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Implement function expressions/anonymous functions

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Looks like 'fn(..arg..) -> ret {body;}. They don't support type
parameters or upvars yet.
This commit is contained in:
Marijn Haverbeke 2011-06-14 15:20:04 +02:00
parent 8c06d1bcb0
commit 471436a299
12 changed files with 114 additions and 30 deletions
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29
src/comp/front/parser.rs
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@ -815,7 +815,8 @@ fn parse_bottom_expr(&parser p) -> @ast::expr {
ret parse_alt_expr(p);
} else if (eat_word(p, "spawn")) {
ret parse_spawn_expr(p);
} else if (eat_word(p, "fn")) {
ret parse_fn_expr(p);
} else if (eat_word(p, "tup")) {
fn parse_elt(&parser p) -> ast::elt {
auto m = parse_mutability(p);
@ -1114,8 +1115,11 @@ fn parse_self_method(&parser p) -> @ast::expr {
}
fn parse_dot_or_call_expr(&parser p) -> @ast::expr {
auto lo = p.get_lo_pos();
auto e = parse_bottom_expr(p);
ret parse_dot_or_call_expr_with(p, parse_bottom_expr(p));
}
fn parse_dot_or_call_expr_with(&parser p, @ast::expr e) -> @ast::expr {
auto lo = e.span.lo;
auto hi = e.span.hi;
while (true) {
alt (p.peek()) {
@ -1357,6 +1361,14 @@ fn parse_if_expr(&parser p) -> @ast::expr {
ret @spanned(lo, hi, ast::expr_if(cond, thn, els, p.get_ann()));
}
fn parse_fn_expr(&parser p) -> @ast::expr {
auto lo = p.get_last_lo_pos();
auto decl = parse_fn_decl(p, ast::impure_fn);
auto body = parse_block(p);
auto _fn = rec(decl=decl, proto=ast::proto_fn, body=body);
ret @spanned(lo, body.span.hi, ast::expr_fn(_fn, p.get_ann()));
}
fn parse_else_expr(&parser p) -> @ast::expr {
if (eat_word(p, "if")) {
ret parse_if_expr(p);
@ -1630,10 +1642,14 @@ fn parse_source_stmt(&parser p) -> @ast::stmt {
auto decl = @spanned(lo, hi, ast::decl_item(i));
ret @spanned(lo, hi, ast::stmt_decl(decl, p.get_ann()));
}
case (fn_no_item) { // parse_item will have already skipped "fn"
auto e = parse_fn_expr(p);
e = parse_dot_or_call_expr_with(p, e);
ret @spanned(lo, e.span.hi, ast::stmt_expr(e, p.get_ann()));
}
case (no_item) {
// Remainder are line-expr stmts.
auto e = parse_expr(p);
auto hi = p.get_span();
ret @spanned(lo, e.span.hi, ast::stmt_expr(e, p.get_ann()));
}
}
@ -1676,6 +1692,7 @@ fn stmt_ends_with_semi(&ast::stmt stmt) -> bool {
case (ast::expr_while(_,_,_)) { ret false; }
case (ast::expr_do_while(_,_,_)) { ret false; }
case (ast::expr_alt(_,_,_)) { ret false; }
case (ast::expr_fn(_,_)) { ret false; }
case (ast::expr_block(_,_)) { ret false; }
case (ast::expr_assign(_,_,_)) { ret true; }
case (ast::expr_assign_op(_,_,_,_))
@ -2152,16 +2169,18 @@ fn parse_auth(&parser p) -> ast::_auth {
fail;
}
// FIXME will be extended to help parse anon functions
tag parsed_item {
got_item(@ast::item);
no_item;
fn_no_item;
}
fn parse_item(&parser p) -> parsed_item {
if (eat_word(p, "const")) {
ret got_item(parse_item_const(p));
} else if (eat_word(p, "fn")) {
// This is an anonymous function
if (p.peek() == token::LPAREN) { ret fn_no_item; }
ret got_item(parse_item_fn_or_iter(p, ast::impure_fn, ast::proto_fn));
} else if (eat_word(p, "pred")) {
ret got_item(parse_item_fn_or_iter(p, ast::pure_fn, ast::proto_fn));