Linus Torvalds Injects Tabs To Thwart Kconfig Parsers Not Correctly Handling Them

[freerunner]

Having the configuration defined as model allows to view and edit it in human readable form while in binary format. And you don't even need a text editor, just run the application in configuration mode. Plus the type safety and input validation and whatnot. And it actually shows you the configuration tree, so you don't have to know it by heart or look it up elsewhere.

How is dumb old text better?

Let's just wait for systemd integration. /s
(How I despise a binary syslog)

[Old Grouch]

It's worth remembering what a horizontal tab character actually means.

It is an instruction to the device displaying the data in which the horizontal tab character is found to move the virtual print head to the next tab-stop after the current position of the virtual print head on the displaying device. The virtual print head does not backtrack to a previously 'unused' tab-stop.

This has several consequences:

1) It means that the tab stop settings are not necessarily described in the data itself. Although they can be in, for example, word-processing documents, they are usually extrinsic to the data, and a setting of the display device. It is a control character instructing the displaying device to do something. Different devices can have different defaults.

2) It is not a character that instructs its own replacement by a (variable, possibly calculated) number of space characters, although that is one implementation.

3) Tab stops also work when using proportional fonts, because they are not defined by character widths. They are 'simply' a distance from the start point of the (virtual) print head. In monospaced fonts, that can correspond with a multiple of a character width, but it need not necessarily do so. That distance can be measured in points, pica, inches, centimetres, furlongs, light-years, and also multiples of the (current) character width in the (current) font.

4) If no tab stops are set, an instruction to move to the next one is difficult to interpret. In a mechanical typewriter, the carriage would move to the extreme left. This is a consequence of the mechanical implementation. Other possible behaviours are to ignore the horizontal tab character (i.e. it is zero width), or replace it with a single space character.

This stackoverflow answer covers much the same: https://stackoverflow.com/questions/...of-systems-and

I have no strong opinions on the use of horizontal tabs or spaces in formatting code.

Vertical tab stops and the vertical tab character operate in the same way. The vertical tab stops are a distance from the top of the document page. A combination of horizontal tabs, carriage returns, and vertical tabs allows rapid movement around the print area which is useful when entering information onto pre-printed forms using impact printers. You get to the start of the next form using the form feed character, which could have an implied carriage return.

This fast navigation to fields in a form is why the horizontal tab key is used to step through from field to field in on-screen forms.

[anarki2]

This time he's wrong. Tabs have no purpose in anything. It's an ancient gimmick aimed at saving meaningless amounts of storage space and computing resources by inventing a silly character that can substitute multiple somewhat redundant characters, while also including annoying side-effects, and sometimes even bugs as evident. Those days are gone, have been for 30 years already.

I hope you don't work on frontend. You confuse markup with content. This is the equivalent of putting multiple line breaks in the HTML text, instead of adjusting paragraph padding via CSS.

Which one do you think makes more sense? Did you really want to have multiple empty paragraphs, or were you just lazy to use the appropriate tool for the task?

If you don't understand the difference, that's fine, just stop judging Linus for that.

[ddriver]

Which means that sharing a config file with someone for comments or removing configuration mishaps isn't generally possible: and if your object model changes, the config could change as well, so being able to interpret the binary config correctly could well be software version dependant. It also make independent detection and possible correction of corruption rather difficult.

If you have come up with a better way, then perhaps it should become standard practice. Standard practices do need testing every now and then to see if they are still relevant or can be improved, and perhaps your way is the way forward. I will be surprised if it is generally adopted, but life is full of surprises.

It is a model first approach through and through. This includes the full system state - to create a new application, to run an existing application, to make modifications to something pre-existing, if authorized to.

All file operations go through that as well. In fact, under my model use, the user is not expected or encouraged to manually tamper with files. Doing a dumb file copy from one system to another is not supported - the file would not work on another installation, the proper way to initiate a file transfer is through the object model. You can still make a configuration snapshot and use the proper channel to transfer it to another system, which will transfer it in the target system's native format. It will be recognized for what it is on the other end, and any incompatibilities or breaking changes will be immediately highlighted when the configuration is received and resolved, before being applied.

The architecture does remove a lot of legacy manual labor stuff, and that includes working with files the olden way. All that stuff is completely abstracted away, and can be implemented in a number of different back-ends, not necessarily a file storage device.

Last but not least - having functionality where a critical section can be modified by means of parsing some arbitrary file anyone could have left of the system in any arbitrary state is a big no-no in my book. Under my usage model, unauthorized modification should not occur under any circumstances.