[project @ 2003-03-17 14:51:00 by simonmar]

Fix for lexing of floating point numbers.  '9e2' should be a float.

Noticed-by: Ross Paterson.

diff --git a/ghc/compiler/parser/Lex.lhs b/ghc/compiler/parser/Lex.lhs
index 2c78f39..162995f 100644 (file)
--- a/ghc/compiler/parser/Lex.lhs
+++ b/ghc/compiler/parser/Lex.lhs
@@ -826,33 +826,39 @@ lex_num cont exts acc buf =
              -- files is not that common. (ToDo)
            case expandWhile# is_digit (incCurrentPos buf') of
               buf2 -> -- points to first non digit char
-
-               let l = case currentChar# buf2 of
-                         'E'# -> do_exponent
-                         'e'# -> do_exponent
-                         _ -> buf2
-
-                   do_exponent 
-                       = let buf3 = incCurrentPos buf2 in
-                         case currentChar# buf3 of
-                               '-'# | is_digit (lookAhead# buf3 1#)
-                                  -> expandWhile# is_digit (incCurrentPos buf3)
-                               '+'# | is_digit (lookAhead# buf3 1#)
-                                  -> expandWhile# is_digit (incCurrentPos buf3)
-                               x | is_digit x -> expandWhile# is_digit buf3
-                               _ -> buf2
-
-                   v = readRational__ (lexemeToString l)
-
-               in case currentChar# l of -- glasgow exts only
-                     '#'# | glaExtsEnabled exts -> let l' = incCurrentPos l in
-                             case currentChar# l' of
-                               '#'# -> cont (ITprimdouble v) (incCurrentPos l')
-                               _    -> cont (ITprimfloat  v) l'
-                     _ -> cont (ITrational v) l
-
-         _ -> after_lexnum cont exts acc' buf'
+                 case currentChar# buf of
+                       'E'# -> float_exponent cont exts buf2
+                       'e'# -> float_exponent cont exts buf2
+                       _    -> float_done cont exts buf2
+
+        -- numbers like '9e4' are floats
+        'E'# -> float_exponent cont exts buf'
+        'e'# -> float_exponent cont exts buf'
+         _    -> after_lexnum cont exts acc' buf' -- it's an integer
                
+float_exponent cont exts buf2 =
+  let buf3 = incCurrentPos buf2
+      buf4 = case currentChar# buf3 of
+               '-'# | is_digit (lookAhead# buf3 1#)
+                       -> expandWhile# is_digit (incCurrentPos buf3)
+               '+'# | is_digit (lookAhead# buf3 1#)
+                       -> expandWhile# is_digit (incCurrentPos buf3)
+               x | is_digit x -> expandWhile# is_digit buf3
+               _ -> buf2
+  in 
+     float_done cont exts buf4
+
+float_done cont exts buf =
+   case currentChar# buf of -- glasgow exts only
+       '#'# | glaExtsEnabled exts -> 
+             let buf' = incCurrentPos buf in
+             case currentChar# buf' of
+               '#'# -> cont (ITprimdouble v) (incCurrentPos buf')
+               _    -> cont (ITprimfloat  v) buf'
+       _ -> cont (ITrational v) buf
+ where
+   v = readRational__ (lexemeToString buf)
+
 after_lexnum cont exts i buf
   = case currentChar# buf of
        '#'# | glaExtsEnabled exts -> cont (ITprimint i) (incCurrentPos buf)