I'm working on a feature in DMD to query lexical, syntactic and
semantic context at a given byte offset in a given source file.
In the long run my vision is to add libclang-like functionality
directly into DMD and a specific mode in DMD that just starts up
DMD to query some information at a file and offset in a given
source file typically given by an editor.
For practise and to learn the insides of DMD I've so far added
the following to Lexer::nextToken() a long with some other stuff
in lexer.[ch] and mars.c not shown here.
TOK Lexer::nextToken()
{
if (token.next)
{
Token *t = token.next;
memcpy(&token,t,sizeof(Token));
t->next = freelist;
freelist = t;
}
else
{
scan(&token);
}
const long begin = token.ptr - this->base; // token begin
offset
const long end = begin + strlen(token.toChars(token.value));
// token end offset
if (begin <= global.params.queryAtOffset &&
global.params.queryAtOffset < end)
{
token.printDoc();
exit(0);
}
return token.value;
}
to query lexical information at point using a new DMD flag
-query=FILE:OFFSET
However, most calls to DMD parses several source files. So I need
some way to know which file I'm currently parsing from inside the
lexer. GDB stack is
0 in Lexer::nextToken of lexer.c:706
1 in Parser::check of parse.c:5148
2 in Parser::parseStatement of parse.c:4126
3 in Parser::parseStatement of parse.c:4289
4 in Parser::parseContracts of parse.c:3660
5 in Parser::parseDeclarations of parse.c:3480
6 in Parser::parseDeclDefs of parse.c:293
7 in Parser::parseAggregate of parse.c:1933
8 in Parser::parseDeclarations of parse.c:3303
9 in Parser::parseDeclDefs of parse.c:293
10 in Parser::parseModule of parse.c:162
11 in Module::parse of module.c:515
12 in tryMain of mars.c:1512
13 in main of mars.c:1827
The only way I see of solving this for now is to add a global
copy of the Module::srcfile accessible to make this information
accessible within the lexer. Does anybody have a better idea?
