How can we make it easier to experiment with the compiler?

[Iain Buclaw]

On Monday, 24 May 2021 at 02:56:14 UTC, Walter Bright wrote:
>   import dmd.argtypes_x86;
>   import dmd.argtypes_sysv_x64;
>   import core.stdc.string : strlen;
>   import dmd.cond;
>   import dmd.cppmangle;
>   import dmd.cppmanglewin;
>   import dmd.dclass;
>   import dmd.declaration;
>   import dmd.dscope;
>   import dmd.dstruct;
>   import dmd.dsymbol;
>   import dmd.expression;
>   import dmd.func;
>   import dmd.globals;
>   import dmd.id;
>   import dmd.identifier;
>   import dmd.mtype;
>   import dmd.statement;
>   import dmd.typesem;
>   import dmd.tokens : TOK;
>   import dmd.root.ctfloat;
>   import dmd.root.outbuffer;
>   import dmd.root.string : toDString;
>
> If I want to understand the code, I have to understand half of 
> the rest of the compiler. On a more abstract level, why on 
> earth would a target abstraction need to know about AST nodes? 
> At least half of these imports shouldn't be here, and if they 
> are, the code needs to be redesigned.
>

To be fair, most of this is imported because a function needs the 
definition of one or more symbols.  This can be made better by 
either:

1. Making these selective imports, or...
2. Moving type definitions of AST nodes into modules that _only_ 
contain definitions.