rust/src/libsyntax/ext/expand.rs
Patrick Walton 887c656970 librustc: Introduce a new visitor type based on traits and port syntax to it.
This is preparation for removing `@fn`.

This does *not* use default methods yet, because I don't know
whether they work. If they do, a forthcoming PR will use them.

This also changes the precedence of `as`.
2013-08-02 21:57:58 -07:00

1206 lines
40 KiB
Rust

// Copyright 2012 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
use ast::{Block, Crate, NodeId, expr_, expr_mac, ident, mac_invoc_tt};
use ast::{item_mac, stmt_, stmt_mac, stmt_expr, stmt_semi};
use ast::{illegal_ctxt};
use ast;
use ast_util::{new_rename, new_mark, resolve};
use attr;
use attr::AttrMetaMethods;
use codemap;
use codemap::{span, spanned, ExpnInfo, NameAndSpan};
use ext::base::*;
use fold::*;
use parse;
use parse::{parse_item_from_source_str};
use parse::token;
use parse::token::{ident_to_str, intern};
use visit;
use visit::Visitor;
use std::vec;
pub fn expand_expr(extsbox: @mut SyntaxEnv,
cx: @ExtCtxt,
e: &expr_,
s: span,
fld: @ast_fold,
orig: @fn(&expr_, span, @ast_fold) -> (expr_, span))
-> (expr_, span) {
match *e {
// expr_mac should really be expr_ext or something; it's the
// entry-point for all syntax extensions.
expr_mac(ref mac) => {
match (*mac).node {
// Token-tree macros:
mac_invoc_tt(ref pth, ref tts) => {
if (pth.idents.len() > 1u) {
cx.span_fatal(
pth.span,
fmt!("expected macro name without module \
separators"));
}
let extname = &pth.idents[0];
let extnamestr = ident_to_str(extname);
// leaving explicit deref here to highlight unbox op:
match (*extsbox).find(&extname.name) {
None => {
cx.span_fatal(
pth.span,
fmt!("macro undefined: '%s'", extnamestr))
}
Some(@SE(NormalTT(SyntaxExpanderTT{
expander: exp,
span: exp_sp
}))) => {
cx.bt_push(ExpnInfo {
call_site: s,
callee: NameAndSpan {
name: extnamestr,
span: exp_sp,
},
});
let expanded = match exp(cx, mac.span, *tts) {
MRExpr(e) => e,
MRAny(expr_maker,_,_) => expr_maker(),
_ => {
cx.span_fatal(
pth.span,
fmt!(
"non-expr macro in expr pos: %s",
extnamestr
)
)
}
};
//keep going, outside-in
let fully_expanded =
fld.fold_expr(expanded).node.clone();
cx.bt_pop();
(fully_expanded, s)
}
_ => {
cx.span_fatal(
pth.span,
fmt!("'%s' is not a tt-style macro", extnamestr)
)
}
}
}
}
}
// Desugar expr_for_loop
// From: `foreach <src_pat> in <src_expr> <src_loop_block>`
ast::expr_for_loop(src_pat, src_expr, ref src_loop_block) => {
let src_pat = src_pat.clone();
let src_expr = src_expr.clone();
// Expand any interior macros etc.
// NB: we don't fold pats yet. Curious.
let src_expr = fld.fold_expr(src_expr).clone();
let src_loop_block = fld.fold_block(src_loop_block).clone();
let span = s;
let lo = s.lo;
let hi = s.hi;
pub fn mk_expr(cx: @ExtCtxt, span: span,
node: expr_) -> @ast::expr {
@ast::expr {
id: cx.next_id(),
node: node,
span: span,
}
}
fn mk_block(cx: @ExtCtxt,
stmts: &[@ast::stmt],
expr: Option<@ast::expr>,
span: span) -> ast::Block {
ast::Block {
view_items: ~[],
stmts: stmts.to_owned(),
expr: expr,
id: cx.next_id(),
rules: ast::DefaultBlock,
span: span,
}
}
fn mk_simple_path(ident: ast::ident, span: span) -> ast::Path {
ast::Path {
span: span,
global: false,
idents: ~[ident],
rp: None,
types: ~[]
}
}
// to:
//
// {
// let _i = &mut <src_expr>;
// loop {
// match i.next() {
// None => break,
// Some(<src_pat>) => <src_loop_block>
// }
// }
// }
let local_ident = token::gensym_ident("i");
let some_ident = token::str_to_ident("Some");
let none_ident = token::str_to_ident("None");
let next_ident = token::str_to_ident("next");
let local_path_1 = mk_simple_path(local_ident, span);
let local_path_2 = mk_simple_path(local_ident, span);
let some_path = mk_simple_path(some_ident, span);
let none_path = mk_simple_path(none_ident, span);
// `let i = &mut <src_expr>`
let iter_decl_stmt = {
let ty = ast::Ty {
id: cx.next_id(),
node: ast::ty_infer,
span: span
};
let local = @ast::Local {
is_mutbl: false,
ty: ty,
pat: @ast::pat {
id: cx.next_id(),
node: ast::pat_ident(ast::bind_infer, local_path_1, None),
span: src_expr.span
},
init: Some(mk_expr(cx, src_expr.span,
ast::expr_addr_of(ast::m_mutbl, src_expr))),
id: cx.next_id(),
span: src_expr.span,
};
let e = @spanned(src_expr.span.lo,
src_expr.span.hi,
ast::decl_local(local));
@spanned(lo, hi, ast::stmt_decl(e, cx.next_id()))
};
// `None => break;`
let none_arm = {
let break_expr = mk_expr(cx, span, ast::expr_break(None));
let break_stmt = @spanned(lo, hi, ast::stmt_expr(break_expr, cx.next_id()));
let none_block = mk_block(cx, [break_stmt], None, span);
let none_pat = @ast::pat {
id: cx.next_id(),
node: ast::pat_ident(ast::bind_infer, none_path, None),
span: span
};
ast::arm {
pats: ~[none_pat],
guard: None,
body: none_block
}
};
// `Some(<src_pat>) => <src_loop_block>`
let some_arm = {
let pat = @ast::pat {
id: cx.next_id(),
node: ast::pat_enum(some_path, Some(~[src_pat])),
span: src_pat.span
};
ast::arm {
pats: ~[pat],
guard: None,
body: src_loop_block
}
};
// `match i.next() { ... }`
let match_stmt = {
let local_expr = mk_expr(cx, span, ast::expr_path(local_path_2));
let next_call_expr = mk_expr(cx, span,
ast::expr_method_call(cx.next_id(),
local_expr, next_ident,
~[], ~[], ast::NoSugar));
let match_expr = mk_expr(cx, span, ast::expr_match(next_call_expr,
~[none_arm, some_arm]));
@spanned(lo, hi, ast::stmt_expr(match_expr, cx.next_id()))
};
// `loop { ... }`
let loop_block = {
let loop_body_block = mk_block(cx, [match_stmt], None, span);
let loop_body_expr = mk_expr(cx, span, ast::expr_loop(loop_body_block, None));
let loop_body_stmt = @spanned(lo, hi, ast::stmt_expr(loop_body_expr, cx.next_id()));
mk_block(cx, [iter_decl_stmt,
loop_body_stmt],
None, span)
};
(ast::expr_block(loop_block), span)
}
_ => orig(e, s, fld)
}
}
// This is a secondary mechanism for invoking syntax extensions on items:
// "decorator" attributes, such as #[auto_encode]. These are invoked by an
// attribute prefixing an item, and are interpreted by feeding the item
// through the named attribute _as a syntax extension_ and splicing in the
// resulting item vec into place in favour of the decorator. Note that
// these do _not_ work for macro extensions, just ItemDecorator ones.
//
// NB: there is some redundancy between this and expand_item, below, and
// they might benefit from some amount of semantic and language-UI merger.
pub fn expand_mod_items(extsbox: @mut SyntaxEnv,
cx: @ExtCtxt,
module_: &ast::_mod,
fld: @ast_fold,
orig: @fn(&ast::_mod, @ast_fold) -> ast::_mod)
-> ast::_mod {
// Fold the contents first:
let module_ = orig(module_, fld);
// For each item, look through the attributes. If any of them are
// decorated with "item decorators", then use that function to transform
// the item into a new set of items.
let new_items = do vec::flat_map(module_.items) |item| {
do item.attrs.rev_iter().fold(~[*item]) |items, attr| {
let mname = attr.name();
match (*extsbox).find(&intern(mname)) {
Some(@SE(ItemDecorator(dec_fn))) => {
cx.bt_push(ExpnInfo {
call_site: attr.span,
callee: NameAndSpan {
name: mname,
span: None
}
});
let r = dec_fn(cx, attr.span, attr.node.value, items);
cx.bt_pop();
r
},
_ => items,
}
}
};
ast::_mod { items: new_items, ..module_ }
}
// eval $e with a new exts frame:
macro_rules! with_exts_frame (
($extsboxexpr:expr,$macros_escape:expr,$e:expr) =>
({let extsbox = $extsboxexpr;
let oldexts = *extsbox;
*extsbox = oldexts.push_frame();
extsbox.insert(intern(special_block_name),
@BlockInfo(BlockInfo{macros_escape:$macros_escape,pending_renames:@mut ~[]}));
let result = $e;
*extsbox = oldexts;
result
})
)
static special_block_name : &'static str = " block";
// When we enter a module, record it, for the sake of `module!`
pub fn expand_item(extsbox: @mut SyntaxEnv,
cx: @ExtCtxt,
it: @ast::item,
fld: @ast_fold,
orig: @fn(@ast::item, @ast_fold) -> Option<@ast::item>)
-> Option<@ast::item> {
// need to do expansion first... it might turn out to be a module.
let maybe_it = match it.node {
ast::item_mac(*) => expand_item_mac(extsbox, cx, it, fld),
_ => Some(it)
};
match maybe_it {
Some(it) => {
match it.node {
ast::item_mod(_) | ast::item_foreign_mod(_) => {
cx.mod_push(it.ident);
let macro_escape = contains_macro_escape(it.attrs);
let result = with_exts_frame!(extsbox,macro_escape,orig(it,fld));
cx.mod_pop();
result
}
_ => orig(it,fld)
}
}
None => None
}
}
// does this attribute list contain "macro_escape" ?
pub fn contains_macro_escape(attrs: &[ast::Attribute]) -> bool {
attr::contains_name(attrs, "macro_escape")
}
// Support for item-position macro invocations, exactly the same
// logic as for expression-position macro invocations.
pub fn expand_item_mac(extsbox: @mut SyntaxEnv,
cx: @ExtCtxt, it: @ast::item,
fld: @ast_fold)
-> Option<@ast::item> {
let (pth, tts) = match it.node {
item_mac(codemap::spanned { node: mac_invoc_tt(ref pth, ref tts), _}) => {
(pth, (*tts).clone())
}
_ => cx.span_bug(it.span, "invalid item macro invocation")
};
let extname = &pth.idents[0];
let extnamestr = ident_to_str(extname);
let expanded = match (*extsbox).find(&extname.name) {
None => cx.span_fatal(pth.span,
fmt!("macro undefined: '%s!'", extnamestr)),
Some(@SE(NormalTT(ref expand))) => {
if it.ident != parse::token::special_idents::invalid {
cx.span_fatal(pth.span,
fmt!("macro %s! expects no ident argument, \
given '%s'", extnamestr,
ident_to_str(&it.ident)));
}
cx.bt_push(ExpnInfo {
call_site: it.span,
callee: NameAndSpan {
name: extnamestr,
span: expand.span
}
});
((*expand).expander)(cx, it.span, tts)
}
Some(@SE(IdentTT(ref expand))) => {
if it.ident == parse::token::special_idents::invalid {
cx.span_fatal(pth.span,
fmt!("macro %s! expects an ident argument",
extnamestr));
}
cx.bt_push(ExpnInfo {
call_site: it.span,
callee: NameAndSpan {
name: extnamestr,
span: expand.span
}
});
((*expand).expander)(cx, it.span, it.ident, tts)
}
_ => cx.span_fatal(
it.span, fmt!("%s! is not legal in item position", extnamestr))
};
let maybe_it = match expanded {
MRItem(it) => fld.fold_item(it),
MRExpr(_) => cx.span_fatal(pth.span,
fmt!("expr macro in item position: %s", extnamestr)),
MRAny(_, item_maker, _) => item_maker().chain(|i| {fld.fold_item(i)}),
MRDef(ref mdef) => {
insert_macro(*extsbox,intern(mdef.name), @SE((*mdef).ext));
None
}
};
cx.bt_pop();
return maybe_it;
}
// insert a macro into the innermost frame that doesn't have the
// macro_escape tag.
fn insert_macro(exts: SyntaxEnv, name: ast::Name, transformer: @Transformer) {
let is_non_escaping_block =
|t : &@Transformer| -> bool{
match t {
&@BlockInfo(BlockInfo {macros_escape:false,_}) => true,
&@BlockInfo(BlockInfo {_}) => false,
_ => fail!(fmt!("special identifier %? was bound to a non-BlockInfo",
special_block_name))
}
};
exts.insert_into_frame(name,transformer,intern(special_block_name),
is_non_escaping_block)
}
// expand a stmt
pub fn expand_stmt(extsbox: @mut SyntaxEnv,
cx: @ExtCtxt,
s: &stmt_,
sp: span,
fld: @ast_fold,
orig: @fn(&stmt_, span, @ast_fold)
-> (Option<stmt_>, span))
-> (Option<stmt_>, span) {
let (mac, pth, tts, semi) = match *s {
stmt_mac(ref mac, semi) => {
match mac.node {
mac_invoc_tt(ref pth, ref tts) => {
((*mac).clone(), pth, (*tts).clone(), semi)
}
}
}
_ => return orig(s, sp, fld)
};
if (pth.idents.len() > 1u) {
cx.span_fatal(
pth.span,
fmt!("expected macro name without module \
separators"));
}
let extname = &pth.idents[0];
let extnamestr = ident_to_str(extname);
let (fully_expanded, sp) = match (*extsbox).find(&extname.name) {
None =>
cx.span_fatal(pth.span, fmt!("macro undefined: '%s'", extnamestr)),
Some(@SE(NormalTT(
SyntaxExpanderTT{expander: exp, span: exp_sp}))) => {
cx.bt_push(ExpnInfo {
call_site: sp,
callee: NameAndSpan { name: extnamestr, span: exp_sp }
});
let expanded = match exp(cx, mac.span, tts) {
MRExpr(e) =>
@codemap::spanned { node: stmt_expr(e, cx.next_id()),
span: e.span},
MRAny(_,_,stmt_mkr) => stmt_mkr(),
_ => cx.span_fatal(
pth.span,
fmt!("non-stmt macro in stmt pos: %s", extnamestr))
};
//keep going, outside-in
let fully_expanded = match fld.fold_stmt(expanded) {
Some(stmt) => {
let fully_expanded = &stmt.node;
cx.bt_pop();
(*fully_expanded).clone()
}
None => {
cx.span_fatal(pth.span,
"macro didn't expand to a statement")
}
};
(fully_expanded, sp)
}
_ => {
cx.span_fatal(pth.span,
fmt!("'%s' is not a tt-style macro", extnamestr))
}
};
(match fully_expanded {
stmt_expr(e, stmt_id) if semi => Some(stmt_semi(e, stmt_id)),
_ => { Some(fully_expanded) } /* might already have a semi */
}, sp)
}
#[deriving(Clone)]
struct NewNameFinderContext {
ident_accumulator: @mut ~[ast::ident],
}
impl Visitor<()> for NewNameFinderContext {
fn visit_pat(@mut self, pattern: @ast::pat, _: ()) {
match *pattern {
// we found a pat_ident!
ast::pat {
id: _,
node: ast::pat_ident(_, ref path, ref inner),
span: _
} => {
match path {
// a path of length one:
&ast::Path {
global: false,
idents: [id],
span: _,
rp: _,
types: _
} => self.ident_accumulator.push(id),
// I believe these must be enums...
_ => ()
}
// visit optional subpattern of pat_ident:
foreach subpat in inner.iter() {
self.visit_pat(*subpat, ())
}
}
// use the default traversal for non-pat_idents
_ => visit::visit_pat(self as @Visitor<()>, pattern, ())
}
}
// XXX: Methods below can become default methods.
fn visit_mod(@mut self, module: &ast::_mod, _: span, _: NodeId, _: ()) {
visit::visit_mod(self as @Visitor<()>, module, ())
}
fn visit_view_item(@mut self, view_item: &ast::view_item, _: ()) {
visit::visit_view_item(self as @Visitor<()>, view_item, ())
}
fn visit_item(@mut self, item: @ast::item, _: ()) {
visit::visit_item(self as @Visitor<()>, item, ())
}
fn visit_foreign_item(@mut self,
foreign_item: @ast::foreign_item,
_: ()) {
visit::visit_foreign_item(self as @Visitor<()>, foreign_item, ())
}
fn visit_local(@mut self, local: @ast::Local, _: ()) {
visit::visit_local(self as @Visitor<()>, local, ())
}
fn visit_block(@mut self, block: &ast::Block, _: ()) {
visit::visit_block(self as @Visitor<()>, block, ())
}
fn visit_stmt(@mut self, stmt: @ast::stmt, _: ()) {
visit::visit_stmt(self as @Visitor<()>, stmt, ())
}
fn visit_arm(@mut self, arm: &ast::arm, _: ()) {
visit::visit_arm(self as @Visitor<()>, arm, ())
}
fn visit_decl(@mut self, decl: @ast::decl, _: ()) {
visit::visit_decl(self as @Visitor<()>, decl, ())
}
fn visit_expr(@mut self, expr: @ast::expr, _: ()) {
visit::visit_expr(self as @Visitor<()>, expr, ())
}
fn visit_expr_post(@mut self, _: @ast::expr, _: ()) {
// Empty!
}
fn visit_ty(@mut self, typ: &ast::Ty, _: ()) {
visit::visit_ty(self as @Visitor<()>, typ, ())
}
fn visit_generics(@mut self, generics: &ast::Generics, _: ()) {
visit::visit_generics(self as @Visitor<()>, generics, ())
}
fn visit_fn(@mut self,
function_kind: &visit::fn_kind,
function_declaration: &ast::fn_decl,
block: &ast::Block,
span: span,
node_id: NodeId,
_: ()) {
visit::visit_fn(self as @Visitor<()>,
function_kind,
function_declaration,
block,
span,
node_id,
())
}
fn visit_ty_method(@mut self, ty_method: &ast::TypeMethod, _: ()) {
visit::visit_ty_method(self as @Visitor<()>, ty_method, ())
}
fn visit_trait_method(@mut self,
trait_method: &ast::trait_method,
_: ()) {
visit::visit_trait_method(self as @Visitor<()>, trait_method, ())
}
fn visit_struct_def(@mut self,
struct_def: @ast::struct_def,
ident: ident,
generics: &ast::Generics,
node_id: NodeId,
_: ()) {
visit::visit_struct_def(self as @Visitor<()>,
struct_def,
ident,
generics,
node_id,
())
}
fn visit_struct_field(@mut self,
struct_field: @ast::struct_field,
_: ()) {
visit::visit_struct_field(self as @Visitor<()>, struct_field, ())
}
}
// return a visitor that extracts the pat_ident paths
// from a given pattern and puts them in a mutable
// array (passed in to the traversal)
pub fn new_name_finder(idents: @mut ~[ast::ident]) -> @Visitor<()> {
let context = @mut NewNameFinderContext {
ident_accumulator: idents,
};
context as @Visitor<()>
}
pub fn expand_block(extsbox: @mut SyntaxEnv,
_cx: @ExtCtxt,
blk: &Block,
fld: @ast_fold,
orig: @fn(&Block, @ast_fold) -> Block)
-> Block {
// see note below about treatment of exts table
with_exts_frame!(extsbox,false,orig(blk,fld))
}
// get the (innermost) BlockInfo from an exts stack
fn get_block_info(exts : SyntaxEnv) -> BlockInfo {
match exts.find_in_topmost_frame(&intern(special_block_name)) {
Some(@BlockInfo(bi)) => bi,
_ => fail!(fmt!("special identifier %? was bound to a non-BlockInfo",
@" block"))
}
}
// given a mutable list of renames, return a tree-folder that applies those
// renames.
fn renames_to_fold(renames : @mut ~[(ast::ident,ast::Name)]) -> @ast_fold {
let afp = default_ast_fold();
let f_pre = @AstFoldFns {
fold_ident: |id,_| {
// the individual elements are memoized... it would
// also be possible to memoize on the whole list at once.
let new_ctxt = renames.iter().fold(id.ctxt,|ctxt,&(from,to)| {
new_rename(from,to,ctxt)
});
ast::ident{name:id.name,ctxt:new_ctxt}
},
.. *afp
};
make_fold(f_pre)
}
// perform a bunch of renames
fn apply_pending_renames(folder : @ast_fold, stmt : ast::stmt) -> @ast::stmt {
match folder.fold_stmt(&stmt) {
Some(s) => s,
None => fail!(fmt!("renaming of stmt produced None"))
}
}
pub fn new_span(cx: @ExtCtxt, sp: span) -> span {
/* this discards information in the case of macro-defining macros */
return span {lo: sp.lo, hi: sp.hi, expn_info: cx.backtrace()};
}
// FIXME (#2247): this is a moderately bad kludge to inject some macros into
// the default compilation environment. It would be much nicer to use
// a mechanism like syntax_quote to ensure hygiene.
pub fn std_macros() -> @str {
return
@"mod __std_macros {
#[macro_escape];
#[doc(hidden)];
macro_rules! ignore (($($x:tt)*) => (()))
macro_rules! error (
($arg:expr) => (
__log(1u32, fmt!( \"%?\", $arg ))
);
($( $arg:expr ),+) => (
__log(1u32, fmt!( $($arg),+ ))
)
)
macro_rules! warn (
($arg:expr) => (
__log(2u32, fmt!( \"%?\", $arg ))
);
($( $arg:expr ),+) => (
__log(2u32, fmt!( $($arg),+ ))
)
)
macro_rules! info (
($arg:expr) => (
__log(3u32, fmt!( \"%?\", $arg ))
);
($( $arg:expr ),+) => (
__log(3u32, fmt!( $($arg),+ ))
)
)
// conditionally define debug!, but keep it type checking even
// in non-debug builds.
macro_rules! __debug (
($arg:expr) => (
__log(4u32, fmt!( \"%?\", $arg ))
);
($( $arg:expr ),+) => (
__log(4u32, fmt!( $($arg),+ ))
)
)
#[cfg(debug)]
#[macro_escape]
mod debug_macro {
macro_rules! debug (($($arg:expr),*) => {
__debug!($($arg),*)
})
}
#[cfg(not(debug))]
#[macro_escape]
mod debug_macro {
macro_rules! debug (($($arg:expr),*) => {
if false { __debug!($($arg),*) }
})
}
macro_rules! fail(
() => (
fail!(\"explicit failure\")
);
($msg:expr) => (
::std::sys::FailWithCause::fail_with($msg, file!(), line!())
);
($( $arg:expr ),+) => (
::std::sys::FailWithCause::fail_with(fmt!( $($arg),+ ), file!(), line!())
)
)
macro_rules! assert(
($cond:expr) => {
if !$cond {
::std::sys::FailWithCause::fail_with(
\"assertion failed: \" + stringify!($cond), file!(), line!())
}
};
($cond:expr, $msg:expr) => {
if !$cond {
::std::sys::FailWithCause::fail_with($msg, file!(), line!())
}
};
($cond:expr, $( $arg:expr ),+) => {
if !$cond {
::std::sys::FailWithCause::fail_with(fmt!( $($arg),+ ), file!(), line!())
}
}
)
macro_rules! assert_eq (
($given:expr , $expected:expr) => (
{
let given_val = $given;
let expected_val = $expected;
// check both directions of equality....
if !((given_val == expected_val) && (expected_val == given_val)) {
fail!(\"assertion failed: `(left == right) && (right == \
left)` (left: `%?`, right: `%?`)\", given_val, expected_val);
}
}
)
)
macro_rules! assert_approx_eq (
($given:expr , $expected:expr) => (
{
use std::cmp::ApproxEq;
let given_val = $given;
let expected_val = $expected;
// check both directions of equality....
if !(
given_val.approx_eq(&expected_val) &&
expected_val.approx_eq(&given_val)
) {
fail!(\"left: %? does not approximately equal right: %?\",
given_val, expected_val);
}
}
);
($given:expr , $expected:expr , $epsilon:expr) => (
{
use std::cmp::ApproxEq;
let given_val = $given;
let expected_val = $expected;
let epsilon_val = $epsilon;
// check both directions of equality....
if !(
given_val.approx_eq_eps(&expected_val, &epsilon_val) &&
expected_val.approx_eq_eps(&given_val, &epsilon_val)
) {
fail!(\"left: %? does not approximately equal right: %? with epsilon: %?\",
given_val, expected_val, epsilon_val);
}
}
)
)
macro_rules! condition (
{ pub $c:ident: $input:ty -> $out:ty; } => {
pub mod $c {
#[allow(non_uppercase_statics)];
static key: ::std::local_data::Key<
@::std::condition::Handler<$input, $out>> =
&::std::local_data::Key;
pub static cond :
::std::condition::Condition<$input,$out> =
::std::condition::Condition {
name: stringify!($c),
key: key
};
}
};
{ $c:ident: $input:ty -> $out:ty; } => {
// FIXME (#6009): remove mod's `pub` below once variant above lands.
pub mod $c {
#[allow(non_uppercase_statics)];
static key: ::std::local_data::Key<
@::std::condition::Handler<$input, $out>> =
&::std::local_data::Key;
pub static cond :
::std::condition::Condition<$input,$out> =
::std::condition::Condition {
name: stringify!($c),
key: key
};
}
}
)
//
// A scheme-style conditional that helps to improve code clarity in some instances when
// the `if`, `else if`, and `else` keywords obscure predicates undesirably.
//
// # Example
//
// ~~~
// let clamped =
// if x > mx { mx }
// else if x < mn { mn }
// else { x };
// ~~~
//
// Using `cond!`, the above could be written as:
//
// ~~~
// let clamped = cond!(
// (x > mx) { mx }
// (x < mn) { mn }
// _ { x }
// );
// ~~~
//
// The optional default case is denoted by `_`.
//
macro_rules! cond (
( $(($pred:expr) $body:block)+ _ $default:block ) => (
$(if $pred $body else)+
$default
);
// for if the default case was ommitted
( $(($pred:expr) $body:block)+ ) => (
$(if $pred $body)else+
);
)
macro_rules! printf (
($arg:expr) => (
print(fmt!(\"%?\", $arg))
);
($( $arg:expr ),+) => (
print(fmt!($($arg),+))
)
)
macro_rules! printfln (
($arg:expr) => (
println(fmt!(\"%?\", $arg))
);
($( $arg:expr ),+) => (
println(fmt!($($arg),+))
)
)
}";
}
// add a bunch of macros as though they were placed at the head of the
// program (ick). This should run before cfg stripping.
pub fn inject_std_macros(parse_sess: @mut parse::ParseSess,
cfg: ast::CrateConfig, c: &Crate) -> @Crate {
let sm = match parse_item_from_source_str(@"<std-macros>",
std_macros(),
cfg.clone(),
~[],
parse_sess) {
Some(item) => item,
None => fail!("expected core macros to parse correctly")
};
let injecter = @AstFoldFns {
fold_mod: |modd, _| {
// just inject the std macros at the start of the first
// module in the crate (i.e the crate file itself.)
let items = vec::append(~[sm], modd.items);
ast::_mod {
items: items,
// FIXME #2543: Bad copy.
.. (*modd).clone()
}
},
.. *default_ast_fold()
};
@make_fold(injecter).fold_crate(c)
}
pub fn expand_crate(parse_sess: @mut parse::ParseSess,
cfg: ast::CrateConfig, c: &Crate) -> @Crate {
// adding *another* layer of indirection here so that the block
// visitor can swap out one exts table for another for the duration
// of the block. The cleaner alternative would be to thread the
// exts table through the fold, but that would require updating
// every method/element of AstFoldFns in fold.rs.
let extsbox = @mut syntax_expander_table();
let afp = default_ast_fold();
let cx = ExtCtxt::new(parse_sess, cfg.clone());
let f_pre = @AstFoldFns {
fold_expr: |expr,span,recur|
expand_expr(extsbox, cx, expr, span, recur, afp.fold_expr),
fold_mod: |modd,recur|
expand_mod_items(extsbox, cx, modd, recur, afp.fold_mod),
fold_item: |item,recur|
expand_item(extsbox, cx, item, recur, afp.fold_item),
fold_stmt: |stmt,span,recur|
expand_stmt(extsbox, cx, stmt, span, recur, afp.fold_stmt),
fold_block: |blk,recur|
expand_block(extsbox, cx, blk, recur, afp.fold_block),
new_span: |a| new_span(cx, a),
.. *afp};
let f = make_fold(f_pre);
@f.fold_crate(c)
}
// given a function from idents to idents, produce
// an ast_fold that applies that function:
pub fn fun_to_ident_folder(f: @fn(ast::ident)->ast::ident) -> @ast_fold{
let afp = default_ast_fold();
let f_pre = @AstFoldFns{
fold_ident : |id, _| f(id),
.. *afp
};
make_fold(f_pre)
}
// update the ctxts in a path to get a rename node
pub fn new_ident_renamer(from: ast::ident,
to: ast::Name) ->
@fn(ast::ident)->ast::ident {
|id : ast::ident|
ast::ident{
name: id.name,
ctxt: new_rename(from,to,id.ctxt)
}
}
// update the ctxts in a path to get a mark node
pub fn new_ident_marker(mark: uint) ->
@fn(ast::ident)->ast::ident {
|id : ast::ident|
ast::ident{
name: id.name,
ctxt: new_mark(mark,id.ctxt)
}
}
// perform resolution (in the MTWT sense) on all of the
// idents in the tree. This is the final step in expansion.
pub fn new_ident_resolver() ->
@fn(ast::ident)->ast::ident {
|id : ast::ident|
ast::ident {
name : resolve(id),
ctxt : illegal_ctxt
}
}
#[cfg(test)]
mod test {
use super::*;
use ast;
use ast::{Attribute_, AttrOuter, MetaWord, empty_ctxt};
use codemap;
use codemap::spanned;
use parse;
use parse::token::{intern, get_ident_interner};
use print::pprust;
use util::parser_testing::{string_to_item, string_to_pat, strs_to_idents};
use oldvisit::{mk_vt};
// make sure that fail! is present
#[test] fn fail_exists_test () {
let src = @"fn main() { fail!(\"something appropriately gloomy\");}";
let sess = parse::new_parse_sess(None);
let crate_ast = parse::parse_crate_from_source_str(
@"<test>",
src,
~[],sess);
let crate_ast = inject_std_macros(sess, ~[], crate_ast);
// don't bother with striping, doesn't affect fail!.
expand_crate(sess,~[],crate_ast);
}
// these following tests are quite fragile, in that they don't test what
// *kind* of failure occurs.
// make sure that macros can leave scope
#[should_fail]
#[test] fn macros_cant_escape_fns_test () {
let src = @"fn bogus() {macro_rules! z (() => (3+4))}\
fn inty() -> int { z!() }";
let sess = parse::new_parse_sess(None);
let crate_ast = parse::parse_crate_from_source_str(
@"<test>",
src,
~[],sess);
// should fail:
expand_crate(sess,~[],crate_ast);
}
// make sure that macros can leave scope for modules
#[should_fail]
#[test] fn macros_cant_escape_mods_test () {
let src = @"mod foo {macro_rules! z (() => (3+4))}\
fn inty() -> int { z!() }";
let sess = parse::new_parse_sess(None);
let crate_ast = parse::parse_crate_from_source_str(
@"<test>",
src,
~[],sess);
// should fail:
expand_crate(sess,~[],crate_ast);
}
// macro_escape modules shouldn't cause macros to leave scope
#[test] fn macros_can_escape_flattened_mods_test () {
let src = @"#[macro_escape] mod foo {macro_rules! z (() => (3+4))}\
fn inty() -> int { z!() }";
let sess = parse::new_parse_sess(None);
let crate_ast = parse::parse_crate_from_source_str(
@"<test>",
src,
~[], sess);
// should fail:
expand_crate(sess,~[],crate_ast);
}
#[test] fn std_macros_must_parse () {
let src = super::std_macros();
let sess = parse::new_parse_sess(None);
let cfg = ~[];
let item_ast = parse::parse_item_from_source_str(
@"<test>",
src,
cfg,~[],sess);
match item_ast {
Some(_) => (), // success
None => fail!("expected this to parse")
}
}
#[test] fn test_contains_flatten (){
let attr1 = make_dummy_attr (@"foo");
let attr2 = make_dummy_attr (@"bar");
let escape_attr = make_dummy_attr (@"macro_escape");
let attrs1 = ~[attr1, escape_attr, attr2];
assert_eq!(contains_macro_escape (attrs1),true);
let attrs2 = ~[attr1,attr2];
assert_eq!(contains_macro_escape (attrs2),false);
}
// make a MetaWord outer attribute with the given name
fn make_dummy_attr(s: @str) -> ast::Attribute {
spanned {
span:codemap::dummy_sp(),
node: Attribute_ {
style: AttrOuter,
value: @spanned {
node: MetaWord(s),
span: codemap::dummy_sp(),
},
is_sugared_doc: false,
}
}
}
#[test]
fn renaming () {
let maybe_item_ast = string_to_item(@"fn a() -> int { let b = 13; b }");
let item_ast = match maybe_item_ast {
Some(x) => x,
None => fail!("test case fail")
};
let a_name = intern("a");
let a2_name = intern("a2");
let renamer = new_ident_renamer(ast::ident{name:a_name,ctxt:empty_ctxt},
a2_name);
let renamed_ast = fun_to_ident_folder(renamer).fold_item(item_ast).get();
let resolver = new_ident_resolver();
let resolved_ast = fun_to_ident_folder(resolver).fold_item(renamed_ast).get();
let resolved_as_str = pprust::item_to_str(resolved_ast,
get_ident_interner());
assert_eq!(resolved_as_str,~"fn a2() -> int { let b = 13; b }");
}
// sigh... it looks like I have two different renaming mechanisms, now...
#[test]
fn pat_idents(){
let pat = string_to_pat(@"(a,Foo{x:c @ (b,9),y:Bar(4,d)})");
let idents = @mut ~[];
let pat_idents = new_name_finder(idents);
pat_idents.visit_pat(pat, ());
assert_eq!(idents, @mut strs_to_idents(~["a","c","b","d"]));
}
}