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#include <synext.hpp>
#include <parse/tokentree.hpp>
#include <parse/lex.hpp>
#include <parse/common.hpp>
bool check_cfg(const ::AST::MetaItem& mi) {
// TODO: Handle cfg conditions
throw ::std::runtime_error("TODO: Handle #[cfg] or cfg! conditions");
return true;
}
class CCfgExpander:
public ExpandProcMacro
{
bool expand_early() const override { return true; }
::std::unique_ptr<TokenStream> expand(Span sp, const ::std::string& ident, const TokenTree& tt, AST::Module& mod) override
{
if( ident != "" ) {
ERROR(sp, E0000, "cfg! doesn't take an identifier");
}
auto lex = TTStreamO(tt);
auto attrs = Parse_MetaItem(lex);
DEBUG("cfg!() - " << attrs);
if( check_cfg(attrs) ) {
return box$( TTStreamO(TokenTree(TOK_RWORD_TRUE )) );
}
else {
return box$( TTStreamO(TokenTree(TOK_RWORD_FALSE)) );
}
}
};
class CCfgHandler:
public ExpandDecorator
{
AttrStage stage() const override { return AttrStage::EarlyPre; }
void handle(const AST::MetaItem& mi, AST::Crate& crate, AST::MacroInvocation& mac) const override {
if( check_cfg(mi) ) {
// Leave as is
}
else {
mac.clear();
}
}
void handle(const AST::MetaItem& mi, AST::Crate& crate, const AST::Path& path, AST::Module& mod, AST::Item&i) const override {
if( check_cfg(mi) ) {
// Leave
}
else {
i = AST::Item::make_None({});
}
}
void handle(const AST::MetaItem& mi, ::std::unique_ptr<AST::ExprNode>& expr) const override {
if( check_cfg(mi) ) {
// Leave
}
else {
expr.reset();
}
}
};
STATIC_MACRO("cfg", CCfgExpander);
STATIC_DECORATOR("cfg", CCfgHandler);
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