Parse multiple statements

- parse() now parses a Vec<Statement> that can represent basically a
  full program
- Now multiple lines / statements are parsed together

plang2/src/main.rs

@@ -4,7 +4,9 @@ use plang2_lib::*;
 fn main() {
 
     let code = r#"
-        a = 54 * sqrt(9);
+        a = 54 * 3;
+        b = 5;
+        print("{}", a + b);
     "#;
 
     let mut lexer = Lexer::new(code);

plang2_lib/src/parser.rs

@@ -48,8 +48,21 @@ impl Parser {
         self.tokens.advance()
     }
 
-    pub fn parse(&mut self) -> PRes<Statement> {
+    pub fn parse(&mut self) -> PRes<Vec<Statement>> {
-        self.parse_statement()
+        let mut prog = Vec::new();
+
+        while let Some(tok) = self.curr() {
+            match tok {
+                // Skip empty statements like duplicate or redundant semicolons
+                Token::Semicolon => {
+                    self.advance();
+                    continue;
+                }
+                _ => prog.push(self.parse_statement()?),
+            }
+        }
+
+        Ok(prog)
     }
 
     pub fn parse_statement(&mut self) -> PRes<Statement> {