Added support for strings and improved print statement syntax

1 files changed, 47 insertions, 13 deletions

diff --git a/src/Compiler/Parser.java b/src/Compiler/Parser.java
index 68851bf..7eb22df 100644
--- a/src/Compiler/Parser.java
+++ b/src/Compiler/Parser.java
@@ -28,19 +28,37 @@ public class Parser {
     //Clean up and reduce code mess
     private Statement declaration(){
         if (matchAndAdvance(TokenType.INT)){
-            if (matchOrError(TokenType.DEFINE, ":: Required for variable definition")){
-                if (matchOrError(TokenType.IDENTIFIER,"Expected variable name.")){
-                    Token varName = getPreviousToken();
-                    return new Statement.VariableDeclaration(varName,"int");
-                } 
-            }
+            matchOrError(TokenType.DEFINE, ":: Required for variable definition");
+            matchOrError(TokenType.IDENTIFIER,"Expected variable name.");
+            Token varName = getPreviousToken();
+            return new Statement.VariableDeclaration(varName,"int");
         } else if (matchAndAdvance(TokenType.REAL)){
-            if (matchOrError(TokenType.DEFINE, ":: Required for variable definition")){
-                if (matchOrError(TokenType.IDENTIFIER,"Expected variable name.")){
-                    Token varName = getPreviousToken();
-                    return new Statement.VariableDeclaration(varName,"real");
-                } 
+            matchOrError(TokenType.DEFINE, ":: Required for variable definition");
+            matchOrError(TokenType.IDENTIFIER,"Expected variable name.");
+            Token varName = getPreviousToken();
+            return new Statement.VariableDeclaration(varName,"real");
+        
+        //Could be improved significatly when verifiying length is a positive integer
+        } else if (matchAndAdvance(TokenType.STRING)){
+            matchOrError(TokenType.LEFT_PAREN, "Length of string must be defined");
+            matchOrError(TokenType.LEN, "Length of string must be defined");
+            matchOrError(TokenType.EQUALS, "Length of string must be defined");
+            Expression length = expression();
+            if(!(length instanceof Expression.Literal)){
+                throw error("String length must be a number");
+            }
+            if(!((Expression.Literal)length).type.equals("int")){
+                throw error("String length must be a integer"); 
             }
+            if((int)((Expression.Literal)length).value.value<1){
+                throw error("String length must be greater then 0"); 
+            }
+            matchOrError(TokenType.RIGHT_PAREN, "Length of string must be defined");
+
+            matchOrError(TokenType.DEFINE, ":: Required for variable definition");
+            matchOrError(TokenType.IDENTIFIER,"Expected variable name.");
+            Token varName = getPreviousToken();
+            return new Statement.StringDeclaration(varName,length);
         }
         
         return statement();
@@ -48,8 +66,7 @@ public class Parser {
 
     private Statement statement(){
         if (matchAndAdvance(TokenType.PRINT)){
-            Expression expression = expression();
-            return new Statement.PrintStatement(expression);
+            return printStatement();
         }else if (matchAndAdvance(TokenType.IF)){
             Statement statement = ifStatement();
             return statement;
@@ -57,6 +74,20 @@ public class Parser {
         return expressionStatement();
     }
 
+    private Statement printStatement(){
+        matchOrError(TokenType.STAR, "Syntax, print *, item1, item2...");
+        List<Expression> exprList = new ArrayList<>();
+        while(!matchAndAdvance(TokenType.ENDPRINT)){
+            if(checkEOF()){
+                throw error("Missing close parentheses");
+            }
+            matchOrError(TokenType.COMMA, "Print items must be seperated by ,");
+            Expression expr = expression();
+            exprList.add(expr);
+        }
+        return new Statement.PrintStatement(exprList);
+    }
+
     //Could be cleaned up to handle else statements better
     private Statement ifStatement(){
         Expression condition = expression();
@@ -155,6 +186,9 @@ public class Parser {
                 return new Expression.Literal(getPreviousToken(),"double");
             }
         }
+        if (matchAndAdvance(TokenType.STRING)){
+            return new Expression.Literal(getPreviousToken(), "string");
+        }
 
         if (matchAndAdvance(TokenType.IDENTIFIER)) {