First commit

LICENSE

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+Copyright Author name here (c) 2021
+
+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 Author name here 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.

README.md

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+# Cherry Lisp
+A tiny and lazy lisp.
+
+```
+  /\
+ |  \
+ @   @
+
+cherry> (+ 2 3 4)
+9
+```
+
+Work in progress...

Setup.hs

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+import Distribution.Simple
+main = defaultMain

cherry-lisp.cabal

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+name:                cherry-lisp
+version:             0.1.0.0
+-- synopsis:
+-- description:
+--homepage:            https://github.com/githubuser/lisp#readme
+license:             BSD3
+license-file:        LICENSE
+author:              Suguivy
+maintainer:          suguivy@riseup.com
+copyright:           2021 Suguivy
+category:            Language
+build-type:          Simple
+cabal-version:       >=1.10
+extra-source-files:  README.md
+
+executable cherry
+  hs-source-dirs:      src
+  main-is:             Main.hs
+  default-language:    Haskell2010
+
+  other-modules:       ExprType,
+                       ExprParser,
+                       TokenType,
+                       TokenParser,
+                       Evaluator,
+                       ParserUtils,
+                       TokenParser
+
+  build-depends:       base >= 4.7 && < 5,
+                       containers,
+                       parsec

src/Evaluator.hs

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+module Evaluator where
+
+import qualified Data.Map as M
+import ExprType
+
+type Env = M.Map String Expr
+type Proc = String
+type Args = [Expr]
+
+eval :: Expr -> Expr
+eval (IntE x)            = IntE x
+eval (VarE v)            = VarE v
+eval (DefinitionE v exp) = NilE
+eval (ProcedureE p args) = apply p args
+eval NilE                = NilE
+
+apply :: Proc -> Args -> Expr
+apply p args
+    | p == "+" = builtinPlus $ map eval args
+
+-- TODO: create a BuiltinProc or something like that in data Expr, and make + a builtin proc
+
+builtinPlus :: [Expr] -> Expr
+builtinPlus [IntE x, IntE y] = IntE $ x + y
+builtinPlus ((IntE x):xs) = IntE $ x + n
+  where (IntE n) = builtinPlus xs

src/ExprParser.hs

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+module ExprParser where
+
+import Text.Parsec
+import Text.Parsec.String
+import TokenParser
+import TokenType
+import ExprType
+
+parseExpression :: String -> Either ParseError Expr
+parseExpression s = do
+  tokns <- parse parseTokens "lexical error" s
+  expr <- parse parseExpressionFromTokens "parsing error" tokns
+  return expr
+
+parseExpressionFromTokens :: GenParser Token st Expr
+parseExpressionFromTokens = intE <|> try defineE <|> try nilE <|> varE <|> procedureE
+
+intE :: GenParser Token st Expr
+intE = do
+    (IntT num) <- parseIntT
+    return $ IntE num
+
+procedureE :: GenParser Token st Expr
+procedureE = do
+  _ <- parseLeftParenT
+  (VarT p) <- parseVarT
+  args <- many parseExpressionFromTokens
+  _ <- parseRightParenT
+  return $ ProcedureE p args
+
+varE :: GenParser Token st Expr
+varE = do
+  (VarT var) <- parseVarT
+  return $ VarE var
+
+nilE :: GenParser Token st Expr
+nilE = do
+  _ <- parseNilT
+  return NilE
+
+defineE :: GenParser Token st Expr
+defineE = do
+  _ <- parseLeftParenT
+  _ <- parseDefineT
+  (VarT var) <- parseVarT
+  expr <- parseExpressionFromTokens
+  _ <- parseRightParenT
+  return $ DefinitionE var expr
+
+------------------------------------------------------------
+
+satisfyT :: (Stream s m a, Show a) => (a -> Bool) -> ParsecT s u m a
+satisfyT f = tokenPrim show
+                       (\pos _ _ -> incSourceColumn pos 1)
+                       (\t -> if f t then Just t else Nothing)
+
+parseLeftParenT :: GenParser Token st Token
+parseLeftParenT = satisfyT (== LeftParenT)
+
+parseRightParenT :: GenParser Token st Token
+parseRightParenT = satisfyT (== RightParenT)
+
+parseDefineT :: GenParser Token st Token
+parseDefineT = satisfyT (== DefineT)
+
+parseNilT :: GenParser Token st Token
+parseNilT = satisfyT (== NilT)
+
+parseVarT :: GenParser Token st Token
+parseVarT = satisfyT isVarT
+  where isVarT (VarT _) = True
+        isVarT _        = False
+
+parseIntT :: GenParser Token st Token
+parseIntT = satisfyT isIntT
+  where isIntT (IntT _) = True
+        isIntT _        = False

src/ExprType.hs

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+module ExprType where
+
+data Expr = IntE Integer
+          | VarE String
+          | ProcedureE String [Expr]
+          | DefinitionE String Expr
+          | NilE
+
+instance Show Expr where
+  show (IntE x) = show x
+  show (VarE x) = x ++ " ; var"
+  show NilE     = "nil"

src/Main.hs

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+module Main where
+
+import Evaluator
+import ExprParser
+import Text.Parsec.Error
+import Data.Either
+import System.IO
+
+main :: IO ()
+main = do
+  putStrLn ""
+  putLogo
+  putStrLn ""
+  cycle
+  where cycle = do
+          putPrompt
+          hFlush stdout
+          s <- getLine
+          let r = readEval s
+          putStrLn $ case r of
+            (Right res) -> res
+            (Left err) -> show err
+          cycle
+
+readEval :: String -> Either ParseError String
+readEval s = do
+  expr <- parseExpression s
+  let result = eval expr
+  return $ show result
+
+putLogo :: IO ()
+putLogo = putStr . concat $ map (++"\n") ["  /\\", " |  \\", " @   @"]
+
+putPrompt :: IO ()
+putPrompt = putStr "chery> "

src/ParserUtils.hs

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+module ParserUtils where
+
+import Text.ParserCombinators.Parsec
+import Data.Char
+
+caseInsensitiveString :: String -> GenParser Char st String
+caseInsensitiveString ""     = return ""
+caseInsensitiveString [x]    = (: []) <$> caseInsensitiveChar x
+caseInsensitiveString (x:xs) = do
+    c <- caseInsensitiveChar x
+    s <- caseInsensitiveString xs
+    return (c:s)
+
+caseInsensitiveChar :: Char -> GenParser Char st Char
+caseInsensitiveChar c = char (toLower c) <|> char (toUpper c)

src/TokenParser.hs

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+module TokenParser where
+
+import Text.ParserCombinators.Parsec
+import ParserUtils
+import Data.Char
+import TokenType
+
+parseTokens :: GenParser Char st [Token]
+parseTokens = do
+    _ <-  spaces
+    many $ (spaces >> anyLispToken)
+
+anyLispToken :: GenParser Char st Token
+anyLispToken = leftParenT <|> rightParenT <|> try nilT <|> try defineT <|> varT <|> intT
+
+------------------------------------------------------------
+
+intT :: GenParser Char st Token
+intT = do
+    number <- read <$> many1 digit
+    return $ IntT number
+
+leftParenT :: GenParser Char st Token
+leftParenT = char '(' >> return LeftParenT
+
+rightParenT :: GenParser Char st Token
+rightParenT = char ')' >> return RightParenT
+
+defineT :: GenParser Char st Token
+defineT = caseInsensitiveString "define" >> return DefineT
+
+nilT :: GenParser Char st Token
+nilT = caseInsensitiveString "nil" >> return NilT
+
+varT :: GenParser Char st Token
+varT = do
+    var <- map toLower <$> many1 (letter <|> oneOf "+-*/!|@#$~%&/=<>")
+    return $ VarT var

src/TokenType.hs

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+module TokenType where
+
+data Token = LeftParenT
+           | RightParenT
+           | DefineT
+           | VarT String
+           | IntT Integer
+           | NilT
+           deriving (Show, Eq)

stack.yaml

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+# This file was automatically generated by 'stack init'
+#
+# Some commonly used options have been documented as comments in this file.
+# For advanced use and comprehensive documentation of the format, please see:
+# https://docs.haskellstack.org/en/stable/yaml_configuration/
+
+# Resolver to choose a 'specific' stackage snapshot or a compiler version.
+# A snapshot resolver dictates the compiler version and the set of packages
+# to be used for project dependencies. For example:
+#
+# resolver: lts-3.5
+# resolver: nightly-2015-09-21
+# resolver: ghc-7.10.2
+#
+# The location of a snapshot can be provided as a file or url. Stack assumes
+# a snapshot provided as a file might change, whereas a url resource does not.
+#
+# resolver: ./custom-snapshot.yaml
+# resolver: https://example.com/snapshots/2018-01-01.yaml
+resolver: lts-17.0
+
+# User packages to be built.
+# Various formats can be used as shown in the example below.
+#
+# packages:
+# - some-directory
+# - https://example.com/foo/bar/baz-0.0.2.tar.gz
+#   subdirs:
+#   - auto-update
+#   - wai
+packages:
+- .
+# Dependency packages to be pulled from upstream that are not in the resolver.
+# These entries can reference officially published versions as well as
+# forks / in-progress versions pinned to a git hash. For example:
+#
+# extra-deps:
+# - acme-missiles-0.3
+# - git: https://github.com/commercialhaskell/stack.git
+#   commit: e7b331f14bcffb8367cd58fbfc8b40ec7642100a
+#
+# extra-deps: []
+
+# Override default flag values for local packages and extra-deps
+# flags: {}
+
+# Extra package databases containing global packages
+# extra-package-dbs: []
+
+# Control whether we use the GHC we find on the path
+# system-ghc: true
+#
+# Require a specific version of stack, using version ranges
+# require-stack-version: -any # Default
+# require-stack-version: ">=2.3"
+#
+# Override the architecture used by stack, especially useful on Windows
+# arch: i386
+# arch: x86_64
+#
+# Extra directories used by stack for building
+# extra-include-dirs: [/path/to/dir]
+# extra-lib-dirs: [/path/to/dir]
+#
+# Allow a newer minor version of GHC than the snapshot specifies
+# compiler-check: newer-minor