Add #concat_idents[] and #ident_to_str[]

Author: paulstansifer

src/comp/rustc.rc

@@ -57,10 +57,13 @@ mod syntax {
     }
     mod ext {
         mod base;
+        mod expand;
+
         mod fmt;
         mod env;
         mod simplext;
-        mod expand;
+        mod concat_idents;
+        mod ident_to_str;
     }
     mod print {
         mod pprust;

src/comp/syntax/ext/base.rs

@@ -25,6 +25,10 @@ fn syntax_expander_table() -> hashmap[str, syntax_extension] {
     syntax_expanders.insert("env", normal(ext::env::expand_syntax_ext));
     syntax_expanders.insert("macro",
                             macro_defining(ext::simplext::add_new_extension));
+    syntax_expanders.insert("concat_idents",
+                            normal(ext::concat_idents::expand_syntax_ext));
+    syntax_expanders.insert("ident_to_str",
+                            normal(ext::ident_to_str::expand_syntax_ext));
     ret syntax_expanders;
 }
 
@@ -107,6 +111,12 @@ fn expr_to_ident(cx: &ext_ctxt, expr: @ast::expr, error: str) -> ast::ident {
     }
 }
 
+fn make_new_lit(cx: &ext_ctxt, sp: codemap::span, lit: ast::lit_) ->
+   @ast::expr {
+    let sp_lit = @{node: lit, span: sp};
+    ret @{id: cx.next_id(), node: ast::expr_lit(sp_lit), span: sp};
+}
+
 
 
 //

src/comp/syntax/ext/concat_idents.rs

@@ -0,0 +1,22 @@
+import std::ivec;
+import std::option;
+import base::*;
+import syntax::ast;
+
+fn expand_syntax_ext(cx: &ext_ctxt, sp: codemap::span, arg: @ast::expr,
+                     body: option::t[str]) -> @ast::expr {
+    let args: (@ast::expr)[] = alt arg.node {
+      ast::expr_vec(elts, _, _) { elts }
+      _ { cx.span_fatal(sp, "#concat_idents requires a vector argument .") }
+    };
+    let res: ast::ident = "";
+    for e: @ast::expr in args {
+        res += expr_to_ident(cx, e, "expected an ident");
+    }
+
+    ret @{id: cx.next_id(),
+          node: ast::expr_path( {
+              node: {global: false, idents: ~[res], types: ~[]},
+              span: sp}),
+          span: sp};
+}

src/comp/syntax/ext/env.rs

@@ -1,12 +1,10 @@
 
-
 /*
  * The compiler code necessary to support the #env extension.  Eventually this
  * should all get sucked into either the compiler syntax extension plugin
  * interface.
  */
 import std::ivec;
-import std::str;
 import std::option;
 import std::generic_os;
 import base::*;
@@ -31,12 +29,6 @@ fn expand_syntax_ext(cx: &ext_ctxt, sp: codemap::span, arg: @ast::expr,
     }
 }
 
-fn make_new_lit(cx: &ext_ctxt, sp: codemap::span, lit: ast::lit_) ->
-   @ast::expr {
-    let sp_lit = @{node: lit, span: sp};
-    ret @{id: cx.next_id(), node: ast::expr_lit(sp_lit), span: sp};
-}
-
 fn make_new_str(cx: &ext_ctxt, sp: codemap::span, s: str) -> @ast::expr {
     ret make_new_lit(cx, sp, ast::lit_str(s, ast::sk_rc));
 }

src/comp/syntax/ext/ident_to_str.rs

@@ -0,0 +1,21 @@
+import std::ivec;
+import std::option;
+import base::*;
+import syntax::ast;
+
+fn expand_syntax_ext(cx: &ext_ctxt, sp: codemap::span, arg: @ast::expr,
+                     body: option::t[str]) -> @ast::expr {
+    let args: (@ast::expr)[] = alt arg.node {
+      ast::expr_vec(elts, _, _) { elts }
+      _ { cx.span_fatal(sp, "#ident_to_str requires a vector argument .") }
+    };
+    if ivec::len[@ast::expr](args) != 1u {
+        cx.span_fatal(sp, "malformed #ident_to_str call");
+    }
+
+    ret make_new_lit(cx, sp,
+                     ast::lit_str(expr_to_ident(cx, args.(0u),
+                                                "expected an ident"),
+                                  ast::sk_rc));
+
+}

src/test/run-pass/syntax-extension-minor.rs

@@ -0,0 +1,8 @@
+
+fn main() {
+    let asdf_fdsa = "<.<";
+    assert(#concat_idents[asd,f_f,dsa] == "<.<");
+
+    assert(#ident_to_str[use_mention_distinction]
+           == "use_mention_distinction");
+}