From: Ralph Ronnquist <ralph.ronnquist@gmail.com>
Date: Mon, 24 Apr 2023 05:27:04 +0000 (+1000)
Subject: Adding pre-fill. Editorial
X-Git-Url: https://git.rrq.au/?a=commitdiff_plain;h=130e7ff320ade199cdedb1a26b2e4a5fb087d5fa;p=rrq%2Flsp-utils.git

Adding pre-fill. Editorial
---

diff --git a/lsp-misc/misc.lsp b/lsp-misc/misc.lsp
index 9e77db9..ff76d5a 100644
--- a/lsp-misc/misc.lsp
+++ b/lsp-misc/misc.lsp
@@ -1,3 +1,5 @@
+;; This module provides some global utility functions.
+
 (define (prog1 X) X)
 (global 'prog1)
 
@@ -6,8 +8,14 @@
   (and N (exit N)))
 (global 'die)
 
-(define (char2hex STR)
-  (join (map (curry format "%2x") (map char (explode STR)))))
+;; Prepend with C onto S so as to fill width W, if it's a number.
+(define (pre-fill C S W)
+  (if (and (number? W) (> (setf W (- W (length S))))) (string (dup C W) S) S))
+(global 'pre-fill)
+
+;; Make a hex string from a data block pad with "0" to W if non-nil
+(define (char2hex STR W)
+  (pre-fill "0" (join (map (curry format "%2x") (map char (explode STR)))) W))
 (global 'char2hex)
 
 ;; Print binary byte as octal or as ASCII character [32-126]
@@ -20,12 +28,12 @@
   (join (map octal-byte (unpack (dup "b" (length S)) S))))
 (global 'octals-string)
 
-;; Return byte code as printable or as code.
+;; Return byte code as printable or as decimal number.
 (define (human-byte B)
   (if (and (> B 32) (< B 127)) (char B) B))
 (global 'human-byte)
 
-;; Return a packed encoding of a list of bytes, joining string elements
+;; Return a packed encoding of a list of bytes, joining its string elements
 (define (human-bytes BL)
   (let ((OUT '()) (X nil))
     (dolist (B (map human-byte BL))