[jira] [Commented] (THRIFT-4270) Generate Erlang mapping functions for const maps and lists

["ASF GitHub Bot (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/THRIFT-4270?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16109215#comment-16109215 ] 

ASF GitHub Bot commented on THRIFT-4270:
----------------------------------------

Github user dhull commented on the issue:

    https://github.com/apache/thrift/pull/1320
  
    @djnym, thanks for pointing out my build problem. I had developed the code in this pull request on top of my code for #1319 but thought it would be better to separate it back out for the pull request; unfortunately I made a mistake.
    
    I have fixed the problem and rebased on the current HEAD and the tests are now passing.


> Generate Erlang mapping functions for const maps and lists
> ----------------------------------------------------------
>
>                 Key: THRIFT-4270
>                 URL: https://issues.apache.org/jira/browse/THRIFT-4270
>             Project: Thrift
>          Issue Type: Improvement
>          Components: Erlang - Compiler
>    Affects Versions: 0.10.0
>            Reporter: David Hull
>            Priority: Minor
>
> The Thrift Erlang compiler generates macros for consts. This is great for scalar types and structs. However the macro that is generated for a map is something like
> {code:none}
> -define(CONSTANTS_DEMO_GEN_MAP, dict:from_list([{35532,233},{43523,853}])).
> {code}
> This is not as useful as the other macros, because any use of this macro will generate the dict at run time. (It is possible to work around this issue by using the ct_expand parse transform.)
> It would be better to generate a function directly to do the transform. The function for the previous example would be
> {code:none}
> gen_map(35532) -> 233;
> gen_map(43523) -> 853.
> {code}
> Similarly, the macro that is generated for a list is something like:
> {code:none}
> -define(CONSTANTS_DEMO_GEN_LIST, [235235,23598352,3253523]).
> {code}
> This representation is fine if you want to iterate over the elements of the list, but is not efficient if you need to look an element because lists in Erlang are implemented as singly-linked lists. For lookups, it would be better to generate a tuple and then use {{element(N, Tuple)}} to extract the nth element.
> The thrift generator could generate a function to do the lookup:
> {code:none}
> gen_list(N) -> element(N, {235235,23598352,3253523}).
> {code}



--
This message was sent by Atlassian JIRA
(v6.4.14#64029)