13 files changed, 309 insertions, 0 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
new file mode 100644
index 0000000..0b5e45b
--- /dev/null
+++ b/CHANGELOG.md
@@ -0,0 +1,3 @@
+# Revision history for lisk
+
+<!-- populate this as we progress -->
diff --git a/Setup.hs b/Setup.hs
new file mode 100644
index 0000000..9a994af
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+++ b/Setup.hs
@@ -0,0 +1,2 @@
+import Distribution.Simple
+main = defaultMain
diff --git a/bin/Main.hs b/bin/Main.hs
new file mode 100644
index 0000000..2942566
--- /dev/null
+++ b/bin/Main.hs
@@ -0,0 +1,26 @@
+module Main where
+
+import           Evaluator                     (eval)
+import           Parser                        (Expr (..), parseLispValue)
+import           System.Console.Readline
+import           Text.ParserCombinators.Parsec
+
+readExpr :: String -> Expr
+readExpr inp =
+    case parse parseLispValue "(unknown)" inp of
+      Left err  -> StringLiteral $ show err
+      Right val -> val
+
+repl :: IO ()
+repl = do
+    inp <- readline "(lisk)> "
+    case inp of
+      Nothing -> return ()
+      Just ",q" -> return ()
+      Just line -> do
+          addHistory line
+          print . eval . readExpr $ line
+          repl
+
+main :: IO ()
+main = repl
diff --git a/cabal.project.local b/cabal.project.local
new file mode 100644
index 0000000..8909668
--- /dev/null
+++ b/cabal.project.local
@@ -0,0 +1 @@
+tests: True
diff --git a/default.nix b/default.nix
new file mode 100644
index 0000000..1890d35
--- /dev/null
+++ b/default.nix
@@ -0,0 +1,10 @@
+{ mkDerivation, base, parsec, readline, stdenv }:
+mkDerivation {
+  pname = "lisk";
+  version = "0.1.0.0";
+  src = ./.;
+  isLibrary = false;
+  isExecutable = true;
+  executableHaskellDepends = [ base parsec readline ];
+  license = stdenv.lib.licenses.gpl3;
+}
diff --git a/lisk.cabal b/lisk.cabal
new file mode 100644
index 0000000..627815d
--- /dev/null
+++ b/lisk.cabal
@@ -0,0 +1,55 @@
+cabal-version: >=1.10
+-- Initial package description 'lisk.cabal' generated by 'cabal init'.  For
+--  further documentation, see http://haskell.org/cabal/users-guide/
+
+name: lisk
+version: 0.1.0.0
+synopsis: a lisp interpreter
+description: an educational lisp interpreter written in haskell by DSCRV
+-- bug-reports:
+license: GPL-3
+-- license-file:        LICENSE
+author: Akshay
+maintainer: [email protected]
+-- copyright:
+-- category:
+build-type: Simple
+extra-source-files: CHANGELOG.md
+
+library
+  default-language: Haskell2010
+  build-depends: 
+    base >=4.12 && <4.13,
+    parsec == 3.*,
+    mtl >= 2.1
+  hs-source-dirs: src
+  exposed-modules: 
+    Parser,
+    Evaluator,
+    Operators
+
+executable lisk
+  default-language: Haskell2010
+  main-is: Main.hs
+  build-depends: 
+    base >=4.12 && <4.13,
+    parsec == 3.*,
+    readline >= 1.0,
+    lisk
+  hs-source-dirs: bin
+
+test-suite properties
+  default-language: Haskell2010
+  type: exitcode-stdio-1.0
+  main-is: Main.hs
+  hs-source-dirs: tests
+  build-depends:
+    base >=4.12 && <4.13, 
+    parsec == 3.*,
+    QuickCheck >= 2.4 && < 3,
+    test-framework >= 0.6 && < 0.9,
+    test-framework-hunit >= 0.3 && < 0.5,
+    test-framework-quickcheck2 >= 0.2 && < 0.4,
+    test-framework-th >= 0.2 && < 0.4,
+    lisk
+  other-modules: Properties
diff --git a/release.nix b/release.nix
new file mode 100644
index 0000000..8180314
--- /dev/null
+++ b/release.nix
@@ -0,0 +1,4 @@
+let 
+  pkgs = import <nixpkgs> {};
+in
+  pkgs.haskellPackages.callPackage ./default.nix {}
diff --git a/shell.nix b/shell.nix
new file mode 100644
index 0000000..b1a597f
--- /dev/null
+++ b/shell.nix
@@ -0,0 +1,40 @@
+let
+
+  all-hies = fetchTarball {
+    url = "https://github.com/infinisil/all-hies/tarball/534ac517b386821b787d1edbd855b9966d0c0775";
+    sha256 = "0bw1llpwxbh1dnrnbxkj2l0j58s523hjivszf827c3az5i4py1i2";
+  };
+
+  pkgs = import <nixpkgs> {
+    # Pass no config for purity
+    config = {};
+    overlays = [
+      (import all-hies {}).overlay
+    ];
+  };
+
+  inherit (pkgs) haskellPackages;
+
+  haskellDeps = ps: with ps; [
+    base
+    lens
+    parsec
+    mtl
+    readline
+  ];
+
+  ghc = haskellPackages.ghcWithPackages haskellDeps;
+
+  externalPackages = [
+    ghc
+    pkgs.gdb
+    pkgs.cabal2nix
+    haskellPackages.cabal-install
+    haskellPackages.hie
+    haskellPackages.hoogle
+  ];
+in
+pkgs.stdenv.mkDerivation {
+  name = "env";
+  buildInputs = externalPackages;
+}
diff --git a/src/Evaluator.hs b/src/Evaluator.hs
new file mode 100644
index 0000000..f264ee0
--- /dev/null
+++ b/src/Evaluator.hs
@@ -0,0 +1,22 @@
+module Evaluator (
+    eval
+    ) where
+
+import           Operators
+import           Parser
+import           Text.ParserCombinators.Parsec
+
+apply :: String -> [Expr] -> Expr
+apply fn args =
+    case lookup fn primitives of
+      Just f -> f args
+      _      -> BoolLiteral False -- TODO: error out instead
+
+eval :: Expr -> Expr
+eval v@(StringLiteral s)     = v
+eval v@(IntLiteral i)        = v
+eval v@(BoolLiteral b)       = v
+-- handle quotes as literals
+eval (List[Id "quote", val]) = val
+eval (List (Id fn : args))   = apply fn $ map eval args
+
diff --git a/src/Operators.hs b/src/Operators.hs
new file mode 100644
index 0000000..e57f885
--- /dev/null
+++ b/src/Operators.hs
@@ -0,0 +1,22 @@
+module Operators (
+    primitives
+    ) where
+
+import           Parser
+
+primitives :: [(String, [Expr] -> Expr)]
+primitives =
+    [
+    ("+", arithmetic (+))
+    , ("-", arithmetic (-))
+    , ("*", arithmetic (*))
+    , ("/", arithmetic div)
+    ]
+
+arithmetic :: (Integer -> Integer -> Integer) -> [Expr] -> Expr
+arithmetic op args = IntLiteral $ foldl1 op $ map unwrapNum args
+
+unwrapNum :: Expr -> Integer
+unwrapNum (IntLiteral n) = n
+unwrapNum _              = undefined
+
diff --git a/src/Parser.hs b/src/Parser.hs
new file mode 100644
index 0000000..dcbfdb1
--- /dev/null
+++ b/src/Parser.hs
@@ -0,0 +1,101 @@
+module Parser ( parseLispValue
+              , Expr(..)
+              , parseString
+              , parseInt
+              , parseFloat
+              , parseAtom
+              , parseList
+              , parseQuote
+              , parseDottedList
+              ) where
+
+import           Control.Applicative           ((<$>))
+import           Control.Monad                 (liftM)
+import           Text.ParserCombinators.Parsec
+
+
+type Ident = String
+
+data Expr = List [Expr]
+          | DottedList [Expr] Expr
+          | StringLiteral String
+          | IntLiteral Integer
+          | FloatLiteral Double
+          | BoolLiteral Bool
+          | Id Ident
+          deriving (Eq)
+
+parseString :: Parser Expr
+parseString = do
+    char '"'
+    innards <- many (noneOf "\"")
+    char '"'
+    return (StringLiteral innards)
+
+parseInt :: Parser Expr
+parseInt = IntLiteral . read <$> many1 digit
+
+parseFloat :: Parser Expr
+parseFloat = do
+    characteristic <- many digit
+    char '.'
+    mantissa <- many1 digit
+    return $ (FloatLiteral . read) $ characteristic ++ "." ++ mantissa
+
+symbol :: Parser Char
+symbol = oneOf "!#$%&|*+:/-=<?>@^_~"
+
+parseAtom :: Parser Expr
+parseAtom = do
+    first <- letter <|> symbol
+    rest <- many (letter <|> symbol <|> digit)
+    let atom = first:rest
+    return $ case atom of
+               "#t" -> BoolLiteral True
+               "#f" -> BoolLiteral False
+               _    -> Id atom
+
+whiteSpace :: Parser ()
+whiteSpace = skipMany1 space
+
+parseList :: Parser Expr
+parseList = List <$> sepBy parseLispValue whiteSpace
+
+parseDottedList :: Parser Expr
+parseDottedList = do
+    head <- endBy parseLispValue whiteSpace
+    char '.'
+    whiteSpace
+    DottedList head <$> parseLispValue
+
+parseQuote :: Parser Expr
+parseQuote = do
+    char '\''
+    x <- parseLispValue
+    return $ List [Id "quote", x]
+
+
+parseLispValue :: Parser Expr
+parseLispValue =
+    try parseAtom
+    <|> parseString
+    <|> parseInt
+    <|> parseQuote
+    -- TODO: figure out a way to have floats and dotted lists
+    -- <|> parseFloat
+    <|> do
+        char '('
+        x <- try parseList <|> parseDottedList
+        char ')'
+        return x
+    <?> "expected lisp value!"
+
+instance Show Expr where
+    show (DottedList xs x)   = "(" ++ unwords (map show xs) ++ " . " ++ show x ++ ")"
+    show (List xs)           = "(" ++ unwords (map show xs) ++ ")"
+    show (StringLiteral s)   = "\"" ++ s ++ "\""
+    show (IntLiteral n)      = show n
+    show (FloatLiteral n)    = show n
+    show (BoolLiteral True)  = "#t"
+    show (BoolLiteral False) = "#f"
+    show (Id i) = i
diff --git a/tests/Main.hs b/tests/Main.hs
new file mode 100644
index 0000000..a05ddb1
--- /dev/null
+++ b/tests/Main.hs
@@ -0,0 +1,8 @@
+module Main where
+
+import           Properties
+import           Test.Framework.Providers.QuickCheck2
+import           Test.Framework.Runners.Console       (defaultMain)
+import           Test.QuickCheck
+
+main = defaultMain [ Properties.tests ]
diff --git a/tests/Properties.hs b/tests/Properties.hs
new file mode 100644
index 0000000..b42cd4b
--- /dev/null
+++ b/tests/Properties.hs
@@ -0,0 +1,15 @@
+{-# LANGUAGE TemplateHaskell #-}
+module Properties where
+
+import           Parser                               (Expr (..),
+                                                       parseLispValue,
+                                                       parseQuote)
+
+import           Test.Framework.Providers.QuickCheck2
+import           Test.Framework.TH
+import           Test.QuickCheck
+import           Text.ParserCombinators.Parsec
+
+-- some tests would go here hopefully
+
+tests = $testGroupGenerator