From e1f2c6b88b12e380153dbbe2c3fc78a1b0c25630 Mon Sep 17 00:00:00 2001
From: Eryn Wells <eryn@erynwells.me>
Date: Thu, 29 Dec 2016 16:58:02 -0500
Subject: [PATCH] Basic parsing infrastructure .. doesn't actually do anything

---
 src/parser/mod.rs              | 37 ++++++++++++++++++++++++++++++++++
 src/parser/nodes/constant.rs   | 19 ++++++++++-------
 src/parser/nodes/expression.rs |  5 +++++
 src/parser/nodes/mod.rs        | 13 +++---------
 src/parser/nodes/program.rs    | 10 ++++++++-
 5 files changed, 66 insertions(+), 18 deletions(-)
 create mode 100644 src/parser/nodes/expression.rs

diff --git a/src/parser/mod.rs b/src/parser/mod.rs
index 31c5a54..e768349 100644
--- a/src/parser/mod.rs
+++ b/src/parser/mod.rs
@@ -2,4 +2,41 @@
  * Eryn Wells <eryn@erynwells.me>
  */
 
+pub use self::nodes::Program;
+
 mod nodes;
+
+use lexer::Lexer;
+
+pub struct Parser {
+    lexer: Lexer,
+}
+
+impl Parser {
+    pub fn new(lexer: Lexer) -> Parser {
+        Parser { lexer: lexer }
+    }
+
+    pub fn parse(&self) -> nodes::Program {
+        self.parse_program()
+    }
+}
+
+impl Parser {
+    fn parse_program(&self) -> nodes::Program {
+        let program = Program::new();
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use lexer::Lexer;
+
+    #[test]
+    fn parses_empty_input() {
+        let parser = Parser::new(Lexer::new(""));
+        let parsed = parser.parse();
+        assert_eq!(parsed, Program::new());
+    }
+}
diff --git a/src/parser/nodes/constant.rs b/src/parser/nodes/constant.rs
index cd40049..473a562 100644
--- a/src/parser/nodes/constant.rs
+++ b/src/parser/nodes/constant.rs
@@ -5,20 +5,25 @@
 use std::fmt;
 use types::{Boolean, Number};
 use super::TreeDebug;
+use super::expression::Expression;
 
 pub trait ConstantValue {}
 impl ConstantValue for Boolean {}
 impl ConstantValue for Number {}
 
-#[derive(Debug)]
-pub struct Constant<V: ConstantValue> {
+pub struct Constant<'a, V: ConstantValue> {
+    parent: Option<&'a Expression>,
     value: V
 }
 
-impl<V: ConstantValue + fmt::Debug> TreeDebug for Constant<V> {}
-
-impl<V: ConstantValue> Constant<V> {
-    pub fn new(value: V) -> Constant<V> {
-        Constant { value: value }
+impl<'a, V: ConstantValue> Constant<'a, V> {
+    pub fn new(value: V) -> Constant<'a, V> {
+        Constant { parent: None, value: value }
+    }
+}
+
+impl<'a, V: ConstantValue + fmt::Debug> fmt::Debug for Constant<'a, V> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "Constant {{ {:?} }}", self.value)
     }
 }
diff --git a/src/parser/nodes/expression.rs b/src/parser/nodes/expression.rs
new file mode 100644
index 0000000..979c004
--- /dev/null
+++ b/src/parser/nodes/expression.rs
@@ -0,0 +1,5 @@
+/* parser/nodes/expression.rs
+ * Eryn Wells <eryn@erynwells.me>
+ */
+
+pub trait Expression {}
diff --git a/src/parser/nodes/mod.rs b/src/parser/nodes/mod.rs
index 83aeedc..2c943a8 100644
--- a/src/parser/nodes/mod.rs
+++ b/src/parser/nodes/mod.rs
@@ -5,20 +5,13 @@
 use std::fmt;
 
 pub use self::constant::Constant;
+pub use self::program::Program;
 
 mod constant;
+mod expression;
 mod program;
 
-use self::constant::ConstantValue;
-
-trait Expression {}
-impl fmt::Debug for Expression {
-    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
-        write!(f, "Expression")
-    }
-}
-impl TreeDebug for Expression {}
-impl<T: constant::ConstantValue> Expression for Constant<T> {}
+use self::expression::Expression;
 
 /// Conveniently print out a node in the tree
 trait TreeDebug: fmt::Debug {
diff --git a/src/parser/nodes/program.rs b/src/parser/nodes/program.rs
index cdf9ed6..3cf71eb 100644
--- a/src/parser/nodes/program.rs
+++ b/src/parser/nodes/program.rs
@@ -5,12 +5,19 @@
 use std::fmt;
 
 use super::TreeDebug;
-use super::Expression;
+use super::expression::Expression;
 
 pub struct Program {
     forms: Vec<Box<Expression>>,
 }
 
+impl Program {
+    pub fn new() -> Program {
+        Program { forms: Vec::new() }
+    }
+}
+
+/*
 impl fmt::Debug for Program {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         self.tree_fmt(f, 0)
@@ -30,3 +37,4 @@ impl TreeDebug for Program {
         result
     }
 }
+*/