[ECOS] Baffled yet again by CDL

[ECOS] Baffled yet again by CDL

[Grant Edwards]

How do I get a quoted string as a default value for a CDL option?


If I put

  default_value {"Foobar"}

I get this:

  #define CYG_WHATEVER Foobar

But when user_value like this

  user_value {"Foobar"}

Then I get this:

  #define CYG_WHATEVER "Foobar"

Why do they behave differently?  How do I get the latter result with a
default value?  [This reminds me yet again why I loathe TCL]

-- 
Grant Edwards               grant.b.edwards        Yow! I Know A Joke!!
                                  at               
                              gmail.com            


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Re: [ECOS] Baffled yet again by CDL

[Jay Foster]

Use

     default_value { "\"Foobar\"" }

There are many examples in the eCos repository that do this.

Jay

On 3/21/2012 1:31 PM, Grant Edwards wrote:
> How do I get a quoted string as a default value for a CDL option?
>
>
> If I put
>
>    default_value {"Foobar"}
>
> I get this:
>
>    #define CYG_WHATEVER Foobar
>
> But when user_value like this
>
>    user_value {"Foobar"}
>
> Then I get this:
>
>    #define CYG_WHATEVER "Foobar"
>
> Why do they behave differently?  How do I get the latter result with a
> default value?  [This reminds me yet again why I loathe TCL]
>

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[ECOS] Re: Baffled yet again by CDL

[Grant Edwards]

On 2012-03-21, Jay Foster <jay@systech.com> wrote:
> Use
>
>      default_value { "\"Foobar\"" }
>
> There are many examples in the eCos repository that do this.

Thanks. I did find some examples after fixing my grep command.

I still don't get why it's { "\"Foobar\"" } in a default value and {
"Foobar" } when a user value.  That doesn't seem intuitive at all.

-- 
Grant Edwards               grant.b.edwards        Yow! An INK-LING?  Sure --
                                  at               TAKE one!!  Did you BUY any
                              gmail.com            COMMUNIST UNIFORMS??


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Re: [ECOS] Re: Baffled yet again by CDL

[Sergei Gavrikov]

On Wed, 21 Mar 2012, Grant Edwards wrote:

> On 2012-03-21, Jay Foster <jay@systech.com> wrote:
> > Use
> >
> >      default_value { "\"Foobar\"" }
> >
> > There are many examples in the eCos repository that do this.
> 
> Thanks. I did find some examples after fixing my grep command.
> 
> I still don't get why it's { "\"Foobar\"" } in a default value and {
> "Foobar" } when a user value.  That doesn't seem intuitive at all.

Hi

Grant, I would explain it so, defalt_value vs user_value is something
like MI (machine interface) vs HI (human interface). Look at the value
of a 'defalt_value' as MI instance (i.e. an expression), but, the value
of a 'user_value' is a user input (an input in configtool, or editing
ecos.ecc config file).  **No wrong with TCL here**. Well, then in C

  #include <stdio.h>
  main()
  {
      const char     *default_value = "\"Foobar\"";       // MI
      char            user_value[256];
      printf("default_value is %s\n", default_value);
      printf("user_value? ");
      fflush(stdout);
      fgets(user_value, sizeof(user_value) - 1, stdin);   // HI
      printf("user_value is %s\n", user_value);
      return (0);
  }


compare

  % ./a.out
  default_value is "Foobar"
  user_value? Baz
  user_value is Baz

and

  % ./a.out
  default_value is "Foobar"
  user_value? "Baz"
  user_value is "Baz"


CDL != TCL. CDL is a huge interface in C++ (~40K lines of code) which
uses TCL for some cases. There are useful comments in these sources

  host/libcdl/cdlcore.cxx
  host/libcdl/value.cxx

by the topic.

Sergei

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[ECOS] Re: Baffled yet again by CDL

[Grant Edwards]

On 2012-03-22, Sergei Gavrikov <sergei.gavrikov@gmail.com> wrote:

> CDL != TCL. CDL is a huge interface in C++ (~40K lines of code) which
> uses TCL for some cases.

I thought all of the expression evaluation was done in TCL.  I tried
writing reasonably sized a TCL/Tk application once, and gave up
because the quoting semantics were entirely too obtuse. Writing the
same app in Scheme/Tk or Python/Tk was far easier.

> There are useful comments in these sources
>
>   host/libcdl/cdlcore.cxx
>   host/libcdl/value.cxx
>
> by the topic.

Thanks.

-- 
Grant Edwards               grant.b.edwards        Yow! ... he dominates the
                                  at               DECADENT SUBWAY SCENE.
                              gmail.com            


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