Base repo

[MartinNowak]

Issue by wilzbach
Wednesday May 25, 2016 at 19:15 GMT
Originally opened as https://github.com/drepl/drepl-old/issues/1

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1. drepl

• uses libdparse to parse the structure, pipes everything to a temporary file and runs rdmd on it
• uses liblineoise for the terminal interaction (small C lib)
  2) dabble
• defines its own grammer & parser (via pegged)
  • uses union and Var structs to ship it's own a JIT compiler (with libdparse)
  3. From scratch

dabble's approach looks generally good and more scalable, but I have no idea how one can import custom packages in there

[MartinNowak]

Comment by carljv
Wednesday May 25, 2016 at 20:29 GMT

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Did you get dabble to compile? Relying on the lexer/parser in libdparse feels better to me, since it gives you consistency with the whole DScanner, DCD, dfmt, ecosystem. Is there any reason to prefer the pegged approach?

I haven't dug really deeply into this, but it seems like both of these require making/using shared libs. Is that a blocker for OS X?

Thanks for picking this up, I think it will be really useful, as well as a nice component of "the first five minutes."

[MartinNowak]

Comment by wilzbach
Wednesday May 25, 2016 at 20:37 GMT

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Did you get dabble to compile?

Nope :/

Relying on the lexer/parser in libdparse feels better to me, since it gives you consistency with the whole DScanner, DCD, dfmt, ecosystem. Is there any reason to prefer the pegged approach?

I think both REPLs use libdparse, but dabble uses pegged for it's own Meta command

https://github.com/callumenator/dabble/blob/master/src/dabble/grammars.d
https://github.com/callumenator/dabble/blob/master/src/dabble/parser.d
https://github.com/callumenator/dabble/blob/master/src/dabble/meta.d#L26

which makes it more powerful (in theory - as said I couldn't compile).

I haven't dug really deeply into this, but it seems like both of these require making/using shared libs. Is that a blocker for OS X?

Nope, but we should be aware that compiling the external lib can require more effort.
E.g. for linenoise you currently have to run

curl -sSL https://github.com/antirez/linenoise/archive/master.tar.gz | tar -zxf -
cd linenoise-master && cc -shared -fPIC linenoise.c -o liblinenoise.so

Of course a good Makefile can deal with all this, but currently dub is the package manager and standard build tool.

Thanks for picking this up, I think it will be really useful, as well as a nice component of "the first five minutes."

Great to hear that you share my opinion :)

[MartinNowak]

Comment by wilzbach
Wednesday May 25, 2016 at 20:49 GMT

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Pinging @John-Colvin - the author of PydMagic.
John: we are trying to bundle forces to create a great REPL and Jupyter kernel for D.

[MartinNowak]

Comment by carljv
Wednesday May 25, 2016 at 23:51 GMT

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Ah. Yes, meta commands are nice. It's not clear to me that an actual grammar w/ parser is necessary for them. But I'd have to think about it harder.

[MartinNowak]

Meta commands could simply use :help or :dub vibe.d, no fancy parser needed.

Also see #6