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Simplify and rename macro API

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Now that procedural macros can be implemented outside of the compiler,
it's more important to have a reasonable API to work with. Here are the
basic changes:

* Rename SyntaxExpanderTTTrait to MacroExpander, SyntaxExpanderTT to
    BasicMacroExpander, etc. I think "procedural macro" is the right
    term for these now, right? The other option would be SynExtExpander
    or something like that.

* Stop passing the SyntaxContext to extensions. This was only ever used
    by macro_rules, which doesn't even use it anymore. I can't think of
    a context in which an external extension would need it, and removal
    allows the API to be significantly simpler - no more
    SyntaxExpanderTTItemExpanderWithoutContext wrappers to worry about.
This commit is contained in:
Steven Fackler 2014-01-25 13:34:26 -08:00
parent de57a22b9a
commit ab5bbd3c17
4 changed files with 72 additions and 141 deletions
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61
src/libsyntax/ext/expand.rs
View file

@ -13,7 +13,7 @@ use ast::{Local, Ident, MacInvocTT};
use ast::{ItemMac, Mrk, Stmt, StmtDecl, StmtMac, StmtExpr, StmtSemi};
use ast::{TokenTree};
use ast;
use ast_util::{mtwt_outer_mark, new_rename, new_mark};
use ast_util::{new_rename, new_mark};
use ext::build::AstBuilder;
use attr;
use attr::AttrMetaMethods;
@ -44,7 +44,7 @@ pub fn expand_expr(e: @ast::Expr, fld: &mut MacroExpander) -> @ast::Expr {
// for the other three macro invocation chunks of code
// in this file.
// Token-tree macros:
MacInvocTT(ref pth, ref tts, ctxt) => {
MacInvocTT(ref pth, ref tts, _) => {
if pth.segments.len() > 1u {
fld.cx.span_err(
pth.span,
@ -77,7 +77,6 @@ pub fn expand_expr(e: @ast::Expr, fld: &mut MacroExpander) -> @ast::Expr {
let fm = fresh_mark();
// mark before:
let marked_before = mark_tts(*tts,fm);
let marked_ctxt = new_mark(fm, ctxt);
// The span that we pass to the expanders we want to
// be the root of the call stack. That's the most
@ -87,8 +86,7 @@ pub fn expand_expr(e: @ast::Expr, fld: &mut MacroExpander) -> @ast::Expr {
let expanded = match expandfun.expand(fld.cx,
mac_span.call_site,
marked_before,
marked_ctxt) {
marked_before) {
MRExpr(e) => e,
MRAny(any_macro) => any_macro.make_expr(),
_ => {
@ -286,12 +284,12 @@ pub fn contains_macro_escape(attrs: &[ast::Attribute]) -> bool {
// logic as for expression-position macro invocations.
pub fn expand_item_mac(it: @ast::Item, fld: &mut MacroExpander)
-> SmallVector<@ast::Item> {
let (pth, tts, ctxt) = match it.node {
let (pth, tts) = match it.node {
ItemMac(codemap::Spanned {
node: MacInvocTT(ref pth, ref tts, ctxt),
node: MacInvocTT(ref pth, ref tts, _),
..
}) => {
(pth, (*tts).clone(), ctxt)
(pth, (*tts).clone())
}
_ => fld.cx.span_bug(it.span, "invalid item macro invocation")
};
@ -325,8 +323,7 @@ pub fn expand_item_mac(it: @ast::Item, fld: &mut MacroExpander)
});
// mark before expansion:
let marked_before = mark_tts(tts,fm);
let marked_ctxt = new_mark(fm,ctxt);
expander.expand(fld.cx, it.span, marked_before, marked_ctxt)
expander.expand(fld.cx, it.span, marked_before)
}
Some(&IdentTT(ref expander, span)) => {
if it.ident.name == parse::token::special_idents::invalid.name {
@ -344,8 +341,7 @@ pub fn expand_item_mac(it: @ast::Item, fld: &mut MacroExpander)
});
// mark before expansion:
let marked_tts = mark_tts(tts,fm);
let marked_ctxt = new_mark(fm,ctxt);
expander.expand(fld.cx, it.span, it.ident, marked_tts, marked_ctxt)
expander.expand(fld.cx, it.span, it.ident, marked_tts)
}
_ => {
fld.cx.span_err(it.span, format!("{}! is not legal in item position", extnamestr));
@ -464,11 +460,11 @@ fn load_extern_macros(crate: &ast::ViewItem, fld: &mut MacroExpander) {
pub fn expand_stmt(s: &Stmt, fld: &mut MacroExpander) -> SmallVector<@Stmt> {
// why the copying here and not in expand_expr?
// looks like classic changed-in-only-one-place
let (pth, tts, semi, ctxt) = match s.node {
let (pth, tts, semi) = match s.node {
StmtMac(ref mac, semi) => {
match mac.node {
MacInvocTT(ref pth, ref tts, ctxt) => {
(pth, (*tts).clone(), semi, ctxt)
MacInvocTT(ref pth, ref tts, _) => {
(pth, (*tts).clone(), semi)
}
}
}
@ -498,7 +494,6 @@ pub fn expand_stmt(s: &Stmt, fld: &mut MacroExpander) -> SmallVector<@Stmt> {
let fm = fresh_mark();
// mark before expansion:
let marked_tts = mark_tts(tts,fm);
let marked_ctxt = new_mark(fm,ctxt);
// See the comment in expand_expr for why we want the original span,
// not the current mac.span.
@ -506,8 +501,7 @@ pub fn expand_stmt(s: &Stmt, fld: &mut MacroExpander) -> SmallVector<@Stmt> {
let expanded = match expandfun.expand(fld.cx,
mac_span.call_site,
marked_tts,
marked_ctxt) {
marked_tts) {
MRExpr(e) => {
@codemap::Spanned {
node: StmtExpr(e, ast::DUMMY_NODE_ID),
@ -923,15 +917,6 @@ pub fn replace_ctxts(expr : @ast::Expr, ctxt : SyntaxContext) -> @ast::Expr {
fun_to_ctxt_folder(@Repainter{ctxt:ctxt}).fold_expr(expr)
}
// take the mark from the given ctxt (that has a mark at the outside),
// and apply it to everything in the token trees, thereby cancelling
// that mark.
pub fn mtwt_cancel_outer_mark(tts: &[ast::TokenTree], ctxt: ast::SyntaxContext)
-> ~[ast::TokenTree] {
let outer_mark = mtwt_outer_mark(ctxt);
mark_tts(tts,outer_mark)
}
fn original_span(cx: &ExtCtxt) -> @codemap::ExpnInfo {
let mut relevant_info = cx.backtrace();
let mut einfo = relevant_info.unwrap();
@ -1090,28 +1075,6 @@ mod test {
}
}
#[test] fn cancel_outer_mark_test(){
let invalid_name = token::special_idents::invalid.name;
let ident_str = @"x";
let tts = string_to_tts(ident_str);
let fm = fresh_mark();
let marked_once = fold::fold_tts(tts,&mut new_mark_folder(fm));
assert_eq!(marked_once.len(),1);
let marked_once_ctxt =
match marked_once[0] {
ast::TTTok(_,token::IDENT(id,_)) => id.ctxt,
_ => fail!(format!("unexpected shape for marked tts: {:?}",marked_once[0]))
};
assert_eq!(mtwt_marksof(marked_once_ctxt,invalid_name),~[fm]);
let remarked = mtwt_cancel_outer_mark(marked_once,marked_once_ctxt);
assert_eq!(remarked.len(),1);
match remarked[0] {
ast::TTTok(_,token::IDENT(id,_)) =>
assert_eq!(mtwt_marksof(id.ctxt,invalid_name),~[]),
_ => fail!(format!("unexpected shape for marked tts: {:?}",remarked[0]))
}
}
#[test]
fn renaming () {
let item_ast = string_to_crate(@"fn f() -> int { a }");