git.iko.soy/Idris-dev
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Idris-dev/libs/base/System.idr
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1module System
3import Prelude
5%default partial
6%access public
8||| Get the command-line arguments that the program was called with.
9getArgs : IO (List String)
10getArgs = do n <- numArgs
11 ga' [] 0 n
12 where
13 numArgs : IO Int
14 numArgs = mkForeign (FFun "idris_numArgs" [] FInt)
16 getArg : Int -> IO String
17 getArg x = mkForeign (FFun "idris_getArg" [FInt] FString) x
19 ga' : List String -> Int -> Int -> IO (List String)
20 ga' acc i n = if (i == n) then (return $ reverse acc) else
21 do arg <- getArg i
22 ga' (arg :: acc) (i+1) n
24||| Retrieves an value from the environment, if the given key is present,
25||| otherwise it returns Nothing.
26getEnv : String -> IO (Maybe String)
27getEnv key = do
28 str_ptr <- getEnv'
29 is_nil <- nullStr str_ptr
30 if is_nil
31 then pure Nothing
32 else pure (Just str_ptr)
33 where
34 getEnv' : IO String
35 getEnv' = mkForeign (FFun "getenv" [FString] FString) key
37||| Sets an environment variable with a given value.
38||| Returns true if the operation was successful.
39setEnv : String -> String -> IO Bool
40setEnv key value = do
41 ok <- mkForeign (FFun "setenv" [FString, FString, FInt] FInt) key value 1
42 return (ok == 0)
44||| Unsets an environment variable.
45||| Returns true if the variable was able to be unset.
46unsetEnv : String -> IO Bool
47unsetEnv key = do
48 ok <- mkForeign (FFun "unsetenv" [FString] FInt) key
49 return (ok == 0)
51getEnvironment : IO (List (String, String))
52getEnvironment = getAllPairs 0 []
53 where
54 getEnvPair : Int -> IO String
55 getEnvPair i = mkForeign (FFun "getEnvPair" [FInt] FString) i
57 splitEq : String -> (String, String)
58 splitEq str =
59 -- FIXME: There has to be a better way to split this up
60 let (k, v) = break (== '=') str in
61 let (_, v') = break (/= '=') v in
62 (k, v')
64 getAllPairs : Int -> List String -> IO (List (String, String))
65 getAllPairs n acc = do
66 envPair <- getEnvPair n
67 is_nil <- nullStr envPair
68 if is_nil
69 then return $ reverse $ map splitEq acc
70 else getAllPairs (n + 1) (envPair :: acc)
72||| Quit with a particular exit code
73exit : Int -> IO ()
74exit code = mkForeign (FFun "exit" [FInt] FUnit) code
76||| Get the Unix time
77time : IO Int
78time = mkForeign (FFun "idris_time" [] FInt)
80usleep : Int -> IO ()
81usleep i = mkForeign (FFun "usleep" [FInt] FUnit) i