[Emc-developers] Re: INI file format

[Mark P. <mp...@ya...>]

Hello all.

There's been some discussion of either creating a
program to make it easier to work with the .ini file,
or changing the format.

What if we write a program which gets extra info from
special comments placed in the ini file and aids the
user in editing?  

There is one very big advantage to doing it this way:
EMC does not need to be modified, it just sees a whole
bunch of extra comments.

I intended this post to be short, but it's more of a
specification now... hope it's not a waste of effort
:)

The program goes through the INI file looking for
blocks of lines; these blocks start with the first
comment after the previous parameter definition *or*
section start. There don't have to be *any* comments
at all, actually: a one-line block. In this case, the
user doesn't get any extra help or error checking.

The block ends with the parameter definition, i.e.
"HELP_FILE =   doc/help.txt"

For each block, there can be any number of regular
comments, and as many special comments as make sense.


Anything in between the start and end of the block-
either a plain comment or a special comment - refers
to this particular parameter.  For any of these lines,
if they are a plain comment, they are displayed to the
user; the special comments are interpreted by the
program.

A portion of the INI file, with special comments
added.
"special comments" start with ;@<keyword> rather than
just ;
Keywords listed below this sample.
---------------sample-----------------

 [DISPLAY]
 ; Name of display program, e.g., xemc
 ;@TYPE string
 ;@CHOICE tkemc xemc yemc keystick emcpanel @OTHER
 DISPLAY =             tkemc
 
 ; Cycle time, in seconds, that display will sleep
between polls
 ;@TYPE float
 ;@MIN 0.01
 CYCLE_TIME =            0.100
 
 ; Path to help file
 ;@TYPE file
 HELP_FILE =             doc/help.txt
 
 ; Initial display setting for position, RELATIVE or
MACHINE
 ;@CHOICE MACHINE RELATIVE
 POSITION_OFFSET =       MACHINE

----------end of sample-----------------

;@TYPE tells the program what types of input to
accept, such as int (integer), float, string, file
(pop up File Open dialog box) and so on. TYPE is not
necessary if the user can only make a choice between
options already in the @CHOICE line.  
For @TYPE file, a button is created in the GUI which,
when clicked, causes a dialog box to pop up so the
user can choose the file; they could also simply type
in the file path/name in the entry instead of using
the dialog.  @TYPE file can be followed by a
wildcarded file name, such as *.nml or *mod.o (for
EMCMOT, but wouldn't work with emcmotsim unless
renamed or symlinked)
   ;make user select NML file
;@TYPE file *.nml

;@MIN is the minimum allowable value (int and float
only), the program shouldn't accept anything less; put
on screen for the user when they enter a value.

;@MAX - see @MIN

;@CHOICE - use a pop-up menu (or listbox) for this
item.  The first word after @CHOICE is the default. 
See also @OTHER

;@OTHER is used in the @CHOICE line.  It is optional.
If it is on the line, the user is allowed to type in
something that isn't among the pre-defined choices. 
If @OTHER isn't present, they must choose from among
the pre-defined choices.

Not shown in above example:
;@CONVERSION_FACTOR can be used, for example, to
convert from mm to inches, or to convert depending on
a parameter already set within the file.  It can only
be used with numbers, and the user's input is
multiplied or divided by this value before being
written to the file.  If a parameter is used which
isn't within the current section, the section name
must be prepended to its name. (below)
examples:
   ;this would divide the user's input by 3.45
;@CONVERSION_FACTOR / 3.45
   ;multiply by LINEAR_UNITS in [TRAJ] section
;@CONVERSION_FACTOR * [TRAJ]LINEAR_UNITS

;@EQUALS - used to set one parameter identical to
another. EQUALS can only be used by itself, and the
program advances to the next parameter automatically.
;@EQUALS [TRAJ]LINEAR_UNITS

;@SKIP - like EQUALS, can only be used by itself. 
Causes program to skip over this parameter without
changing it.

;@EXPERTISE - conditional SKIP.  At startup, the
program asks the user what level of tuning they want,
such as beginner, intermediate (show more), expert
(show all).  Hides complicated stuff from beginners. 
In a block, defaults to beginner (always shown) if not
used.
    ;a block including this line would only show at
intermediate level or higher
;@EXPERTISE intermediate

For any block, up to several keywords can be used;
however if there aren't any keywords no error checking
will be performed on the user's input.  Some
combinations don't make sense, such as "TYPE string"
along with MIN or MAX, or "TYPE file" along with
CHOICE (for this, use "TYPE string")

I started writing a tcl script to work with this... I
don't know when/if it will be done.

Mark

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