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author | Andy Wingo <wingo@pobox.com> | 2009-04-17 11:19:42 +0200 |
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committer | Andy Wingo <wingo@pobox.com> | 2009-04-17 11:19:42 +0200 |
commit | 6d66647d5b2c6649bb4dade734f6d583d10d797c (patch) | |
tree | 3c05d62af67617f0949fbe4a4228ac3564da0be5 /module/scripts/read-text-outline.scm | |
parent | 798244609bfd3b4d2b12f722d9130d47abcfeb1a (diff) | |
download | guile-6d66647d5b2c6649bb4dade734f6d583d10d797c.tar.gz |
guile-tools is a scheme script that loads scheme modules
* meta/guile-tools: Changed to be a scheme script. Instead of looking for
executables in a "scripts dir", we just look for modules in (scripts),
and load the modules directly.
* module/Makefile.am:
* module/scripts/: Move the scripts into module/ so they can be compiled.
Rename scripts from `foo' to `foo.scm'.
* libguile/Makefile.am: Invoke the snarf->texi code via guile-tools.
* configure.in:
* .gitignore: Update for changes.
Diffstat (limited to 'module/scripts/read-text-outline.scm')
-rw-r--r-- | module/scripts/read-text-outline.scm | 250 |
1 files changed, 250 insertions, 0 deletions
diff --git a/module/scripts/read-text-outline.scm b/module/scripts/read-text-outline.scm new file mode 100644 index 000000000..579fb6934 --- /dev/null +++ b/module/scripts/read-text-outline.scm @@ -0,0 +1,250 @@ +;;; read-text-outline --- Read a text outline and display it as a sexp + +;; Copyright (C) 2002, 2006 Free Software Foundation, Inc. +;; +;; This program is free software; you can redistribute it and/or +;; modify it under the terms of the GNU General Public License as +;; published by the Free Software Foundation; either version 2, or +;; (at your option) any later version. +;; +;; This program 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 +;; General Public License for more details. +;; +;; You should have received a copy of the GNU General Public License +;; along with this software; see the file COPYING. If not, write to +;; the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, +;; Boston, MA 02110-1301 USA + +;;; Author: Thien-Thi Nguyen <ttn@gnu.org> + +;;; Commentary: + +;; Usage: read-text-outline OUTLINE +;; +;; Scan OUTLINE file and display a list of trees, the structure of +;; each reflecting the "levels" in OUTLINE. The recognized outline +;; format (used to indicate outline headings) is zero or more pairs of +;; leading spaces followed by "-". Something like: +;; +;; - a 0 +;; - b 1 +;; - c 2 +;; - d 1 +;; - e 0 +;; - f 1 +;; - g 2 +;; - h 1 +;; +;; In this example the levels are shown to the right. The output for +;; such a file would be the single line: +;; +;; (("a" ("b" "c") "d") ("e" ("f" "g") "h")) +;; +;; Basically, anything at the beginning of a list is a parent, and the +;; remaining elements of that list are its children. +;; +;; +;; Usage from a Scheme program: These two procs are exported: +;; +;; (read-text-outline . args) ; only first arg is used +;; (read-text-outline-silently port) +;; (make-text-outline-reader re specs) +;; +;; `make-text-outline-reader' returns a proc that reads from PORT and +;; returns a list of trees (similar to `read-text-outline-silently'). +;; +;; RE is a regular expression (string) that is used to identify a header +;; line of the outline (as opposed to a whitespace line or intervening +;; text). RE must begin w/ a sub-expression to match the "level prefix" +;; of the line. You can use `level-submatch-number' in SPECS (explained +;; below) to specify a number other than 1, the default. +;; +;; Normally, the level of the line is taken directly as the length of +;; its level prefix. This often results in adjacent levels not mapping +;; to adjacent numbers, which confuses the tree-building portion of the +;; program, which expects top-level to be 0, first sub-level to be 1, +;; etc. You can use `level-substring-divisor' or `compute-level' in +;; SPECS to specify a constant scaling factor or specify a completely +;; alternative procedure, respectively. +;; +;; SPECS is an alist which may contain the following key/value pairs: +;; +;; - level-submatch-number NUMBER +;; - level-substring-divisor NUMBER +;; - compute-level PROC +;; - body-submatch-number NUMBER +;; - extra-fields ((FIELD-1 . SUBMATCH-1) (FIELD-2 . SUBMATCH-2) ...) +;; +;; The PROC value associated with key `compute-level' should take a +;; Scheme match structure (as returned by `regexp-exec') and return a +;; number, the normalized level for that line. If this is specified, +;; it takes precedence over other level-computation methods. +;; +;; Use `body-submatch-number' if RE specifies the whole body, or if you +;; want to make use of the extra fields parsing. The `extra-fields' +;; value is a sub-alist, whose keys name additional fields that are to +;; be recognized. These fields along with `level' are set as object +;; properties of the final string ("body") that is consed into the tree. +;; If a field name ends in "?" the field value is set to be #t if there +;; is a match and the result is not an empty string, and #f otherwise. +;; +;; +;; Bugs and caveats: +;; +;; (1) Only the first file specified on the command line is scanned. +;; (2) TAB characters at the beginnings of lines are not recognized. +;; (3) Outlines that "skip" levels signal an error. In other words, +;; this will fail: +;; +;; - a 0 +;; - b 1 +;; - c 3 <-- skipped 2 -- error! +;; - d 1 +;; +;; +;; TODO: Determine what's the right thing to do for skips. +;; Handle TABs. +;; Make line format customizable via longopts. + +;;; Code: + +(define-module (scripts read-text-outline) + :export (read-text-outline + read-text-outline-silently + make-text-outline-reader) + :use-module (ice-9 regex) + :autoload (ice-9 rdelim) (read-line) + :autoload (ice-9 getopt-long) (getopt-long)) + +(define (?? symbol) + (let ((name (symbol->string symbol))) + (string=? "?" (substring name (1- (string-length name)))))) + +(define (msub n) + (lambda (m) + (match:substring m n))) + +(define (??-predicates pair) + (cons (car pair) + (if (?? (car pair)) + (lambda (m) + (not (string=? "" (match:substring m (cdr pair))))) + (msub (cdr pair))))) + +(define (make-line-parser re specs) + (let* ((rx (let ((fc (substring re 0 1))) + (make-regexp (if (string=? "^" fc) + re + (string-append "^" re))))) + (check (lambda (key) + (assq-ref specs key))) + (level-substring (msub (or (check 'level-submatch-number) 1))) + (extract-level (cond ((check 'compute-level) + => (lambda (proc) + (lambda (m) + (proc m)))) + ((check 'level-substring-divisor) + => (lambda (n) + (lambda (m) + (/ (string-length (level-substring m)) + n)))) + (else + (lambda (m) + (string-length (level-substring m)))))) + (extract-body (cond ((check 'body-submatch-number) + => msub) + (else + (lambda (m) (match:suffix m))))) + (misc-props! (cond ((check 'extra-fields) + => (lambda (alist) + (let ((new (map ??-predicates alist))) + (lambda (obj m) + (for-each + (lambda (pair) + (set-object-property! + obj (car pair) + ((cdr pair) m))) + new))))) + (else + (lambda (obj m) #t))))) + ;; retval + (lambda (line) + (cond ((regexp-exec rx line) + => (lambda (m) + (let ((level (extract-level m)) + (body (extract-body m))) + (set-object-property! body 'level level) + (misc-props! body m) + body))) + (else #f))))) + +(define (make-text-outline-reader re specs) + (let ((parse-line (make-line-parser re specs))) + ;; retval + (lambda (port) + (let* ((all '(start)) + (pchain (list))) ; parents chain + (let loop ((line (read-line port)) + (prev-level -1) ; how this relates to the first input + ; level determines whether or not we + ; start in "sibling" or "child" mode. + ; in the end, `start' is ignored and + ; it's much easier to ignore parents + ; than siblings (sometimes). this is + ; not to encourage ignorance, however. + (tp all)) ; tail pointer + (or (eof-object? line) + (cond ((parse-line line) + => (lambda (w) + (let* ((words (list w)) + (level (object-property w 'level)) + (diff (- level prev-level))) + (cond + + ;; sibling + ((zero? diff) + ;; just extend the chain + (set-cdr! tp words)) + + ;; child + ((positive? diff) + (or (= 1 diff) + (error "unhandled diff not 1:" diff line)) + ;; parent may be contacted by uncle later (kids + ;; these days!) so save its level + (set-object-property! tp 'level prev-level) + (set! pchain (cons tp pchain)) + ;; "push down" car into hierarchy + (set-car! tp (cons (car tp) words))) + + ;; uncle + ((negative? diff) + ;; prune back to where levels match + (do ((p pchain (cdr p))) + ((= level (object-property (car p) 'level)) + (set! pchain p))) + ;; resume at this level + (set-cdr! (car pchain) words) + (set! pchain (cdr pchain)))) + + (loop (read-line port) level words)))) + (else (loop (read-line port) prev-level tp))))) + (set! all (car all)) + (if (eq? 'start all) + '() ; wasteland + (cdr all)))))) + +(define read-text-outline-silently + (make-text-outline-reader "(([ ][ ])*)- *" + '((level-substring-divisor . 2)))) + +(define (read-text-outline . args) + (write (read-text-outline-silently (open-file (car args) "r"))) + (newline) + #t) ; exit val + +(define main read-text-outline) + +;;; read-text-outline ends here |