7b28f48f52704158cca8b02e3128b537a6ec6851
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Commits
| Author | SHA1 | Message | Date | |
|---|---|---|---|---|
 Anachronaut
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87d819847e |
A program can say how it went
SWI osExit takes a status in A, and the shell keeps it. Fifty eight exits across twenty three programs now say deliberately whether they worked: 25 did what they were asked, 24 did not, 9 were asked wrongly. Compare is the exception and says so - one there means the files differ, which is a result rather than a failure, the way diff has always had it. IN A RATHER THAN Q, which is not a departure from the rule that a service answers in Q. This one takes an ARGUMENT, the way osPrintNumber takes A and B, and it never returns to answer anything. A is free precisely because a return would have put it back - and Q is the ALU's output, so a small number costs four instructions there against one in A. The shell does not print it. A program that failed has already said so in words and a number beside that is noise, so osLastStatus hands it back and Status is the program that shows it. That indirection is the point: the number exists for the thing that cannot read words. MARKING THE EXITS FOUND A DEFECT ON THE FIRST RUN. Type and More printed why they had failed and then fell through into the success exit, reporting that all was well. Nobody had noticed, because while the only reader was a person, the person could see both the complaint and the claim. Two smaller things. Snake sets the console to line mode and then exits with zero, and the linter flagged the second RSTA as redundant - an exit status and a console mode, equal by accident, which is the class that must never be collapsed. And the README still taught answering by writing into the frame, three months of habit that SRET replaced yesterday; that section is gone and the one describing SRET stands in its place. |
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 AnachronautandClaude Opus 5
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da91a36d92 |
D4: the machine makes directories too
mkdir and rmdir are the machine's own now, and a file goes where its path says rather than always in the root. A disk can be organised without the host tool touching it. Everything below the surface works in terms of a directory and a name rather than a path. sbfsWalkParent splits the last name off, walks the rest, and hands back the two - and the separator stays on the end of the head, which is what makes one rule cover every kind of path: "/x" leaves "/", which is the root; "x" leaves nothing, which is where the machine already is; and "A/x" leaves "A/", which is neither and needs no special case to say so. Saving works in those two as well, and had to. The careful order a save uses - make a temporary, write it, delete the original, rename the temporary - only works if the temporary is made in the SAME directory as the file, because the rename at the end changes a name and does not move anything. Renaming to a path naming a different directory is refused for that reason, rather than quietly being a lie the disk goes along with. Three things this cost, all found by running it: mkdir Apps/Deep made /Apps/Apps. The leaf was worked out into SbfsWanted and then the head was walked - and walking goes through sbfsPathNext, which puts every name it meets into SbfsWanted on the way past. The head's last name landed exactly where the leaf was. It has somewhere of its own now. rmdir took a directory with something still in it, which is the one failure the whole design is arranged to prevent. Looking for children clobbered DP2 and rebuilt it from the buffer and the entry count with the subtraction the wrong way round, so the pointer walked off the end of the block and found nothing. The comparison goes through a CALL now, like the two beside it, and DP2 comes back on the entry because a RET puts it there. SplitDisk's "in use but not reachable from the root" line is what caught it. Refusing a name longer than twenty two used to read the twenty third character of a shorter one, which is somebody else's string. It is measured now. Tests/agree.sh is new and is the gate this rung was for: the same disk built twice, once with SplitDisk and once with CosmOS, compared byte for byte. The two share no code and only a written specification, and every field one writes and the other only reads is checked there and nowhere else - which entry a thing lands in, which block, what a directory's unused fields hold, the version, the free count. It caught a wrong parent immediately when that was broken on purpose. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01E2JrLzFvuFX9fgi1LDRjrW |
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AnachronautandClaude Opus 5
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36ce9f6ccf |
D3: the machine knows where it is
cd moves it, dir lists the directory it is in, and the prompt says which one - but only when that is not the root, so a machine nobody has moved about on looks exactly as it always did and every recorded test that never says "cd" keeps its recorded prompt. A path beginning with a separator is measured from the root and anything else from where the machine is, so a bare name means a file in the current directory. NO PROGRAM HAD TO BE TOLD: the working directory lives in sbfs.asm beside the thing that resolves paths, because it is what a relative path MEANS. Keeping it in the shell would have meant either handing it down on every call or pasting it onto the front of every name, and the second of those is how a name that is already absolute gets ruined. Nothing stores the path. The working directory is an entry index and two bytes, and the text on the prompt is built each time by walking the chain of parents upward, writing names from the end of a buffer towards the front - which is the order they arrive in, and saves reversing them afterwards. sbfsFind splits into a walk and a check. "cd /" and "cd .." both end at the root quite legitimately, and had no way to say so through a routine whose only word for the root was "missing". Typing a program's name now tries two places in order: where you are, then /Apps. The first makes a program you are working on the one that runs; the second lets Snake work from anywhere. A word already beginning with a separator has said where to look, so only that place is tried. osChangeDir exists so that "a program may move about, and the shell puts the working directory back" is a thing that can happen rather than a promise about nothing. Both halves of that were unfalsifiable without it: with no way for a program to move, removing the restore changed no test. Wander is the program that moves - it goes where it is told and reads a file there by a bare name - and with it on the disk, removing the restore fails. The remembered file is dropped whenever what a relative path means changes: a cd, a program calling osChangeDir, a program exiting. Removing all of them fails the test and removing any one of them does not, because today every path into that cache belongs to a program that exits. It is kept in all three because the cost is a call and the failure is a file's blocks being handed out under another file's name. The cwd fixture holds two files called notes.txt saying different things, and a Say.sbx in /A that is really hello. Two copies of one program, or two copies of one file, would have passed with the whole of this deleted. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01E2JrLzFvuFX9fgi1LDRjrW |
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AnachronautandClaude Opus 5
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2b0aeeefd4 |
Start a program by typing its name
A word the shell has no command for is now looked for on the disk as "<name>.sbx", and if it is there it is loaded and started exactly as load and run would do it. Whatever followed the word reaches the program through osArgument by the same route as whatever follows run, so "Say hello there" and "Type notes.txt" work without either program knowing how it was started. load and run are unchanged and both stay. load is how the monitor puts an arbitrary file in front of itself, which typing a name deliberately cannot do: the extension is added rather than assumed, so "notes.txt" looks for notes.txt.sbx and a text file is unreachable by name whatever is inside it. Three things this had to get right: The built-ins are tried first and always win. The search hangs off the end of the dispatch chain, so a file called dir.sbx cannot become dir, and the commands worth trusting when the disk is what you are doubting stay trustworthy. The invoke disk carries a working dir.sbx so that this is checked rather than asserted. A file that is found but is broken says so. "not a program" and "I do not know" are different answers, and giving the second about a file sitting on the disk would send somebody looking in the wrong place. loadProgram therefore hands back a status as well as a message, since only "no file of that name" can fairly be reported as anything other than a fault. doLoad became that subroutine rather than being copied. It ends in RET instead of a jump to the prompt, and each way of failing sets its number and its text together so a new one cannot leave half of the answer behind. cosmosBreak moves because Break prints the pointers it was handed and those are the shell's leftovers, which a CALL now puts back. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01E2JrLzFvuFX9fgi1LDRjrW |