From 31620dd79f352259cc88dd70e8d955fe0b57e933 Mon Sep 17 00:00:00 2001
From: DaQuirm <leo.daquirm@gmail.com>
Date: Tue, 8 Jan 2019 00:44:08 +0100
Subject: [PATCH 1/3] Add defs and an AST type to support it

---
 example.lambda             |  1 -
 examples/def.lambda        |  3 +++
 examples/helloworld.lambda |  1 +
 src/AST.hs                 | 41 ++++++++++++++++++++++++++++++++++++++
 4 files changed, 45 insertions(+), 1 deletion(-)
 delete mode 100644 example.lambda
 create mode 100644 examples/def.lambda
 create mode 100644 examples/helloworld.lambda
 create mode 100644 src/AST.hs

diff --git a/example.lambda b/example.lambda
deleted file mode 100644
index f79d9f3..0000000
--- a/example.lambda
+++ /dev/null
@@ -1 +0,0 @@
-((λ x (λ y x)) "Hello, world!")
diff --git a/examples/def.lambda b/examples/def.lambda
new file mode 100644
index 0000000..91c0918
--- /dev/null
+++ b/examples/def.lambda
@@ -0,0 +1,3 @@
+const = (λ x (λ y x))
+id = (λ x x)
+main = (((const id) const) (λ y (λ x (λ z y))))
\ No newline at end of file
diff --git a/examples/helloworld.lambda b/examples/helloworld.lambda
new file mode 100644
index 0000000..0280b9c
--- /dev/null
+++ b/examples/helloworld.lambda
@@ -0,0 +1 @@
+((λ x (λ y x)) "Hello, world!")
\ No newline at end of file
diff --git a/src/AST.hs b/src/AST.hs
new file mode 100644
index 0000000..5b2222b
--- /dev/null
+++ b/src/AST.hs
@@ -0,0 +1,41 @@
+{-# OPTIONS_GHC -fno-warn-unused-do-bind #-}
+
+module AST where
+
+import Control.Applicative (Alternative, some)
+import Control.Monad (guard)
+
+import Lib (Expr, Identifier, Error, betaReduce, compile)
+import Parser (Parser, char, identifier, expr)
+
+type Definition = (Identifier, Expr)
+
+data AST = AST
+  { defs :: [Definition]
+  , main :: Expr
+  } deriving (Show)
+
+definition :: (Alternative m, Monad m) => Parser String m Definition
+definition = do
+  name <- identifier
+  char ' '
+  char '='
+  char ' '
+  ex <- expr
+  pure (name, ex)
+
+ast :: (Alternative m, Monad m) => Parser String m AST
+ast = AST <$> some p <*> mainP
+  where
+    p = do
+      def@(name, _) <- definition
+      guard $ name /= "main"
+      char '\n'
+      pure def
+    mainP = do
+      def@(name, ex) <- definition
+      guard $ name == "main"
+      pure ex
+
+compileAst :: AST -> Either Error String
+compileAst (AST defs main) = betaReduce defs main >>= compile
\ No newline at end of file

From 96005e72e126fde0a554b01654b9d394992a3014 Mon Sep 17 00:00:00 2001
From: DaQuirm <leo.daquirm@gmail.com>
Date: Tue, 8 Jan 2019 00:52:35 +0100
Subject: [PATCH 2/3] Add a Church numerals example

---
 examples/church.lambda | 6 ++++++
 1 file changed, 6 insertions(+)
 create mode 100644 examples/church.lambda

diff --git a/examples/church.lambda b/examples/church.lambda
new file mode 100644
index 0000000..d4b19fb
--- /dev/null
+++ b/examples/church.lambda
@@ -0,0 +1,6 @@
+zero = (λ f (λ x x))
+one = (λ f (λ x (f x)))
+two = (λ f (λ x (f (f x))))
+three = (λ f (λ x (f ((two f) x))))
+const = (λ x (λ y x))
+main = (three const) "whoa"
\ No newline at end of file

From b8766e29a72254d57d332f22d579b35eef402206 Mon Sep 17 00:00:00 2001
From: DaQuirm <leo.daquirm@gmail.com>
Date: Tue, 8 Jan 2019 01:01:59 +0100
Subject: [PATCH 3/3] Change naming to address linting issues

---
 src/AST.hs | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/AST.hs b/src/AST.hs
index 5b2222b..8af97b4 100644
--- a/src/AST.hs
+++ b/src/AST.hs
@@ -11,8 +11,8 @@ import Parser (Parser, char, identifier, expr)
 type Definition = (Identifier, Expr)
 
 data AST = AST
-  { defs :: [Definition]
-  , main :: Expr
+  { defs     :: [Definition]
+  , mainExpr :: Expr
   } deriving (Show)
 
 definition :: (Alternative m, Monad m) => Parser String m Definition
@@ -33,9 +33,9 @@ ast = AST <$> some p <*> mainP
       char '\n'
       pure def
     mainP = do
-      def@(name, ex) <- definition
+      (name, ex) <- definition
       guard $ name == "main"
       pure ex
 
 compileAst :: AST -> Either Error String
-compileAst (AST defs main) = betaReduce defs main >>= compile
\ No newline at end of file
+compileAst (AST definitions mainEx) = betaReduce definitions mainEx >>= compile
\ No newline at end of file