Two Pass Macro Processor

Problem Statement: Write a program to implement 2 pass Macro Processor

Solution:

import java.util.*;
import java.io.*;
class twopassmacro
{
 static String mnt[][]=new String[5][3]; //assuming 5 macros in 1 program
 static String ala[][]=new String[10][2]; //assuming 2 arguments in each macro
 static String mdt[][]=new String[20][1]; //assuming 4 LOC for each macro
 static int mntc=0,mdtc=0,alac=0;
 public static void main(String args[])
 {
 pass1();
 System.out.println("Macro Name Table(MNT)");
 display(mnt,mntc,3);
 System.out.println("Argument List Array(ALA) for Pass1");
 display(ala,alac,2);
 System.out.println("Macro Definition Table(MDT)");
 display(mdt,mdtc,1);
 pass2();
 System.out.println("Argument List Array(ALA) for Pass2");
 display(ala,alac,2);
 System.out.println("Note:All tables are displayed here whereas intermediate pass1 output & expanded pass2 output is stored in files");
 }
 static void pass1()
 {
 int index=0,i;
 String s,prev="",substring;
 try
 {
 BufferedReader inp = new BufferedReader(new FileReader("input.txt"));
 File op = new File("pass1_output.txt");
 if (!op.exists())
 op.createNewFile();
 BufferedWriter output = new BufferedWriter(new FileWriter(op.getAbsoluteFile()));
 while((s=inp.readLine())!=null)
 {
 if(s.equalsIgnoreCase("MACRO"))
 {
 prev=s;
 for(;!(s=inp.readLine()).equalsIgnoreCase("MEND");mdtc++,prev=s)
 {
 if(prev.equalsIgnoreCase("MACRO"))
 {
 StringTokenizer st=new StringTokenizer(s);
 String str[]=new String[st.countTokens()];
 for(i=0;i<str.length;i++)
 str[i]=st.nextToken();
 mnt[mntc][0]=(mntc+1)+""; //mnt formation
 mnt[mntc][1]=str[0];
 mnt[mntc++][2]=(++mdtc)+"";
 st=new StringTokenizer(str[1],","); //tokenizing the arguments
 String string[]=new String[st.countTokens()];
 for(i=0;i<string.length;i++)
 {
 string[i]=st.nextToken();
 ala[alac][0]=alac+""; //ala table formation
 index=string[i].indexOf("=");
 if(index!=-1)
 ala[alac++][1]=string[i].substring(0,index);
 else
 ala[alac++][1]=string[i];
 }
 }
 else //automatically eliminates tagging of arguments in definition
 { //mdt formation
 index=s.indexOf("&");
 substring=s.substring(index);
 for(i=0;i<alac;i++)
 if(ala[i][1].equals(substring))
 s=s.replaceAll(substring,"#"+ala[i][0]);
 }
 mdt[mdtc-1][0]=s;
 }
 mdt[mdtc-1][0]=s;
 }
 else
 {
 output.write(s);
 output.newLine();
 }
 }
 output.close();
 }
 catch(FileNotFoundException ex)
 {
 System.out.println("Unable to find file ");
 }
 catch(IOException e)
 {
 e.printStackTrace(); 
 }
 }
 static void pass2()
 {
 int alap=0,index,mdtp,flag=0,i,j;
 String s,temp;
 try
 {
 BufferedReader inp = new BufferedReader(new FileReader("pass1_output.txt"));
 File op = new File("pass2_output.txt");
 if (!op.exists())
 op.createNewFile();
 BufferedWriter output = new BufferedWriter(new FileWriter(op.getAbsoluteFile()));
 for(;(s=inp.readLine())!=null;flag=0)
 {
 StringTokenizer st=new StringTokenizer(s);
 String str[]=new String[st.countTokens()];
 for(i=0;i<str.length;i++)
 str[i]=st.nextToken();
 for(j=0;j<mntc;j++)
 {
 if(str[0].equals(mnt[j][1]))
 {
 mdtp=Integer.parseInt(mnt[j][2]);
 st=new StringTokenizer(str[1],",");
 String arg[]=new String[st.countTokens()];
 for(i=0;i<arg.length;i++)
 {
 arg[i]=st.nextToken();
 ala[alap++][1]=arg[i];
 }
 for(i=mdtp;!(mdt[i][0].equalsIgnoreCase("MEND"));i++) //expand till MEND
 {
 index=mdt[i][0].indexOf("#");
 temp=mdt[i][0].substring(0,index);
 temp+=ala[Integer.parseInt(""+mdt[i][0].charAt(index+1))][1]; //converting char->string->integer & appending it
 output.write(temp);
 output.newLine();
 }
 flag=1;
 }
 }
 if(flag==0) //when it is not a macro
 {
 output.write(s);
 output.newLine();
 }
 }
 output.close();
 }
 catch(FileNotFoundException ex)
 {
 System.out.println("Unable to find file ");
 }
 catch(IOException e)
 {
 e.printStackTrace();
 } 
 }
 static void display(String a[][],int n,int m)
 {
 int i,j;
 for(i=0;i<n;i++)
 {
 for(j=0;j<m;j++)
 System.out.print(a[i][j]+" ");
 System.out.println();
 }
 }
}

 

Input:

MACRO
INCR1 &FIRST,&SECOND=DATA9
A 1,&FIRST
L 2,&SECOND
MEND
MACRO
INCR2 &ARG1,&ARG2=DATA5
L 3,&ARG1
ST 4,&ARG2
MEND
PRG2 START
 USING *,BASE
 INCR1 DATA1,DATA2
 INCR2 DATA3,DATA4
FOUR DC F'4'
FIVE DC F'5'
BASE EQU 8
TEMP DS 1F
 DROP 8
 END

 

Output:

Intermediate Pass 1 Output:

PRG2 START
 USING *,BASE
 INCR1 DATA1,DATA2
 INCR2 DATA3,DATA4
FOUR DC F'4'
FIVE DC F'5'
BASE EQU 8
TEMP DS 1F
 DROP 8
 END

 

Expanded Pass 2 Output:

PRG2 START
 USING *,BASE
A 1,DATA1
L 2,DATA2
L 3,DATA3
ST 4,DATA4
FOUR DC F'4'
FIVE DC F'5'
BASE EQU 8
TEMP DS 1F
 DROP 8
 END