From 9e6c89f1fa93287104381e02f0bbbdd6060a9382 Mon Sep 17 00:00:00 2001
From: AidenRushbrooke <72034940+AidenRushbrooke@users.noreply.github.com>
Date: Sun, 5 Dec 2021 03:27:18 +0000
Subject: Added subroutines and comments for most files

---
 src/Compiler/Translator.java | 197 +++++++++++++++++++++++++++++++++++++++----
 1 file changed, 182 insertions(+), 15 deletions(-)

(limited to 'src/Compiler/Translator.java')

diff --git a/src/Compiler/Translator.java b/src/Compiler/Translator.java
index e0bff23..d520b67 100644
--- a/src/Compiler/Translator.java
+++ b/src/Compiler/Translator.java
@@ -6,16 +6,25 @@ import java.util.List;
 import Compiler.Expression.*;
 import Compiler.Statement.*;
 
-
+/**
+ * Class to take a convert a list of statements into equivalent C source code
+ */
 public class Translator{
 
     List<String> CCode = new ArrayList<>();
     private Environment environment = new Environment();
 
-
+    /**
+     * Method to take a list of statements and convert to C code
+     * @param statements a list of statement objects
+     * @param printC a variable to say if the produced C code should be outputted
+     * @return a list of strings for each line of the produced C code
+     */
     public List<String> compileToC(List<Statement> statements, boolean printC){
+        //Write basic include header files
         CCode.add("#include <stdio.h>");
         CCode.add("#include <string.h>");
+        //Try and write each statement, with a space between each
         try{
             for (Statement statement: statements){
                 evaluateStatement(statement);
@@ -25,6 +34,7 @@ public class Translator{
 
         }
 
+        //Output the C code if desired
         if (printC) {
             for(String t:CCode){
                 System.out.println(t);
@@ -34,7 +44,12 @@ public class Translator{
         return CCode; 
     }
 
+    /**
+     * Method to write a single statement to C
+     * @param statement the statement to write to C
+     */
     private void evaluateStatement(Statement statement){
+        //Call the correct function for each statement type
         switch(statement.getStatmentType()){
             case "main":
                 evalMainFunction((MainFunction)statement);
@@ -78,40 +93,76 @@ public class Translator{
         }
     } 
 
+    /**
+     * Method to write the main function
+     * @param stmt statement to write
+     */
     private void evalMainFunction(MainFunction stmt){
         CCode.add("int main(){");
         evaluateStatement(stmt.block);
         CCode.add("}");
     }
 
+    /**
+     * Method to write a function
+     * @param stmt statement to write
+     */
     private void evalFunction(Function stmt){
-
-        String functionString = stmt.returnType+" "+stmt.name.text+"(";
+        String functionString;
+        if(!(stmt.returnType==null)){
+            functionString = stmt.returnType+" "+stmt.name.text+"(";
+        }else{
+            functionString = "void "+stmt.name.text+"(";
+        }
         boolean first=true;
+        //Write each function argument into C
         for(int i=0;i<stmt.arguments.size();i++){
             if(!first){
                 functionString+=",";
             }
-            environment.defineVariable(evaluateExpression(stmt.arguments.get(i)), stmt.argumentTypes.get(i));
-            functionString+=stmt.argumentTypes.get(i)+" "+evaluateExpression(stmt.arguments.get(i));
+            String type = stmt.argumentTypes.get(i);
+            Expression arg = stmt.arguments.get(i);
+
+            //Define each argument variable in the environment
+            if(type.equals("char*")){
+                environment.defineVariable(evaluateExpression(arg), "string");
+            }else{
+                environment.defineVariable(evaluateExpression(arg), type);
+            }
+
+            functionString+=type+" "+evaluateExpression(arg);
             first=false;
         }
         functionString+="){";
+
+        //Write function block
         CCode.add(functionString);
         evaluateStatement(stmt.block);
         CCode.add("}");
     }
 
+    /**
+     * Method to write a return statement
+     * @param stmt statement to write
+     */
     private void evalReturnStatement(ReturnStatement stmt){
         CCode.add("return "+evaluateExpression(stmt.returnValue)+";");
-
-        
     }
 
+    /**
+     * Method to write a function declaration
+     * @param stmt statement to write
+     */
     private void evalFunctionDeclaration(FunctionDeclaration stmt){
-
-        String functionString = stmt.returnType+" "+stmt.name.text+"(";
+        String functionString;
+        if(!(stmt.returnType==null)){
+            functionString = stmt.returnType+" "+stmt.name.text+"(";
+        }else{
+            functionString = "void "+stmt.name.text+"(";
+        }
         boolean first=true;
+
+        //Write each argument data type
         for(int i=0;i<stmt.argumentTypes.size();i++){
             if(!first){
                 functionString+=",";
@@ -120,22 +171,42 @@ public class Translator{
             first=false;
         }
         functionString+=");";
+
         CCode.add(functionString);
     }
 
+    /**
+     * Method to write an expression statement
+     * @param stmt statement to write
+     */
     private void evalExpressionStatement(ExpressionStatement stmt){
-        evaluateExpression(stmt.expr);
+        String value = evaluateExpression(stmt.expr);
+        CCode.add(value+";");
     }
 
+    /**
+     * Method to write a string declaration statement
+     * @param stringdec statement to write
+     */
     private void evalStringDeclaration(StringDeclaration stringdec){
+        //Add variable to the environment
         environment.defineVariable(stringdec.name.text, "string");
+
+        //Get the size of the string
         int size = (int)((Expression.Literal)stringdec.length).value.value;
+        //Increase the size of the string by 1 to match C code correctly
         size++;
         CCode.add("char "+stringdec.name.text+"["+size+"];");
     }
 
+    /**
+     * Method to write a variable declaration
+     * @param vardec statement to write
+     */
     private void evalVariableDeclaration(VariableDeclaration vardec){
+        //Add variable to the environment
         environment.defineVariable(vardec.name.text, vardec.type);
+        //Write correct data type
         if(vardec.type.equals("int")){
             CCode.add("int "+vardec.name.text+";");
         } else if(vardec.type.equals("real")){
@@ -143,8 +214,15 @@ public class Translator{
         } 
     }
 
+    /**
+     * Method to write an array declaration
+     * @param arraydec statement to write
+     */
     private void evalArrayDeclaration(ArrayDeclaration arraydec){
+        //Add variable to the environment
         environment.defineVariable(arraydec.name.text, arraydec.type);
+
+        //Get the array data type
         String arrayString = "";
         if(arraydec.type.equals("int")){
             arrayString+="int ";
@@ -152,6 +230,8 @@ public class Translator{
             arrayString+="real ";
         } 
         arrayString+=arraydec.name.text;
+
+        //Write each dimension of the array
         for(Expression expr:arraydec.dimensions){
             arrayString+="[";
             arrayString+=evaluateExpression(expr);
@@ -163,23 +243,36 @@ public class Translator{
         
     }
 
+    /**
+     * Method to write a block statement
+     * @param block statement to write
+     */
     private void evalBlockStatement(BlockStatement block){
+        //Write each statement in the block
         for(Statement stmt:block.statements){
             evaluateStatement(stmt);
         }
     }
 
+    /**
+     * Method to write a print statement
+     * @param print statement to write
+     */
     private void evalPrintStatement(PrintStatement print){
         String types="";
         String values="";
         boolean first=true;
+
+        //Write each expression in the print statement
         for(Expression expr:print.exprList){
+            //Don't add a comma for the first value in the print statement
             if(!first){
                 values+=",";
             }else{
                 first=false;
             }
             String exprType="";
+            //Get the data type for each expression
             if(expr instanceof Expression.Literal){
                 exprType=((Expression.Literal)expr).type;
             }
@@ -189,6 +282,8 @@ public class Translator{
             else if (expr instanceof Expression.ArrayVariable){
                 exprType=(String)environment.getVariable((((Expression.ArrayVariable)expr).name));
             }
+
+            //Set the correct data type for the print statement
             if (exprType.equals("int")){
                 types+="%d";
             } else if (exprType.equals("double")){
@@ -196,16 +291,24 @@ public class Translator{
             } else if (exprType.equals("string")){
                 types+="%s";
             }
+            //Add the actual expression value
             values+=evaluateExpression(expr);
         }
+        //Add a line break at the end of the print statement text
         types+="\\n";
         CCode.add("printf(\""+types+"\","+values+");");  
     }
 
+    /**
+     * Method to write an if statement
+     * @param ifstatement statement to write
+     */
     private void evalIfStatement(IfStatement ifstatement){
-        
+        //Write if statement block
         CCode.add("if("+evaluateExpression(ifstatement.condition)+"){");
         evaluateStatement(ifstatement.ifBlock);
+        
+        //Write else block if needed
         if(!(ifstatement.elseBlock==null)){
             CCode.add("}");
             CCode.add("else {");
@@ -214,24 +317,43 @@ public class Translator{
         CCode.add("}");
     }
 
+    /**
+     * Method to write a do statement
+     * @param dostatement statement to write
+     */
     private void evalDoStatement(DoStatement dostatement){
+        //Form the sections of the for loop, assuming the step variable has not been defined
         String start = evaluateExpression(dostatement.variable)+"="+evaluateExpression(dostatement.start);
         String stop = evaluateExpression(dostatement.variable)+"<="+evaluateExpression(dostatement.stop);
         String step = evaluateExpression(dostatement.variable)+"++";
+
+        //Update step variable if needed
         if(!(dostatement.step==null)){
             step = evaluateExpression(dostatement.variable)+"+="+evaluateExpression(dostatement.step);
         }
+    
         CCode.add("for("+start+";"+stop+";"+step+"){");
         evaluateStatement(dostatement.codeBlock);
         CCode.add("}");
     }
 
+    /**
+     * Method to write a do while loop
+     * @param dowhilestatement statement to write
+     */
     private void evalDoWhileStatement(DoWhileStatement dowhilestatement){
         CCode.add("while("+evaluateExpression(dowhilestatement.condition)+"){");
         evaluateStatement(dowhilestatement.codeBlock);
         CCode.add("}");
     }
 
+    /**
+     * Method to write the correct expression object to C
+     * Since an expression is not a full line, the string is returned
+     * Except for assignment expressions
+     * @param expression the expression to write
+     * @return the string representation of an expression
+     */
     private String evaluateExpression(Expression expression){
         switch(expression.getExpressionType()){
             case "binary":
@@ -243,6 +365,7 @@ public class Translator{
             case "bracket":
                 return evaluateBracketedExpression((BracketedExpression)expression);
             case "assign":
+                //Assignments are full lines, so no need to return the string
                 evaluateAssignmentExpression((AssignmentExpression)expression);
                 return "";
             case "arrayvar":
@@ -256,6 +379,11 @@ public class Translator{
         }
     }
 
+    /**
+     * Method to write a binary expression
+     * @param expr the expression to write
+     * @return the string representation of the expression
+     */
     private String evaluateBinaryExpression(Binary expr){
         switch (expr.op.type){
             case PLUS:
@@ -288,6 +416,11 @@ public class Translator{
         return null;
     }
 
+    /**
+     * Method to write a singular expression
+     * @param expr the expression to write
+     * @return the string representation of the expression
+     */
     private String evaluateSingularExpression(Singular expr){
         switch (expr.op.type){
             case NOT:
@@ -298,24 +431,42 @@ public class Translator{
         return null;
     }
 
+    /**
+     * Method to write a literal expression
+     * @param expr the expression to write
+     * @return the string representation of the expression
+     */
     private String evaluateLiteralExpression(Literal expr){
         return (expr.value.value).toString();
     }
 
+    /**
+     * Method to write a bracketed expression
+     * @param expr the expression to write
+     * @return the string representation of the expression
+     */
     private String evaluateBracketedExpression(BracketedExpression expr){
         return "("+evaluateExpression(expr.expr)+")";
     }
 
+    /**
+     * Method to write an assignment expression
+     * @param expr the expression to write
+     */
     private void evaluateAssignmentExpression(AssignmentExpression expr){
         Token name=null;
+        //Get the name of the variable being assigned to
         if(expr.variable instanceof Expression.Variable){
             name = ((Expression.Variable)expr.variable).name;
         }
         else if(expr.variable instanceof Expression.ArrayVariable){
             name = ((Expression.ArrayVariable)expr.variable).name;
         }
+        //Check if the variable has been previously declared
         if(environment.checkVariable(name)){
+            //Check if the value being assigned is a literal or some other expression
             if(expr.value instanceof Expression.Literal){
+                //Strings are handled differently in C, so the string has to be copied into the variable
                 if(((Expression.Literal)expr.value).type.equals("string")){
                     CCode.add("strcpy("+evaluateExpression(expr.variable)+","+evaluateExpression(expr.value)+");");
                 }else{
@@ -328,10 +479,17 @@ public class Translator{
         }
     }
 
+    /**
+     * Method to write an array variable
+     * @param expr the expression to write
+     * @return the string representation of the expression
+     */
     private String evaluateArrayVariable(ArrayVariable expr){
+        //Check the array has been defined
         if(environment.checkVariable(expr.name)){
             String arrayString="";
             arrayString+=expr.name.text;
+            //Write each dimension value
             for(Expression position:expr.positions){
                 arrayString+="[";
                 arrayString+=evaluateExpression(position);
@@ -342,14 +500,26 @@ public class Translator{
         return null;
     }
 
+    /**
+     * Method to write a variable expression
+     * @param expr the expression to write
+     * @return the string representation of the expression
+     */
     private String evaluateVariableExpression(Variable expr){
         return expr.name.text;
     }
 
+    /**
+     * Method to write a function call
+     * @param expr the expression to write
+     * @return the string representation of the expression
+     */
     private String evaluateFunctionCall(FunctionCall expr){
         String functioncall="";
         functioncall+=expr.name.text+"(";
         boolean first=true;
+
+        //Write each argument of the function call
         for(Token arg:expr.arguments){
             if(!first){
                 functioncall+=",";
@@ -360,9 +530,6 @@ public class Translator{
         functioncall+=")";
         return functioncall;
     }
-
-
-
 }
 
 
-- 
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