[m-users.] Initialising a map with static data

[Fabrice Nicol]

Below is an alternative, which has pros and cons.

A bit more concise, but you have to align the data carefully to avoid 
input errors.

Or, if you have lots of data, you can write a database in a file, and 
parse (use the GH csv library for example).

%%

:-module map_test.
:-interface.
:-import_module io.
:-import_module map.
:-import_module string.
:-pred create_maps(map(string, string), map(string, string)).
:-mode create_maps(out, out) is det.

:-pred main(io::di, io::uo) is det.

:-implementation.

:-import_module list.

%% create

create_maps(Types, Vars) :-
     K1 = ["i",       "psz",         "    v",            "pv",
              "c",       "sc",               "uc",           "pc",
              "ppc",    "cpc",             "cppc"],
     V1 = ["int",     "char*",           "void",       "void*",
             "char",   "signed char", "unsigned char", "char*",
             "char**", "const char*", "const char**"],
     K2 = ["argc",   "argv"],
     V2 = ["int",    "ppc"],
     det_insert_from_corresponding_lists(K1, V1, map.init, Types),
     det_insert_from_corresponding_lists(K2, V2, map.init, Vars).

%% test

main(!IO) :- create_maps(Types, Vars),
     write_string(Types^det_elem("cpc"), !IO),
     nl(!IO),
     write_string(Vars^det_elem("argc"), !IO),
     nl(!IO).

:-end_module

%%

$ ./map_test

const char*
int

%%

Fabrice


> Is there a more concise way of creating a map full of static data? The 
> best I have obtained is this:
>
> default_typemap = Out :-
>     map.from_assoc_list([
>         ("i"    - "int"),
>         ("psz"  - "char*"),
>         ("v"    - "void"),
>         ("pv"   - "void*"),
>         ("c"    - "char"),
>         ("sc"   - "signed char"),
>         ("uc"   - "unsigned char"),
>         ("pc"   - "char*"),
>         ("ppc"  - "char**"),
>         ("cpc"  - "const char*"),
>         ("cppc" - "const char**")
>     ],
>     Types),
>     map.from_assoc_list([
>         ("argc" - "int"),
>         ("argv" - "ppc")
>     ],
>     Vars),
> :
> : .. more code..
> :
>
> Each backend coder that is a for typed language will be providing an 
> initial lookup of both variables and types so it can infer necessary 
> typing at code render time.
>
> Thanks,
> Sean
>
>
> _______________________________________________
> users mailing list
> users at lists.mercurylang.org
> https://lists.mercurylang.org/listinfo/users
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