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What is Frege? ------------- Frege is a non-strict, pure functional programming language in the spirit of Haskell for the JVM. It enjoys a strong static type system with type inference. Higher rank types are supported, though type annotations are required for that. Frege programs are compiled to Java and run in a JVM. Existing Java Classes and Methods can be used seamlessly from Frege. The Frege programming language is named after and in honor of Gottlob Frege. Project State: ------------- The compiler, an Eclipse plugin and a provisional version of the documentation can be downloaded from here https://github.com/Frege/frege/releases. The REPL can be downloaded from here https://github.com/Frege/frege-repl/releases. An online REPL is running here http://try.frege-lang.org/. Examples: -------- 1) Command Line Clock: https://github.com/Frege/frege/blob/master/examples/CommandLineClock.fr 2) Brainfuck: https://github.com/Frege/frege/blob/master/examples/Brainfuck.fr 3) Concurrency: https://github.com/Frege/frege/blob/master/examples/Concurrent.fr 4) Sudoku: https://github.com/Frege/frege/blob/master/examples/Sudoku.fr 5) Java Swing examples: https://github.com/Frege/frege/blob/master/examples/SwingExamples.fr
44 lines
1.1 KiB
Plaintext
44 lines
1.1 KiB
Plaintext
{--
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This program displays the
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current time on stdandard output
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every other second.
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-}
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module examples.CommandLineClock where
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data Date = native java.util.Date where
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native new :: () -> IO (MutableIO Date) -- new Date()
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native toString :: Mutable s Date -> ST s String -- d.toString()
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--- 'IO' action to give us the current time as 'String'
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current :: IO String
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current = do
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d <- Date.new ()
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d.toString
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{-
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"java.lang.Thread.sleep" takes a "long" and
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returns nothing, but may throw an InterruptedException.
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This is without doubt an IO action.
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public static void sleep(long millis)
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throws InterruptedException
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Encoded in Frege:
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- argument type long Long
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- result void ()
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- does IO IO ()
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- throws ... throws ....
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-}
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-- .... defined in frege.java.Lang
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-- native sleep java.lang.Thread.sleep :: Long -> IO () throws InterruptedException
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main args =
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forever do
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current >>= print
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print "\r"
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stdout.flush
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Thread.sleep 999
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