gb.args - alternate form of usage.

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casperl
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Joined: Wednesday 01st February 2017 10:07am

gb.args - alternate form of usage.

Post by casperl » Friday 10th February 2017 8:54am

Greetings Everyone!

Benoït has an excellent explanation on using gb.args in this thread:

http://gambas.8142.n7.nabble.com/New-co ... 31829.html

However, my mind is wrapped around the way command line arguments are used in most Ruby libraries. Simply because I am used to it, I use gb.Args in a different way, and it works. Now whenever I am swimming against the flow, I am wondering whether I am doing the right thing. Any comments from the experienced coders on this?

Code: Select all

Public Sub Main()

  Dim strTemp As String
    
  If Args.Count > 1
    For Each strTemp In Args
      Select strTemp
        Case "--help"
          DisplayHelp()
        Case "--version"
          DisplayVersion()
        Case "--tmux"
          ExecTmuxStartTranslate()
        Case "--chdir"
          HandleChdir()
        Case "--term"
          CatFileGrep(strTerminologyFile)
        Case "--trans"
          CatFileGrep(strTranslateFile)
        Case "--test" ' for running arbitrary testing code
          DoTest()
        Case Else
          Print "Unknown parameter: " & strTemp
      End Select
    Next
  Else
    Print "No parameters provided" ' this is useful to run the prog within the IDE to find syntax errors before compiling an executable to be executed in a shell
  Endif
  
End

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casperl
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Joined: Wednesday 01st February 2017 10:07am

Re: gb.args - Something I forgot...

Post by casperl » Friday 10th February 2017 9:21am

I forgot to include this in the above...

I access the value of the parameter through a function that is used in the routines called in the case loop. Here is the code for that:

Code: Select all

Public Sub GetStrParam() As String
  
  Dim arrParams As String[]
  Dim strParam As String
  
  arrParams = Args.All
  If arrParams.Count = 3 Then strParam = arrParams[2] Else strParam = "NIL"
   
  Return strParam
  
End

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cogier
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Re: gb.args - alternate form of usage.

Post by cogier » Saturday 11th February 2017 11:39am

I have looked at your code in your first post and if you need all the options then the code you have written looks good to me. To reduce the amount of code you could put all the 'Args' into a single string and use InStr() to look in the string for the 'Arg'. This method would catch '--version' or '-version' etc.

Code: Select all

	 Dim strTemp, sAllArgs As String

    For Each strTemp In Args
      sAllArgs &= strTemp
    Next
    
    If InStr(sAllArgs, "help") Then DisplayHelp()
    If InStr(sAllArgs, "version") Then DisplayVersion()
    ...
    
Sorry but I could not work out the purpose of your second post.

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jornmo
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Re: gb.args - alternate form of usage.

Post by jornmo » Sunday 12th February 2017 11:52am

Well, you will lose the benefit of getting useful information from using --help and you are also only getting the long option names. The last can easily be solve by adding
Select strTemp
        Case "--help", "-h"
          DisplayHelp()
        [...]

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jornmo
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Re: gb.args - alternate form of usage.

Post by jornmo » Sunday 12th February 2017 12:41pm

@cogier: if you want to convert an array to a string, you can always use .Join. No need to use a loop :)

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casperl
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Joined: Wednesday 01st February 2017 10:07am

Re: gb.args - alternate form of usage.

Post by casperl » Monday 13th February 2017 9:41am

@jornmo, I have done exactly what you have suggested.

Code: Select all

Case "--help", "-h"
However, I have many CLI scripts that call other scripts in turn. When developing custom CLI scripts it is ridiculous how often the short version is simply impractical since numerous commands will share the same first letter of the alphabet. I now tend to use the short version only for frequently used commands that I have to type, and use the long versions in cases where a script will call another script.

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casperl
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Re: gb.args - alternate form of usage.

Post by casperl » Monday 13th February 2017 10:14am

@cogier
The second post was to illustrate how to get the value passed to the parameter in a CLI command. For example,

Given the CLI command convention:

Code: Select all

command --argument value 
as in

Code: Select all

$ myclicmd --foo bar
would return the value "bar" by accessing Args[3] (or Args[4]...) for multiple values. The coded example is a bit verbose, but it serves the purpose of just having a single function to call anywhere else in the program to access whatever value was passed to the the --parameter. Since this is an important part of making the alternate usage of gb.args functional, I felt I had to mention this.

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cogier
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Re: gb.args - alternate form of usage.

Post by cogier » Monday 13th February 2017 6:36pm

jornmo wrote:@cogier: if you want to convert an array to a string, you can always use .Join. No need to use a loop :)
Thanks jornmo for that. I also noticed: -

Code: Select all

Dim arrParams As String[]
  Dim strParam As String
  
  arrParams = Args.All
could have been simplified with

Code: Select all

Dim arrParams As String[] = Args.All
  Dim strParam As String

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jornmo
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Re: gb.args - alternate form of usage.

Post by jornmo » Monday 13th February 2017 7:10pm

If you want to do it all in one line
Dim s As String = Args.All.Join(";", "[]")

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