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01/04: utils: Add a procedure for pretty printing tabular data.
From: |
guix-commits |
Subject: |
01/04: utils: Add a procedure for pretty printing tabular data. |
Date: |
Thu, 15 Jul 2021 16:12:46 -0400 (EDT) |
apteryx pushed a commit to branch master
in repository guix.
commit b73b9aae0d986b59f9b235788cfb758bf6b5411d
Author: Steve Sprang <scs@stevesprang.com>
AuthorDate: Tue Jan 9 14:00:11 2018 -0800
utils: Add a procedure for pretty printing tabular data.
* guix/utils.scm (pretty-print-table): New procedure.
Co-authored-by: Maxim Cournoyer <maxim.cournoyer@gmail.com>
Signed-off-by: Maxim Cournoyer <maxim.cournoyer@gmail.com>
---
guix/utils.scm | 33 ++++++++++++++++++++++++++++++++-
1 file changed, 32 insertions(+), 1 deletion(-)
diff --git a/guix/utils.scm b/guix/utils.scm
index 05af86f..2c56c8b 100644
--- a/guix/utils.scm
+++ b/guix/utils.scm
@@ -10,6 +10,8 @@
;;; Copyright © 2020 Efraim Flashner <efraim@flashner.co.il>
;;; Copyright © 2021 Simon Tournier <zimon.toutoune@gmail.com>
;;; Copyright © 2021 Chris Marusich <cmmarusich@gmail.com>
+;;; Copyright © 2018 Steve Sprang <scs@stevesprang.com>
+;;; Copyright © 2021 Maxim Cournoyer <maxim.cournoyer@gmail.com>
;;;
;;; This file is part of GNU Guix.
;;;
@@ -123,7 +125,9 @@
canonical-newline-port
string-distance
- string-closest))
+ string-closest
+
+ pretty-print-table))
;;;
@@ -935,6 +939,33 @@ according to THRESHOLD, then #f is returned."
#f +inf.0
tests)))
+
+;;;
+;;; Prettified output.
+;;;
+
+(define* (pretty-print-table rows #:key (max-column-width 20))
+ "Print ROWS in neat columns. All rows should be lists of strings and each
+row should have the same length. The columns are separated by a tab
+character, and aligned using spaces. The maximum width of each column is
+bound by MAX-COLUMN-WIDTH."
+ (let* ((number-of-columns-to-pad (if (null? rows)
+ 0
+ (1- (length (first rows)))))
+ ;; Ignore the last column as it is left aligned and doesn't need
+ ;; padding; this prevents printing extraneous trailing spaces.
+ (column-widths (fold (lambda (row maximums)
+ (map max (map string-length row) maximums))
+ ;; Initial max width is 0 for each column.
+ (make-list number-of-columns-to-pad 0)
+ (map (cut drop-right <> 1) rows)))
+ (column-formats (map (cut format #f "~~~da" <>)
+ (map (cut min <> max-column-width)
+ column-widths)))
+ (fmt (string-append (string-join column-formats "\t") "\t~a")))
+ (setvbuf (current-output-port) 'block) ;for better performance
+ (for-each (cut format #t "~?~%" fmt <>) rows)))
+
;;; Local Variables:
;;; eval: (put 'call-with-progress-reporter 'scheme-indent-function 1)
;;; End: