Simplify creating a parser from a token tree

Closes #15306

Author: Sawyer47

src/libfourcc/lib.rs

@@ -59,7 +59,6 @@ use syntax::codemap::{Span, mk_sp};
 use syntax::ext::base;
 use syntax::ext::base::{ExtCtxt, MacExpr};
 use syntax::ext::build::AstBuilder;
-use syntax::parse;
 use syntax::parse::token;
 use syntax::parse::token::InternedString;
 use rustc::plugin::Registry;
@@ -135,11 +134,7 @@ struct Ident {
 
 fn parse_tts(cx: &ExtCtxt,
              tts: &[ast::TokenTree]) -> (Gc<ast::Expr>, Option<Ident>) {
-    let p = &mut parse::new_parser_from_tts(cx.parse_sess(),
-                                            cx.cfg(),
-                                            tts.iter()
-                                               .map(|x| (*x).clone())
-                                               .collect());
+    let p = &mut cx.new_parser_from_tts(tts);
     let ex = p.parse_expr();
     let id = if p.token == token::EOF {
         None

src/libhexfloat/lib.rs

@@ -54,7 +54,6 @@ use syntax::codemap::{Span, mk_sp};
 use syntax::ext::base;
 use syntax::ext::base::{ExtCtxt, MacExpr};
 use syntax::ext::build::AstBuilder;
-use syntax::parse;
 use syntax::parse::token;
 use rustc::plugin::Registry;
 
@@ -167,11 +166,7 @@ struct Ident {
 
 fn parse_tts(cx: &ExtCtxt,
              tts: &[ast::TokenTree]) -> (Gc<ast::Expr>, Option<Ident>) {
-    let p = &mut parse::new_parser_from_tts(cx.parse_sess(),
-                                            cx.cfg(),
-                                            tts.iter()
-                                               .map(|x| (*x).clone())
-                                               .collect());
+    let p = &mut cx.new_parser_from_tts(tts);
     let ex = p.parse_expr();
     let id = if p.token == token::EOF {
         None

src/libregex_macros/lib.rs

@@ -32,7 +32,6 @@ use syntax::ast;
 use syntax::codemap;
 use syntax::ext::build::AstBuilder;
 use syntax::ext::base::{ExtCtxt, MacResult, MacExpr, DummyResult};
-use syntax::parse;
 use syntax::parse::token;
 use syntax::print::pprust;
 
@@ -615,8 +614,7 @@ fn exec<'t>(which: ::regex::native::MatchKind, input: &'t str,
 /// Looks for a single string literal and returns it.
 /// Otherwise, logs an error with cx.span_err and returns None.
 fn parse(cx: &mut ExtCtxt, tts: &[ast::TokenTree]) -> Option<String> {
-    let mut parser = parse::new_parser_from_tts(cx.parse_sess(), cx.cfg(),
-                                                Vec::from_slice(tts));
+    let mut parser = cx.new_parser_from_tts(tts);
     let entry = cx.expand_expr(parser.parse_expr());
     let regex = match entry.node {
         ast::ExprLit(lit) => {

src/libsyntax/ext/asm.rs

@@ -16,7 +16,6 @@ use ast;
 use codemap::Span;
 use ext::base;
 use ext::base::*;
-use parse;
 use parse::token::InternedString;
 use parse::token;
 
@@ -48,12 +47,7 @@ static OPTIONS: &'static [&'static str] = &["volatile", "alignstack", "intel"];
 
 pub fn expand_asm(cx: &mut ExtCtxt, sp: Span, tts: &[ast::TokenTree])
                   -> Box<base::MacResult> {
-    let mut p = parse::new_parser_from_tts(cx.parse_sess(),
-                                           cx.cfg(),
-                                           tts.iter()
-                                              .map(|x| (*x).clone())
-                                              .collect());
-
+    let mut p = cx.new_parser_from_tts(tts);
     let mut asm = InternedString::new("");
     let mut asm_str_style = None;
     let mut outputs = Vec::new();

src/libsyntax/ext/base.rs

@@ -15,6 +15,7 @@ use codemap::{CodeMap, Span, ExpnInfo};
 use ext;
 use ext::expand;
 use parse;
+use parse::parser;
 use parse::token;
 use parse::token::{InternedString, intern, str_to_ident};
 use util::small_vector::SmallVector;
@@ -433,6 +434,11 @@ impl<'a> ExtCtxt<'a> {
         }
     }
 
+    pub fn new_parser_from_tts(&self, tts: &[ast::TokenTree])
+        -> parser::Parser<'a> {
+        parse::tts_to_parser(self.parse_sess, Vec::from_slice(tts), self.cfg())
+    }
+
     pub fn codemap(&self) -> &'a CodeMap { &self.parse_sess.span_diagnostic.cm }
     pub fn parse_sess(&self) -> &'a parse::ParseSess { self.parse_sess }
     pub fn cfg(&self) -> ast::CrateConfig { self.cfg.clone() }
@@ -586,11 +592,7 @@ pub fn get_single_str_from_tts(cx: &ExtCtxt,
 pub fn get_exprs_from_tts(cx: &mut ExtCtxt,
                           sp: Span,
                           tts: &[ast::TokenTree]) -> Option<Vec<Gc<ast::Expr>>> {
-    let mut p = parse::new_parser_from_tts(cx.parse_sess(),
-                                           cx.cfg(),
-                                           tts.iter()
-                                              .map(|x| (*x).clone())
-                                              .collect());
+    let mut p = cx.new_parser_from_tts(tts);
     let mut es = Vec::new();
     while p.token != token::EOF {
         es.push(cx.expand_expr(p.parse_expr()));

src/libsyntax/ext/cfg.rs

@@ -24,17 +24,11 @@ use attr::*;
 use parse::attr::ParserAttr;
 use parse::token::InternedString;
 use parse::token;
-use parse;
 
 
 pub fn expand_cfg(cx: &mut ExtCtxt, sp: Span, tts: &[ast::TokenTree])
                   -> Box<base::MacResult> {
-    let mut p = parse::new_parser_from_tts(cx.parse_sess(),
-                                           cx.cfg(),
-                                           tts.iter()
-                                              .map(|x| (*x).clone())
-                                              .collect());
-
+    let mut p = cx.new_parser_from_tts(tts);
     let mut cfgs = Vec::new();
     // parse `cfg!(meta_item, meta_item(x,y), meta_item="foo", ...)`
     while p.token != token::EOF {

src/libsyntax/ext/format.rs

@@ -16,7 +16,6 @@ use ext::base;
 use ext::build::AstBuilder;
 use parse::token::InternedString;
 use parse::token;
-use rsparse = parse;
 
 use parse = fmt_macros;
 use std::collections::HashMap;
@@ -81,11 +80,7 @@ fn parse_args(ecx: &mut ExtCtxt, sp: Span, allow_method: bool,
     let mut names = HashMap::<String, Gc<ast::Expr>>::new();
     let mut order = Vec::new();
 
-    let mut p = rsparse::new_parser_from_tts(ecx.parse_sess(),
-                                             ecx.cfg(),
-                                             tts.iter()
-                                                .map(|x| (*x).clone())
-                                                .collect());
+    let mut p = ecx.new_parser_from_tts(tts);
     // Parse the leading function expression (maybe a block, maybe a path)
     let invocation = if allow_method {
         let e = p.parse_expr();

src/libsyntax/ext/quote.rs

@@ -15,7 +15,6 @@ use ext::base;
 use ext::build::AstBuilder;
 use parse::token::*;
 use parse::token;
-use parse;
 
 use std::gc::Gc;
 
@@ -583,11 +582,7 @@ fn expand_tts(cx: &ExtCtxt, sp: Span, tts: &[ast::TokenTree])
     // it has to do with transition away from supporting old-style macros, so
     // try removing it when enough of them are gone.
 
-    let mut p = parse::new_parser_from_tts(cx.parse_sess(),
-                                           cx.cfg(),
-                                           tts.iter()
-                                              .map(|x| (*x).clone())
-                                              .collect());
+    let mut p = cx.new_parser_from_tts(tts);
     p.quote_depth += 1u;
 
     let cx_expr = p.parse_expr();