Missing property name after reference operator-CodePudding

I have a map, that is originally c code, file read, and parsed into a map. The original code was an enum, and didn't have values for all items. $fileContent:

enum{
    Error_A = 110,    
    Error_B,               
    Error_C,               
    Error_D,             
    Error_E,             
    Error_F,          
    Error_G = 118,  
...
};

I have read the file contents and put it in a map like this (works fine):

  function Get-Contents_b{
    [cmdletbinding()]
    Param ([string]$fileContent)

            #Error_AA = 20
  
    # create an ordered hashtable to store the results
    $errorMap = [ordered]@{}
    # process the lines one-by-one
    switch -Regex ($fileContent -split '\r?\n') {
      '^[\s]*([\w] )[\s=]*([-\d]*)' { # Error...=12345
        $key,$value = ($matches[1,2])|ForEach-Object Trim
        $errorMap[$key] = $value
    }
  }
...

Then I want to iterate over the map, and for the ones with enum values dependent on single digit increase from the previous, I want to assign the value of the previous value plus one. I'm trying to do that below, but getting the $previousKey, using $key-1, and then getting the value from that, is giving the error shown in the comment.

  foreach ($key in $errorMap.$keys)
  {
      $previousKey = $errorMap.[($key-1)]  #missing property name after the reference operator
      Write-Host $errorMap.$previousKey
      if(($errorMap.$key).Value = "")
      {
        $errorMap.$key.Value = $errorMap.$previousKey.Value   1
      }
  }

Any ideas how to fix this or get the previous value and assign the next empty value the previous value plus one?

This is with powershell 5.1 and VSCode.

CodePudding user response：

You're mistakenly mixing member (property) access via the . operator with indexed access via [...] - you must use one or the other.

However, what you want is positional access to your keys (which only works with an ordered hashtable):

foreach ($keyIndex in 0..($errorMap.Count-1))
{
  if ('' -eq $errorMap[$keyIndex]) {
    $previousValue = $errorMap[$keyIndex - 1] 
    Write-Host $previousValue
    $errorMap[$keyIndex] = 1   $previousValue
  }
}

CodePudding user response：

Why not create the values in your Hashtable straight away instead of filling the empties afterwards?

function Get-Contents_b{
    [cmdletbinding()]
    Param ([string]$fileContent)
    # create an ordered hashtable to store the results
    $errorMap     = [ordered]@{}
    $currentValue = 0
    # process the lines one-by-one
    switch -Regex ($fileContent -split '\r?\n') {
        '^\s (\w )\s*[,=]'{
            $key, $value = ($_ -split '[,=]', 2).Trim()
            if ([string]::IsNullOrWhiteSpace($value)) { $value = $currentValue }
            $errorMap[$key] = [int]$value
            $currentValue   = [int]$value   1
        }
    }
    # return the map
    $errorMap
}

Get-Contents_b $enum

Output:

Name                           Value
----                           -----
Error_A                        110
Error_B                        111
Error_C                        112
Error_D                        113
Error_E                        114
Error_F                        115
Error_G                        118