git.iko.soy/Idris-dev
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Idris-dev/libs/base/System.idr
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1module System
3import Prelude
5%include C "unistd.h"
6%default partial
7%access public
9||| Get the command-line arguments that the program was called with.
10getArgs : IO (List String)
11getArgs = do n <- numArgs
12 ga' [] 0 n
13 where
14 numArgs : IO Int
15 numArgs = mkForeign (FFun "idris_numArgs" [] FInt)
17 getArg : Int -> IO String
18 getArg x = mkForeign (FFun "idris_getArg" [FInt] FString) x
20 ga' : List String -> Int -> Int -> IO (List String)
21 ga' acc i n = if (i == n) then (return $ reverse acc) else
22 do arg <- getArg i
23 ga' (arg :: acc) (i+1) n
25||| Retrieves an value from the environment, if the given key is present,
26||| otherwise it returns Nothing.
27getEnv : String -> IO (Maybe String)
28getEnv key = do
29 str_ptr <- getEnv'
30 is_nil <- nullStr str_ptr
31 if is_nil
32 then pure Nothing
33 else pure (Just str_ptr)
34 where
35 getEnv' : IO String
36 getEnv' = mkForeign (FFun "getenv" [FString] FString) key
38||| Sets an environment variable with a given value.
39||| Returns true if the operation was successful.
40setEnv : String -> String -> IO Bool
41setEnv key value = do
42 ok <- mkForeign (FFun "setenv" [FString, FString, FInt] FInt) key value 1
43 return (ok == 0)
45||| Unsets an environment variable.
46||| Returns true if the variable was able to be unset.
47unsetEnv : String -> IO Bool
48unsetEnv key = do
49 ok <- mkForeign (FFun "unsetenv" [FString] FInt) key
50 return (ok == 0)
52getEnvironment : IO (List (String, String))
53getEnvironment = getAllPairs 0 []
54 where
55 getEnvPair : Int -> IO String
56 getEnvPair i = mkForeign (FFun "getEnvPair" [FInt] FString) i
58 splitEq : String -> (String, String)
59 splitEq str =
60 -- FIXME: There has to be a better way to split this up
61 let (k, v) = break (== '=') str in
62 let (_, v') = break (/= '=') v in
63 (k, v')
65 getAllPairs : Int -> List String -> IO (List (String, String))
66 getAllPairs n acc = do
67 envPair <- getEnvPair n
68 is_nil <- nullStr envPair
69 if is_nil
70 then return $ reverse $ map splitEq acc
71 else getAllPairs (n + 1) (envPair :: acc)
73||| Quit with a particular exit code
74exit : Int -> IO ()
75exit code = mkForeign (FFun "exit" [FInt] FUnit) code
77||| Get the Unix time
78time : IO Int
79time = mkForeign (FFun "idris_time" [] FInt)
81usleep : Int -> IO ()
82usleep i = mkForeign (FFun "usleep" [FInt] FUnit) i
84system : String -> IO Int
85system cmd = mkForeign (FFun "system" [FString] FInt) cmd