IniFiles

IniFiles is part of the CategoryAplApl project.

Overview

INI files are still useful to provide settings to an application. Vista is not going to change this.

The Windows API methods provided to read a particular value have an advantage: they follow a clearly defined search path, and following that path they take not only the INI file into account, they also check the Windows registry and the command line parameter. Furthermore, they deliver always up-to-date values.

They have disadvantages as well:

• They are slow
• They return everything as a string

If you are not interested in the Windows registry and command line parameters, and if nobody else is changing your INI files while your application is running, then the "IniFile" class introduced in this article might attract your attention.

This class allows you to use a kind of APL-Syntax in your INI files. Values not enclosed in quotes will be converted to numbers, everything else gets a string.

Details

Character Values

An entry like:

HomeFolder='C:/Windows/Appl/'

results in a string holding the path.

Numeric Values

An entry like:

FormSize=300 400

results in a two-element-vector "FormSize" holding two integers.

References

Furthermore, an entry like:

LogFolder='{"HomeFolder}Logsfiles/'

is treated in a special way: the name between the curlies is taken as the name of an already defined value. It is then replaced by the value of that entry.

Note that of course "HomeFolder" must be specified upfront. Prior to version 1.5, this must be specified within the same section. As a result the same variable needed to be specified more than once if the same path needed to be available in more than one section.

Since version 1.5 this restriction was lifted by the introduction of "local" variables, see there.

Local Variables

Local values are those specified above the first section. They have only one purpose: to be used as references in several section.

There are some restrictions:

• They can only be used during the instanciation
• They must not be nested
• Although it is possible to specify a numeric value this does not make any sense since numeric values cannot be used as references

Example

Creating an Instance

After creating an instance from the class:

myIni←⎕New #.IniClass (,⊂'C:/Appl/Example.ini')

Accessing Data with the "Get" method

you can get all information you are interested in by calling the method "Get". Note that names are not case sensitive.

Given this file "Example.ini":

[GENERAL]
MaxNoOfErrors=20
FormSize=800 1200
LogfileFlag=1
LogLevels=1 2 3 ; from 1 to 9

[DIR]
Home='C:/mainfolder/'
AppFolder='{Home}appls/'
DocsFolder='{Home}docs/'
LogFileFolder='{Home}Logs/'

You can get any level of information you are interested in:

• get everything
• get all keys and values of a particular section
• get a particular value from a particular section

Examples with "Get"

      myIni.Get ⍬ ⍬ 
 GENERAL                                      
          MAXNOOFERRORS                    20 
          FORMSIZE                   800 1200 
          LOGFILEFLAG                       1 
          LOGLEVELS                     1 2 3 
 DIR                                          
          HOME                 C:/mainfolder/ 
          APPFOLDER      C:/mainfolder/appls/ 
          DOCSFOLDER      C:/mainfolder/docs/ 
          LOGFILEFOLDER   C:/mainfolder/Logs/ 
      myIni.Get'General' ⍬
MAXNOOFERRORS        20 
FORMSIZE       800 1200 
LOGFILEFLAG           1 
LOGLEVELS         1 2 3 
      myIni.Get'General' 'FormSize'
800 1200
      ¯1 myIni.Get'General' 'Unknown' ⍝ with default
¯1
      myIni.Get'General' 'Unknown' ⍝ without default
Value Error: "Unknown"
myDoc.Get'General' 'Unknown'

Indexing

Since version 1.1, the class provides a default property. That means you can access values by indexing.

Examples (with the same INI file listed above):

      myIni[⊂'GeneRAL:']
20  800 1200  1  1 2 3
            ⊃myIni[⊂'GeneRAL:FormSize']
800 1200

Assigning

• myIni[⊂'GeneRAL:FormSize']←⊂12 23

The "Put" method

• (12 23) myIni.Put 'GeneRAL:FormSize'

Nested Entries

Since version 1.4 nested values are supported. Imagine an INI file that sets an "AcceptIP" value to a number of IP addresses to be accepted when a client tries to connect to your application. That's how that might look like:

AcceptID='192.168.68.1,192.168.68.100,195.64.2.2,127.0.0.1,85.86.87.88,156.147.123.1'

and maybe even much longer. Horrible, and prone to error when that needs to be changed. By initializing the value as an empty vector and then using the ",=" syntax one can overcome the problem:

AcceptID=''
AcceptID,='192.168.68.1'
AcceptID,='192.168.68.100'
AcceptID,='195.64.2.2'
AcceptID,='127.0.0.1'
AcceptID,='85.86.87.88'
AcceptID,='156.147.123.1'

This results in a nexted vector of length 6 were each item holds a single IP addres. This works with numbers as well:

vector=''
vector,=1 2 3
vector,=200 300

leads to:

(1 2 3) (200 300)

The "Save" method

You can also change a particular value but the changed value will persist only if you execute the "Save" method at some point:

      myIni[⊂'GeneRAL:FormSize']←⊂'¯1 1000
      myIni.Save

A Warning

An INI file is by definition not a kind of database and should not be used to save data by the application itself. However, the "Save" method might be useful to initialise an INI file.

"Save" and Comments

Since version 1.5, the "Save" methods does it's best to preserve any comments. However, this is not always possible. Imagine several comments made on all lines of a nested assignment. As long as a value remains the same, "Save" is able to preserve it, but when a former value is changed, the associated comment will be lost.

Check Keys before indexing

Note that when indexing is used there is no default. That means that specifying an unknown value leads to an error. There are two ways to escape this problem:

      myIni.Exist 'General:Unknown'
0
      myIni.Default← ¯1 ¯1
      myIni[⊂'General:Unknown']
¯1 ¯1
      myIni[⊂'General:Unknown']←200
      myIni[⊂'General:Unknown']
200

Creating an INI file

To create a new INI file, don't specify a filename:

myIni←⎕New #.IniClass 

Adding a Section

The only way to add a new section is to use the AddSection-method:

      myIni←⎕New #.IniClass
      myIni.AddSection'NewSection'

Adding Values

Adding new values can be done the same way you would cange a value: either use the "Put"-method or simply assign a value.

Other Methods

Delete

Examples with supported syntax:

      myIni←⎕New #.IniClass
      myIni.Delete 'MySection:key1'
      myIni.Delete 'MySection' 'key2'
      myIni.Delete 'MySection:' ⍝ this will delete the entire section

The "Delete" method returns a shy boolean which gets 1 in case something was to be deleted.

Exist

Let's assume that "myIni" is an instance of the IniFile class, and that there is a section "Config" which contains exactly one key: "Size":

      1 <-> myIni.Exist 'Config:Size'
      0 <-> myIni.Exist 'Config' 'unknow'
      1 <-> myIni.Exist 'Config:' 

DeleteDefault

Setting the "Default" property might be appropriate if you need a default value for undefined keys. However, as soon as the "Default" property is set, one can get rid of it only be calling the "DeleteDefault" method. The method returns a shy Boolean which gets 1 only if there was a default.

History

For a full version history: History

Version Information

Download

You have two options: you can either download the script for usage:

Download IniFiles script right now

or get the whole thing from the AplWikiRepository, including the development workspace and the script and maybe more for any development or for running the test cases:

svn list svn://aplteam2.com/os/dyalog/IniFiles/tags

If you plan to contribute please note that all stuff published as part of the APLAPL project must follow certain APLAPL-specific standards.

CategoryAplApl