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6176 :: Resolving environment variables in a string

• squattingmonk (orginal) [2020-04-08T19:29:18+02:00] view original

  Hi, all! I need to resolve environment variables in a string. I'm not seeing a proc for this in the standard library, so I whipped this up:

  import os, strtabs
  
  proc envTable: StringTableRef =
    result = newStringTable(modeCaseSensitive)
    for key, value in envPairs():
      result[key] = value
  
  let
    envs = envTable()
    path = paramStr(1)
  
  echo path % envs
  Run

  Is there a better or more idomatic way to do this?

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• Yardanico (orginal) [2020-04-08T21:04:57+02:00] view original

  Well maybe the reason is that it's a bit too much to import a whole new module to implement 1 additional procedure (so if you use os that module will be imported too, not that it would matter after compilation anyway).

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• squattingmonk (orginal) [2020-04-08T22:03:18+02:00] view original

  I'm also noticing that this will throw an exception if any of the variables in the string are not found among the environment variables.

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• Araq (orginal) [2020-04-09T19:06:38+02:00] view original

  import os, strtabs proc envTable: StringTableRef = result = newStringTable(modeCaseSensitive) for key, value in envPairs(): result[key] = value let envs = envTable() path = paramStr(1) echo(`%`(path, envs, {useEmpty})) # or simply echo(`%`(path, newStringTable(modeCaseSensitive), {useEnvironment, useEmpty}))

  Run

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• squattingmonk (orginal) [2020-04-09T19:23:16+02:00] view original

  Thanks, Araq! That's exactly what I needed.

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