Add 'stack' project for literate programming

Author: Sven Tennie

.gitignore

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 *.out
 *.snm
 *.toc
+.stack-work/
+lambda-calculus-presentation.cabal
+*~

LICENSE

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+# lambda-calculus-presentation

README.md

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+import Distribution.Simple
+main = defaultMain

Setup.hs

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+name:                lambda-calculus-presentation
+version:             0.1.0.0
+github:              "supersven/lambda-calculus-presentation"
+author:              "Sven Tennie"
+maintainer:          "[email protected]"
+copyright:           "2018 - Sven Tennie"
+
+extra-source-files:
+- README.md
+
+# Metadata used when publishing your package
+# synopsis:            Short description of your package
+# category:            Web
+
+# To avoid duplicated efforts in documentation and dealing with the
+# complications of embedding Haddock markup inside cabal files, it is
+# common to point users to the README.md file.
+description:         Please see the README on GitHub at <https://github.com/supersven/lambda-calculus-presentation#readme>
+
+dependencies:
+- base >= 4.7 && < 5
+
+library:
+  source-dirs: src
+  dependencies: containers >= 0.5.10.2
+
+tests:
+  lambda-calculus-presentation-test:
+    main:                Spec.hs
+    source-dirs:         test
+    ghc-options:
+    - -threaded
+    - -rtsopts
+    - -with-rtsopts=-N
+    dependencies:
+    - lambda-calculus-presentation

package.yaml

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+#+BEGIN_SRC haskell :tangle src/UntypedEval.hs
+  module UntypedEval where
+  import qualified Data.Map.Strict as Map
+
+  type Name = String
+  type Environment = Map.Map Name Term
+
+  data Term = Variable Name |
+              Application Term Term |
+              Abstraction Name Term
+              deriving (Eq, Show)
+
+  eval ::Environment -> Term -> Maybe Term
+  eval env (Variable name) = find env name
+  eval env (Application term1 term2) = case term1 of
+    (Abstraction name _) -> eval (Map.insert name term2 env) term1
+    _ -> Nothing
+  eval _ abstraction@(Abstraction _ _) = Just abstraction
+
+  find ::  Environment -> Name -> Maybe Term
+  find env name = Map.lookup name env
+#+END_SRC

presentation_2.org

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+module UntypedEval where
+import qualified Data.Map.Strict as Map
+
+type Name = String
+type Environment = Map.Map Name Term
+
+data Term = Variable Name |
+            Application Term Term |
+            Abstraction Name Term
+            deriving (Eq, Show)
+
+eval ::Environment -> Term -> Maybe Term
+eval env (Variable name) = find env name
+eval env (Application term1 term2) = case term1 of
+  (Abstraction name _) -> eval (Map.insert name term2 env) term1
+  _ -> Nothing
+eval _ abstraction@(Abstraction _ _) = Just abstraction
+
+find ::  Environment -> Name -> Maybe Term
+find env name = Map.lookup name env

src/UntypedEval.hs

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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
+# resolver: ghcjs-0.1.0_ghc-7.10.2
+# resolver:
+#  name: custom-snapshot
+#  location: "./custom-snapshot.yaml"
+resolver: lts-11.21
+
+# 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
+# - location:
+#    git: https://github.com/commercialhaskell/stack.git
+#    commit: e7b331f14bcffb8367cd58fbfc8b40ec7642100a
+# - location: https://github.com/commercialhaskell/stack/commit/e7b331f14bcffb8367cd58fbfc8b40ec7642100a
+#   extra-dep: true
+#  subdirs:
+#  - auto-update
+#  - wai
+#
+# A package marked 'extra-dep: true' will only be built if demanded by a
+# non-dependency (i.e. a user package), and its test suites and benchmarks
+# will not be run. This is useful for tweaking upstream packages.
+packages:
+- .
+# Dependency packages to be pulled from upstream that are not in the resolver
+# (e.g., acme-missiles-0.3)
+# 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: ">=1.6"
+#
+# 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

stack.yaml

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+main :: IO ()
+main = putStrLn "Test suite not yet implemented"