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Show HN: Replify – Create a REPL for any command

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Re: Show HN: Replify – Create a REPL for any command

#11

Post by Sir_Cmpwn »

jbbarth wrote: post #10
Sir_Cmpwn wrote: post #8

Earlier quoted context omitted.

I find it hilarious that there's a ruby version of a tool that can be implemented in 10 lines of bash. It's like atwood's law all over again. Use the right tool for the job, please.

I'd be happy to see your 10 lines bash version of this ruby tool, with the same options/properties (debug messages, customizable prompt, history logging, same safeguards, rlwrap support, man page).

You're missing the point. I could do all of that in a similar (or likely smaller) number of lines with bash compared to the ruby tool, only mine would be much faster and wouldn't depend on the enormous ruby runtime.

Re: Show HN: Replify – Create a REPL for any command

#12

Post by joh6nn »

unfletch wrote: post #7

Another generic `repl` utility, this one in ruby: https://github.com/defunkt/repl

i actually ported this over to POSIX shell a few years back: https://github.com/joh6nn/shrepl

afaik, it will work just about anywhere you can invoke a shell (i haven't tested it all that extensively)

Re: Show HN: Replify – Create a REPL for any command

#13

Post by joh6nn »

Sir_Cmpwn wrote: post #11
jbbarth wrote: post #10

Earlier quoted context omitted.

I'd be happy to see your 10 lines bash version of this ruby tool, with the same options/properties (debug messages, customizable prompt, history logging, same safeguards, rlwrap support, man page).

You're missing the point. I could do all of that in a similar (or likely smaller) number of lines with bash compared to the ruby tool, only mine would be much faster and wouldn't depend on the enormous ruby runtime.

the bash version might be technically faster, but i doubt it would be faster in any practical, meaningful way: most of the time spent in the script is waiting for input, or waiting for a command to return. that it need not depend on ruby is a perfectly valid argument though, and is in fact why i bothered redoing it in POSIX shell.

to do so however didn't just require a similar number of lines, it actually required 4 more (though to be fair, both scripts have comments and a fair bit of formatting, so it may not be a fair comparison. also it probably doesn't need stating, but i'm a bit of a hack, so my implementation maybe shouldn't be the reference point. but i digress)

in any event, i don't think atwood's law comes into play, given that a) this isn't in javascript and b) defunkt is a well known member of the ruby community who spends a lot of time working in ruby and probably wrote this to actually use it, as quickly as he could think of it. his choice of language here is perfectly reasonable in that context.

if you remain convinced that the only correct language for such a tool is bash/shell, i imagine OP certainly welcomes PRs; i know i do.

Re: Show HN: Replify – Create a REPL for any command

#14

Post by jbbarth »

Sir_Cmpwn wrote: post #11
jbbarth wrote: post #10

Earlier quoted context omitted.

I'd be happy to see your 10 lines bash version of this ruby tool, with the same options/properties (debug messages, customizable prompt, history logging, same safeguards, rlwrap support, man page).

You're missing the point. I could do all of that in a similar (or likely smaller) number of lines with bash compared to the ruby tool, only mine would be much faster and wouldn't depend on the enormous ruby runtime.

It's likely that with the feature set growing, a version that uses a slightly more advanced language would be easier to maintain and have less "traps" than the bash version...

Re: Show HN: Replify – Create a REPL for any command

#15

Post by mateuszf »

kazinator wrote: post #9

Here is my version: #!/bin/bash printf "REPL for %s\n" "$@" notblank() { [ $# -gt 0 ] } while true ; do printf "%s> " "$@" read -r || break; notblank $REPLY || continue; eval command \"\$@\" "$REPLY" done We keep the original parameters and expand them with "$@". There is a Bash feature that read with no args reads the line into the REPLY variable. We want that to be subject to splitting. If $REPLY expands to nothing…

Maybe using rlwrap command would help with the autocompletion and history?

Re: Show HN: Replify – Create a REPL for any command

#16

Post by Jtsummers »

kazinator wrote: post #9

Here is my version: #!/bin/bash printf "REPL for %s\n" "$@" notblank() { [ $# -gt 0 ] } while true ; do printf "%s> " "$@" read -r || break; notblank $REPLY || continue; eval command \"\$@\" "$REPLY" done We keep the original parameters and expand them with "$@". There is a Bash feature that read with no args reads the line into the REPLY variable. We want that to be subject to splitting. If $REPLY expands to nothing…

https://github.com/hanslub42/rlwrap

EDIT: beat to the punch, should've refreshed.

Re: Show HN: Replify – Create a REPL for any command

#17

Post by Bino »

seibelj wrote: post #4

Neat trick - the only change I made is to exit the while loop by typing "exit". That way the enter key runs the command with no arguments, and you can exit with control+c or by typing "exit".

And what if you want "exit" as argument. You should think bigger in general if your into tooling for others....

Re: Show HN: Replify – Create a REPL for any command

#19

Post by seibelj »

Bino wrote: post #17
seibelj wrote: post #4

Neat trick - the only change I made is to exit the while loop by typing "exit". That way the enter key runs the command with no arguments, and you can exit with control+c or by typing "exit".

And what if you want "exit" as argument. You should think bigger in general if your into tooling for others....

Yes, if you have a commonly used command that has "exit" as a commonly used flag that means something other than exiting, then by all means use something more specific like "exit2".
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