Re: [PATCH 02/12] doc/learn-poke-in-y-minutes.pk: Update

[Jose E. Marchesi]

This is OK for master.

> 2021-05-22  Mohammad-Reza Nabipoor  <mnabipoor@gnu.org>
>
>       * doc/learn-poke-in-y-minutes.pk (Struct Field Initializers): Update
>       the example according to the recent change in behavior of field
>       initializers.
> ---
>  ChangeLog                               |  6 ++++
>  doc/learn-poke-language-in-y-minutes.pk | 45 ++++++++++++++-----------
>  2 files changed, 31 insertions(+), 20 deletions(-)
>
> diff --git a/ChangeLog b/ChangeLog
> index dff3e282..d62dd68c 100644
> --- a/ChangeLog
> +++ b/ChangeLog
> @@ -1,3 +1,9 @@
> +2021-05-22  Mohammad-Reza Nabipoor  <mnabipoor@gnu.org>
> +
> +     * doc/learn-poke-in-y-minutes.pk (Struct Field Initializers): Update
> +     the example according to the recent change in behavior of field
> +     initializers.
> +
>  2021-05-21  Mohammad-Reza Nabipoor  <mnabipoor@gnu.org>
>  
>       * AUTHORS: Change my email address to gnu account.
> diff --git a/doc/learn-poke-language-in-y-minutes.pk 
> b/doc/learn-poke-language-in-y-minutes.pk
> index c72a78e7..738319d4 100644
> --- a/doc/learn-poke-language-in-y-minutes.pk
> +++ b/doc/learn-poke-language-in-y-minutes.pk
> @@ -455,6 +455,27 @@ var packet_size     = 1#Packet / 1#B;    /* 10 */
>  var two_packet_size = 2 #Packet/#B;      /* 20 */
>  
>  
> +/* Struct Field Initializers
> + *
> + * Initialize the field to an expression.
> + */
> +type HeaderWithInit =
> +  struct
> +  {
> +    uint<8> magic = 100UB;
> +    uint<8> version = 3;
> +
> +    offset<uint<32>,B> data_length;
> +    uint<8>[data_length] data;
> +  };
> +
> +var hdrauto = HeaderWithInit {};
> +/* hdrauto.magic == 100UB && hdrauto.version == 3UB */
> +
> +/* It is possible to change the value of initialized fields: */
> +hdrauto.magic = 200UB;
> +
> +
>  /* Struct Field Constraints
>   *
>   * It is common for struct fields to be constrained to their values to
> @@ -485,27 +506,10 @@ var hdrmagic =
>      magic = 100UB,
>    };
>  
> -/* There is another way to specify the constraints: field initializers  */
> -
> -/* Struct Field Initializers
> - *
> - * Field initializer has two roles:
> - *   - Introduce constraint of the form: `field == initializer_expression`
> - *   - Initialize the field with initializer expression
> +/* The following statement will raise an exception, because it violates
> + * the field constraint.
>   */
> -type HeaderWithInit =
> -  struct
> -  {
> -    uint<8> magic = 100UB;
> -    uint<8> version = 3;
> -
> -    offset<uint<32>,B> data_length;
> -    uint<8>[data_length] data;
> -  };
> -
> -/* With field initializers, this is possible: */
> -var hdrauto = HeaderWithInit {};
> -/* hdrauto.magic == 100UB && hdrauto.version == 3UB */
> +/* hdrmagic.magic = 200UB; */
>  
>  /* It is also possible to specify both a constraint and an initializer in
>   * the same field.
> @@ -518,6 +522,7 @@ type HeaderMagicVersion =
>    };
>  var hdrmagver = HeaderMagicVersion {};
>  /* hdrmagver.magic == 0x55UB && hdrmagver.version == 0x2UB */
> +hdrmagver.magic = 0xaaUB;
>  
>  
>  /* Integral Structs