diff --git a/AlexPrelude.hs b/AlexPrelude.hs new file mode 100644 --- /dev/null +++ b/AlexPrelude.hs @@ -0,0 +1,137 @@ +-- | This is a collection of really useful functions. They are mostly aimed towards writing console applications. +-- +-- For example: +-- +-- > import AlexPrelude +-- > +-- > main :: IO () +-- > main = do +-- > clear_screen +-- > print "Hello my name is Alex" +-- > name <- prompt "What is your name? " +-- > print ("Hello, " ++ name) +-- > print "Let me ponder on what I think about your name..." +-- > sleep 10 +-- > print "It is ridiculous! Why would your parents do that to you!" +-- +-- As you can see, these functions try to fill in the missing gaps for when you want to write a real application in haskell. +module AlexPrelude + ( prompt + , sleep + , clear_screen + ) where + +import System.IO +import Data.Time.Clock.POSIX + +-- | Asks a user for some input +prompt :: String -> IO String +prompt question = do + -- This is INSANELY tricky. Sometimes it does not print the question! Fortunately I found the answer on stackoverflow: you need to use `hFlush stdout`. + putStr question + putStr " " + hFlush stdout + answer <- getLine + hFlush stdout -- To make sure? I don't really see how `getLine` works + return answer + +-- | Wait for a given number of seconds +sleep :: Int -> IO () +sleep secs = do + now <- get_time_as_int + let goal = now + secs + sleep_helper goal + +sleep_helper :: Int -> IO () +sleep_helper goal = do + now <- get_time_as_int + if now >= goal then return () else sleep_helper goal + +get_time_as_int :: IO Int +get_time_as_int = + -- What does fmap do?? I found it here: https://stackoverflow.com/questions/17909770/get-time-as-int + round `fmap` getPOSIXTime + +-- | This clears the screen. Unfortunately, this only works if the terminal has less than 80 rows. If the terminal has more rows, you can just call this a couple of times until the entire screen is cleared. +clear_screen :: IO () +clear_screen = do + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" + print "\n" diff --git a/ChangeLog.md b/ChangeLog.md new file mode 100644 --- /dev/null +++ b/ChangeLog.md @@ -0,0 +1,5 @@ +# Revision history for alex-prelude + +## 0.1.0.0 -- YYYY-mm-dd + +* First version. Released on an unsuspecting world. diff --git a/LICENSE b/LICENSE new file mode 100644 --- /dev/null +++ b/LICENSE @@ -0,0 +1,30 @@ +Copyright (c) 2017, Alex Sayers + +All rights reserved. + +Redistribution and use in source and binary forms, with or without +modification, are permitted provided that the following conditions are met: + + * Redistributions of source code must retain the above copyright + notice, this list of conditions and the following disclaimer. + + * Redistributions in binary form must reproduce the above + copyright notice, this list of conditions and the following + disclaimer in the documentation and/or other materials provided + with the distribution. + + * Neither the name of Alex Sayers nor the names of other + contributors may be used to endorse or promote products derived + from this software without specific prior written permission. + +THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR +A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT +OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT +LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE +OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. diff --git a/Setup.hs b/Setup.hs new file mode 100644 --- /dev/null +++ b/Setup.hs @@ -0,0 +1,2 @@ +import Distribution.Simple +main = defaultMain diff --git a/alex-prelude.cabal b/alex-prelude.cabal new file mode 100644 --- /dev/null +++ b/alex-prelude.cabal @@ -0,0 +1,70 @@ +-- Initial alex-prelude.cabal generated by cabal init. For further +-- documentation, see http://haskell.org/cabal/users-guide/ + +-- The name of the package. +name: alex-prelude + +-- The package version. See the Haskell package versioning policy (PVP) +-- for standards guiding when and how versions should be incremented. +-- https://wiki.haskell.org/Package_versioning_policy +-- PVP summary: +-+------- breaking API changes +-- | | +----- non-breaking API additions +-- | | | +--- code changes with no API change +version: 0.1.0.0 + +-- A short (one-line) description of the package. +synopsis: Collection of useful functions for writing console applications + +-- A longer description of the package. +description: Collection of useful functions for writing console applications + +-- URL for the project homepage or repository. +homepage: https://www.asayers.com/ + +-- The license under which the package is released. +license: BSD3 + +-- The file containing the license text. +license-file: LICENSE + +-- The package author(s). +author: Alex Sayers + +-- An email address to which users can send suggestions, bug reports, and +-- patches. +maintainer: alex.sayers@protonmail.com + +-- A copyright notice. +-- copyright: + +category: System + +build-type: Simple + +-- Extra files to be distributed with the package, such as examples or a +-- README. +extra-source-files: ChangeLog.md + +-- Constraint on the version of Cabal needed to build this package. +cabal-version: >=1.10 + + +library + -- Modules exported by the library. + exposed-modules: AlexPrelude + + -- Modules included in this library but not exported. + -- other-modules: + + -- LANGUAGE extensions used by modules in this package. + -- other-extensions: + + -- Other library packages from which modules are imported. + build-depends: base >=4.9 && <4.10, time >=1.6 && <1.7 + + -- Directories containing source files. + -- hs-source-dirs: + + -- Base language which the package is written in. + default-language: Haskell98 +