pad-start

Summary

Pad a string to a certain length by prepending another string.

Description

This function will, if necessary, prepend padding on to the beginning of text repeatedly until the desired pad-length is reached.

Because of this the string in padding can be truncated if the amount of characters that need to be added can't be evenly divided through the length of padding.

This means that you have to be careful not to use unicode characters as a padding, or make sure that it can be used without truncation.

Arguments

Return value

Examples

(pad-start '123 6 ".-")
"-.-123"

(pad-start 123 6 "0")
"000123"

(pad-start "123" 6)
"   123"

Bytecode

Probably only interesting to you if you want to understand more about the Nujel VM or care very much about performance.

(    0 ($get/val 'padding))
(    2 ($jf* 7))
(    5 ($push/nil))
(    6 ($jmp* 7))
(    9 ($push/val  ))
(   11 ($set/val 'padding))
(   13 ($drop))
(   14 ($push/val :string))
(   16 ($get/val 'type-of))
(   18 ($get/val 'text))
(   20 ($apply 1))
(   22 ($=))
(   23 ($jf* 7))
(   26 ($push/nil))
(   27 ($jmp* 11))
(   30 ($get/val 'string))
(   32 ($get/val 'text))
(   34 ($apply 1))
(   36 ($set/val 'text))
(   38 ($drop))
(   39 ($push/val :string))
(   41 ($get/val 'type-of))
(   43 ($get/val 'padding))
(   45 ($apply 1))
(   47 ($=))
(   48 ($jf* 7))
(   51 ($push/nil))
(   52 ($jmp* 21))
(   55 ($get/val 'throw))
(   57 ($get/val 'list))
(   59 ($push/val :type-error))
(   61 ($push/val pad-start needs char as a string, so that one can pad with multiple characters))
(   63 ($get/val 'padding))
(   65 ($get/val 'current-lambda))
(   67 ($apply 0))
(   69 ($apply 4))
(   71 ($apply 1))
(   73 ($drop))
(   74 ($push/nil))
(   75 ($jmp* 14))
(   78 ($drop))
(   79 ($get/val 'cat))
(   81 ($get/val 'padding))
(   83 ($get/val 'text))
(   85 ($apply 2))
(   87 ($set/val 'text))
(   89 ($get/val 'buffer/length))
(   91 ($get/val 'text))
(   93 ($apply 1))
(   95 ($get/val 'pad-length))
(   97 ($<))
(   98 ($jt* -20))
(  101 ($drop))
(  102 ($get/val 'buffer/length))
(  104 ($get/val 'text))
(  106 ($apply 1))
(  108 ($get/val 'pad-length))
(  110 ($>))
(  111 ($jf* 27))
(  114 ($get/val 'string/cut))
(  116 ($get/val 'text))
(  118 ($get/val 'buffer/length))
(  120 ($get/val 'text))
(  122 ($apply 1))
(  124 ($get/val 'pad-length))
(  126 ($sub))
(  127 ($get/val 'buffer/length))
(  129 ($get/val 'text))
(  131 ($apply 1))
(  133 ($apply 3))
(  135 ($jmp* 5))
(  138 ($get/val 'text))
(  140 ($ret))

Related