From 88eacc9c6a95d2147ec7f6005014891667da7f1e Mon Sep 17 00:00:00 2001
From: thesayyn <thesayyn@gmail.com>
Date: Sat, 17 Feb 2024 13:45:25 -0800
Subject: [PATCH] feat: evaluation logic

---
 program/src/context.rs |  2 +-
 program/src/eval.rs    | 57 ++++++++++++++++++++++++++++++++++++++++++
 program/src/lib.rs     |  3 ++-
 program/src/program.rs | 10 ++++----
 program/src/value.rs   | 45 ++++++++-------------------------
 5 files changed, 75 insertions(+), 42 deletions(-)
 create mode 100644 program/src/eval.rs

diff --git a/program/src/context.rs b/program/src/context.rs
index 0618b4f..e44457b 100644
--- a/program/src/context.rs
+++ b/program/src/context.rs
@@ -1,5 +1,5 @@
 pub struct Context {
-
+    
 }
 
 impl Default for Context {
diff --git a/program/src/eval.rs b/program/src/eval.rs
new file mode 100644
index 0000000..80e45be
--- /dev/null
+++ b/program/src/eval.rs
@@ -0,0 +1,57 @@
+use crate::{value::Value, Context};
+use parser::{ArithmeticOp, Atom, Expression, RelationOp};
+
+impl From<Atom> for Value {
+    fn from(atom: Atom) -> Self {
+        match atom {
+            Atom::Int(i) => Value::Int(i),
+            Atom::UInt(ui) => Value::UInt(ui),
+            Atom::Float(f) => Value::Float(f),
+            Atom::Bool(b) => Value::Bool(b),
+            Atom::Null => Value::Null,
+            Atom::Bytes(b) => Value::Bytes(b),
+            Atom::String(s) => Value::String(s),
+        }
+    }
+}
+
+pub struct Eval {
+    ctx: Context,
+}
+
+impl Eval {
+    pub fn new(ctx: Context) -> Self {
+        Eval { ctx }
+    }
+    pub fn eval(&self, expr: Expression) -> Value {
+        match expr {
+            Expression::Atom(atom) => atom.into(),
+            Expression::Relation(left, op, right) => {
+                let left = self.eval(*left);
+                let right = self.eval(*right);
+                let result = match op {
+                    RelationOp::Equals => left.eq(&right),
+                    RelationOp::LessThan => todo!("lt"),
+                    RelationOp::LessThanEq => todo!("lte"),
+                    RelationOp::GreaterThan => todo!("gt"),
+                    RelationOp::GreaterThanEq => todo!("gte"),
+                    RelationOp::NotEquals => todo!("ne"),
+                    RelationOp::In => todo!("in"),
+                };
+                Value::Bool(result)
+            }
+            Expression::Arithmetic(left, op, right) => {
+                let left = self.eval(*left);
+                let right = self.eval(*right);
+                match op {
+                    ArithmeticOp::Add => left + right,
+                    ArithmeticOp::Subtract => left - right,
+                    ArithmeticOp::Divide => left / right,
+                    ArithmeticOp::Multiply => left * right,
+                    ArithmeticOp::Modulus => todo!("modulus"),
+                }
+            }
+            _ => todo!(),
+        }
+    }
+}
diff --git a/program/src/lib.rs b/program/src/lib.rs
index 94096cc..04195a3 100644
--- a/program/src/lib.rs
+++ b/program/src/lib.rs
@@ -2,4 +2,5 @@ pub mod context;
 pub mod program;
 pub use crate::program::Program;
 pub use crate::context::Context;
-mod value;
\ No newline at end of file
+mod value;
+mod eval;
\ No newline at end of file
diff --git a/program/src/program.rs b/program/src/program.rs
index 0f49fba..da97fe7 100644
--- a/program/src/program.rs
+++ b/program/src/program.rs
@@ -1,11 +1,10 @@
-use parser::{Expression};
+use parser::Expression;
 use parser::parser::ExpressionParser;
-
 use std::fmt;
-
 use std::result::Result;
 use crate::context::Context;
 use crate::value::Value;
+use crate::eval::Eval;
 
 pub struct Program {
     expr: Expression
@@ -31,8 +30,9 @@ impl Program {
         }
     }
 
-    pub fn execute(&self, context: Context) -> bool {
-        match Value::from(&self.expr) {
+    pub fn execute(self, context: Context) -> bool {
+        let e = Eval::new(context);
+        match e.eval(self.expr) {
             Value::Bool(b) => b,
             _ => panic!("this was not supposed to happen!")
         }
diff --git a/program/src/value.rs b/program/src/value.rs
index 6ff70af..2fffcc6 100644
--- a/program/src/value.rs
+++ b/program/src/value.rs
@@ -12,44 +12,19 @@ pub enum Value {
     String(Rc<String>),
 }
 
-impl From<&Atom> for Value {
-    fn from(atom: &Atom) -> Self {
-        match atom {
-            Atom::Int(i) => Value::Int(*i),
-            Atom::UInt(ui) => Value::UInt(*ui),
-            Atom::Float(f) => Value::Float(*f),
-            Atom::Bool(b) => Value::Bool(*b),
-            Atom::Bytes(b) => Value::Bytes(b.clone()),
-            Atom::Null => Value::Null,
-            Atom::String(s) => Value::String(s.clone()),
-        }
+impl std::ops::Mul for Value {
+    type Output = Value;
+
+    fn mul(self, rhs: Self) -> Self::Output {
+        todo!()
     }
 }
 
-impl<'a> Value {
-    pub fn from(expr: &'a Expression) -> Value {
-        match expr {
-            Expression::Atom(atom) => atom.into(),
-            Expression::Relation(left, op, right) => {
-                let left = Value::from(left);
-                let right = Value::from(right);
-                let result = match op {
-                    RelationOp::Equals => left.eq(&right),
-                    _ => unimplemented!(),
-                };
-                Value::Bool(result)
-            }
-            Expression::Arithmetic(left, op, right) => {
-                let left = Value::from(left);
-                let right = Value::from(right);
-                match op {
-                    ArithmeticOp::Add => left + right,
-                    ArithmeticOp::Subtract => left - right,
-                    _ => todo!(),
-                }
-            }
-            _ => todo!(),
-        }
+impl std::ops::Div for Value {
+    type Output = Value;
+
+    fn div(self, rhs: Self) -> Self::Output {
+        todo!()
     }
 }