X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=docs%2Fusers_guide%2Fghci.xml;h=9fa5d875b0326c6a7f29ebee337aec01452435d3;hb=c24bd1bbbdc4e20ea5c31b8779a70a5421f44962;hp=b092953b361bc51ce427a920b81d2e2846b4463f;hpb=da4dda13a3faf2ecc2138d16b7faa79cff264037;p=ghc-hetmet.git
diff --git a/docs/users_guide/ghci.xml b/docs/users_guide/ghci.xml
index b092953..9fa5d87 100644
--- a/docs/users_guide/ghci.xml
+++ b/docs/users_guide/ghci.xml
@@ -368,7 +368,6 @@ hello
IO monad.
Prelude> x <- return 42
-42
Prelude> print x
42
Prelude>
@@ -380,7 +379,8 @@ Prelude>
x in future statements, for example to print
it as we did above.
- GHCi will print the result of a statement if and only if:
+ If is set then
+ GHCi will print the result of a statement if and only if:
The statement is not a binding, or it is a monadic binding
@@ -393,13 +393,8 @@ Prelude>
Show
- The automatic printing of binding results can be suppressed with
- (this does not
- suppress printing the result of non-binding statements).
- .
- You might want to do this to prevent the result of binding
- statements from being fully evaluated by the act of printing
- them, for example.
+ .
+ Of course, you can also bind normal non-IO expressions
using the let-statement:
@@ -616,7 +611,7 @@ Prelude IO>
- The :main command
+ The :main and :run commands
When a program is compiled and executed, it can use the
@@ -641,6 +636,37 @@ Prelude> :main foo bar
["foo","bar"]
+
+ We can also quote arguments which contains characters like
+ spaces, and they are treated like Haskell strings, or we can
+ just use Haskell list syntax:
+
+
+
+Prelude> :main foo "bar baz"
+["foo","bar baz"]
+Prelude> :main ["foo", "bar baz"]
+["foo","bar baz"]
+
+
+
+ Finally, other functions can be called, either with the
+ -main-is flag or the :run
+ command:
+
+
+
+Prelude> let foo = putStrLn "foo" >> System.Environment.getArgs >>= print
+Prelude> let bar = putStrLn "bar" >> System.Environment.getArgs >>= print
+Prelude> :set -main-is foo
+Prelude> :main foo "bar baz"
+foo
+["foo","bar baz"]
+Prelude> :run bar ["foo", "bar baz"]
+bar
+["foo","bar baz"]
+
+
@@ -1442,7 +1468,7 @@ as = 'b' : 'c' : (_t1::[Char])
import Prelude hiding (map)
-map :: (a->b) -> a -> b
+map :: (a->b) -> [a] -> [b]
map f [] = []
map f (x:xs) = f x : map f xs
@@ -1745,6 +1771,32 @@ $ ghci -lm
The !-form also annotates the listing
with comments giving possible imports for each group of
entries.
+
+Prelude> :browse! Data.Maybe
+-- not currently imported
+Data.Maybe.catMaybes :: [Maybe a] -> [a]
+Data.Maybe.fromJust :: Maybe a -> a
+Data.Maybe.fromMaybe :: a -> Maybe a -> a
+Data.Maybe.isJust :: Maybe a -> Bool
+Data.Maybe.isNothing :: Maybe a -> Bool
+Data.Maybe.listToMaybe :: [a] -> Maybe a
+Data.Maybe.mapMaybe :: (a -> Maybe b) -> [a] -> [b]
+Data.Maybe.maybeToList :: Maybe a -> [a]
+-- imported via Prelude
+Just :: a -> Maybe a
+data Maybe a = Nothing | Just a
+Nothing :: Maybe a
+maybe :: b -> (a -> b) -> Maybe a -> b
+
+
+ This output shows that, in the context of the current session, in the scope
+ of Prelude, the first group of items from
+ Data.Maybe have not been imported (but are available in
+ fully qualified form in the GHCi session - see ), whereas the second group of items have been
+ imported via Prelude and are therefore available either
+ unqualified, or with a Prelude. qualifier.
+
@@ -1970,6 +2022,17 @@ Prelude> :. cmds.ghci
+
+ :
+ :
+
+
+ Repeat the previous command.
+
+
+
+
+
:history [num]:history
@@ -2087,6 +2150,37 @@ Prelude> :main foo bar
["foo","bar"]
+
+ We can also quote arguments which contains characters like
+ spaces, and they are treated like Haskell strings, or we can
+ just use Haskell list syntax:
+
+
+
+Prelude> :main foo "bar baz"
+["foo","bar baz"]
+Prelude> :main ["foo", "bar baz"]
+["foo","bar baz"]
+
+
+
+ Finally, other functions can be called, either with the
+ -main-is flag or the :run
+ command:
+
+
+
+Prelude> let foo = putStrLn "foo" >> System.Environment.getArgs >>= print
+Prelude> let bar = putStrLn "bar" >> System.Environment.getArgs >>= print
+Prelude> :set -main-is foo
+Prelude> :main foo "bar baz"
+foo
+["foo","bar baz"]
+Prelude> :run bar ["foo", "bar baz"]
+bar
+["foo","bar baz"]
+
+