feat: add a propositional logic expression tree

argus-core/Cargo.toml

@@ -6,3 +6,6 @@ edition = "2021"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
+
+[dev-dependencies]
+proptest = "1.1.0"

argus-core/src/expr.rs

@@ -0,0 +1,51 @@
+/// All expressions that are numeric
+#[derive(Clone, Debug)]
+pub enum NumExpr {
+    IntLit(i64),
+    UIntLit(u64),
+    FloatLit(f64),
+    IntVar { name: String },
+    UIntVar { name: String },
+    FloatVar { name: String },
+
+    Neg { arg: Box<NumExpr> },
+    Add { args: Vec<NumExpr> },
+    Mul { args: Vec<NumExpr> },
+    Div { dividend: Box<NumExpr>, divisor: Box<NumExpr> },
+}
+
+/// Types of comparison operations
+#[derive(Clone, Copy, Debug)]
+pub enum Ordering {
+    Eq,
+    NotEq,
+    Less { strict: bool },
+    Greater { strict: bool },
+}
+
+/// All expressions that are evaluated to be of type `bool`
+#[derive(Clone, Debug)]
+pub enum BoolExpr {
+    BoolLit(bool),
+    BoolVar {
+        name: String,
+    },
+    Cmp {
+        op: Ordering,
+        lhs: Box<NumExpr>,
+        rhs: Box<NumExpr>,
+    },
+    Not {
+        arg: Box<BoolExpr>,
+    },
+    And {
+        args: Vec<BoolExpr>,
+    },
+    Or {
+        args: Vec<BoolExpr>,
+    },
+}
+
+/// Expression builder
+#[derive(Clone, Debug)]
+pub struct ExprBuilder {}

argus-core/src/lib.rs

@@ -1,14 +1 @@
-pub fn add(left: usize, right: usize) -> usize {
-    left + right
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    #[test]
-    fn it_works() {
-        let result = add(2, 2);
-        assert_eq!(result, 4);
-    }
-}
+pub mod expr;