Improved error handling

Replace unwrap with ? and added line numbers to error messages

src/C1_parser.rs

@@ -17,13 +17,14 @@ impl<'a> C1Parser<'a>  {
 
         println!("Starting parsing");
 
-        instance.program().unwrap();
-
-        Ok(())
+        instance.program()
     }
 
     fn program(&mut self) -> ParseResult {
-        self.functiondefinition().unwrap();
+        while self.lx.current_token().is_some() {
+            self.functiondefinition()?;
+        }
+
         Ok(())
     }
 
@@ -31,16 +32,14 @@ impl<'a> C1Parser<'a>  {
         if self.lx.current_token() == Some(C1Token::KwInt) || self.lx.current_token() == Some(C1Token::KwVoid) || self.lx.current_token() == Some(C1Token::KwBoolean) || self.lx.current_token() == Some(C1Token::KwFloat) {
             self.lx.eat();
 
-            self.check_and_eat_token(C1Token::Identifier).unwrap();
-            self.check_and_eat_token(C1Token::LeftParenthesis).unwrap();
-            self.check_and_eat_token(C1Token::RightParenthesis).unwrap();
-            self.check_and_eat_token(C1Token::LeftBrace).unwrap();
-            self.statementlist().unwrap();
-            self.check_and_eat_token(C1Token::RightBrace).unwrap();
-
-            return Ok(());
+            self.check_and_eat_token(C1Token::Identifier)?;
+            self.check_and_eat_token(C1Token::LeftParenthesis)?;
+            self.check_and_eat_token(C1Token::RightParenthesis)?;
+            self.check_and_eat_token(C1Token::LeftBrace)?;
+            self.statementlist()?;
+            return self.check_and_eat_token(C1Token::RightBrace);
         }
-        return Err(format!("Expected token group 'type' but found {:?}", self.lx.current_token()));
+        return Err(format!("Expected token group 'type' in line {} but found {:?}", self.lx.current_line_number().unwrap(), self.lx.current_token()));
     }
 
     fn statementlist(&mut self) -> ParseResult {
@@ -73,7 +72,7 @@ impl<'a> C1Parser<'a>  {
         }*/
 
         while !(self.lx.current_token() == Some(C1Token::RightBrace)) {
-            self.block().unwrap();
+            self.block()?;
         }
 
         Ok(())
@@ -82,140 +81,130 @@ impl<'a> C1Parser<'a>  {
     fn block(&mut self) -> ParseResult {
         print!("block->");
         if self.lx.current_token() == Some(C1Token::LeftBrace){
-            self.check_and_eat_token(C1Token::LeftBrace).unwrap();
-            self.statementlist().unwrap();
-            self.check_and_eat_token(C1Token::RightBrace).unwrap();
+            self.check_and_eat_token(C1Token::LeftBrace)?;
+            self.statementlist()?;
+            return self.check_and_eat_token(C1Token::RightBrace);
         }else{
-            self.statement().unwrap();
+            return self.statement();
         }
-        Ok(())
     }
 
     fn statement(&mut self) -> ParseResult {
         print!("statement->");
         match self.lx.current_token() {
             Some(C1Token::KwIf) => {
-                self.ifstatement().unwrap();
-                Ok(())
+                return self.ifstatement();
             },
             Some(C1Token::KwReturn) => {
-                self.returnstatement().unwrap();
-                self.check_and_eat_token(C1Token::Semicolon).unwrap();
-                Ok(())
+                self.returnstatement()?;
+                return self.check_and_eat_token(C1Token::Semicolon);
             },
             Some(C1Token::KwPrintf) => {
-                self.printfstatement().unwrap();
-                self.check_and_eat_token(C1Token::Semicolon).unwrap();
-                Ok(())
+                self.printfstatement()?;
+                return self.check_and_eat_token(C1Token::Semicolon);
             },
             Some(C1Token::Identifier) => {
                 if self.lx.peek_token() == Some(C1Token::Assign) {
-                    self.statassignment().unwrap();
-                    self.check_and_eat_token(C1Token::Semicolon).unwrap();
+                    self.statassignment()?;
+                    return self.check_and_eat_token(C1Token::Semicolon);
                 }else{
-                    self.functioncall().unwrap();
-                    self.check_and_eat_token(C1Token::Semicolon).unwrap();
+                    self.functioncall()?;
+                    return self.check_and_eat_token(C1Token::Semicolon);
                 }
-                Ok(())
             },
-            _ => Err(format!("Expected token group 'statement' but found {:?}", self.lx.current_token().unwrap())),
+            _ => Err(format!("Expected token group 'statement' in line {} but found {:?}", self.lx.current_line_number().unwrap(), self.lx.current_token().unwrap())),
         }
     }
 
     fn functioncall(&mut self) -> ParseResult {
         print!("functioncall->");
-        self.check_and_eat_token(C1Token::Identifier).unwrap();
-        self.check_and_eat_token(C1Token::LeftParenthesis).unwrap();
-        self.check_and_eat_token(C1Token::RightParenthesis).unwrap();
-        Ok(())
+        self.check_and_eat_token(C1Token::Identifier)?;
+        self.check_and_eat_token(C1Token::LeftParenthesis)?;
+        self.check_and_eat_token(C1Token::RightParenthesis)
     }
 
     fn statassignment(&mut self) -> ParseResult {
         print!("statassignment->");
-        self.check_and_eat_token(C1Token::Identifier).unwrap();
-        self.check_and_eat_token(C1Token::Assign).unwrap();
-        self.assignment().unwrap();
-        Ok(())
+        self.check_and_eat_token(C1Token::Identifier)?;
+        self.check_and_eat_token(C1Token::Assign)?;
+        self.assignment()
     }
 
 
     fn returnstatement(&mut self) -> ParseResult {
         print!("returnstatement->");
-        self.check_and_eat_token(C1Token::KwReturn).unwrap();
-        self.assignment(); //TODO: Maybe?
-        Ok(())
+        self.check_and_eat_token(C1Token::KwReturn)?;
+        if self.lx.current_token() == Some(C1Token::Semicolon) {
+            return Ok(());
+        }
+
+        self.assignment()
     }
 
     fn printfstatement(&mut self) -> ParseResult {
         print!("printfstatement->");
-        self.check_and_eat_token(C1Token::KwPrintf).unwrap();
-        self.check_and_eat_token(C1Token::LeftParenthesis).unwrap();
-        self.assignment().unwrap();
-        self.check_and_eat_token(C1Token::RightParenthesis).unwrap();
-        Ok(())
+        self.check_and_eat_token(C1Token::KwPrintf)?;
+        self.check_and_eat_token(C1Token::LeftParenthesis)?;
+        self.assignment()?;
+        self.check_and_eat_token(C1Token::RightParenthesis)
     }
 
     fn ifstatement(&mut self) -> ParseResult {
         print!("ifstatement->");
-        self.check_and_eat_token(C1Token::KwIf).unwrap();
-        self.check_and_eat_token(C1Token::LeftParenthesis).unwrap();
-        self.assignment().unwrap();
-        //TODO: self.check_and_eat_token(C1Token::RightParenthesis).unwrap();
-        self.block().unwrap();
-        Ok(())
+        self.check_and_eat_token(C1Token::KwIf)?;
+        self.check_and_eat_token(C1Token::LeftParenthesis)?;
+        self.assignment()?;
+        self.check_and_eat_token(C1Token::RightParenthesis)?;
+        self.block()
     }
 
     fn assignment(&mut self) -> ParseResult {
         print!("assignment->");
         println!("test: {:?} {:?}", self.lx.current_text(), self.lx.peek_text());
         if self.lx.current_token() == Some(C1Token::Identifier) && self.lx.peek_token() == Some(C1Token::Assign) {
-            self.check_and_eat_token(C1Token::Identifier).unwrap();
-            self.check_and_eat_token(C1Token::Assign).unwrap();
-            self.assignment().unwrap();
-            return Ok(());
+            self.check_and_eat_token(C1Token::Identifier)?;
+            self.check_and_eat_token(C1Token::Assign)?;
+            self.assignment()
         }else{
             println!("assignment: Not Identifier");
-            self.expr().unwrap();
-            return Ok(());
+            self.expr()
         }
     }
 
     fn expr(&mut self) -> ParseResult {
         print!("expr->");
-        self.simpexpr().unwrap();
+        self.simpexpr()?;
 
         let tk = self.lx.current_token();
         if tk == Some(C1Token::Equal) || tk == Some(C1Token::NotEqual) || tk == Some(C1Token::Less) || tk == Some(C1Token::LessEqual) || tk == Some(C1Token::Greater) || tk == Some(C1Token::GreaterEqual) {
             self.lx.eat();
-            self.simpexpr().unwrap();
-        }else{
-            return Ok(());
+            self.simpexpr()?;
         }
-        self.check_and_eat_token(C1Token::RightParenthesis).unwrap();
+        
         Ok(())
     }
 
     fn simpexpr(&mut self) -> ParseResult {
         print!("simpexpr->");
         if self.lx.current_token() == Some(C1Token::Minus){
-            self.check_and_eat_token(C1Token::Minus).unwrap();
+            self.check_and_eat_token(C1Token::Minus)?;
         }
-        self.term().unwrap();
+        self.term()?;
 
         while self.lx.current_token() == Some(C1Token::Plus) || self.lx.current_token() == Some(C1Token::Minus) || self.lx.current_token() == Some(C1Token::Or)  {
             self.lx.eat();
-            self.term().unwrap();
+            self.term()?;
         }
         Ok(())
     }
 
     fn term(&mut self) -> ParseResult {
         print!("term->");
-        self.factor().unwrap();
+        self.factor()?;
 
         while self.lx.current_token() == Some(C1Token::Asterisk) || self.lx.current_token() == Some(C1Token::Slash) || self.lx.current_token() == Some(C1Token::And) {
             self.lx.eat();
-            self.factor().unwrap();
+            self.factor()?;
         }
         Ok(())
     }
@@ -227,37 +216,32 @@ impl<'a> C1Parser<'a>  {
 
         match self.lx.current_token() {
             Some(C1Token::ConstInt) => {
-                self.check_and_eat_token(C1Token::ConstInt).unwrap();
-                Ok(())
+                self.check_and_eat_token(C1Token::ConstInt)
             },
             Some(C1Token::ConstFloat) => {
-                self.check_and_eat_token(C1Token::ConstFloat).unwrap();
-                Ok(())
+                self.check_and_eat_token(C1Token::ConstFloat)
             },
             Some(C1Token::ConstBoolean) => {
-                self.check_and_eat_token(C1Token::ConstBoolean).unwrap();
-                Ok(())
+                self.check_and_eat_token(C1Token::ConstBoolean)
             },
             Some(C1Token::Identifier) => {
 
                 if self.lx.peek_token() == Some(C1Token::LeftParenthesis) {
-                    self.functioncall().unwrap();
+                    return self.functioncall();
                 }else{
-                    self.check_and_eat_token(C1Token::Identifier).unwrap();
+                    return self.check_and_eat_token(C1Token::Identifier);
                 }
-
-                Ok(())
             },
             Some(C1Token::LeftParenthesis) => {
 
                 print!("factor left parenthesis->");
 
-                self.check_and_eat_token(C1Token::LeftParenthesis).unwrap();
-                self.assignment().unwrap();
-                self.check_and_eat_token(C1Token::RightParenthesis).unwrap();
+                self.check_and_eat_token(C1Token::LeftParenthesis)?;
+                self.assignment()?;
+                self.check_and_eat_token(C1Token::RightParenthesis)?;
                 Ok(())
             },
-            _ => Err(format!("Expected token group 'factor' but found {:?}", self.lx.current_token().unwrap())),
+            _ => Err(format!("Expected token group 'factor' in line {} but found {:?}", self.lx.current_line_number().unwrap(), self.lx.current_token().unwrap())),
         }
 
     }
@@ -267,7 +251,7 @@ impl<'a> C1Parser<'a>  {
         if self.lx.current_token() == Some(token) {
             Ok(())
         } else {
-            Err(format!("Expected token {:?}", token))
+            Err(format!("Expected token {:?} in line {}", token, self.lx.current_line_number().unwrap()))
         }
     }
 
@@ -281,7 +265,7 @@ impl<'a> C1Parser<'a>  {
                     return Ok(());
                 }
                 println!("Wrong: {:?}", x);
-                return Err(format!("Expected token {:?} but found {:?}", token, x));
+                return Err(format!("Expected token {:?} in line {} but found {:?}", token, self.lx.current_line_number().unwrap(), x));
             },
             None => Err("No token".to_owned()),
         }