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Dennis Ritchie’s first C compiler (c. 1972)

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Re: Dennis Ritchie’s first C compiler (c. 1972)

#41

Post by amelius »

andreareina wrote: post #37
bawolff wrote: post #30

Earlier quoted context omitted.

I dont think it would look that out of place if he was using the ternary operator which is the same thing after all. E.g.: if (peekc) { c = peekc; peekc = 0; } else eof ? return(0) : c = getchar(); The first else clause sill looks weird, but the final part isn't nearly as out of place (well i guess assigning in a ternary would be weird, but in terms of indentation) and its not like we actually changed anything.

Can't return in a ternary.

Correct, return is not an expression. But then again, he could if he wanted to, as the language designer ;)

Re: Dennis Ritchie’s first C compiler (c. 1972)

#42

Post by josephg »

astroanax wrote: post #24

The original keywords - https://github.com/mortdeus/legacy-cc/blob/master/last1120c/... Interestingly, long was commented

It makes sense long would have needed a comment. It needs a comment because “long” and “double” are terrible names for data types. Long what? Double length what? Those type names could easily have opposite meanings and meant long floating point / double length integer. WORD/DWORD are nearly as bad - calling something a "word" incorrectly implies the data type has something to do with strings.

If you don't believe me, ask a non programmer friend what kind of thing an "integer" is in a computer program. Then ask them to guess what kind of thing a "long" is.

The only saving grace of these terms is they’re relatively easy to memorise. int_16/int_32/int_64 and float_32/float_64 (or i32/i64/f32/f64/...) are much better names, and I'm relieved that’s the direction most modern languages are taking.

(Edit: Oops I thought Microsoft came up with the names WORD / DWORD. Thanks for the correction!)

Re: Dennis Ritchie’s first C compiler (c. 1972)

#44

Post by zokier »

josephg wrote: post #42
astroanax wrote: post #24

The original keywords - https://github.com/mortdeus/legacy-cc/blob/master/last1120c/... Interestingly, long was commented

It makes sense long would have needed a comment. It needs a comment because “long” and “double” are terrible names for data types. Long what ? Double length what ? Those type names could easily have opposite meanings and meant long floating point / double length integer. WORD/DWORD are nearly as bad - calling something a "word" incorrectly implies the data type has something to do with strings. If you don't believe m…

> Microsoft’s WORD/DWORD are nearly as bad. Don’t call something a “word” if it doesn’t store characters.

"Word" as a term has been in the wide use since at least 50s-60s, you can't really blame MS for that

https://en.wikipedia.org/wiki/Word_(computer_architecture)

Re: Dennis Ritchie’s first C compiler (c. 1972)

#45

Post by kiwidrew »

code_sloth wrote: post #27
amyjess wrote: post #20

I have to say, the way indentation and brackets were done here looks like it's just inviting subtle bugs. Take this for example: if (peekc) { c = peekc; peekc = 0; } else if (eof) return(0); else c = getchar();

If you judge the coding style of the early 1970s with modern standards, it isn't going to look great. 50 years is a loooong time. dmr was one of, if not the first C programmer(s).

And he was almost certainly using ed(1) as his editor and a mechanical teletype at 7.5 or 10.0 characters per second as his terminal...

The C language (and all of Unix) was designed to be very terse as a consequence.

Re: Dennis Ritchie’s first C compiler (c. 1972)

#46

Post by kiwidrew »

pabs3 wrote: post #26
retrac wrote: post #9

Earlier quoted context omitted.

It was written in B. And B was written in B. To trace the bootstrap up into the high level, you have to go further back than the PDP-11. To bootstrap B on the PDP-7 and GE-635 machines he had access too, Ritchie wrote the minimum subset required to compile a compiler in B, in a language known as TMG (in the vein of, and a big influence on, Yacc and similar). This minimal bootstrap was then used to compile a B compile…

I like that the Bootstrappable Builds folks are working on a bootstrap process that goes from a small amount of machine code (~512 bytes) all the way up to a full Linux distro, including compilers/interpreters for modern languages. https://bootstrappable.org/

Nice, I hadn't heard of this project before!

In particular BOOTSTRA [1] looks really fun. I have also toyed with the idea of using MS-DOS 3.30 as a guaranteed-ubiquitous build environment.

It comes with a filesystem, a text editor (EDLIN.EXE), an object file linker (yup!), a debugger/assembler (DEBUG.EXE is an amazing tool), a programming language with decent string handling (GWBASIC.EXE), and a command interpreter with batch file scripting to glue it all together.

Not sure I would write the assembler as batch files though, that is really hardcore. :)

That entire build environment would fit on a single 360KB floppy.

[1] https://github.com/mniip/BOOTSTRA

Re: Dennis Ritchie’s first C compiler (c. 1972)

#47

Post by innocenat »

josephg wrote: post #42
astroanax wrote: post #24

The original keywords - https://github.com/mortdeus/legacy-cc/blob/master/last1120c/... Interestingly, long was commented

It makes sense long would have needed a comment. It needs a comment because “long” and “double” are terrible names for data types. Long what ? Double length what ? Those type names could easily have opposite meanings and meant long floating point / double length integer. WORD/DWORD are nearly as bad - calling something a "word" incorrectly implies the data type has something to do with strings. If you don't believe m…

Float doesn't make sense either. What is floating?

(I know it's floating point, but it's the same as long/double).

Re: Dennis Ritchie’s first C compiler (c. 1972)

#48

Post by wruza »

yitchelle wrote: post #23
amyjess wrote: post #20

I have to say, the way indentation and brackets were done here looks like it's just inviting subtle bugs. Take this for example: if (peekc) { c = peekc; peekc = 0; } else if (eof) return(0); else c = getchar();

It would have made code review a nightmarish activity for the team.

Why nightmarish? A reviewer may explain that it is prone for other human to overlook the end of conditional and go sleep as usual. I never understood the emotional component of blaming someone’s personal code styles, as if it were a religion with sacrifices and blasphemy instead of just a practical way of coding in a heterogeneous team.

This triggers me because many people jump on “bad c0de” in the forums, but then you read some practical code on github, and it is (a) not as perfectly beautiful as they imagine at all and (b) is still readable without nightmares they promised and (c) the algorithms and structure itself requires programmer’s perception and understanding levels far beyond the “it’s monday morning so i feel like missing an end of statement in a hand-written scanner” anyway.

Re: Dennis Ritchie’s first C compiler (c. 1972)

#49

Post by tralarpa »

kiwidrew wrote: post #45
code_sloth wrote: post #27

Earlier quoted context omitted.

If you judge the coding style of the early 1970s with modern standards, it isn't going to look great. 50 years is a loooong time. dmr was one of, if not the first C programmer(s).

And he was almost certainly using ed(1) as his editor and a mechanical teletype at 7.5 or 10.0 characters per second as his terminal... The C language (and all of Unix) was designed to be very terse as a consequence.

Was it different for the designers of ALGOL/SIMULA/Pascal?

Re: Dennis Ritchie’s first C compiler (c. 1972)

#50

Post by wruza »

josephg wrote: post #42
astroanax wrote: post #24

The original keywords - https://github.com/mortdeus/legacy-cc/blob/master/last1120c/... Interestingly, long was commented

It makes sense long would have needed a comment. It needs a comment because “long” and “double” are terrible names for data types. Long what ? Double length what ? Those type names could easily have opposite meanings and meant long floating point / double length integer. WORD/DWORD are nearly as bad - calling something a "word" incorrectly implies the data type has something to do with strings. If you don't believe m…

int is neither 32 nor 64. Its width corresponded to a platform’s register width, which is now even more blurred because today’s 64 bit is often too big for practical use and CPUs have separate instructions for 16/32/64 bit operations, and we agreed that int should be likely 32 and long 64, but the latter depends on a platform ABI. So ints with modifiers may be 16, 32, 64 or even 128 on some future platform. intN_t are different fixed-width types (see also int_leastN_t, int_mostN_t, etc in stdint.h; see also limits.h).

Also, don’t forget about short, it feels so sad and alone!

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