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c-blake / cligen

Nim library to infer/generate command-line-interfaces / option / argument parsing; Docs at
https://c-blake.github.io/cligen/
ISC License
501 stars 23 forks source link

allow const variables to be used as doc; fixes #110 #130

Closed enthus1ast closed 4 years ago

enthus1ast commented 4 years ago

Signed-off-by: David Krause david@code0.xyz

i am by far an macro expert and this maybe has side effects that i'm unaware of. But it seems to work.


import cligen
const help = """

  help
  ====
  my 
  help

"""

proc foo() = discard

dispatch(foo, doc = help)
enthus1ast commented 4 years ago

maybe the same could apply for shortH

enthus1ast commented 4 years ago 
import cligen
const help = """

  help
  ====
  my 
  help

"""

proc foo() = discard
proc baa() = discard

dispatchMulti([foo, doc = help], [baa, doc = help])
c-blake commented 4 years ago

The way you structured things to switch off the Nim node kind, I don't think side effects are likely. So, I'm merging this for now. We can revisit if it causes trouble and thanks for the patch!

I agree that the same approach would probably work for many more parameters which have simple Nim data types like string. I always use literals in my own CL programs, but especially for large strings various compile-time string-builder helpers make a lot of sense.

Note that the user for https://github.com/c-blake/cligen/pull/110 requested that short work. shortH is just some internal abbreviation for short["help"]. So, we should maybe keep that issue open. Technically, what @0xACE specifically requested was invalid syntax. One cannot just say const name = { x: y } in Nim. {} is an incomplete/non-typed literal only syntax for what Lispers call "association lists". It is not interpreted as an actual Table type (which is how it should be - there are several Table-like types anyway). Rather {} is more like a seq[key, val: untyped] that must be compile-time converted to whatever is wanted at the site where {} is used.

Even so, short in cligen is notionally always really a Table[string, char]. And help is always a Table[string, string]. So, I think short and help could also be made to work with maybe a little more cligen work than you did for doc, and definitely with the user having to say something more like this than what he initially wrote:

const appshort = {"output": 'f'}.toTable

I've actually had at least one version of Nim in the past year where that kind of const Table construction failed on me while picking apart the literal has never failed, but it has always been the intent of Nim core devs for such to work.