From cf26a7d7b952cf94fb4bb185c2eb0cb47e4551ce Mon Sep 17 00:00:00 2001 From: Paul Stansifer Date: Mon, 19 Nov 2012 20:31:22 -0500 Subject: [PATCH] Make it possible to expand stmt macros. --- src/libsyntax/ext/base.rs | 16 +++---- src/libsyntax/ext/expand.rs | 66 ++++++++++++++++++++++++++--- src/libsyntax/ext/tt/macro_rules.rs | 7 +-- 3 files changed, 72 insertions(+), 17 deletions(-) diff --git a/src/libsyntax/ext/base.rs b/src/libsyntax/ext/base.rs index 3701614f13798..01193a0b483f6 100644 --- a/src/libsyntax/ext/base.rs +++ b/src/libsyntax/ext/base.rs @@ -44,7 +44,7 @@ type syntax_expander_tt_item_ enum mac_result { mr_expr(@ast::expr), mr_item(@ast::item), - mr_expr_or_item(fn@()-> @ast::expr, fn@()-> Option<@ast::item>), + mr_any(fn@()-> @ast::expr, fn@()-> Option<@ast::item>, fn@()->@ast::stmt), mr_def(macro_def) } @@ -109,18 +109,18 @@ fn syntax_expander_table() -> HashMap<~str, syntax_extension> { ext::deriving::expand_deriving_iter_bytes)); // Quasi-quoting expanders - syntax_expanders.insert(~"quote_tokens", - builtin_expr_tt(ext::quote::expand_quote_tokens)); + syntax_expanders.insert( + ~"quote_tokens", builtin_normal_tt(ext::quote::expand_quote_tokens)); syntax_expanders.insert(~"quote_expr", - builtin_expr_tt(ext::quote::expand_quote_expr)); + builtin_normal_tt(ext::quote::expand_quote_expr)); syntax_expanders.insert(~"quote_type", - builtin_expr_tt(ext::quote::expand_quote_type)); + builtin_normal_tt(ext::quote::expand_quote_type)); syntax_expanders.insert(~"quote_item", - builtin_expr_tt(ext::quote::expand_quote_item)); + builtin_normal_tt(ext::quote::expand_quote_item)); syntax_expanders.insert(~"quote_pat", - builtin_expr_tt(ext::quote::expand_quote_pat)); + builtin_normal_tt(ext::quote::expand_quote_pat)); syntax_expanders.insert(~"quote_stmt", - builtin_expr_tt(ext::quote::expand_quote_stmt)); + builtin_normal_tt(ext::quote::expand_quote_stmt)); syntax_expanders.insert(~"line", builtin(ext::source_util::expand_line)); diff --git a/src/libsyntax/ext/expand.rs b/src/libsyntax/ext/expand.rs index c296938d5d2f5..b997106b4ed01 100644 --- a/src/libsyntax/ext/expand.rs +++ b/src/libsyntax/ext/expand.rs @@ -1,7 +1,7 @@ use std::map::HashMap; use ast::{crate, expr_, expr_mac, mac_invoc, mac_invoc_tt, - tt_delim, tt_tok, item_mac}; + tt_delim, tt_tok, item_mac, stmt_, stmt_mac}; use fold::*; use ext::base::*; use ext::qquote::{qq_helper}; @@ -20,9 +20,9 @@ fn expand_expr(exts: HashMap<~str, syntax_extension>, cx: ext_ctxt, // entry-point for all syntax extensions. expr_mac(mac) => { - // Old-style macros, for compatibility, will erase this whole - // block once we've transitioned. match mac.node { + // Old-style macros. For compatibility, will erase this whole + // block once we've transitioned. mac_invoc(pth, args, body) => { assert (vec::len(pth.idents) > 0u); /* using idents and token::special_idents would make the @@ -81,7 +81,7 @@ fn expand_expr(exts: HashMap<~str, syntax_extension>, cx: ext_ctxt, Some(normal_tt({expander: exp, span: exp_sp})) => { let expanded = match exp(cx, mac.span, tts) { mr_expr(e) => e, - mr_expr_or_item(expr_maker,_) => expr_maker(), + mr_any(expr_maker,_,_) => expr_maker(), _ => cx.span_fatal( pth.span, fmt!("non-expr macro in expr pos: %s", *extname)) @@ -234,7 +234,7 @@ fn expand_item_mac(exts: HashMap<~str, syntax_extension>, mr_expr(_) => cx.span_fatal(pth.span, ~"expr macro in item position: " + *extname), - mr_expr_or_item(_, item_maker) => + mr_any(_, item_maker, _) => option::chain(item_maker(), |i| {fld.fold_item(i)}), mr_def(mdef) => { exts.insert(mdef.name, mdef.ext); @@ -248,6 +248,59 @@ fn expand_item_mac(exts: HashMap<~str, syntax_extension>, } } +fn expand_stmt(exts: HashMap<~str, syntax_extension>, cx: ext_ctxt, + && s: stmt_, sp: span, fld: ast_fold, + orig: fn@(&&s: stmt_, span, ast_fold) -> (stmt_, span)) + -> (stmt_, span) +{ + return match s { + stmt_mac(mac) => { + match mac.node { + mac_invoc_tt(pth, tts) => { + assert(vec::len(pth.idents) == 1u); + let extname = cx.parse_sess().interner.get(pth.idents[0]); + match exts.find(*extname) { + None => { + cx.span_fatal( + pth.span, + fmt!("macro undefined: '%s'", *extname)) + } + Some(normal_tt({expander: exp, span: exp_sp})) => { + let expanded = match exp(cx, mac.span, tts) { + mr_expr(e) => + @{node: ast::stmt_expr(e, cx.next_id()), + span: e.span}, + mr_any(_,_,stmt_mkr) => stmt_mkr(), + _ => cx.span_fatal( + pth.span, + fmt!("non-stmt macro in stmt pos: %s", + *extname)) + }; + + cx.bt_push(ExpandedFrom( + {call_site: sp, + callie: {name: *extname, span: exp_sp}})); + //keep going, outside-in + let fully_expanded = fld.fold_stmt(expanded).node; + cx.bt_pop(); + + (fully_expanded, sp) + } + _ => { + cx.span_fatal(pth.span, + fmt!("'%s' is not a tt-style macro", + *extname)) + } + } + } + _ => cx.span_bug(mac.span, ~"naked syntactic bit") + } + } + _ => orig(s, sp, fld) + }; +} + + fn new_span(cx: ext_ctxt, 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()}; @@ -298,7 +351,8 @@ fn expand_crate(parse_sess: parse::parse_sess, @{fold_expr: |a,b,c| expand_expr(exts, cx, a, b, c, afp.fold_expr), fold_mod: |a,b| expand_mod_items(exts, cx, a, b, afp.fold_mod), fold_item: |a,b| expand_item(exts, cx, a, b, afp.fold_item), - new_span: |a|new_span(cx, a), + fold_stmt: |a,b,c| expand_stmt(exts, cx, a, b, c, afp.fold_stmt), + new_span: |a| new_span(cx, a), .. *afp}; let f = make_fold(f_pre); let cm = parse_expr_from_source_str(~"", diff --git a/src/libsyntax/ext/tt/macro_rules.rs b/src/libsyntax/ext/tt/macro_rules.rs index 012e421718ad4..1c62c9b2a6da2 100644 --- a/src/libsyntax/ext/tt/macro_rules.rs +++ b/src/libsyntax/ext/tt/macro_rules.rs @@ -1,4 +1,4 @@ -use base::{ext_ctxt, mac_result, mr_expr_or_item, mr_def, normal_tt}; +use base::{ext_ctxt, mac_result, mr_any, mr_def, normal_tt}; use codemap::span; use ast::{ident, matcher_, matcher, match_tok, match_nonterminal, match_seq, tt_delim}; @@ -92,8 +92,9 @@ fn add_new_extension(cx: ext_ctxt, sp: span, name: ident, // Let the context choose how to interpret the result. // Weird, but useful for X-macros. - return mr_expr_or_item(|| p.parse_expr(), - || p.parse_item(~[/* no attrs*/])); + return mr_any(|| p.parse_expr(), + || p.parse_item(~[/* no attrs*/]), + || p.parse_stmt(~[/* no attrs*/])); } failure(sp, msg) => if sp.lo >= best_fail_spot.lo { best_fail_spot = sp;