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Refactor away expand_item_mac
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@jseyfried
jseyfried committed May 21, 2016
1 parent 3192adb commit a3d705e
Showing 1 changed file with 85 additions and 159 deletions.
244 changes: 85 additions & 159 deletions src/libsyntax/ext/expand.rs
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Expand Up @@ -86,7 +86,7 @@ pub fn expand_expr(e: P<ast::Expr>, fld: &mut MacroExpander) -> P<ast::Expr> {
// expr_mac should really be expr_ext or something; it's the
// entry-point for all syntax extensions.
ast::ExprKind::Mac(mac) => {
expand_mac_invoc(mac, attrs.into_attr_vec(), span, fld)
expand_mac_invoc(mac, None, attrs.into_attr_vec(), span, fld)
}

ast::ExprKind::InPlace(placer, value_expr) => {
Expand Down Expand Up @@ -196,21 +196,17 @@ pub fn expand_expr(e: P<ast::Expr>, fld: &mut MacroExpander) -> P<ast::Expr> {
});
}

/// Expand a (not-ident-style) macro invocation. Returns the result of expansion.
fn expand_mac_invoc<T>(mac: ast::Mac, attrs: Vec<ast::Attribute>, span: Span,
/// Expand a macro invocation. Returns the result of expansion.
fn expand_mac_invoc<T>(mac: ast::Mac, ident: Option<Ident>, attrs: Vec<ast::Attribute>, span: Span,
fld: &mut MacroExpander) -> T
where T: MacroGenerable,
{
// it would almost certainly be cleaner to pass the whole
// macro invocation in, rather than pulling it apart and
// marking the tts and the ctxt separately. This also goes
// for the other three macro invocation chunks of code
// in this file.

// It would almost certainly be cleaner to pass the whole macro invocation in,
// rather than pulling it apart and marking the tts and the ctxt separately.
let Mac_ { path, tts, .. } = mac.node;
let mark = fresh_mark();

fn mac_result<'a>(path: &ast::Path, tts: Vec<TokenTree>, mark: Mrk,
fn mac_result<'a>(path: &ast::Path, ident: Option<Ident>, tts: Vec<TokenTree>, mark: Mrk,
attrs: Vec<ast::Attribute>, call_site: Span, fld: &'a mut MacroExpander)
-> Option<Box<MacResult + 'a>> {
check_attributes(&attrs, fld);
Expand All @@ -231,8 +227,16 @@ fn expand_mac_invoc<T>(mac: ast::Mac, attrs: Vec<ast::Attribute>, span: Span,
return None;
};

let ident = ident.unwrap_or(Ident::with_empty_ctxt(keywords::Invalid.name()));
match *extension {
NormalTT(ref expandfun, exp_span, allow_internal_unstable) => {
if ident.name != keywords::Invalid.name() {
let msg =
format!("macro {}! expects no ident argument, given '{}'", extname, ident);
fld.cx.span_err(path.span, &msg);
return None;
}

fld.cx.bt_push(ExpnInfo {
call_site: call_site,
callee: NameAndSpan {
Expand All @@ -251,15 +255,72 @@ fn expand_mac_invoc<T>(mac: ast::Mac, attrs: Vec<ast::Attribute>, span: Span,
let marked_tts = mark_tts(&tts[..], mark);
Some(expandfun.expand(fld.cx, mac_span, &marked_tts))
}
_ => {

IdentTT(ref expander, tt_span, allow_internal_unstable) => {
if ident.name == keywords::Invalid.name() {
fld.cx.span_err(path.span,
&format!("macro {}! expects an ident argument", extname));
return None;
};

fld.cx.bt_push(ExpnInfo {
call_site: call_site,
callee: NameAndSpan {
format: MacroBang(extname),
span: tt_span,
allow_internal_unstable: allow_internal_unstable,
}
});

let marked_tts = mark_tts(&tts, mark);
Some(expander.expand(fld.cx, call_site, ident, marked_tts))
}

MacroRulesTT => {
if ident.name == keywords::Invalid.name() {
fld.cx.span_err(path.span,
&format!("macro {}! expects an ident argument", extname));
return None;
};

fld.cx.bt_push(ExpnInfo {
call_site: call_site,
callee: NameAndSpan {
format: MacroBang(extname),
span: None,
// `macro_rules!` doesn't directly allow unstable
// (this is orthogonal to whether the macro it creates allows it)
allow_internal_unstable: false,
}
});

// DON'T mark before expansion.
fld.cx.insert_macro(ast::MacroDef {
ident: ident,
id: ast::DUMMY_NODE_ID,
span: call_site,
imported_from: None,
use_locally: true,
body: tts,
export: attr::contains_name(&attrs, "macro_export"),
allow_internal_unstable: attr::contains_name(&attrs, "allow_internal_unstable"),
attrs: attrs,
});

// macro_rules! has a side effect but expands to nothing.
fld.cx.bt_pop();
None
}

MultiDecorator(..) | MultiModifier(..) => {
fld.cx.span_err(path.span,
&format!("'{}' is not a tt-style macro", extname));
&format!("`{}` can only be used in attributes", extname));
None
}
}
}

let opt_expanded = T::make_with(match mac_result(&path, tts, mark, attrs, span, fld) {
let opt_expanded = T::make_with(match mac_result(&path, ident, tts, mark, attrs, span, fld) {
Some(result) => result,
None => return T::dummy(span),
});
Expand Down Expand Up @@ -375,141 +436,6 @@ fn contains_macro_use(fld: &mut MacroExpander, attrs: &[ast::Attribute]) -> bool
false
}

// Support for item-position macro invocations, exactly the same
// logic as for expression-position macro invocations.
pub fn expand_item_mac(it: P<ast::Item>,
fld: &mut MacroExpander) -> SmallVector<P<ast::Item>> {
let (extname, path_span, tts, span, attrs, ident) = it.and_then(|it| match it.node {
ItemKind::Mac(codemap::Spanned { node: Mac_ { path, tts, .. }, .. }) =>
(path.segments[0].identifier.name, path.span, tts, it.span, it.attrs, it.ident),
_ => fld.cx.span_bug(it.span, "invalid item macro invocation")
});

check_attributes(&attrs, fld);

let fm = fresh_mark();
let items = {
let expanded = match fld.cx.syntax_env.find(extname) {
None => {
fld.cx.span_err(path_span,
&format!("macro undefined: '{}!'",
extname));
// let compilation continue
return SmallVector::zero();
}

Some(rc) => match *rc {
NormalTT(ref expander, tt_span, allow_internal_unstable) => {
if ident.name != keywords::Invalid.name() {
fld.cx
.span_err(path_span,
&format!("macro {}! expects no ident argument, given '{}'",
extname,
ident));
return SmallVector::zero();
}
fld.cx.bt_push(ExpnInfo {
call_site: span,
callee: NameAndSpan {
format: MacroBang(extname),
span: tt_span,
allow_internal_unstable: allow_internal_unstable,
}
});
// mark before expansion:
let marked_before = mark_tts(&tts[..], fm);
expander.expand(fld.cx, span, &marked_before[..])
}
IdentTT(ref expander, tt_span, allow_internal_unstable) => {
if ident.name == keywords::Invalid.name() {
fld.cx.span_err(path_span,
&format!("macro {}! expects an ident argument",
extname));
return SmallVector::zero();
}
fld.cx.bt_push(ExpnInfo {
call_site: span,
callee: NameAndSpan {
format: MacroBang(extname),
span: tt_span,
allow_internal_unstable: allow_internal_unstable,
}
});
// mark before expansion:
let marked_tts = mark_tts(&tts[..], fm);
expander.expand(fld.cx, span, ident, marked_tts)
}
MacroRulesTT => {
if ident.name == keywords::Invalid.name() {
fld.cx.span_err(path_span, "macro_rules! expects an ident argument");
return SmallVector::zero();
}

fld.cx.bt_push(ExpnInfo {
call_site: span,
callee: NameAndSpan {
format: MacroBang(extname),
span: None,
// `macro_rules!` doesn't directly allow
// unstable (this is orthogonal to whether
// the macro it creates allows it)
allow_internal_unstable: false,
}
});
// DON'T mark before expansion.

let allow_internal_unstable = attr::contains_name(&attrs,
"allow_internal_unstable");

let export = attr::contains_name(&attrs, "macro_export");
let def = ast::MacroDef {
ident: ident,
attrs: attrs,
id: ast::DUMMY_NODE_ID,
span: span,
imported_from: None,
export: export,
use_locally: true,
allow_internal_unstable: allow_internal_unstable,
body: tts,
};
fld.cx.insert_macro(def);

// macro_rules! has a side effect but expands to nothing.
fld.cx.bt_pop();
return SmallVector::zero();
}
_ => {
fld.cx.span_err(span,
&format!("{}! is not legal in item position",
extname));
return SmallVector::zero();
}
}
};

expanded.make_items()
};

let items = match items {
Some(items) => {
items.into_iter()
.map(|i| mark_item(i, fm))
.flat_map(|i| fld.fold_item(i).into_iter())
.collect()
}
None => {
fld.cx.span_err(path_span,
&format!("non-item macro in item position: {}",
extname));
return SmallVector::zero();
}
};

fld.cx.bt_pop();
items
}

/// Expand a stmt
fn expand_stmt(stmt: Stmt, fld: &mut MacroExpander) -> SmallVector<Stmt> {
// perform all pending renames
Expand All @@ -525,7 +451,7 @@ fn expand_stmt(stmt: Stmt, fld: &mut MacroExpander) -> SmallVector<Stmt> {
};

let mut fully_expanded: SmallVector<ast::Stmt> =
expand_mac_invoc(mac.unwrap(), attrs.into_attr_vec(), stmt.span, fld);
expand_mac_invoc(mac.unwrap(), None, attrs.into_attr_vec(), stmt.span, fld);

// If this is a macro invocation with a semicolon, then apply that
// semicolon to the final statement produced by expansion.
Expand Down Expand Up @@ -742,7 +668,7 @@ fn expand_pat(p: P<ast::Pat>, fld: &mut MacroExpander) -> P<ast::Pat> {
}
p.and_then(|ast::Pat {node, span, ..}| {
match node {
PatKind::Mac(mac) => expand_mac_invoc(mac, Vec::new(), span, fld),
PatKind::Mac(mac) => expand_mac_invoc(mac, None, Vec::new(), span, fld),
_ => unreachable!()
}
})
Expand Down Expand Up @@ -813,7 +739,13 @@ fn expand_annotatable(a: Annotatable,
let mut new_items: SmallVector<Annotatable> = match a {
Annotatable::Item(it) => match it.node {
ast::ItemKind::Mac(..) => {
expand_item_mac(it, fld).into_iter().map(|i| Annotatable::Item(i)).collect()
let new_items: SmallVector<P<ast::Item>> = it.and_then(|it| match it.node {
ItemKind::Mac(mac) =>
expand_mac_invoc(mac, Some(it.ident), it.attrs, it.span, fld),
_ => unreachable!(),
});

new_items.into_iter().map(|i| Annotatable::Item(i)).collect()
}
ast::ItemKind::Mod(_) | ast::ItemKind::ForeignMod(_) => {
let valid_ident =
Expand Down Expand Up @@ -997,7 +929,7 @@ fn expand_impl_item(ii: ast::ImplItem, fld: &mut MacroExpander)
span: fld.new_span(ii.span)
}),
ast::ImplItemKind::Macro(mac) => {
expand_mac_invoc(mac, ii.attrs, ii.span, fld)
expand_mac_invoc(mac, None, ii.attrs, ii.span, fld)
}
_ => fold::noop_fold_impl_item(ii, fld)
}
Expand Down Expand Up @@ -1041,7 +973,7 @@ pub fn expand_type(t: P<ast::Ty>, fld: &mut MacroExpander) -> P<ast::Ty> {
let t = match t.node.clone() {
ast::TyKind::Mac(mac) => {
if fld.cx.ecfg.features.unwrap().type_macros {
expand_mac_invoc(mac, Vec::new(), t.span, fld)
expand_mac_invoc(mac, None, Vec::new(), t.span, fld)
} else {
feature_gate::emit_feature_err(
&fld.cx.parse_sess.span_diagnostic,
Expand Down Expand Up @@ -1310,12 +1242,6 @@ fn mark_tts(tts: &[TokenTree], m: Mrk) -> Vec<TokenTree> {
noop_fold_tts(tts, &mut Marker{mark:m})
}

// apply a given mark to the given item. Used following the expansion of a macro.
fn mark_item(expr: P<ast::Item>, m: Mrk) -> P<ast::Item> {
Marker{mark:m}.fold_item(expr)
.expect_one("marking an item didn't return exactly one item")
}

/// Check that there are no macro invocations left in the AST:
pub fn check_for_macros(sess: &parse::ParseSess, krate: &ast::Crate) {
visit::walk_crate(&mut MacroExterminator{sess:sess}, krate);
Expand Down

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