syntax: Extract some functions into mod common

Author: brson

src/librustsyntax/parse/attr.rs

@@ -1,11 +1,11 @@
 import either::{either, left, right};
-import parser::{parse_seq,
+import common::{parse_seq,
                 seq_sep,
                 expect,
-                parse_lit,
                 parse_ident,
-                parse_syntax_ext_naked,
                 spanned};
+import parser::{parse_lit,
+                parse_syntax_ext_naked};
 
 export attr_or_ext;
 export parse_outer_attributes;

src/librustsyntax/parse/common.rs

@@ -0,0 +1,201 @@
+import std::map::{hashmap};
+import ast::spanned;
+import parser::parser;
+
+fn token_to_str(reader: reader, token: token::token) -> str {
+    token::to_str(*reader.interner, token)
+}
+
+fn unexpected_last(p: parser, t: token::token) -> ! {
+    p.span_fatal(p.last_span,
+                 "unexpected token: '" + token_to_str(p.reader, t) + "'");
+}
+
+fn unexpected(p: parser) -> ! {
+    p.fatal("unexpected token: '" + token_to_str(p.reader, p.token) + "'");
+}
+
+fn expect(p: parser, t: token::token) {
+    if p.token == t {
+        p.bump();
+    } else {
+        let mut s: str = "expecting '";
+        s += token_to_str(p.reader, t);
+        s += "' but found '";
+        s += token_to_str(p.reader, p.token);
+        p.fatal(s + "'");
+    }
+}
+
+fn spanned<T: copy>(lo: uint, hi: uint, node: T) -> spanned<T> {
+    ret {node: node, span: ast_util::mk_sp(lo, hi)};
+}
+
+fn parse_ident(p: parser) -> ast::ident {
+    alt p.token {
+      token::IDENT(i, _) { p.bump(); ret p.get_str(i); }
+      _ { p.fatal("expecting ident, found "
+                  + token_to_str(p.reader, p.token)); }
+    }
+}
+
+fn parse_path_list_ident(p: parser) -> ast::path_list_ident {
+    let lo = p.span.lo;
+    let ident = parse_ident(p);
+    let hi = p.span.hi;
+    ret spanned(lo, hi, {name: ident, id: p.get_id()});
+}
+
+fn parse_value_ident(p: parser) -> ast::ident {
+    check_bad_word(p);
+    ret parse_ident(p);
+}
+
+fn eat(p: parser, tok: token::token) -> bool {
+    ret if p.token == tok { p.bump(); true } else { false };
+}
+
+// A sanity check that the word we are asking for is a known keyword
+fn require_keyword(p: parser, word: str) {
+    if !p.keywords.contains_key(word) {
+        p.bug(#fmt("unknown keyword: %s", word));
+    }
+}
+
+fn is_word(p: parser, word: str) -> bool {
+    require_keyword(p, word);
+    ret alt p.token {
+          token::IDENT(sid, false) { str::eq(word, p.get_str(sid)) }
+          _ { false }
+        };
+}
+
+fn eat_word(p: parser, word: str) -> bool {
+    require_keyword(p, word);
+    alt p.token {
+      token::IDENT(sid, false) {
+        if str::eq(word, p.get_str(sid)) {
+            p.bump();
+            ret true;
+        } else { ret false; }
+      }
+      _ { ret false; }
+    }
+}
+
+fn expect_word(p: parser, word: str) {
+    require_keyword(p, word);
+    if !eat_word(p, word) {
+        p.fatal("expecting " + word + ", found " +
+                    token_to_str(p.reader, p.token));
+    }
+}
+
+fn check_bad_word(p: parser) {
+    if token::is_bad_expr_word(p.token, p.bad_expr_words,
+                               *p.reader.interner) {
+        let w = token_to_str(p.reader, p.token);
+        p.fatal("found " + w + " in expression position");
+    }
+}
+
+fn expect_gt(p: parser) {
+    if p.token == token::GT {
+        p.bump();
+    } else if p.token == token::BINOP(token::LSR) {
+        p.swap(token::GT, p.span.lo + 1u, p.span.hi);
+    } else if p.token == token::BINOP(token::ASR) {
+        p.swap(token::BINOP(token::LSR), p.span.lo + 1u, p.span.hi);
+    } else {
+        let mut s: str = "expecting ";
+        s += token_to_str(p.reader, token::GT);
+        s += ", found ";
+        s += token_to_str(p.reader, p.token);
+        p.fatal(s);
+    }
+}
+
+fn parse_seq_to_before_gt<T: copy>(sep: option<token::token>,
+                                  f: fn(parser) -> T,
+                                  p: parser) -> [T] {
+    let mut first = true;
+    let mut v = [];
+    while p.token != token::GT && p.token != token::BINOP(token::LSR) &&
+              p.token != token::BINOP(token::ASR) {
+        alt sep {
+          some(t) { if first { first = false; } else { expect(p, t); } }
+          _ { }
+        }
+        v += [f(p)];
+    }
+
+    ret v;
+}
+
+fn parse_seq_to_gt<T: copy>(sep: option<token::token>,
+                           f: fn(parser) -> T, p: parser) -> [T] {
+    let v = parse_seq_to_before_gt(sep, f, p);
+    expect_gt(p);
+
+    ret v;
+}
+
+fn parse_seq_lt_gt<T: copy>(sep: option<token::token>,
+                           f: fn(parser) -> T,
+                           p: parser) -> spanned<[T]> {
+    let lo = p.span.lo;
+    expect(p, token::LT);
+    let result = parse_seq_to_before_gt::<T>(sep, f, p);
+    let hi = p.span.hi;
+    expect_gt(p);
+    ret spanned(lo, hi, result);
+}
+
+fn parse_seq_to_end<T: copy>(ket: token::token, sep: seq_sep,
+                            f: fn(parser) -> T, p: parser) -> [T] {
+    let val = parse_seq_to_before_end(ket, sep, f, p);
+    p.bump();
+    ret val;
+}
+
+type seq_sep = {
+    sep: option<token::token>,
+    trailing_opt: bool   // is trailing separator optional?
+};
+
+fn seq_sep(t: token::token) -> seq_sep {
+    ret {sep: option::some(t), trailing_opt: false};
+}
+fn seq_sep_opt(t: token::token) -> seq_sep {
+    ret {sep: option::some(t), trailing_opt: true};
+}
+fn seq_sep_none() -> seq_sep {
+    ret {sep: option::none, trailing_opt: false};
+}
+
+fn parse_seq_to_before_end<T: copy>(ket: token::token,
+                                   sep: seq_sep,
+                                   f: fn(parser) -> T, p: parser) -> [T] {
+    let mut first: bool = true;
+    let mut v: [T] = [];
+    while p.token != ket {
+        alt sep.sep {
+          some(t) { if first { first = false; } else { expect(p, t); } }
+          _ { }
+        }
+        if sep.trailing_opt && p.token == ket { break; }
+        v += [f(p)];
+    }
+    ret v;
+}
+
+fn parse_seq<T: copy>(bra: token::token, ket: token::token,
+                     sep: seq_sep, f: fn(parser) -> T,
+                     p: parser) -> spanned<[T]> {
+    let lo = p.span.lo;
+    expect(p, bra);
+    let result = parse_seq_to_before_end::<T>(ket, sep, f, p);
+    let hi = p.span.hi;
+    p.bump();
+    ret spanned(lo, hi, result);
+}