From c7edcb3a72f3991962acce0874c2ee24a4f38cf5 Mon Sep 17 00:00:00 2001
From: Brian Anderson <andersrb@gmail.com>
Date: Sun, 17 Apr 2011 13:10:02 -0400
Subject: Support #fmt precision for string types

---
 src/lib/ExtFmt.rs | 27 +++++++++++++++++++++++++--
 1 file changed, 25 insertions(+), 2 deletions(-)

(limited to 'src/lib/ExtFmt.rs')

diff --git a/src/lib/ExtFmt.rs b/src/lib/ExtFmt.rs
index 432e936f..af18a0d6 100644
--- a/src/lib/ExtFmt.rs
+++ b/src/lib/ExtFmt.rs
@@ -246,7 +246,17 @@ mod CT {
         }
 
         if (s.(i) == '.' as u8) {
-            ret parse_count(s, i + 1u, lim);
+            auto count = parse_count(s, i + 1u, lim);
+            // If there were no digits specified, i.e. the precision
+            // was ".", then the precision is 0
+            alt (count._0) {
+                case (count_implied) {
+                    ret tup(count_is(0), count._1);
+                }
+                case (_) {
+                    ret count;
+                }
+            }
         } else {
             ret tup(count_implied, i);
         }
@@ -318,6 +328,7 @@ mod RT {
     // instead just use a bool per flag
     type conv = rec(vec[flag] flags,
                     count width,
+                    count precision,
                     ty ty);
 
     fn conv_int(&conv cv, int i) -> str {
@@ -356,7 +367,19 @@ mod RT {
     }
 
     fn conv_str(&conv cv, str s) -> str {
-        ret pad(cv, s);
+        auto unpadded = s;
+        alt (cv.precision) {
+            case (count_implied) {
+            }
+            case (count_is(?max)) {
+                // For strings, precision is the maximum characters displayed
+                if (max as uint < _str.char_len(s)) {
+                    // FIXME: substr works on bytes, not chars!
+                    unpadded = _str.substr(s, 0u, max as uint);
+                }
+            }
+        }
+        ret pad(cv, unpadded);
     }
 
     fn pad(&conv cv, str s) -> str {
-- 
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