luqian2017 / software-tools-in-c

C/C++ source code for Software Tools in Pascal by Kernighan and Plauger

Software Tools in C/C++

C/C++ source code for Software Tools in Pascal by Kernighan and Plauger, 1981.

This repository consists of two parts:

1. A customized Pascal-to-C converter written in Java using ANTLR4, located in p2c/
2. Rewrite of the tools in C, in cpp/

The converted code is mostly C, but use a tiny bit of C++11 syntax like passing-by-reference for Pascal's Variable_parameter, and using for type aliases.

To run the first part,

make convert

and check Pascal and C++ code in orig/

To run the second part,

make tests

which builds C++ code in cpp/ to binaries in bin/ and run some tests written in Python.

Example:

Original Pascal code of orig/intro/wordcount.p:

{ Copyright (C) 1981 by Bell Laboratories, Inc., and Whitesmiths Ltd. }
{ wordcount -- count words in standard input }
procedure wordcount;
var
    nw : integer;
    c : character;
    inword : boolean;
begin
    nw := 0;
    inword := false;
    while (getc(c) <> ENDFILE) do
        if (c = BLANK) or (c = NEWLINE) or (c = TAB) then
            inword := false
        else if (not inword) then begin
            inword := true;
            nw := nw + 1
        end;
    putdec(nw, 1);
    putc(NEWLINE)
end;

Converted literally to C++ in orig/intro/wordcount.cc:

// Copyright (C) 1981 by Bell Laboratories, Inc., and Whitesmiths Ltd.
#include "../p2c.h"
#include "intro.h"

// wordcount -- count words in standard input
void wordcount()
{
    integer nw;
    character c;
    boolean inword;

    nw = 0;
    inword = false;
    while (getc(c) != ENDFILE)
        if ((c == BLANK) or (c == NEWLINE) or (c == TAB))
            inword = false;
        else if (not inword) {
            inword = true;
            nw = nw + 1;
        }
    putdec(nw, 1);
    putc(NEWLINE);
}

Rewrite in C as cpp/intro/wordcount.cc:

#include <ctype.h>
#include <stdio.h>

int main()
{
    size_t nw = 0;
    bool inword = false;
    int c;

    while ( (c = getchar()) != EOF)
        if (isspace(c))
            inword = false;
        else if (!inword) {
            inword = true;
            ++nw;
        }

    printf("%zd\n", nw);
}

Progress

1. The p2c converter is almost done.
2. The following directories has been made working:
   • intro/ from Chapter 1, mostly rewritten.
   • filters/ from Chapter 2, only rewrote echo.
   • translit/ from Chapter 2, with original code.