bjoernager/rust
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syntax: implement foreach .. in .. { .. } via desugaring.

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This commit is contained in:
Graydon Hoare 2013-07-29 17:25:00 -07:00
parent 9a2d183d6a
commit c29e9fb60b
17 changed files with 215 additions and 3 deletions
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19
src/libsyntax/parse/parser.rs
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@ -29,7 +29,7 @@ use ast::{expr_method_call, expr_paren, expr_path, expr_repeat};
use ast::{expr_ret, expr_self, expr_struct, expr_tup, expr_unary};
use ast::{expr_vec, expr_vstore, expr_vstore_mut_box};
use ast::{expr_vstore_slice, expr_vstore_box};
use ast::{expr_vstore_mut_slice, expr_while, extern_fn, Field, fn_decl};
use ast::{expr_vstore_mut_slice, expr_while, expr_for_loop, extern_fn, Field, fn_decl};
use ast::{expr_vstore_uniq, Onceness, Once, Many};
use ast::{foreign_item, foreign_item_static, foreign_item_fn, foreign_mod};
use ast::{ident, impure_fn, inherited, item, item_, item_static};
@ -1622,6 +1622,8 @@ impl Parser {
hi = self.span.hi;
} else if self.eat_keyword(keywords::If) {
return self.parse_if_expr();
} else if self.eat_keyword(keywords::ForEach) {
return self.parse_for_expr();
} else if self.eat_keyword(keywords::For) {
return self.parse_sugary_call_expr(lo, ~"for", ForSugar,
expr_loop_body);
@ -2323,6 +2325,21 @@ impl Parser {
}
}
// parse a 'foreach' .. 'in' expression ('foreach' token already eaten)
pub fn parse_for_expr(&self) -> @expr {
// Parse: `foreach <src_pat> in <src_expr> <src_loop_block>`
let lo = self.last_span.lo;
let pat = self.parse_pat();
self.expect_keyword(keywords::In);
let expr = self.parse_expr();
let loop_block = self.parse_block();
let hi = self.span.hi;
self.mk_expr(lo, hi, expr_for_loop(pat, expr, loop_block))
}
// parse a 'for' or 'do'.
// the 'for' and 'do' expressions parse as calls, but look like
// function calls followed by a closure expression.