Re: TAB KEY
- Posted by achury Oct 13, 2020
- 1315 views
I think is a severe bug that must to be fixed and may cause a lot of confusion.
I noted this because edx.ex editor on windows don't accept TAB
From: https://en.wikipedia.org/wiki/Tab_key
In software engineering, when developing computer programs or storing and manipulating data in files, the Tab character is often used for indentation purposes to help guide the flow of reading and add semantic structure to the code or data. Some programmers and programming languages prefer the usage of multiple whitespace characters instead for that purpose. Because of this, many text editors have an option that makes the tab key insert the number of whitespace characters that a tab character is set to be equivalent to (by default mostly four).
Tab characters
The most known and common tab is a horizontal tabulation (HT) or character tabulation, which in ASCII has the decimal character code of 9, and may be referred to as Ctrl+I or ^I. In C and many other programming languages the escape code \t can be used to put this character into a string constant. The horizontal tab is usually inserted when the Tab key on a standard keyboard is pressed.
A vertical tabulation (VT) also exists and has ASCII decimal character code 11 (Ctrl+K or ^K), escape character \v.
In EBCDIC the code for HT is 5. VT is 11 (coincidentally the same as in ASCII).
And near the end of the same article wikipedia says about TAB on unicode
The Unicode code points for the (horizontal) tab character, and the more rarely used vertical tab character are copied from ASCII [14]
U+0009 <control-0009> (CHARACTER TABULATION, horizontal tabulation (HT), tab)
U+000B <control-000B> (LINE TABULATION, vertical tabulation (VT))
U+000B <control-000B> (LINE TABULATION, vertical tabulation (VT))
The tab characters can be graphically represented by special symbols:
U+2409 ␉ SYMBOL FOR HORIZONTAL TABULATION
U+240B ␋ SYMBOL FOR VERTICAL TABULATION
U+240B ␋ SYMBOL FOR VERTICAL TABULATION
Unicode also has characters for the symbols to represent or be printed on the tab key [15]
U+21B9 ↹ LEFTWARDS ARROW TO BAR OVER RIGHTWARDS ARROW TO BAR (tab with shift tab)
U+21C6 ⇆ LEFTWARDS ARROW OVER RIGHTWARDS ARROW
U+21E4 ⇤ LEFTWARDS ARROW TO BAR (leftward tab)
U+21E5 ⇥ RIGHTWARDS ARROW TO BAR (rightward tab)
U+21C6 ⇆ LEFTWARDS ARROW OVER RIGHTWARDS ARROW
U+21E4 ⇤ LEFTWARDS ARROW TO BAR (leftward tab)
U+21E5 ⇥ RIGHTWARDS ARROW TO BAR (rightward tab)
So Unicode has glyphs to represent the tabulation and the symbol that appear on the Tab key, but in the keyboard input itself is allways 9
And obviously, If you run this program:
? "\t"
You will get as result a {9}
And any program that get keyboard input and save it to a file, is supposed that will save 9...
Marco Achury
