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When replacing $(...) with $0 preserve spacing for better error messages.

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That is:
  x + $(foo) + y
becomes:
  x + $0     + y
not:
  x + $0 + y
This commit is contained in:
Kevin Atkinson 2012-01-28 18:20:43 -07:00
parent c0f9073557
commit 099290bc73
1 changed files with 19 additions and 7 deletions
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26
src/comp/syntax/ext/qquote.rs
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@ -38,6 +38,10 @@ fn visit_expr_aq(expr: @ast::expr, &&cx: aq_ctxt, v: vt<aq_ctxt>)
}
}
fn is_space(c: char) -> bool {
syntax::parse::lexer::is_whitespace(c)
}
fn expand_qquote(ecx: ext_ctxt, sp: span, e: @ast::expr) -> @ast::expr {
let str = codemap::span_to_snippet(sp, ecx.session().parse_sess.cm);
let qcx = gather_anti_quotes(sp.lo, e);
@ -48,20 +52,28 @@ fn expand_qquote(ecx: ext_ctxt, sp: span, e: @ast::expr) -> @ast::expr {
prev = lo;
}
let str2 = "";
let active = true;
enum state {active, skip(uint), blank};
let state = active;
let i = 0u, j = 0u;
let g_len = vec::len(cx.gather);
str::chars_iter(str) {|ch|
if (active && j < g_len && i == cx.gather[j].lo) {
if (j < g_len && i == cx.gather[j].lo) {
assert ch == '$';
active = false;
str2 += #fmt(" $%u ", j);
let repl = #fmt("$%u ", j);
state = skip(str::char_len(repl));
str2 += repl;
}
alt state {
active {str::push_char(str2, ch);}
skip(1u) {state = blank;}
skip(sk) {state = skip (sk-1u);}
blank if is_space(ch) {str::push_char(str2, ch);}
blank {str::push_char(str2, ' ');}
}
if (active) {str::push_char(str2, ch);}
i += 1u;
if (!active && j < g_len && i == cx.gather[j].hi) {
if (j < g_len && i == cx.gather[j].hi) {
assert ch == ')';
active = true;
state = active;
j += 1u;
}
}