4 files changed, 74 insertions, 7 deletions

diff --git a/src/comp/front/ast.rs b/src/comp/front/ast.rs
index cdeea241..d48792d1 100644
--- a/src/comp/front/ast.rs
+++ b/src/comp/front/ast.rs
@@ -256,6 +256,7 @@ tag lit_ {
     lit_uint(uint);
     lit_mach_int(ty_mach, int);
     lit_float(str);
+    lit_mach_float(ty_mach, str);
     lit_nil;
     lit_bool(bool);
 }
diff --git a/src/comp/front/lexer.rs b/src/comp/front/lexer.rs
index d4948503..aa7f2ce1 100644
--- a/src/comp/front/lexer.rs
+++ b/src/comp/front/lexer.rs
@@ -3,6 +3,9 @@ import std._str;
 import std._int;
 import std.map;
 import std.map.hashmap;
+import std.option;
+import std.option.some;
+import std.option.none;
 import util.common;
 import util.common.new_str_hash;
 
@@ -333,6 +336,27 @@ impure fn scan_dec_digits(reader rdr) -> int {
     ret accum_int;
 }
 
+impure fn scan_exponent(reader rdr) -> option.t[int] {
+    auto c = rdr.curr();
+    auto sign = 1;
+
+    if (c == 'e' || c == 'E') {
+        rdr.bump();
+        c = rdr.curr();
+        if (c == '-') {
+            sign = -1;
+            rdr.bump();
+        } else if (c == '+') {
+            rdr.bump();
+        }
+        auto exponent = scan_dec_digits(rdr);
+        ret(some(sign * exponent));
+    }
+    else {
+        ret none[int];
+    }
+}
+
 impure fn scan_number(mutable char c, reader rdr) -> token.token {
     auto accum_int = 0;
     auto n = rdr.next();
@@ -418,17 +442,54 @@ impure fn scan_number(mutable char c, reader rdr) -> token.token {
             ret token.LIT_UINT(accum_int as uint);
         }
     }
-    n = rdr.curr();
-    if(n == '.') {
+    c = rdr.curr();
+    if (c == '.') {
         // Parse a floating-point number.
         rdr.bump();
         auto accum_int1 = scan_dec_digits(rdr);
-        ret token.LIT_FLOAT(_int.to_str(accum_int, 10u) + "."
-                          + _int.to_str(accum_int1, 10u));
-        // FIXME: Parse exponent.
+        auto base_str =   _int.to_str(accum_int, 10u) + "."
+            + _int.to_str(accum_int1, 10u);
+        c = rdr.curr();
+        auto exponent_str = "";
+        let option.t[int] maybe_exponent = scan_exponent(rdr);
+        alt(maybe_exponent) {
+            case(some[int](?i)) {
+                exponent_str = "e" + _int.to_str(i, 10u);
+            }
+            case(none[int]) {
+            }
+        }
+
+        c = rdr.curr();
+        if (c == 'f') {
+            rdr.bump();
+            c = rdr.curr();
+            n = rdr.next();
+            if (c == '3' && n == '2') {
+                rdr.bump(); rdr.bump();
+                ret token.LIT_MACH_FLOAT(util.common.ty_f32,
+                                         base_str + exponent_str);
+            }
+            else if (c == '6' && n == '4') {
+                rdr.bump(); rdr.bump();
+                ret token.LIT_MACH_FLOAT(util.common.ty_f64,
+                                         base_str + exponent_str);
+            }
+        }
+        else {
+            ret token.LIT_FLOAT(base_str + exponent_str);
+        }
     }
-    else {
-        ret token.LIT_INT(accum_int);
+
+    auto maybe_exponent = scan_exponent(rdr);
+    alt(maybe_exponent) {
+        case(some[int](?i)) {
+            ret token.LIT_FLOAT(_int.to_str(accum_int, 10u)
+                                + "e" + _int.to_str(i, 10u));
+        }
+        case(none[int]) {
+            ret token.LIT_INT(accum_int);
+        }
     }
 }
 
diff --git a/src/comp/front/parser.rs b/src/comp/front/parser.rs
index f1f8a918..9e13e706 100644
--- a/src/comp/front/parser.rs
+++ b/src/comp/front/parser.rs
@@ -545,6 +545,10 @@ impure fn parse_lit(parser p) -> ast.lit {
             p.bump();
             lit = ast.lit_mach_int(tm, i);
         }
+        case (token.LIT_MACH_FLOAT(?tm, ?s)) {
+            p.bump();
+            lit = ast.lit_mach_float(tm, s);
+        }
         case (token.LIT_CHAR(?c)) {
             p.bump();
             lit = ast.lit_char(c);
diff --git a/src/comp/front/token.rs b/src/comp/front/token.rs
index a1fb1cd0..46fd0735 100644
--- a/src/comp/front/token.rs
+++ b/src/comp/front/token.rs
@@ -127,6 +127,7 @@ tag token {
     LIT_UINT(uint);
     LIT_MACH_INT(ty_mach, int);
     LIT_FLOAT(str);
+    LIT_MACH_FLOAT(ty_mach, str);
     LIT_STR(str);
     LIT_CHAR(char);
     LIT_BOOL(bool);