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StdEnv-doc
Commit 5928340c authored by John van Groningen's avatar John van Groningen
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improve accuracy of toReal for strings, fix conversion of denormalized numbers

parent 9c652777
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Showing with 115 additions and 55 deletions
StdEnv 64 Changed Files/StdReal.icl
View file @ 5928340c
......@@ -7,7 +7,7 @@ implementation module StdReal
import StdClass
import StdOverloaded,StdInt,StdArray
from StdBool import &&,||,not
from StdChar import instance == Char, class ==(..)
from StdChar import instance == Char, instance < Char, class ==(..)
instance + Real
where
......@@ -243,7 +243,7 @@ where
instance toReal {#Char}
where
toReal::!{#Char} -> Real
toReal :: !{#Char} -> Real
toReal s
| len == 0
= 0.0
......@@ -254,41 +254,71 @@ where
// otherwise
= val
where
len
= size s
signedval
= toReal2 s 1 0.0 False 1.0 False 0 0
val
= toReal2 s 0 0.0 False 1.0 False 0 0
first
= s.[0]
toReal2 s posn val dec_new dval exp eneg eval
len = size s
first = s.[0]
signedval = toReal1 s 1 0.0
val = toReal1 s 0 0.0
toReal1 :: !{#Char} !Int !Real -> Real
toReal1 s posn val
| posn == len
= val
| digit
= toReal1 s (posn+1) (toReal n + 10.0*val)
| c == '.'
= toRealWithDot s (posn+1) val 0
| c== 'e' || c== 'E'
| posn<len-2 && s.[posn+1] == '-'
= toRealWithExp s (posn+2) val 0 (-1) 0
| posn<len-2 && s.[posn+1] == '+'
= toRealWithExp s (posn+2) val 0 (+1) 0
| posn<len-1
= toRealWithExp s (posn+1) val 0 1 0
= 0.0
= 0.0
where
c = s.[posn]
n = toInt c - toInt '0'
digit = c>='0' && c<='9'
toRealWithDot :: !{#Char} !Int !Real !Int -> Real
toRealWithDot s posn val dn
| posn == len
= val*dval*10.0 ^ toReal (eneg*eval)
| digit && not dec_new && not exp
= toReal2 s (posn+1) (toReal n + 10.0*val) dec_new dval exp eneg eval
| digit && dec_new && not exp
= toReal2 s (posn+1) (toReal n + 10.0*val) dec_new (dval/10.0) exp eneg eval
| digit && exp
= toReal2 s (posn+1) val dec_new dval exp eneg (n + 10*eval )
| not dec_new && not exp && c == '.'
= toReal2 s (posn+1) val True 1.0 exp eneg eval
| not exp && (c== 'e' || c== 'E')
| dn==0
= val
= val / (10.0 ^ toReal dn)
| digit
= toRealWithDot s (posn+1) (toReal n + 10.0*val) (dn+1)
| c== 'e' || c== 'E'
| posn<len-2 && s.[posn+1] == '-'
= toReal2 s (posn+2) val dec_new dval True (-1) 0
= toRealWithExp s (posn+2) val dn (-1) 0
| posn<len-2 && s.[posn+1] == '+'
= toReal2 s (posn+2) val dec_new dval True (+1) 0
= toRealWithExp s (posn+2) val dn (+1) 0
| posn<len-1
= toReal2 s (posn+1) val dec_new dval True 1 0
// otherwise
= toRealWithExp s (posn+1) val dn 1 0
= 0.0
// otherwise
= 0.0
where
c = s.[posn]
n = toInt c - toInt '0'
digit = 0<=n && n<=9
digit = c>='0' && c<='9'
toRealWithExp :: !{#Char} !Int !Real !Int !Int !Int -> Real
toRealWithExp s posn val dn eneg eval
| posn == len
# e = eneg*eval-dn
| e>=0
= val * 10.0 ^ toReal e
| e>= -308
= val / 10.0 ^ toReal (~e)
= (val / 5.0 ^ toReal (~e)) / 2.0 ^ toReal (~e)
| digit
= toRealWithExp s (posn+1) val dn eneg (n + 10*eval)
= 0.0
where
c = s.[posn]
n = toInt c - toInt '0'
digit = c>='0' && c<='9'
entier :: !Real -> Int
entier a
......
StdReal.icl
View file @ 5928340c
......@@ -7,7 +7,7 @@ implementation module StdReal
import StdClass
import StdOverloaded,StdInt,StdArray
from StdBool import &&,||,not
from StdChar import instance == Char, class ==(..)
from StdChar import instance == Char, instance < Char, class ==(..)
instance + Real
where
......@@ -254,41 +254,71 @@ where
// otherwise
= val
where
len
= size s
signedval
= toReal2 s 1 0.0 False 1.0 False 0 0
val
= toReal2 s 0 0.0 False 1.0 False 0 0
first
= s.[0]
toReal2 s posn val dec_new dval exp eneg eval
len = size s
first = s.[0]
signedval = toReal1 s 1 0.0
val = toReal1 s 0 0.0
toReal1 :: !{#Char} !Int !Real -> Real
toReal1 s posn val
| posn == len
= val
| digit
= toReal1 s (posn+1) (toReal n + 10.0*val)
| c == '.'
= toRealWithDot s (posn+1) val 0
| c== 'e' || c== 'E'
| posn<len-2 && s.[posn+1] == '-'
= toRealWithExp s (posn+2) val 0 (-1) 0
| posn<len-2 && s.[posn+1] == '+'
= toRealWithExp s (posn+2) val 0 (+1) 0
| posn<len-1
= toRealWithExp s (posn+1) val 0 1 0
= 0.0
= 0.0
where
c = s.[posn]
n = toInt c - toInt '0'
digit = c>='0' && c<='9'
toRealWithDot :: !{#Char} !Int !Real !Int -> Real
toRealWithDot s posn val dn
| posn == len
= val*dval*10.0 ^ toReal (eneg*eval)
| digit && not dec_new && not exp
= toReal2 s (posn+1) (toReal n + 10.0*val) dec_new dval exp eneg eval
| digit && dec_new && not exp
= toReal2 s (posn+1) (toReal n + 10.0*val) dec_new (dval/10.0) exp eneg eval
| digit && exp
= toReal2 s (posn+1) val dec_new dval exp eneg (n + 10*eval )
| not dec_new && not exp && c == '.'
= toReal2 s (posn+1) val True 1.0 exp eneg eval
| not exp && (c== 'e' || c== 'E')
| dn==0
= val
= val / (10.0 ^ toReal dn)
| digit
= toRealWithDot s (posn+1) (toReal n + 10.0*val) (dn+1)
| c== 'e' || c== 'E'
| posn<len-2 && s.[posn+1] == '-'
= toReal2 s (posn+2) val dec_new dval True (-1) 0
= toRealWithExp s (posn+2) val dn (-1) 0
| posn<len-2 && s.[posn+1] == '+'
= toReal2 s (posn+2) val dec_new dval True (+1) 0
= toRealWithExp s (posn+2) val dn (+1) 0
| posn<len-1
= toReal2 s (posn+1) val dec_new dval True 1 0
// otherwise
= toRealWithExp s (posn+1) val dn 1 0
= 0.0
// otherwise
= 0.0
where
c = s.[posn]
n = toInt c - toInt '0'
digit = 0<=n && n<=9
digit = c>='0' && c<='9'
toRealWithExp :: !{#Char} !Int !Real !Int !Int !Int -> Real
toRealWithExp s posn val dn eneg eval
| posn == len
# e = eneg*eval-dn
| e>=0
= val * 10.0 ^ toReal e
| e>= -308
= val / 10.0 ^ toReal (~e)
= (val / 5.0 ^ toReal (~e)) / 2.0 ^ toReal (~e)
| digit
= toRealWithExp s (posn+1) val dn eneg (n + 10*eval)
= 0.0
where
c = s.[posn]
n = toInt c - toInt '0'
digit = c>='0' && c<='9'
entier :: !Real -> Int
entier a
......
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