diff --git a/src/parser/ast.rs b/src/parser/ast.rs
index b17caf1..057fac0 100644
--- a/src/parser/ast.rs
+++ b/src/parser/ast.rs
@@ -112,6 +112,7 @@ pub enum Expression {
     Call(Box<CallExpr>),
     FieldAccess(Box<FieldAccess>),
     StructInit(Box<StructInit>),
+    ArrayLiteral(Box<ArrayLiteral>),
 }
 
 #[derive(Debug, Clone)]
@@ -178,3 +179,9 @@ pub enum TypeExpr {
     Array(Box<TypeExpr>),
     Optional(Box<TypeExpr>),
 }
+
+#[derive(Debug, Clone)]
+pub struct ArrayLiteral {
+    pub elements: Vec<Expression>,
+    pub span: Span,
+}
diff --git a/src/parser/grammar.pest b/src/parser/grammar.pest
index 9841b2a..fdf0ac9 100644
--- a/src/parser/grammar.pest
+++ b/src/parser/grammar.pest
@@ -23,21 +23,50 @@ param        = { identifier ~ ":" ~ type_expr }
 
 // statements
 block     =  { "{" ~ statement* ~ "}" }
-statement = _{ let_stmt | return_stmt | if_stmt | for_stmt | expression }
+statement = _{ let_stmt | return_stmt | if_stmt | for_stmt | assign_stmt | expression }
 
+assign_stmt = { identifier ~ "=" ~ expression }
 let_stmt    = { "let" ~ identifier ~ (":" ~ type_expr)? ~ "=" ~ expression }
 return_stmt = { "return" ~ expression? }
 if_stmt     = { "if" ~ expression ~ block ~ ("else" ~ block)? }
 for_stmt    = { "for" ~ identifier ~ "in" ~ expression ~ block }
 
-// expressions — broken into precedence layers, no cycles
-expression   =  { primary ~ (access_chain)* }
-access_chain = _{ field_access | call_suffix }
-field_access =  { "." ~ identifier }
-call_suffix  =  { "(" ~ (expression ~ ("," ~ expression)*)? ~ ")" }
-primary      = _{ float | integer | string_lit | boolean | identifier }
-
 // types — optional is a suffix, not a recursive wrapper
 type_expr  =  { base_type ~ "?"? }
 base_type  = _{ array_type | identifier }
 array_type =  { "[" ~ type_expr ~ "]" }
+
+// expressions
+expression =  { term ~ (bin_op ~ term)* }
+bin_op     = _{ add | sub | mul | div | eq | neq | lte | gte | lt | gt | and | or }
+add        =  { "+" }
+sub        =  { "-" }
+mul        =  { "*" }
+div        =  { "/" }
+eq         =  { "==" }
+neq        =  { "!=" }
+lte        =  { "<=" }
+gte        =  { ">=" }
+lt         =  { "<" }
+gt         =  { ">" }
+and        =  { "&&" }
+or         =  { "||" }
+
+struct_literal = {
+    identifier ~ "{" ~ (struct_init_field ~ ("," ~ struct_init_field)*)? ~ "}"
+}
+
+struct_init_field = {
+    identifier ~ ":" ~ expression
+}
+
+array_literal = {
+    "[" ~ (expression ~ ("," ~ expression)*)? ~ "]"
+}
+
+term         =  { primary ~ (field_access | call_suffix)* }
+field_access =  { "." ~ identifier }
+call_suffix  =  { "(" ~ (expression ~ ("," ~ expression)*)? ~ ")" }
+primary      = _{ struct_literal | array_literal | float | integer | string_lit | boolean | self_kw | null_kw | identifier }
+self_kw      =  { "self" }
+null_kw      =  { "null" }
diff --git a/src/parser/mod.rs b/src/parser/mod.rs
index 723005f..5d2bb50 100644
--- a/src/parser/mod.rs
+++ b/src/parser/mod.rs
@@ -219,52 +219,114 @@ fn parse_for(pair: Pair<Rule>) -> ForStatement {
 }
 
 fn parse_expression(pair: Pair<Rule>) -> Expression {
-    // let span = span_of(&pair);
     match pair.as_rule() {
         Rule::expression => {
             let mut inner = pair.into_inner();
-            let mut expr = parse_primary(inner.next().unwrap());
+            let mut expr = parse_term(inner.next().unwrap());
 
-            // chain field accesses and calls as left-to-right suffixes
-            for part in inner {
-                let span = span_of(&part);
-                match part.as_rule() {
-                    Rule::field_access => {
-                        let field = part.into_inner().next().unwrap().as_str().to_string();
-                        expr = Expression::FieldAccess(Box::new(FieldAccess {
-                            object: expr,
-                            field,
-                            span,
-                        }));
-                    }
-                    Rule::call_suffix => {
-                        let args = part.into_inner().map(|p| parse_expression(p)).collect();
-                        expr = Expression::Call(Box::new(CallExpr {
-                            callee: expr,
-                            args,
-                            span,
-                        }));
-                    }
-                    _ => {}
-                }
+            // consume pairs of (bin_op, term)
+            while let Some(op_pair) = inner.next() {
+                let right = parse_term(inner.next().unwrap());
+                let span = span_of(&op_pair);
+                let op = match op_pair.as_rule() {
+                    Rule::add => BinOperator::Add,
+                    Rule::sub => BinOperator::Sub,
+                    Rule::mul => BinOperator::Mul,
+                    Rule::div => BinOperator::Div,
+                    Rule::eq => BinOperator::Eq,
+                    Rule::neq => BinOperator::NotEq,
+                    Rule::lt => BinOperator::Lt,
+                    Rule::gt => BinOperator::Gt,
+                    Rule::lte => BinOperator::LtEq,
+                    Rule::gte => BinOperator::GtEq,
+                    Rule::and => BinOperator::And,
+                    Rule::or => BinOperator::Or,
+                    _ => unreachable!(),
+                };
+                expr = Expression::BinaryOp(Box::new(BinaryOp {
+                    left: expr,
+                    op,
+                    right,
+                    span,
+                }));
             }
 
             expr
         }
-        _ => parse_primary(pair),
+        _ => parse_term(pair),
     }
 }
 
+fn parse_term(pair: Pair<Rule>) -> Expression {
+    let mut inner = pair.into_inner();
+    let mut expr = parse_primary(inner.next().unwrap());
+
+    for part in inner {
+        let span = span_of(&part);
+        match part.as_rule() {
+            Rule::field_access => {
+                let field = part.into_inner().next().unwrap().as_str().to_string();
+                expr = Expression::FieldAccess(Box::new(FieldAccess {
+                    object: expr,
+                    field,
+                    span,
+                }));
+            }
+            Rule::call_suffix => {
+                let args = part.into_inner().map(|p| parse_expression(p)).collect();
+                expr = Expression::Call(Box::new(CallExpr {
+                    callee: expr,
+                    args,
+                    span,
+                }));
+            }
+            _ => {}
+        }
+    }
+
+    expr
+}
+
 fn parse_primary(pair: Pair<Rule>) -> Expression {
     let span = span_of(&pair);
+
     match pair.as_rule() {
+        Rule::struct_literal => {
+            let mut inner = pair.into_inner();
+            let name = inner.next().unwrap().as_str().to_string();
+
+            let mut fields = vec![];
+            for field in inner {
+                let mut f_inner = field.into_inner();
+                let field_name = f_inner.next().unwrap().as_str().to_string();
+                let value = parse_expression(f_inner.next().unwrap());
+                fields.push((field_name, value));
+            }
+
+            Expression::StructInit(Box::new(StructInit { name, fields, span }))
+        }
+
+        Rule::array_literal => {
+            let elements = pair.into_inner().map(|p| parse_expression(p)).collect();
+
+            Expression::ArrayLiteral(Box::new(ArrayLiteral { elements, span }))
+        }
+
         Rule::integer => Expression::Integer(pair.as_str().parse().unwrap(), span),
         Rule::float => Expression::Float(pair.as_str().parse().unwrap(), span),
+
         Rule::string_lit => {
             Expression::StringLit(pair.into_inner().next().unwrap().as_str().to_string(), span)
         }
+
         Rule::boolean => Expression::Bool(pair.as_str() == "true", span),
+
+        Rule::self_kw => Expression::Identifier("self".to_string(), span),
+        Rule::null_kw => Expression::Identifier("null".to_string(), span),
         Rule::identifier => Expression::Identifier(pair.as_str().to_string(), span),
+
+        Rule::term => parse_term(pair),
+
         _ => unreachable!("unexpected primary rule: {:?}", pair.as_rule()),
     }
 }
diff --git a/test/main.ms b/test/main.ms
index 8b154dd..d75832f 100644
--- a/test/main.ms
+++ b/test/main.ms
@@ -1,4 +1,120 @@
+import "fmt"
+import "strings"
+
+// structs are plain data
+struct Point {
+    x: float
+    y: float
+}
+
+// classes have fields and methods
+class Animal {
+    name: string
+    age: int
+
+    fn speak() -> string {
+        return "..."
+    }
+
+    fn describe() -> string {
+        return "I am " + self.name
+    }
+}
+
+class Dog {
+    name: string
+    age: int
+
+    fn speak() -> string {
+        return "Woof!"
+    }
+
+    fn fetch(item: string) -> string {
+        return self.name + " fetched the " + item
+    }
+}
+
+// basic function
+fn add(a: int, b: int) -> int {
+    return a + b
+}
+
+// optional return type
+fn find(name: string) -> string? {
+    if name == "mist" {
+        return name
+    }
+    return null
+}
+
+// array types
+fn sum(numbers: [int]) -> int {
+    let total: int = 0
+    for n in numbers {
+        total = total + n
+    }
+    return total
+}
+
+// multiple params, no return
+fn greet(first: string, last: string) {
+    let full: string = first + " " + last
+    print(full)
+}
+
+// structs initialized with fields
+fn make_point(x: float, y: float) -> Point {
+    return Point {
+        x: x,
+        y: y
+    }
+}
+
+// if / else
+fn classify(n: int) -> string {
+    if n < 0 {
+        return "negative"
+    } else {
+        return "positive"
+    }
+}
+
+// entry point
 fn main() {
-    let message: string = "Hello, World!"
+    // variables
+    let x: int = 10
+    let y: int = 20
+    let result: int = add(x, y)
+
+    // inferred (no type annotation)
+    let message = "Hello from Mist!"
     print(message)
+
+    // struct usage
+    let p: Point = make_point(1.5, 2.5)
+    print(p.x)
+
+    // class usage
+    let dog: Dog = Dog {
+        name: "Rex",
+        age: 3
+    }
+    print(dog.speak())
+    print(dog.fetch("ball"))
+
+    // arrays
+    let nums: [int] = [1, 2, 3, 4, 5]
+    let total: int = sum(nums)
+    print(total)
+
+    // for loop
+    for n in nums {
+        print(n)
+    }
+
+    // optional
+    let found: string? = find("mist")
+    if found {
+        print(found)
+    }
 }