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digitalmars.D - <newbie>"null is not an lvalue"

reply "Asaf Karagila" <kas1 netvision.net.il> writes:
Hi,
i was trying to initialize a list of strings (related to my previous post 
about assembling bytecode) into an associative array,
i got the following error message "null is not an lvalue"
the array declaration is
     const ubyte[char[]] mnemonics;

this is an example for one of the lines i used to initialize the array:

    mnemonics["EXIT"]=cast(ubyte)0xFF;

any ideas ?

- Asaf.
Dec 11 2004
parent reply "Asaf Karagila" <kas1 netvision.net.il> writes:
i feel so stupid :)
i forgot to remove the const from the array declaration when i changed it to 
an associative array..

- Asaf.


"Asaf Karagila" <kas1 netvision.net.il> wrote in message 
news:cpeolu$1vjf$1 digitaldaemon.com...

 Hi,
 i was trying to initialize a list of strings (related to my previous post 
 about assembling bytecode) into an associative array,
 i got the following error message "null is not an lvalue"
 the array declaration is
     const ubyte[char[]] mnemonics;

 this is an example for one of the lines i used to initialize the array:

    mnemonics["EXIT"]=cast(ubyte)0xFF;

 any ideas ?

 - Asaf.
Dec 11 2004
parent reply Sjoerd van Leent <svanleent wanadoo.nl> writes:
I don't understand the reason why you want a constant associative array, 
because this easy solvable using an enumeration and a normal array, just 
as the following:

/*CODE*/
public enum Codes {Exit};
public const static ubyte map[] = [0xff : Codes.Exit];
/*END_CODE*/

You are able to select the right values using the Codes enumeration.

Regards,
Sjoerd

Asaf Karagila wrote:

 i feel so stupid :)
 i forgot to remove the const from the array declaration when i changed it to 
 an associative array..
 
 - Asaf.
 
 
 "Asaf Karagila" <kas1 netvision.net.il> wrote in message 
 news:cpeolu$1vjf$1 digitaldaemon.com...
 

Hi,
i was trying to initialize a list of strings (related to my previous post 
about assembling bytecode) into an associative array,
i got the following error message "null is not an lvalue"
the array declaration is
    const ubyte[char[]] mnemonics;

this is an example for one of the lines i used to initialize the array:

   mnemonics["EXIT"]=cast(ubyte)0xFF;

any ideas ?

- Asaf.
Dec 11 2004
parent reply Sjoerd van Leent <svanleent wanadoo.nl> writes:
Correction:

public enum Codes {Exit = 0xff};

This is sufficient.


Regards,
Sjoerd

Sjoerd van Leent wrote:

 I don't understand the reason why you want a constant associative array, 
 because this easy solvable using an enumeration and a normal array, just 
 as the following:
 
 /*CODE*/
 public enum Codes {Exit};
 public const static ubyte map[] = [0xff : Codes.Exit];
 /*END_CODE*/
 
 You are able to select the right values using the Codes enumeration.
 
 Regards,
 Sjoerd
 
 Asaf Karagila wrote:
 

 i feel so stupid :)
 i forgot to remove the const from the array declaration when i changed 
 it to an associative array..

 - Asaf.


 "Asaf Karagila" <kas1 netvision.net.il> wrote in message 
 news:cpeolu$1vjf$1 digitaldaemon.com...


 Hi,
 i was trying to initialize a list of strings (related to my previous 
 post about assembling bytecode) into an associative array,
 i got the following error message "null is not an lvalue"
 the array declaration is
    const ubyte[char[]] mnemonics;

 this is an example for one of the lines i used to initialize the array:

   mnemonics["EXIT"]=cast(ubyte)0xFF;

 any ideas ?

 - Asaf.
Dec 11 2004
parent "Simon Buchan" <currently no.where> writes:
On Sat, 11 Dec 2004 16:05:23 +0100, Sjoerd van Leent  
<svanleent wanadoo.nl> wrote:


 Correction:

 public enum Codes {Exit = 0xff};

 This is sufficient.




Except he probably wants to be reading strings. An AA is the easiest way  
to do
that by far. Doing this with a Key Value pair array is the only way I can  
think
of doing this without an AA involved.

struct code {char[] name; ubyte value};

const code[] codemap = {{"EXIT", 0xFF}, {"SOMETHING ELSE", 0x3E}};

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Dec 15 2004