax: Uppercase characters represent the corresponding -control directive characters. Lowercase characters represent control -directive parameter descriptions. - -`~A' - Any (print as `display' does). - `~@A' - left pad. - - `~MINCOL,COLINC,MINPAD,PADCHARA' - full padding. - -`~S' - S-expression (print as `write' does). - `~@S' - left pad. - - `~MINCOL,COLINC,MINPAD,PADCHARS' - full padding. - -`~D' - Decimal. - `~@D' - print number sign always. - - `~:D' - print comma separated. - - `~MINCOL,PADCHAR,COMMACHARD' - padding. - -`~X' - Hexadecimal. - `~@X' - print number sign always. - - `~:X' - print comma separated. - - `~MINCOL,PADCHAR,COMMACHARX' - padding. - -`~O' - Octal. - `~@O' - print number sign always. - - `~:O' - print comma separated. - - `~MINCOL,PADCHAR,COMMACHARO' - padding. - -`~B' - Binary. - `~@B' - print number sign always. - - `~:B' - print comma separated. - - `~MINCOL,PADCHAR,COMMACHARB' - padding. - -`~NR' - Radix N. - `~N,MINCOL,PADCHAR,COMMACHARR' - padding. - -`~@R' - print a number as a Roman numeral. - -`~:R' - print a number as an ordinal English number. - -`~:@R' - print a number as a cardinal English number. - -`~P' - Plural. - `~@P' - prints `y' and `ies'. - - `~:P' - as `~P but jumps 1 argument backward.' - - `~:@P' - as `~@P but jumps 1 argument backward.' - -`~C' - Character. - `~@C' - prints a character as the reader can understand it (i.e. `#\' - prefixing). - - `~:C' - prints a character as emacs does (eg. `^C' for ASCII 03). - -`~F' - Fixed-format floating-point (prints a flonum like MMM.NNN). - `~WIDTH,DIGITS,SCALE,OVERFLOWCHAR,PADCHARF' - `~@F' - If the number is positive a plus sign is printed. - -`~E' - Exponential floating-point (prints a flonum like MMM.NNN`E'EE). - `~WIDTH,DIGITS,EXPONENTDIGITS,SCALE,OVERFLOWCHAR,PADCHAR,EXPONENTCHARE' - `~@E' - If the number is positive a plus sign is printed. - -`~G' - General floating-point (prints a flonum either fixed or - exponential). - `~WIDTH,DIGITS,EXPONENTDIGITS,SCALE,OVERFLOWCHAR,PADCHAR,EXPONENTCHARG' - `~@G' - If the number is positive a plus sign is printed. - -`~$' - Dollars floating-point (prints a flonum in fixed with signs - separated). - `~DIGITS,SCALE,WIDTH,PADCHAR$' - `~@$' - If the number is positive a plus sign is printed. - - `~:@$' - A sign is always printed and appears before the padding. - - `~:$' - The sign appears before the padding. - -`~%' - Newline. - `~N%' - print N newlines. - -`~&' - print newline if not at the beginning of the output line. - `~N&' - prints `~&' and then N-1 newlines. - -`~|' - Page Separator. - `~N|' - print N page separators. - -`~~' - Tilde. - `~N~' - print N tildes. - -`~'<newline> - Continuation Line. - `~:'<newline> - newline is ignored, white space left. - - `~@'<newline> - newline is left, white space ignored. - -`~T' - Tabulation. - `~@T' - relative tabulation. - - `~COLNUM,COLINCT' - full tabulation. - -`~?' - Indirection (expects indirect arguments as a list). - `~@?' - extracts indirect arguments from format arguments. - -`~(STR~)' - Case conversion (converts by `string-downcase'). - `~:(STR~)' - converts by `string-capitalize'. - - `~@(STR~)' - converts by `string-capitalize-first'. - - `~:@(STR~)' - converts by `string-upcase'. - -`~*' - Argument Jumping (jumps 1 argument forward). - `~N*' - jumps N arguments forward. - - `~:*' - jumps 1 argument backward. - - `~N:*' - jumps N arguments backward. - - `~@*' - jumps to the 0th argument. - - `~N@*' - jumps to the Nth argument (beginning from 0) - -`~[STR0~;STR1~;...~;STRN~]' - Conditional Expression (numerical clause conditional). - `~N[' - take argument from N. - - `~@[' - true test conditional. - - `~:[' - if-else-then conditional. - - `~;' - clause separator. - - `~:;' - default clause follows. - -`~{STR~}' - Iteration (args come from the next argument (a list)). - `~N{' - at most N iterations. - - `~:{' - args from next arg (a list of lists). - - `~@{' - args from the rest of arguments. - - `~:@{' - args from the rest args (lists). - -`~^' - Up and out. - `~N^' - aborts if N = 0 - - `~N,M^' - aborts if N = M - - `~N,M,K^' - aborts if N <= M <= K - -Not Implemented CL Format Control Directives -............................................ - -`~:A' - print `#f' as an empty list (see below). - -`~:S' - print `#f' as an empty list (see below). - -`~<~>' - Justification. - -`~:^' - (sorry I don't understand its semantics completely) - -Extended, Replaced and Additional Control Directives -.................................................... - -`~MINCOL,PADCHAR,COMMACHAR,COMMAWIDTHD' -`~MINCOL,PADCHAR,COMMACHAR,COMMAWIDTHX' -`~MINCOL,PADCHAR,COMMACHAR,COMMAWIDTHO' -`~MINCOL,PADCHAR,COMMACHAR,COMMAWIDTHB' -`~N,MINCOL,PADCHAR,COMMACHAR,COMMAWIDTHR' - COMMAWIDTH is the number of characters between two comma - characters. - -`~I' - print a R4RS complex number as `~F~@Fi' with passed parameters for - `~F'. - -`~Y' - Pretty print formatting of an argument for scheme code lists. - -`~K' - Same as `~?.' - -`~!' - Flushes the output if format DESTINATION is a port. - -`~_' - Print a `#\space' character - `~N_' - print N `#\space' characters. - -`~/' - Print a `#\tab' character - `~N/' - print N `#\tab' characters. - -`~NC' - Takes N as an integer representation for a character. No arguments - are consumed. N is converted to a character by `integer->char'. N - must be a positive decimal number. - -`~:S' - Print out readproof. Prints out internal objects represented as - `#<...>' as strings `"#<...>"' so that the format output can always - be processed by `read'. - -`~:A' - Print out readproof. Prints out internal objects represented as - `#<...>' as strings `"#<...>"' so that the format output can always - be processed by `read'. - -`~Q' - Prints information and a copyright notice on the format - implementation. - `~:Q' - prints format version. - -`~F, ~E, ~G, ~$' - may also print number strings, i.e. passing a number as a string - and format it accordingly. - -Configuration Variables -....................... - - Format has some configuration variables at the beginning of -`format.scm' to suit the systems and users needs. There should be no -modification necessary for the configuration that comes with SLIB. If -modification is desired the variable should be set after the format -code is loaded. Format detects automatically if the running scheme -system implements floating point numbers and complex numbers. - -FORMAT:SYMBOL-CASE-CONV - Symbols are converted by `symbol->string' so the case type of the - printed symbols is implementation dependent. - `format:symbol-case-conv' is a one arg closure which is either - `#f' (no conversion), `string-upcase', `string-downcase' or - `string-capitalize'. (default `#f') - -FORMAT:IOBJ-CASE-CONV - As FORMAT:SYMBOL-CASE-CONV but applies for the representation of - implementation internal objects. (default `#f') - -FORMAT:EXPCH - The character prefixing the exponent value in `~E' printing. - (default `#\E') - -Compatibility With Other Format Implementations -............................................... - -SLIB format 2.x: - See `format.doc'. - -SLIB format 1.4: - Downward compatible except for padding support and `~A', `~S', - `~P', `~X' uppercase printing. SLIB format 1.4 uses C-style - `printf' padding support which is completely replaced by the CL - `format' padding style. - -MIT C-Scheme 7.1: - Downward compatible except for `~', which is not documented - (ignores all characters inside the format string up to a newline - character). (7.1 implements `~a', `~s', ~NEWLINE, `~~', `~%', - numerical and variable parameters and `:/@' modifiers in the CL - sense). - -Elk 1.5/2.0: - Downward compatible except for `~A' and `~S' which print in - uppercase. (Elk implements `~a', `~s', `~~', and `~%' (no - directive parameters or modifiers)). - -Scheme->C 01nov91: - Downward compatible except for an optional destination parameter: - S2C accepts a format call without a destination which returns a - formatted string. This is equivalent to a #f destination in S2C. - (S2C implements `~a', `~s', `~c', `~%', and `~~' (no directive - parameters or modifiers)). - - This implementation of format is solely useful in the SLIB context -because it requires other components provided by SLIB. - - -File: slib.info, Node: Generic-Write, Next: Line I/O, Prev: Format, Up: Procedures - -Generic-Write -============= - - `(require 'generic-write)' - - `generic-write' is a procedure that transforms a Scheme data value -(or Scheme program expression) into its textual representation and -prints it. The interface to the procedure is sufficiently general to -easily implement other useful formatting procedures such as pretty -printing, output to a string and truncated output. - - - Procedure: generic-write OBJ DISPLAY? WIDTH OUTPUT - OBJ - Scheme data value to transform. - - DISPLAY? - Boolean, controls whether characters and strings are quoted. - - WIDTH - Extended boolean, selects format: - #f - single line format - - integer > 0 - pretty-print (value = max nb of chars per line) - - OUTPUT - Procedure of 1 argument of string type, called repeatedly with - successive substrings of the textual representation. This - procedure can return `#f' to stop the transformation. - - The value returned by `generic-write' is undefined. - - Examples: - (write obj) == (generic-write obj #f #f DISPLAY-STRING) - (display obj) == (generic-write obj #t #f DISPLAY-STRING) - - where - DISPLAY-STRING == - (lambda (s) (for-each write-char (string->list s)) #t) - - -File: slib.info, Node: Line I/O, Next: Multi-Processing, Prev: Generic-Write, Up: Procedures - -Line I/O -======== - - `(require 'line-i/o)' - - - Function: read-line - - Function: read-line PORT - Returns a string of the characters up to, but not including a - newline or end of file, updating PORT to point to the character - following the newline. If no characters are available, an end of - file object is returned. PORT may be omitted, in which case it - defaults to the value returned by `current-input-port'. - - - Function: read-line! STRING - - Function: read-line! STRING PORT - Fills STRING with characters up to, but not including a newline or - end of file, updating the port to point to the last character read - or following the newline if it was read. If no characters are - available, an end of file object is returned. If a newline or end - of file was found, the number of characters read is returned. - Otherwise, `#f' is returned. PORT may be omitted, in which case - it defaults to the value returned by `current-input-port'. - - - Function: write-line STRING - - Function: write-line STRING PORT - Writes STRING followed by a newline to the given port and returns - an unspecified value. Port may be omited, in which case it - defaults to the value returned by `current-input-port'. - - -File: slib.info, Node: Multi-Processing, Next: Object-To-String, Prev: Line I/O, Up: Procedures - -Multi-Processing -================ - - `(require 'process)' - - - Procedure: add-process! PROC - Adds proc, which must be a procedure (or continuation) capable of - accepting accepting one argument, to the `process:queue'. The - value returned is unspecified. The argument to PROC should be - ignored. If PROC returns, the process is killed. - - - Procedure: process:schedule! - Saves the current process on `process:queue' and runs the next - process from `process:queue'. The value returned is unspecified. - - - Procedure: kill-process! - Kills the current process and runs the next process from - `process:queue'. If there are no more processes on - `process:queue', `(slib:exit)' is called (*Note System::). - - -File: slib.info, Node: Object-To-String, Next: Pretty-Print, Prev: Multi-Processing, Up: Procedures - -Object-To-String -================ - - `(require 'object->string)' - - - Function: object->string OBJ - Returns the textual representation of OBJ as a string. - - -File: slib.info, Node: Pretty-Print, Next: Sorting, Prev: Object-To-String, Up: Procedures - -Pretty-Print -============ - - `(require 'pretty-print)' - - - Procedure: pretty-print OBJ - - Procedure: pretty-print OBJ PORT - `pretty-print's OBJ on PORT. If PORT is not specified, - `current-output-port' is used. - - Example: - (pretty-print '((1 2 3 4 5) (6 7 8 9 10) (11 12 13 14 15) - (16 17 18 19 20) (21 22 23 24 25))) - -| ((1 2 3 4 5) - -| (6 7 8 9 10) - -| (11 12 13 14 15) - -| (16 17 18 19 20) - -| (21 22 23 24 25)) - - `(require 'pprint-file)' - - - Procedure: pprint-file INFILE - - Procedure: pprint-file INFILE OUTFILE - Pretty-prints all the code in INFILE. If OUTFILE is specified, - the output goes to OUTFILE, otherwise it goes to - `(current-output-port)'. - - - Function: pprint-filter-file INFILE PROC OUTFILE - - Function: pprint-filter-file INFILE PROC - INFILE is a port or a string naming an existing file. Scheme - source code expressions and definitions are read from the port (or - file) and PROC is applied to them sequentially. - - OUTFILE is a port or a string. If no OUTFILE is specified then - `current-output-port' is assumed. These expanded expressions are - then `pretty-print'ed to this port. - - Whitepsace and comments (introduced by `;') which are not part of - scheme expressions are reproduced in the output. This procedure - does not affect the values returned by `current-input-port' and - `current-output-port'. - - `pprint-filter-file' can be used to pre-compile macro-expansion and -thus can reduce loading time. The following will write into -`exp-code.scm' the result of expanding all defmacros in `code.scm'. - (require 'pprint-file) - (require 'defmacroexpand) - (defmacro:load "my-macros.scm") - (pprint-filter-file "code.scm" defmacro:expand* "exp-code.scm") - |