Make macro arg optional in syntax, again untested.

12 files changed, 41 insertions, 14 deletions

diff --git a/src/comp/syntax/ast.rs b/src/comp/syntax/ast.rs
index 235485fe3f5..576e0ab865a 100644
--- a/src/comp/syntax/ast.rs
+++ b/src/comp/syntax/ast.rs
@@ -272,7 +272,7 @@ enum blk_sort {
 
 type mac = spanned<mac_>;
 
-type mac_arg = @expr;
+type mac_arg = option::t<@expr>;
 
 type mac_body_ = {span: span};
 type mac_body = option::t<mac_body_>;
diff --git a/src/comp/syntax/ext/base.rs b/src/comp/syntax/ext/base.rs
index 824931a759b..415c6cb5d9b 100644
--- a/src/comp/syntax/ext/base.rs
+++ b/src/comp/syntax/ext/base.rs
@@ -118,6 +118,13 @@ fn make_new_lit(cx: ext_ctxt, sp: codemap::span, lit: ast::lit_) ->
     ret @{id: cx.next_id(), node: ast::expr_lit(sp_lit), span: sp};
 }
 
+fn get_mac_arg(cx: ext_ctxt, sp: span, arg: ast::mac_arg) -> @ast::expr {
+    alt (arg) {
+      some(expr) {expr}
+      none {cx.span_fatal(sp, "missing macro args")}
+    }
+}
+
 fn get_mac_body(cx: ext_ctxt, sp: span, args: ast::mac_body)
     -> ast::mac_body_
 {
diff --git a/src/comp/syntax/ext/concat_idents.rs b/src/comp/syntax/ext/concat_idents.rs
index b451e449b30..538c40a9d66 100644
--- a/src/comp/syntax/ext/concat_idents.rs
+++ b/src/comp/syntax/ext/concat_idents.rs
@@ -4,6 +4,7 @@ import syntax::ast;
 
 fn expand_syntax_ext(cx: ext_ctxt, sp: codemap::span, arg: ast::mac_arg,
                      _body: ast::mac_body) -> @ast::expr {
+    let arg = get_mac_arg(cx,sp,arg);
     let args: [@ast::expr] =
         alt arg.node {
           ast::expr_vec(elts, _) { elts }
diff --git a/src/comp/syntax/ext/env.rs b/src/comp/syntax/ext/env.rs
index 8cf299c5e67..b9b42028c0f 100644
--- a/src/comp/syntax/ext/env.rs
+++ b/src/comp/syntax/ext/env.rs
@@ -11,6 +11,7 @@ export expand_syntax_ext;
 
 fn expand_syntax_ext(cx: ext_ctxt, sp: codemap::span, arg: ast::mac_arg,
                      _body: ast::mac_body) -> @ast::expr {
+    let arg = get_mac_arg(cx,sp,arg);
     let args: [@ast::expr] =
         alt arg.node {
           ast::expr_vec(elts, _) { elts }
diff --git a/src/comp/syntax/ext/fmt.rs b/src/comp/syntax/ext/fmt.rs
index b2425079ed8..b7834175d2f 100644
--- a/src/comp/syntax/ext/fmt.rs
+++ b/src/comp/syntax/ext/fmt.rs
@@ -15,6 +15,7 @@ export expand_syntax_ext;
 
 fn expand_syntax_ext(cx: ext_ctxt, sp: span, arg: ast::mac_arg,
                      _body: ast::mac_body) -> @ast::expr {
+    let arg = get_mac_arg(cx,sp,arg);
     let args: [@ast::expr] =
         alt arg.node {
           ast::expr_vec(elts, _) { elts }
diff --git a/src/comp/syntax/ext/ident_to_str.rs b/src/comp/syntax/ext/ident_to_str.rs
index a5a2dedcbf9..9245e5aa6d4 100644
--- a/src/comp/syntax/ext/ident_to_str.rs
+++ b/src/comp/syntax/ext/ident_to_str.rs
@@ -4,6 +4,7 @@ import syntax::ast;
 
 fn expand_syntax_ext(cx: ext_ctxt, sp: codemap::span, arg: ast::mac_arg,
                      _body: ast::mac_body) -> @ast::expr {
+    let arg = get_mac_arg(cx,sp,arg);
     let args: [@ast::expr] =
         alt arg.node {
           ast::expr_vec(elts, _) { elts }
diff --git a/src/comp/syntax/ext/log_syntax.rs b/src/comp/syntax/ext/log_syntax.rs
index 4047a1b95d3..911cf9ff2eb 100644
--- a/src/comp/syntax/ext/log_syntax.rs
+++ b/src/comp/syntax/ext/log_syntax.rs
@@ -4,6 +4,7 @@ import std::io::writer_util;
 
 fn expand_syntax_ext(cx: ext_ctxt, sp: codemap::span, arg: ast::mac_arg,
                      _body: ast::mac_body) -> @ast::expr {
+    let arg = get_mac_arg(cx,sp,arg);
     cx.print_backtrace();
     std::io::stdout().write_line(print::pprust::expr_to_str(arg));
 
diff --git a/src/comp/syntax/ext/simplext.rs b/src/comp/syntax/ext/simplext.rs
index b8722122b69..d8496203e3d 100644
--- a/src/comp/syntax/ext/simplext.rs
+++ b/src/comp/syntax/ext/simplext.rs
@@ -671,6 +671,7 @@ fn p_t_s_r_actual_vector(cx: ext_ctxt, elts: [@expr], _repeat_after: bool,
 
 fn add_new_extension(cx: ext_ctxt, sp: span, arg: ast::mac_arg,
                      _body: ast::mac_body) -> base::macro_def {
+    let arg = get_mac_arg(cx,sp,arg);
     let args: [@ast::expr] =
         alt arg.node {
           ast::expr_vec(elts, _) { elts }
@@ -716,7 +717,7 @@ fn add_new_extension(cx: ext_ctxt, sp: span, arg: ast::mac_arg,
                     }
                     clauses +=
                         [@{params: pattern_to_selectors
-                               (cx, invoc_arg),
+                               (cx, get_mac_arg(cx,mac.span,invoc_arg)),
                            body: elts[1u]}];
 
                     // FIXME: check duplicates (or just simplify
@@ -757,6 +758,7 @@ fn add_new_extension(cx: ext_ctxt, sp: span, arg: ast::mac_arg,
 
     fn generic_extension(cx: ext_ctxt, sp: span, arg: ast::mac_arg,
                          _body: ast::mac_body, clauses: [@clause]) -> @expr {
+        let arg = get_mac_arg(cx,sp,arg);
         for c: @clause in clauses {
             alt use_selectors_to_bind(c.params, arg) {
               some(bindings) { ret transcribe(cx, bindings, c.body); }
diff --git a/src/comp/syntax/fold.rs b/src/comp/syntax/fold.rs
index 1831e30e810..e3a05961bea 100644
--- a/src/comp/syntax/fold.rs
+++ b/src/comp/syntax/fold.rs
@@ -133,7 +133,10 @@ fn fold_mac_(m: mac, fld: ast_fold) -> mac {
     ret {node:
              alt m.node {
                mac_invoc(pth, arg, body) {
-                 mac_invoc(fld.fold_path(pth), fld.fold_expr(arg), body)
+                 mac_invoc(fld.fold_path(pth),
+                           // FIXME: bind should work, but causes a crash
+                           option::map(arg) {|arg| fld.fold_expr(arg)},
+                           body)
                }
                mac_embed_type(ty) { mac_embed_type(fld.fold_ty(ty)) }
                mac_embed_block(blk) { mac_embed_block(fld.fold_block(blk)) }
diff --git a/src/comp/syntax/parse/parser.rs b/src/comp/syntax/parse/parser.rs
index ae00c9fbce7..291f820df18 100644
--- a/src/comp/syntax/parse/parser.rs
+++ b/src/comp/syntax/parse/parser.rs
@@ -985,14 +985,20 @@ fn parse_syntax_ext_naked(p: parser, lo: uint) -> @ast::expr {
     let pth = parse_path(p);
     //temporary for a backwards-compatible cycle:
     let sep = seq_sep(token::COMMA);
-    let es =
-        if p.token == token::LPAREN {
-            parse_seq(token::LPAREN, token::RPAREN, sep, parse_expr, p)
-        } else {
-            parse_seq(token::LBRACKET, token::RBRACKET, sep, parse_expr, p)
-        };
-    let hi = es.span.hi;
-    let e = mk_expr(p, es.span.lo, hi, ast::expr_vec(es.node, ast::imm));
+    let e = none;
+    if (p.token == token::LPAREN || p.token == token::LBRACKET) {
+        let es =
+            if p.token == token::LPAREN {
+                parse_seq(token::LPAREN, token::RPAREN,
+                          sep, parse_expr, p)
+            } else {
+                parse_seq(token::LBRACKET, token::RBRACKET,
+                          sep, parse_expr, p)
+            };
+        let hi = es.span.hi;
+        e = some(mk_expr(p, es.span.lo, hi,
+                         ast::expr_vec(es.node, ast::imm)));
+    }
     let b = none;
     if p.token == token::LBRACE {
         p.bump();
diff --git a/src/comp/syntax/print/pprust.rs b/src/comp/syntax/print/pprust.rs
index 74ebd271b6a..59ea8216c43 100644
--- a/src/comp/syntax/print/pprust.rs
+++ b/src/comp/syntax/print/pprust.rs
@@ -726,8 +726,11 @@ fn print_mac(s: ps, m: ast::mac) {
       ast::mac_invoc(path, arg, body) {
         word(s.s, "#");
         print_path(s, path, false);
-        alt arg.node { ast::expr_vec(_, _) { } _ { word(s.s, " "); } }
-        print_expr(s, arg);
+        alt arg {
+          some(@{node: ast::expr_vec(_, _), _}) { }
+          _ { word(s.s, " "); }
+        }
+        option::may(arg, bind print_expr(s, _));
         // FIXME: extension 'body'
       }
       ast::mac_embed_type(ty) {
diff --git a/src/comp/syntax/visit.rs b/src/comp/syntax/visit.rs
index 0601e8285d4..50a4f2cfbfa 100644
--- a/src/comp/syntax/visit.rs
+++ b/src/comp/syntax/visit.rs
@@ -273,7 +273,8 @@ fn visit_exprs<E>(exprs: [@expr], e: E, v: vt<E>) {
 
 fn visit_mac<E>(m: mac, e: E, v: vt<E>) {
     alt m.node {
-      ast::mac_invoc(pth, arg, body) { visit_expr(arg, e, v); }
+      ast::mac_invoc(pth, arg, body) {
+        option::map(arg) {|arg| visit_expr(arg, e, v)}; }
       ast::mac_embed_type(ty) { v.visit_ty(ty, e, v); }
       ast::mac_embed_block(blk) { v.visit_block(blk, e, v); }
       ast::mac_ellipsis { }