--- /dev/null
+;;;; -*-scheme-*-
+;;;;
+;;;; Copyright (C) 2001, 2004, 2006 Free Software Foundation, Inc.
+;;;;
+;;;; This library is free software; you can redistribute it and/or
+;;;; modify it under the terms of the GNU Lesser General Public
+;;;; License as published by the Free Software Foundation; either
+;;;; version 2.1 of the License, or (at your option) any later version.
+;;;;
+;;;; This library is distributed in the hope that it will be useful,
+;;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+;;;; Lesser General Public License for more details.
+;;;;
+;;;; You should have received a copy of the GNU Lesser General Public
+;;;; License along with this library; if not, write to the Free Software
+;;;; Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+;;;;
+(define-module (ice-9 pretty-print)
+ :use-module (ice-9 optargs)
+ :export (pretty-print))
+
+;; From SLIB.
+
+;;"genwrite.scm" generic write used by pretty-print and truncated-print.
+;; Copyright (c) 1991, Marc Feeley
+;; Author: Marc Feeley (feeley@iro.umontreal.ca)
+;; Distribution restrictions: none
+
+(define genwrite:newline-str (make-string 1 #\newline))
+
+(define (generic-write obj display? width per-line-prefix output)
+
+ (define (read-macro? l)
+ (define (length1? l) (and (pair? l) (null? (cdr l))))
+ (let ((head (car l)) (tail (cdr l)))
+ (case head
+ ((quote quasiquote unquote unquote-splicing) (length1? tail))
+ (else #f))))
+
+ (define (read-macro-body l)
+ (cadr l))
+
+ (define (read-macro-prefix l)
+ (let ((head (car l)))
+ (case head
+ ((quote) "'")
+ ((quasiquote) "`")
+ ((unquote) ",")
+ ((unquote-splicing) ",@"))))
+
+ (define (out str col)
+ (and col (output str) (+ col (string-length str))))
+
+ (define (wr obj col)
+ (cond ((and (pair? obj)
+ (read-macro? obj))
+ (wr (read-macro-body obj)
+ (out (read-macro-prefix obj) col)))
+ (else
+ (out (object->string obj (if display? display write)) col))))
+
+ (define (pp obj col)
+
+ (define (spaces n col)
+ (if (> n 0)
+ (if (> n 7)
+ (spaces (- n 8) (out " " col))
+ (out (substring " " 0 n) col))
+ col))
+
+ (define (indent to col)
+ (and col
+ (if (< to col)
+ (and (out genwrite:newline-str col)
+ (out per-line-prefix 0)
+ (spaces to 0))
+ (spaces (- to col) col))))
+
+ (define (pr obj col extra pp-pair)
+ (if (or (pair? obj) (vector? obj)) ; may have to split on multiple lines
+ (let ((result '())
+ (left (min (+ (- (- width col) extra) 1) max-expr-width)))
+ (generic-write obj display? #f ""
+ (lambda (str)
+ (set! result (cons str result))
+ (set! left (- left (string-length str)))
+ (> left 0)))
+ (if (> left 0) ; all can be printed on one line
+ (out (reverse-string-append result) col)
+ (if (pair? obj)
+ (pp-pair obj col extra)
+ (pp-list (vector->list obj) (out "#" col) extra pp-expr))))
+ (wr obj col)))
+
+ (define (pp-expr expr col extra)
+ (if (read-macro? expr)
+ (pr (read-macro-body expr)
+ (out (read-macro-prefix expr) col)
+ extra
+ pp-expr)
+ (let ((head (car expr)))
+ (if (symbol? head)
+ (let ((proc (style head)))
+ (if proc
+ (proc expr col extra)
+ (if (> (string-length (symbol->string head))
+ max-call-head-width)
+ (pp-general expr col extra #f #f #f pp-expr)
+ (pp-call expr col extra pp-expr))))
+ (pp-list expr col extra pp-expr)))))
+
+ ; (head item1
+ ; item2
+ ; item3)
+ (define (pp-call expr col extra pp-item)
+ (let ((col* (wr (car expr) (out "(" col))))
+ (and col
+ (pp-down (cdr expr) col* (+ col* 1) extra pp-item))))
+
+ ; (item1
+ ; item2
+ ; item3)
+ (define (pp-list l col extra pp-item)
+ (let ((col (out "(" col)))
+ (pp-down l col col extra pp-item)))
+
+ (define (pp-down l col1 col2 extra pp-item)
+ (let loop ((l l) (col col1))
+ (and col
+ (cond ((pair? l)
+ (let ((rest (cdr l)))
+ (let ((extra (if (null? rest) (+ extra 1) 0)))
+ (loop rest
+ (pr (car l) (indent col2 col) extra pp-item)))))
+ ((null? l)
+ (out ")" col))
+ (else
+ (out ")"
+ (pr l
+ (indent col2 (out "." (indent col2 col)))
+ (+ extra 1)
+ pp-item)))))))
+
+ (define (pp-general expr col extra named? pp-1 pp-2 pp-3)
+
+ (define (tail1 rest col1 col2 col3)
+ (if (and pp-1 (pair? rest))
+ (let* ((val1 (car rest))
+ (rest (cdr rest))
+ (extra (if (null? rest) (+ extra 1) 0)))
+ (tail2 rest col1 (pr val1 (indent col3 col2) extra pp-1) col3))
+ (tail2 rest col1 col2 col3)))
+
+ (define (tail2 rest col1 col2 col3)
+ (if (and pp-2 (pair? rest))
+ (let* ((val1 (car rest))
+ (rest (cdr rest))
+ (extra (if (null? rest) (+ extra 1) 0)))
+ (tail3 rest col1 (pr val1 (indent col3 col2) extra pp-2)))
+ (tail3 rest col1 col2)))
+
+ (define (tail3 rest col1 col2)
+ (pp-down rest col2 col1 extra pp-3))
+
+ (let* ((head (car expr))
+ (rest (cdr expr))
+ (col* (wr head (out "(" col))))
+ (if (and named? (pair? rest))
+ (let* ((name (car rest))
+ (rest (cdr rest))
+ (col** (wr name (out " " col*))))
+ (tail1 rest (+ col indent-general) col** (+ col** 1)))
+ (tail1 rest (+ col indent-general) col* (+ col* 1)))))
+
+ (define (pp-expr-list l col extra)
+ (pp-list l col extra pp-expr))
+
+ (define (pp-LAMBDA expr col extra)
+ (pp-general expr col extra #f pp-expr-list #f pp-expr))
+
+ (define (pp-IF expr col extra)
+ (pp-general expr col extra #f pp-expr #f pp-expr))
+
+ (define (pp-COND expr col extra)
+ (pp-call expr col extra pp-expr-list))
+
+ (define (pp-CASE expr col extra)
+ (pp-general expr col extra #f pp-expr #f pp-expr-list))
+
+ (define (pp-AND expr col extra)
+ (pp-call expr col extra pp-expr))
+
+ (define (pp-LET expr col extra)
+ (let* ((rest (cdr expr))
+ (named? (and (pair? rest) (symbol? (car rest)))))
+ (pp-general expr col extra named? pp-expr-list #f pp-expr)))
+
+ (define (pp-BEGIN expr col extra)
+ (pp-general expr col extra #f #f #f pp-expr))
+
+ (define (pp-DO expr col extra)
+ (pp-general expr col extra #f pp-expr-list pp-expr-list pp-expr))
+
+ ; define formatting style (change these to suit your style)
+
+ (define indent-general 2)
+
+ (define max-call-head-width 5)
+
+ (define max-expr-width 50)
+
+ (define (style head)
+ (case head
+ ((lambda let* letrec define) pp-LAMBDA)
+ ((if set!) pp-IF)
+ ((cond) pp-COND)
+ ((case) pp-CASE)
+ ((and or) pp-AND)
+ ((let) pp-LET)
+ ((begin) pp-BEGIN)
+ ((do) pp-DO)
+ (else #f)))
+
+ (pr obj col 0 pp-expr))
+
+ (out per-line-prefix 0)
+ (if width
+ (out genwrite:newline-str (pp obj 0))
+ (wr obj 0))
+ ;; Return `unspecified'
+ (if #f #f))
+
+; (reverse-string-append l) = (apply string-append (reverse l))
+
+(define (reverse-string-append l)
+
+ (define (rev-string-append l i)
+ (if (pair? l)
+ (let* ((str (car l))
+ (len (string-length str))
+ (result (rev-string-append (cdr l) (+ i len))))
+ (let loop ((j 0) (k (- (- (string-length result) i) len)))
+ (if (< j len)
+ (begin
+ (string-set! result k (string-ref str j))
+ (loop (+ j 1) (+ k 1)))
+ result)))
+ (make-string i)))
+
+ (rev-string-append l 0))
+
+(define (pretty-print obj . opts)
+ "Pretty-print OBJ on PORT, which is a keyword argument defaulting to
+the current output port. Formatting can be controlled by a number of
+keyword arguments: Each line in the output is preceded by the string
+PER-LINE-PREFIX, which is empty by default. The output lines will be
+at most WIDTH characters wide; the default is 79. If DISPLAY? is
+true, display rather than write representation will be used.
+
+Instead of with a keyword argument, you can also specify the output
+port directly after OBJ, like (pretty-print OBJ PORT)."
+ (if (pair? opts)
+ (if (keyword? (car opts))
+ (apply pretty-print-with-keys obj opts)
+ (apply pretty-print-with-keys obj #:port (car opts) (cdr opts)))
+ (pretty-print-with-keys obj)))
+
+(define* (pretty-print-with-keys obj
+ #:key
+ (port (current-output-port))
+ (width 79)
+ (display? #f)
+ (per-line-prefix ""))
+ (generic-write obj display?
+ (- width (string-length per-line-prefix))
+ per-line-prefix
+ (lambda (s) (display s port) #t)))
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