Copyright | 2019 Emily Pillmore |
---|---|
License | BSD |
Maintainer | Emily Pillmore <emilypi@cohomolo.gy> |
Stability | Experimental |
Portability | TypeFamilies |
Safe Haskell | Safe |
Language | Haskell2010 |
System.Process.Lens.CommandSpec
Description
This module provides the associated optics and combinators
for working with CommandSpec
objects. CommandSpec
consists of two
cases: a Shell command, which is a command to execute naively in the shell,
and a Raw command which is a command path together with its arguments.
CommandSpec
has two cases, and therefore a prism into those two cases.
There is also a convenient Traversal
available for working with the arglist
of a Raw command, as well as associated Review
s for each prism, and combinators
for working with arguments monoidally.
We provide classy variants for all useful prisms
Traversals
arguments :: IsRaw a => Traversal' a [String] Source #
Traversal'
into the arguments of a command
Examples:
>>>
RawCommand "/bin/ls" ["-l"] ^. arguments
["-l"]
Prisms
_ShellCommand :: Prism' CmdSpec String Source #
A prism into the ShellCommand
case of a CmdSpec
Examples:
>>>
_ShellCommand # "ls -l"
ShellCommand "ls -l"
>>>
ShellCommand "ls -l" ^? _ShellCommand
Just "ls -l"
>>>
RawCommand "/bin/ls" ["-l"] ^? _ShellCommand
Nothing
_RawCommand :: Prism' CmdSpec (FilePath, [String]) Source #
A prism into the RawCommand
case of a CmdSpec
Examples:
>>>
RawCommand "/bin/ls" ["-l"] ^? _RawCommand
Just ("/bin/ls",["-l"])
>>>
RawCommand "/bin/ls" ["-l"] ^? _ShellCommand
Nothing
>>>
RawCommand "/bin/ls" ["-l"] ^. _RawCommand . _1
"/bin/ls"
>>>
RawCommand "/bin/ls" ["-l"] ^. _RawCommand . _2
["-l"]
Classy Prisms
class IsShell a where Source #
Classy prism into the shell command of a CmdSpec
Examples:
>>>
f :: IsShell a => a -> Maybe String; f = preview _Shell
>>>
f $ _ShellCommand # "ls -l"
Just "ls -l"
Classy prism into the raw command of a CmdSpec
Examples:
>>>
f :: IsRaw a => a -> Maybe FilePath; f = preview (_Raw . _1)
>>>
f $ _RawCommand # ("/bin/ls", ["ls -l"])
Just "/bin/ls"
Combinators
arguing :: IsRaw a => String -> a -> a Source #
Append an argument to the argument list of a RawCommand
Examples:
>>>
arguing "-h" $ RawCommand "/bin/ls" ["-l"]
RawCommand "/bin/ls" ["-l","-h"]
>>>
arguing "-h" (RawCommand "/bin/ls" ["-l"]) ^. arguments
["-l","-h"]