commit 394fab8914f165e9b1c76c90ebb1a33dbf7bf4d7
Author: Danila Fedorin <danila.fedorin@gmail.com>
Date:   Tue Feb 28 19:44:24 2023 -0800

    Initial commit + basic Expr impl

diff --git a/.gitignore b/.gitignore
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--- /dev/null
+++ b/.gitignore
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+/bower_components/
+/node_modules/
+/.pulp-cache/
+/output/
+/generated-docs/
+/.psc-package/
+/.psc*
+/.purs*
+/.psa*
+/.spago
diff --git a/packages.dhall b/packages.dhall
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+++ b/packages.dhall
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+{-
+Welcome to your new Dhall package-set!
+
+Below are instructions for how to edit this file for most use
+cases, so that you don't need to know Dhall to use it.
+
+## Use Cases
+
+Most will want to do one or both of these options:
+1. Override/Patch a package's dependency
+2. Add a package not already in the default package set
+
+This file will continue to work whether you use one or both options.
+Instructions for each option are explained below.
+
+### Overriding/Patching a package
+
+Purpose:
+- Change a package's dependency to a newer/older release than the
+    default package set's release
+- Use your own modified version of some dependency that may
+    include new API, changed API, removed API by
+    using your custom git repo of the library rather than
+    the package set's repo
+
+Syntax:
+where `entityName` is one of the following:
+- dependencies
+- repo
+- version
+-------------------------------
+let upstream = --
+in  upstream
+  with packageName.entityName = "new value"
+-------------------------------
+
+Example:
+-------------------------------
+let upstream = --
+in  upstream
+  with halogen.version = "master"
+  with halogen.repo = "https://example.com/path/to/git/repo.git"
+
+  with halogen-vdom.version = "v4.0.0"
+  with halogen-vdom.dependencies = [ "extra-dependency" ] # halogen-vdom.dependencies
+-------------------------------
+
+### Additions
+
+Purpose:
+- Add packages that aren't already included in the default package set
+
+Syntax:
+where `<version>` is:
+- a tag (i.e. "v4.0.0")
+- a branch (i.e. "master")
+- commit hash (i.e. "701f3e44aafb1a6459281714858fadf2c4c2a977")
+-------------------------------
+let upstream = --
+in  upstream
+  with new-package-name =
+    { dependencies =
+       [ "dependency1"
+       , "dependency2"
+       ]
+    , repo =
+       "https://example.com/path/to/git/repo.git"
+    , version =
+        "<version>"
+    }
+-------------------------------
+
+Example:
+-------------------------------
+let upstream = --
+in  upstream
+  with benchotron =
+      { dependencies =
+          [ "arrays"
+          , "exists"
+          , "profunctor"
+          , "strings"
+          , "quickcheck"
+          , "lcg"
+          , "transformers"
+          , "foldable-traversable"
+          , "exceptions"
+          , "node-fs"
+          , "node-buffer"
+          , "node-readline"
+          , "datetime"
+          , "now"
+          ]
+      , repo =
+          "https://github.com/hdgarrood/purescript-benchotron.git"
+      , version =
+          "v7.0.0"
+      }
+-------------------------------
+-}
+let upstream =
+      https://github.com/purescript/package-sets/releases/download/psc-0.15.2-20220706/packages.dhall
+        sha256:7a24ebdbacb2bfa27b2fc6ce3da96f048093d64e54369965a2a7b5d9892b6031
+
+in  upstream
+    with logict.repo = "https://dev.danilafe.com/Everything-I-Know-About-Types/logict.git"
+    with logict.version = "24298710fa940bfcf2d272bc6d5c7417f2bfccfe"
+    with logict.dependencies = [ "control", "lists", "maybe", "prelude", "transformers", "tuples" ]
diff --git a/spago.dhall b/spago.dhall
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+++ b/spago.dhall
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+{-
+Welcome to a Spago project!
+You can edit this file as you like.
+
+Need help? See the following resources:
+- Spago documentation: https://github.com/purescript/spago
+- Dhall language tour: https://docs.dhall-lang.org/tutorials/Language-Tour.html
+
+When creating a new Spago project, you can use
+`spago init --no-comments` or `spago init -C`
+to generate this file without the comments in this block.
+-}
+{ name = "bergamot"
+, dependencies = [ "foldable-traversable", "lists", "logict", "prelude" ]
+, packages = ./packages.dhall
+, sources = [ "src/**/*.purs", "test/**/*.purs" ]
+}
diff --git a/src/Language/Bergamot/Syntax.purs b/src/Language/Bergamot/Syntax.purs
new file mode 100644
index 0000000..f960092
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+++ b/src/Language/Bergamot/Syntax.purs
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+module Language.Bergamot.Syntax where
+
+import Data.List (List)
+import Data.Functor (class Functor, (<$>))
+import Data.Eq (class Eq)
+import Data.Traversable (class Traversable, sequence)
+import Data.Foldable (class Foldable, foldr, foldl, foldMap)
+import Data.Monoid ((<>), mempty)
+
+data Expr v
+    = Var v
+    | Atom String (List (Expr v))
+
+derive instance Eq v => Eq (Expr v)
+derive instance Functor Expr
+
+instance Foldable Expr where
+    foldr f b (Var x) = f x b
+    foldr f b (Atom _ xs) = foldr (\x b' -> foldr f b' x) b xs
+
+    foldl f b (Var x) = f b x
+    foldl f b (Atom _ xs) = foldl (foldl f) b xs
+
+    foldMap f (Var x) = f x
+    foldMap f (Atom _ xs) = foldl (<>) mempty (foldMap f <$> xs)
+
+instance Traversable Expr where
+    sequence (Var f) = Var <$> f
+    sequence (Atom name fs) = Atom name <$> sequence (sequence <$> fs)
+
+    traverse f e = sequence (f <$> e)
diff --git a/src/Main.purs b/src/Main.purs
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+++ b/src/Main.purs
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+module Main where
+
+import Prelude
+
+main :: Unit
+main = unit
diff --git a/test/Main.purs b/test/Main.purs
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+++ b/test/Main.purs
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+module Test.Main where
+
+import Prelude
+
+main :: Unit
+main = unit