JuliaLang/julia

parse command interpolations at parse time

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#3,150 opened on May 19, 2013

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Description

It would be nice to have a way to "double interpolate" a variable with respects to nested possible interpolation contexts to make it easier to write quoted code blocks that wants to interpolate a variable inside a string. e.g., so the below code echos "hi". Not sure what the best way to go about that is.

macro example()
 f="hi"
 quote
  run(`echo $$f`)
 end
end

Contributor guide

Research direction
Investigate Julia's macro expansion and command interpolation mechanisms, particularly how `$$` is handled in `run` commands. Look at the parser code for interpolations and consider alternative syntax or parsing strategies.
Tech stack
julia
Domain
compilers
Issue type
Feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
JuliaMacros
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
55