rust/src/libsyntax/ext/format.rs

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// 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;
use codemap::{Span, respan};
use ext::base::*;
use ext::base;
use ext::build::AstBuilder;
use rsparse = parse;
use parse::token;
use std::fmt::parse;
use std::hashmap::{HashMap, HashSet};
use std::vec;
#[deriving(Eq)]
enum ArgumentType {
Unknown,
Known(@str),
Unsigned,
String,
}
struct Context {
ecx: @ExtCtxt,
fmtsp: Span,
// Parsed argument expressions and the types that we've found so far for
// them.
args: ~[@ast::Expr],
arg_types: ~[Option<ArgumentType>],
// Parsed named expressions and the types that we've found for them so far
names: HashMap<@str, @ast::Expr>,
name_types: HashMap<@str, ArgumentType>,
// Collection of the compiled `rt::Piece` structures
pieces: ~[@ast::Expr],
name_positions: HashMap<@str, uint>,
method_statics: ~[@ast::item],
// Updated as arguments are consumed or methods are entered
nest_level: uint,
next_arg: uint,
}
impl Context {
/// Parses the arguments from the given list of tokens, returning None if
/// there's a parse error so we can continue parsing other fmt! expressions.
fn parse_args(&mut self, sp: Span,
tts: &[ast::token_tree]) -> (@ast::Expr, Option<@ast::Expr>) {
let p = rsparse::new_parser_from_tts(self.ecx.parse_sess(),
self.ecx.cfg(),
tts.to_owned());
// Parse the leading function expression (maybe a block, maybe a path)
let extra = p.parse_expr();
if !p.eat(&token::COMMA) {
self.ecx.span_err(sp, "expected token: `,`");
return (extra, None);
}
if *p.token == token::EOF {
self.ecx.span_err(sp, "requires at least a format string argument");
return (extra, None);
}
let fmtstr = p.parse_expr();
let mut named = false;
while *p.token != token::EOF {
if !p.eat(&token::COMMA) {
self.ecx.span_err(sp, "expected token: `,`");
return (extra, None);
}
if named || (token::is_ident(p.token) &&
p.look_ahead(1, |t| *t == token::EQ)) {
named = true;
let ident = match *p.token {
token::IDENT(i, _) => {
p.bump();
i
}
_ if named => {
self.ecx.span_err(*p.span,
"expected ident, positional arguments \
cannot follow named arguments");
return (extra, None);
}
_ => {
self.ecx.span_err(*p.span,
fmt!("expected ident for named \
argument, but found `%s`",
p.this_token_to_str()));
return (extra, None);
}
};
let name = self.ecx.str_of(ident);
p.expect(&token::EQ);
let e = p.parse_expr();
match self.names.find(&name) {
None => {}
Some(prev) => {
self.ecx.span_err(e.span, fmt!("duplicate argument \
named `%s`", name));
self.ecx.parse_sess.span_diagnostic.span_note(
prev.span, "previously here");
loop
}
}
self.names.insert(name, e);
} else {
self.args.push(p.parse_expr());
self.arg_types.push(None);
}
}
return (extra, Some(fmtstr));
}
/// Verifies one piece of a parse string. All errors are not emitted as
/// fatal so we can continue giving errors about this and possibly other
/// format strings.
fn verify_piece(&mut self, p: &parse::Piece) {
match *p {
parse::String(*) => {}
parse::CurrentArgument => {
if self.nest_level == 0 {
self.ecx.span_err(self.fmtsp,
"`#` reference used with nothing to \
reference back to");
}
}
parse::Argument(ref arg) => {
// width/precision first, if they have implicit positional
// parameters it makes more sense to consume them first.
self.verify_count(arg.format.width);
self.verify_count(arg.format.precision);
// argument second, if it's an implicit positional parameter
// it's written second, so it should come after width/precision.
let pos = match arg.position {
parse::ArgumentNext => {
let i = self.next_arg;
if self.check_positional_ok() {
self.next_arg += 1;
}
Left(i)
}
parse::ArgumentIs(i) => Left(i),
parse::ArgumentNamed(s) => Right(s.to_managed()),
};
let ty = if arg.format.ty == "" {
Unknown
} else { Known(arg.format.ty.to_managed()) };
self.verify_arg_type(pos, ty);
// and finally the method being applied
match arg.method {
None => {}
Some(ref method) => { self.verify_method(pos, *method); }
}
}
}
}
fn verify_pieces(&mut self, pieces: &[parse::Piece]) {
for piece in pieces.iter() {
self.verify_piece(piece);
}
}
fn verify_count(&mut self, c: parse::Count) {
match c {
parse::CountImplied | parse::CountIs(*) => {}
parse::CountIsParam(i) => {
self.verify_arg_type(Left(i), Unsigned);
}
parse::CountIsNextParam => {
if self.check_positional_ok() {
self.verify_arg_type(Left(self.next_arg), Unsigned);
self.next_arg += 1;
}
}
}
}
fn check_positional_ok(&mut self) -> bool {
if self.nest_level != 0 {
self.ecx.span_err(self.fmtsp, "cannot use implicit positional \
arguments nested inside methods");
false
} else {
true
}
}
fn verify_method(&mut self, pos: Either<uint, @str>, m: &parse::Method) {
self.nest_level += 1;
match *m {
parse::Plural(_, ref arms, ref default) => {
let mut seen_cases = HashSet::new();
self.verify_arg_type(pos, Unsigned);
for arm in arms.iter() {
if !seen_cases.insert(arm.selector) {
match arm.selector {
Left(name) => {
self.ecx.span_err(self.fmtsp,
fmt!("duplicate selector \
`%?`", name));
}
Right(idx) => {
self.ecx.span_err(self.fmtsp,
fmt!("duplicate selector \
`=%u`", idx));
}
}
}
self.verify_pieces(arm.result);
}
self.verify_pieces(*default);
}
parse::Select(ref arms, ref default) => {
self.verify_arg_type(pos, String);
let mut seen_cases = HashSet::new();
for arm in arms.iter() {
if !seen_cases.insert(arm.selector) {
self.ecx.span_err(self.fmtsp,
fmt!("duplicate selector `%s`",
arm.selector));
} else if arm.selector == "" {
self.ecx.span_err(self.fmtsp,
"empty selector in `select`");
}
self.verify_pieces(arm.result);
}
self.verify_pieces(*default);
}
}
self.nest_level -= 1;
}
fn verify_arg_type(&mut self, arg: Either<uint, @str>, ty: ArgumentType) {
match arg {
Left(arg) => {
if arg < 0 || self.args.len() <= arg {
let msg = fmt!("invalid reference to argument `%u` (there \
are %u arguments)", arg, self.args.len());
self.ecx.span_err(self.fmtsp, msg);
return;
}
self.verify_same(self.args[arg].span, ty, self.arg_types[arg]);
if ty != Unknown || self.arg_types[arg].is_none() {
self.arg_types[arg] = Some(ty);
}
}
Right(name) => {
let span = match self.names.find(&name) {
Some(e) => e.span,
None => {
let msg = fmt!("There is no argument named `%s`", name);
self.ecx.span_err(self.fmtsp, msg);
return;
}
};
self.verify_same(span, ty,
self.name_types.find(&name).map(|&x| *x));
if ty != Unknown || !self.name_types.contains_key(&name) {
self.name_types.insert(name, ty);
}
// Assign this named argument a slot in the arguments array if
// it hasn't already been assigned a slot.
if !self.name_positions.contains_key(&name) {
let slot = self.name_positions.len();
self.name_positions.insert(name, slot);
}
}
}
}
/// When we're keeping track of the types that are declared for certain
/// arguments, we assume that `None` means we haven't seen this argument
/// yet, `Some(None)` means that we've seen the argument, but no format was
/// specified, and `Some(Some(x))` means that the argument was declared to
/// have type `x`.
///
/// Obviously `Some(Some(x)) != Some(Some(y))`, but we consider it true
/// that: `Some(None) == Some(Some(x))`
fn verify_same(&self, sp: Span, ty: ArgumentType,
before: Option<ArgumentType>) {
if ty == Unknown { return }
let cur = match before {
Some(Unknown) | None => return,
Some(t) => t,
};
if ty == cur { return }
match (cur, ty) {
(Known(cur), Known(ty)) => {
self.ecx.span_err(sp,
fmt!("argument redeclared with type `%s` when \
it was previously `%s`", ty, cur));
}
(Known(cur), _) => {
self.ecx.span_err(sp,
fmt!("argument used to format with `%s` was \
attempted to not be used for formatting",
cur));
}
(_, Known(ty)) => {
self.ecx.span_err(sp,
fmt!("argument previously used as a format \
argument attempted to be used as `%s`",
ty));
}
(_, _) => {
self.ecx.span_err(sp, "argument declared with multiple formats");
}
}
}
/// Translate a `parse::Piece` to a static `rt::Piece`
fn trans_piece(&mut self, piece: &parse::Piece) -> @ast::Expr {
let sp = self.fmtsp;
let parsepath = |s: &str| {
~[self.ecx.ident_of("std"), self.ecx.ident_of("fmt"),
self.ecx.ident_of("parse"), self.ecx.ident_of(s)]
};
let rtpath = |s: &str| {
~[self.ecx.ident_of("std"), self.ecx.ident_of("fmt"),
self.ecx.ident_of("rt"), self.ecx.ident_of(s)]
};
let ctpath = |s: &str| {
~[self.ecx.ident_of("std"), self.ecx.ident_of("fmt"),
self.ecx.ident_of("parse"), self.ecx.ident_of(s)]
};
let none = self.ecx.path_global(sp, ~[
self.ecx.ident_of("std"),
self.ecx.ident_of("option"),
self.ecx.ident_of("None")]);
let none = self.ecx.expr_path(none);
let some = |e: @ast::Expr| {
let p = self.ecx.path_global(sp, ~[
self.ecx.ident_of("std"),
self.ecx.ident_of("option"),
self.ecx.ident_of("Some")]);
let p = self.ecx.expr_path(p);
self.ecx.expr_call(sp, p, ~[e])
};
let trans_count = |c: parse::Count| {
match c {
parse::CountIs(i) => {
self.ecx.expr_call_global(sp, ctpath("CountIs"),
~[self.ecx.expr_uint(sp, i)])
}
parse::CountIsParam(i) => {
self.ecx.expr_call_global(sp, ctpath("CountIsParam"),
~[self.ecx.expr_uint(sp, i)])
}
parse::CountImplied => {
let path = self.ecx.path_global(sp, ctpath("CountImplied"));
self.ecx.expr_path(path)
}
parse::CountIsNextParam => {
let path = self.ecx.path_global(sp, ctpath("CountIsNextParam"));
self.ecx.expr_path(path)
}
}
};
let trans_method = |method: &parse::Method| {
let method = match *method {
parse::Select(ref arms, ref default) => {
let arms = arms.iter().map(|arm| {
let p = self.ecx.path_global(sp, rtpath("SelectArm"));
let result = arm.result.iter().map(|p| {
self.trans_piece(p)
}).collect();
let s = arm.selector.to_managed();
let selector = self.ecx.expr_str(sp, s);
self.ecx.expr_struct(sp, p, ~[
self.ecx.field_imm(sp,
self.ecx.ident_of("selector"),
selector),
self.ecx.field_imm(sp, self.ecx.ident_of("result"),
self.ecx.expr_vec_slice(sp, result)),
])
}).collect();
let default = default.iter().map(|p| {
self.trans_piece(p)
}).collect();
self.ecx.expr_call_global(sp, rtpath("Select"), ~[
self.ecx.expr_vec_slice(sp, arms),
self.ecx.expr_vec_slice(sp, default),
])
}
parse::Plural(offset, ref arms, ref default) => {
let offset = match offset {
Some(i) => { some(self.ecx.expr_uint(sp, i)) }
None => { none.clone() }
};
let arms = arms.iter().map(|arm| {
let p = self.ecx.path_global(sp, rtpath("PluralArm"));
let result = arm.result.iter().map(|p| {
self.trans_piece(p)
}).collect();
let (lr, selarg) = match arm.selector {
Left(t) => {
let p = ctpath(fmt!("%?", t));
let p = self.ecx.path_global(sp, p);
(self.ecx.ident_of("Left"),
self.ecx.expr_path(p))
}
Right(i) => {
(self.ecx.ident_of("Right"),
self.ecx.expr_uint(sp, i))
}
};
let selector = self.ecx.expr_call_ident(sp,
lr, ~[selarg]);
self.ecx.expr_struct(sp, p, ~[
self.ecx.field_imm(sp,
self.ecx.ident_of("selector"),
selector),
self.ecx.field_imm(sp, self.ecx.ident_of("result"),
self.ecx.expr_vec_slice(sp, result)),
])
}).collect();
let default = default.iter().map(|p| {
self.trans_piece(p)
}).collect();
self.ecx.expr_call_global(sp, rtpath("Plural"), ~[
offset,
self.ecx.expr_vec_slice(sp, arms),
self.ecx.expr_vec_slice(sp, default),
])
}
};
let life = self.ecx.lifetime(sp, self.ecx.ident_of("static"));
let ty = self.ecx.ty_path(self.ecx.path_all(
sp,
true,
rtpath("Method"),
Some(life),
~[]
), None);
let st = ast::item_static(ty, ast::MutImmutable, method);
let static_name = self.ecx.ident_of(fmt!("__static_method_%u",
self.method_statics.len()));
// Flag these statics as `address_insignificant` so LLVM can
// merge duplicate globals as much as possible (which we're
// generating a whole lot of).
let unnamed = self.ecx.meta_word(self.fmtsp, @"address_insignificant");
let unnamed = self.ecx.attribute(self.fmtsp, unnamed);
let item = self.ecx.item(sp, static_name, ~[unnamed], st);
self.method_statics.push(item);
self.ecx.expr_ident(sp, static_name)
};
match *piece {
parse::String(s) => {
self.ecx.expr_call_global(sp, rtpath("String"),
~[self.ecx.expr_str(sp, s.to_managed())])
}
parse::CurrentArgument => {
let nil = self.ecx.expr_lit(sp, ast::lit_nil);
self.ecx.expr_call_global(sp, rtpath("CurrentArgument"), ~[nil])
}
parse::Argument(ref arg) => {
// Translate the position
let pos = match arg.position {
// These two have a direct mapping
parse::ArgumentNext => {
let path = self.ecx.path_global(sp,
rtpath("ArgumentNext"));
self.ecx.expr_path(path)
}
parse::ArgumentIs(i) => {
self.ecx.expr_call_global(sp, rtpath("ArgumentIs"),
~[self.ecx.expr_uint(sp, i)])
}
// Named arguments are converted to positional arguments at
// the end of the list of arguments
parse::ArgumentNamed(n) => {
let n = n.to_managed();
let i = match self.name_positions.find_copy(&n) {
Some(i) => i,
None => 0, // error already emitted elsewhere
};
let i = i + self.args.len();
self.ecx.expr_call_global(sp, rtpath("ArgumentIs"),
~[self.ecx.expr_uint(sp, i)])
}
};
// Translate the format
let fill = match arg.format.fill { Some(c) => c, None => ' ' };
let fill = self.ecx.expr_lit(sp, ast::lit_char(fill as u32));
let align = match arg.format.align {
parse::AlignLeft => {
self.ecx.path_global(sp, parsepath("AlignLeft"))
}
parse::AlignRight => {
self.ecx.path_global(sp, parsepath("AlignRight"))
}
parse::AlignUnknown => {
self.ecx.path_global(sp, parsepath("AlignUnknown"))
}
};
let align = self.ecx.expr_path(align);
let flags = self.ecx.expr_uint(sp, arg.format.flags);
let prec = trans_count(arg.format.precision);
let width = trans_count(arg.format.width);
let path = self.ecx.path_global(sp, rtpath("FormatSpec"));
let fmt = self.ecx.expr_struct(sp, path, ~[
self.ecx.field_imm(sp, self.ecx.ident_of("fill"), fill),
self.ecx.field_imm(sp, self.ecx.ident_of("align"), align),
self.ecx.field_imm(sp, self.ecx.ident_of("flags"), flags),
self.ecx.field_imm(sp, self.ecx.ident_of("precision"), prec),
self.ecx.field_imm(sp, self.ecx.ident_of("width"), width),
]);
// Translate the method (if any)
let method = match arg.method {
None => { none.clone() }
Some(ref m) => {
let m = trans_method(*m);
some(self.ecx.expr_addr_of(sp, m))
}
};
let path = self.ecx.path_global(sp, rtpath("Argument"));
let s = self.ecx.expr_struct(sp, path, ~[
self.ecx.field_imm(sp, self.ecx.ident_of("position"), pos),
self.ecx.field_imm(sp, self.ecx.ident_of("format"), fmt),
self.ecx.field_imm(sp, self.ecx.ident_of("method"), method),
]);
self.ecx.expr_call_global(sp, rtpath("Argument"), ~[s])
}
}
}
/// Actually builds the expression which the ifmt! block will be expanded
/// to
fn to_expr(&self, extra: @ast::Expr) -> @ast::Expr {
let mut lets = ~[];
let mut locals = ~[];
let mut names = vec::from_fn(self.name_positions.len(), |_| None);
// First, declare all of our methods that are statics
for &method in self.method_statics.iter() {
let decl = respan(self.fmtsp, ast::DeclItem(method));
lets.push(@respan(self.fmtsp,
ast::StmtDecl(@decl, ast::DUMMY_NODE_ID)));
}
// Next, build up the static array which will become our precompiled
// format "string"
let fmt = self.ecx.expr_vec(self.fmtsp, self.pieces.clone());
let piece_ty = self.ecx.ty_path(self.ecx.path_all(
self.fmtsp,
true, ~[
self.ecx.ident_of("std"),
self.ecx.ident_of("fmt"),
self.ecx.ident_of("rt"),
self.ecx.ident_of("Piece"),
],
Some(self.ecx.lifetime(self.fmtsp, self.ecx.ident_of("static"))),
~[]
), None);
let ty = ast::ty_fixed_length_vec(
self.ecx.ty_mt(piece_ty.clone(), ast::MutImmutable),
self.ecx.expr_uint(self.fmtsp, self.pieces.len())
);
let ty = self.ecx.ty(self.fmtsp, ty);
let st = ast::item_static(ty, ast::MutImmutable, fmt);
let static_name = self.ecx.ident_of("__static_fmtstr");
// see above comment for `address_insignificant` and why we do it
let unnamed = self.ecx.meta_word(self.fmtsp, @"address_insignificant");
let unnamed = self.ecx.attribute(self.fmtsp, unnamed);
let item = self.ecx.item(self.fmtsp, static_name, ~[unnamed], st);
let decl = respan(self.fmtsp, ast::DeclItem(item));
lets.push(@respan(self.fmtsp, ast::StmtDecl(@decl, ast::DUMMY_NODE_ID)));
// Right now there is a bug such that for the expression:
// foo(bar(&1))
// the lifetime of `1` doesn't outlast the call to `bar`, so it's not
// vald for the call to `foo`. To work around this all arguments to the
// fmt! string are shoved into locals. Furthermore, we shove the address
// of each variable because we don't want to move out of the arguments
// passed to this function.
for (i, &e) in self.args.iter().enumerate() {
if self.arg_types[i].is_none() { loop } // error already generated
let name = self.ecx.ident_of(fmt!("__arg%u", i));
let e = self.ecx.expr_addr_of(e.span, e);
lets.push(self.ecx.stmt_let(e.span, false, name, e));
locals.push(self.format_arg(e.span, Left(i),
self.ecx.expr_ident(e.span, name)));
}
for (&name, &e) in self.names.iter() {
if !self.name_types.contains_key(&name) { loop }
let lname = self.ecx.ident_of(fmt!("__arg%s", name));
let e = self.ecx.expr_addr_of(e.span, e);
lets.push(self.ecx.stmt_let(e.span, false, lname, e));
names[*self.name_positions.get(&name)] =
Some(self.format_arg(e.span, Right(name),
self.ecx.expr_ident(e.span, lname)));
}
// Now create the fmt::Arguments struct with all our locals we created.
let args = names.move_iter().map(|a| a.unwrap());
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let mut args = locals.move_iter().chain(args);
let fmt = self.ecx.expr_ident(self.fmtsp, static_name);
let args = self.ecx.expr_vec_slice(self.fmtsp, args.collect());
let result = self.ecx.expr_call_global(self.fmtsp, ~[
self.ecx.ident_of("std"),
self.ecx.ident_of("fmt"),
self.ecx.ident_of("Arguments"),
self.ecx.ident_of("new"),
], ~[fmt, args]);
// We did all the work of making sure that the arguments
// structure is safe, so we can safely have an unsafe block.
let result = self.ecx.expr_block(ast::Block {
view_items: ~[],
stmts: ~[],
expr: Some(result),
id: ast::DUMMY_NODE_ID,
rules: ast::UnsafeBlock(ast::CompilerGenerated),
span: self.fmtsp,
});
let resname = self.ecx.ident_of("__args");
lets.push(self.ecx.stmt_let(self.fmtsp, false, resname, result));
let res = self.ecx.expr_ident(self.fmtsp, resname);
let result = self.ecx.expr_call(extra.span, extra, ~[
self.ecx.expr_addr_of(extra.span, res)]);
self.ecx.expr_block(self.ecx.block(self.fmtsp, lets,
Some(result)))
}
fn format_arg(&self, sp: Span, argno: Either<uint, @str>,
arg: @ast::Expr) -> @ast::Expr {
let ty = match argno {
Left(i) => self.arg_types[i].unwrap(),
Right(s) => *self.name_types.get(&s)
};
let fmt_trait = match ty {
Unknown => "Default",
Known(tyname) => {
match tyname.as_slice() {
"?" => "Poly",
"b" => "Bool",
"c" => "Char",
"d" | "i" => "Signed",
"f" => "Float",
"o" => "Octal",
"p" => "Pointer",
"s" => "String",
"t" => "Binary",
"u" => "Unsigned",
"x" => "LowerHex",
"X" => "UpperHex",
_ => {
self.ecx.span_err(sp, fmt!("unknown format trait \
`%s`", tyname));
"Dummy"
}
}
}
String => {
return self.ecx.expr_call_global(sp, ~[
self.ecx.ident_of("std"),
self.ecx.ident_of("fmt"),
self.ecx.ident_of("argumentstr"),
], ~[arg])
}
Unsigned => {
return self.ecx.expr_call_global(sp, ~[
self.ecx.ident_of("std"),
self.ecx.ident_of("fmt"),
self.ecx.ident_of("argumentuint"),
], ~[arg])
}
};
let format_fn = self.ecx.path_global(sp, ~[
self.ecx.ident_of("std"),
self.ecx.ident_of("fmt"),
self.ecx.ident_of(fmt_trait),
self.ecx.ident_of("fmt"),
]);
self.ecx.expr_call_global(sp, ~[
self.ecx.ident_of("std"),
self.ecx.ident_of("fmt"),
self.ecx.ident_of("argument"),
], ~[self.ecx.expr_path(format_fn), arg])
}
}
pub fn expand_args(ecx: @ExtCtxt, sp: Span,
tts: &[ast::token_tree]) -> base::MacResult {
let mut cx = Context {
ecx: ecx,
args: ~[],
arg_types: ~[],
names: HashMap::new(),
name_positions: HashMap::new(),
name_types: HashMap::new(),
nest_level: 0,
next_arg: 0,
pieces: ~[],
method_statics: ~[],
fmtsp: sp,
};
let (extra, efmt) = match cx.parse_args(sp, tts) {
(extra, Some(e)) => (extra, e),
(_, None) => { return MRExpr(ecx.expr_uint(sp, 2)); }
};
cx.fmtsp = efmt.span;
let fmt = expr_to_str(ecx, efmt,
"format argument must be a string literal.");
let mut err = false;
do parse::parse_error::cond.trap(|m| {
if !err {
err = true;
ecx.span_err(efmt.span, m);
}
}).inside {
for piece in parse::Parser::new(fmt) {
if !err {
cx.verify_piece(&piece);
let piece = cx.trans_piece(&piece);
cx.pieces.push(piece);
}
}
}
if err { return MRExpr(efmt) }
// Make sure that all arguments were used and all arguments have types.
for (i, ty) in cx.arg_types.iter().enumerate() {
if ty.is_none() {
ecx.span_err(cx.args[i].span, "argument never used");
}
}
for (name, e) in cx.names.iter() {
if !cx.name_types.contains_key(name) {
ecx.span_err(e.span, "named argument never used");
}
}
MRExpr(cx.to_expr(extra))
}