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Path: utzoo!mnetor!seismo!nbires!hao!hplabs!hpcea!hpccc!hpl-opus!walker
From: walker@hpl-opus.HP.COM (Rick Walker)
Newsgroups: net.micro
Subject: Re: pascal-->C translator
Message-ID: <1590001@hpl-opus.HP.COM>
Date: Mon, 8-Sep-86 15:59:48 EDT
Article-I.D.: hpl-opus.1590001
Posted: Mon Sep  8 15:59:48 1986
Date-Received: Wed, 10-Sep-86 01:34:53 EDT
References: <3544@brl-smoke.ARPA>
Organization: HP Labs, Instrument Tech. Dept.
Lines: 207

Bruce,

I am interested in any responses that you get to your
request for pascal to c conversion.  I would like to 
convert the public domain "software tools" from pascal
to c.  I am including a crude program which simply substitutes
for some common keywords and operators. The source file is
pretty clear so you should be able to modify it pretty easily.

To do the job right would probably require the use of lex
and yacc to parse the pascal grammar and emit c equivalents.

good luck, 
Rick Walker

cut here --------------------------------------------------
/* Pascal to C - filter to replace Pascal punctuation and and certain key words 
with their C equivalents 

derived from a similar program (see _Byte_, February 1985) which did a C to
Pascal conversion.
   

   C form           Pascal form
   ------           -----------
    "               '
    {               BEGIN
    }               END;
    <tab>           <2 blanks>
    ()              <nothing>
    &&              AND
    ||              OR
    Comment start   {
    Comment end     }
    ==              =
    !=              <>
    =               :=
    printf          writeln
    scanf           readln
    while           WHILE
 
   Usage: p2c < infile >outfile
*/

#include "ctype.h"

#define EOF -1
#define EOS  0

main ()
{
char    c,
       *letter,
        word[100];
int     wordlnth;

    letter = word;
    wordlnth = 0;
    while ((c = getchar ()) != EOF)
    {
	if (isalpha (c))
	    letter[wordlnth++] = c;
	else
	{
	    if (wordlnth > 0)
	    {			/* word ready to check */
		letter[wordlnth] = '\0';
		wtest (word);	/* pass or replace it */
		wordlnth = 0;	/* reset index */
	    } ctest (c);	/* process following char */
	}
    }
}			/* Note: the lastword in the file will be missed if it
			   is immediately followed by EOF with no intervening
			   nonalphanumeric character. This is not a problem
			   for Pascal or C program sources.  However, a
			   general purpose word filter would have to check for
			   a non-zero wordlength after EOF is reached */

wtest (word)
char   *word;
{
char   *swapword;
    swapword = word;
    switch (word[0])
    {				/* test first letter, then rest of word */
	case 'w': 
	    if (strncmp (word, "writeln", 7) == 0)
		swapword = "printf";
	    break;
	case 'W': 
	    if (strncmp (word, "WHILE", 5) == 0)
		swapword = "while";
	    break;
	case 'r': 
	    if (strncmp (word, "readln", 6) == 0)
		swapword = "scanf";
	    break;
	case 'b': 
	    if (strncmp (word, "begin", 5) == 0)
		swapword = "{";
	    break;
	case 'B': 
	    if (strncmp (word, "BEGIN", 5) == 0)
		swapword = "{";
	    break;
	case 'E': 
	    if (strncmp (word, "END", 4) == 0)
		swapword = "}";
	    break;
	case 'e': 
	    if (strncmp (word, "end", 4) == 0)
		swapword = "}";
	    break;
	case 'A':
	    if (strncmp (word, "AND", 3) == 0)
		swapword = "&&";
	    break;
	case 'a':
	    if (strncmp (word, "and", 3) == 0)
		swapword = "&&";
	    break;
	case 'O': 
	    if (strncmp (word, "OR", 2) == 0)
		swapword = "||";
	    break;
	case 'o': 
	    if (strncmp (word, "or", 2) == 0)
		swapword = "||";
	    break;
	case 'd': 
	    if (strncmp (word, "do", 2) == 0)
		swapword = "";
	    break;
	case 'D': 
	    if (strncmp (word, "DO", 2) == 0)
		swapword = "";
	    break;
	case 'n': 
	    if (strncmp (word, "not", 3) == 0)
		swapword = "!";
	    break;
	case 't': 
	    if (strncmp (word, "then", 4) == 0)
		swapword = "";
	    break;
	default: 
	    break;		/* pass unchanged */
    } swap (swapword);
}

ctest (c)
char    c;
{
    switch (c)
    {
	case '\'': 
	    putchar ('"');
	    break;
	case '{': 
		swap ("/*");
	    break; /* fix comments */
	case '}': 
	    swap ("*/");
	    break; /* fix comments */
	case ':': 
	    swapif (':', '=', "=");
	    break; /* replace := with = */
	case '<': 
	    swapif ('<', '>', "!=");
	    break; /* replace <> with != */
	case '=': 
	    swapif ('=', ' ', "==");
	    break; /* replace = with == */	
	case '(': 
	    swapif ('(', '*', "/*");
	    break; /* fix comments */
	case '*': 
	    swapif ('*', ')', "*/");
	    break; /* fix comments */
	default: 
	    putchar (c);
	    break;
    }
}

swap (s)
char   *s;
{
    while (*s != EOS)
	putchar (*s++);
}

swapif (first, second, replacement)
char    first,
        second,
        *replacement;
{
char    c;
    if ((c = getchar ()) == second)
	swap (replacement);
    else
    {
	putchar (first);
	putchar (c);
    }
}