Why are '[' and ']' ascii codes not following each other?

Question

Does anyone know why the design decision of having '[' and ']' or '{' and '}' ASCII key codes being two apart instead of one digit was made? OCD triggered.

Tao

Answer 1

Evolution of Character Codes

Have a look @ the following article: https://web.archive.org/web/20050305043226/http://www.transbay.net/~enf/ascii/ascii.pdf

I found it from the following stackexchange article: https://softwareengineering.stackexchange.com/a/149901/94281

Ascii was an evolutionary result but was based on previous work/inventions such as telegrams and morse code.

Additionally, there were many different versions and proposals before we reached a final order and result.

It seems that in some of the initial proposals [ and ] had been placed together.

For example:

However, after the X3.2 meeting, the \ was added in between:

This is again visible in a publication from 1962:

Source: Source documents on the history of character codes, 1962-06

Substitution Characters

Reading the archive from Source Documents on the history of character Codes page 38 shows that some of the characters were grouped together and were planned to be substituted with other characters in 26 character languages:

A similar note is made about the characters '< = >' in relation to substituting them for more business-friendly characters.

References:

• The Evolution of Character Codes, 1874-1968 - Eric Fischer
• https://github.com/ericfischer/ascii/blob/master/ascii.ms
• Source documents on the history of character codes, 1962-06

Note: Researching this further to see why the X3.2 meeting resulted in this change.

Unwonted

Interesting. I observe that < > were together in the first two versions you show, first in column 2 then in column 3, and they ended up separated by = in column 3. – Limerick

This is unbelievable xD Very interesting results thanks! – Tao

They decided that a left brace ({), vertical line ( ), and right brace (}) would be useful and would remain comprehensible when they were mapped onto the brackets and backslash in upper-case-only versions of the code. – Tao