/* 
 * man2tcl.c --
 *
 *	This file contains a program that turns a man page of the
 *	form used for Tcl and Tk into a Tcl script that invokes
 *	a Tcl command for each construct in the man page.  The
 *	script can then be eval'ed to translate the manual entry
 *	into some other format such as MIF or HTML.
 *
 * Usage:
 *
 *	man2tcl ?fileName?
 *
 * Copyright (c) 1995 Sun Microsystems, Inc.
 *
 * See the file "license.terms" for information on usage and redistribution
 * of this file, and for a DISCLAIMER OF ALL WARRANTIES.
 *
 * RCS: @(#) Id
 */

static char sccsid[] = "@(#) man2tcl.c 1.3 95/08/12 17:34:08";

#include <stdio.h>
#include <string.h>
#include <ctype.h>
#ifndef NO_ERRNO_H
#include <errno.h>
#endif

/*
 * Imported things that aren't defined in header files:
 */

extern int errno;

/*
 * Current line number, used for error messages.
 */

static int lineNumber;

/*
 * The variable below is set to 1 if an error occurs anywhere
 * while reading in the file.
 */

static int status;

/*
 * The variable below is set to 1 if output should be generated.
 * If it's 0, it means we're doing a pre-pass to make sure that
 * the file can be properly parsed.
 */

static int writeOutput;

/*
 * Prototypes for procedures defined in this file:
 */

static void		DoMacro(char *line);
static void		DoText(char *line);
static void		QuoteText(char *string, int count);

/*
 *----------------------------------------------------------------------
 *
 * main --
 *
 *	This procedure is the main program, which does all of the work
 *	of the program.
 *
 * Results:
 *	None: exits with a 0 return status to indicate success, or
 *	1 to indicate that there were problems in the translation.
 *
 * Side effects:
 *	A Tcl script is output to standard output.  Error messages may
 *	be output on standard error.
 *
 *----------------------------------------------------------------------
 */

int
main(argc, argv)
    int argc;			/* Number of command-line arguments. */
    char **argv;		/* Values of command-line arguments. */
{
    FILE *f;
#define MAX_LINE_SIZE 1000
    char line[MAX_LINE_SIZE];
    char *p;

    /*
     * Find the file to read, and open it if it isn't stdin.
     */

    if (argc == 1) {
	f = stdin;
    } else if (argc == 2) {
	f = fopen(argv[1], "r");
	if (f == NULL) {
	    fprintf(stderr, "Couldn't read \"%s\": %s\n", argv[1],
		    strerror(errno));
	    exit(1);
	}
    } else {
	fprintf(stderr, "Usage: %s ?fileName?\n", argv[0]);
    }

    /*
     * Make two passes over the file.  In the first pass, just check
     * to make sure we can handle everything.  If there are problems,
     * generate output and stop.  If everything is OK, make a second
     * pass to actually generate output.
     */

    for (writeOutput = 0; writeOutput < 2; writeOutput++) {
	lineNumber = 0;
	status = 0;
	while (fgets(line, MAX_LINE_SIZE, f) != NULL) {
	    for (p = line; *p != 0; p++) {
		if (*p == '\n') {
		    *p = 0;
		    break;
		}
	    }
	    lineNumber++;
    
	    if ((line[0] == '\'') && (line[1] == '\\') && (line[2] == '\"')) {
		/* 
		 * This line is a comment.  Ignore it.
		 */
    
		continue;
	    }
    
	    if (strlen(line) >= MAX_LINE_SIZE -1) {
		fprintf(stderr, "Too long line. Max is %d chars.\n",
			MAX_LINE_SIZE - 1);
		exit(1);
	    }

	    if ((line[0] == '.') || (line[0] == '\'')) {
		/*
		 * This line is a macro invocation.
		 */
    
		DoMacro(line);
	    } else {
		/*
		 * This line is text, possibly with formatting characters
		 * embedded in it.
		 */
    
		DoText(line);
	    }
	}
	if (status != 0) {
	    break;
	}
	fseek(f, 0, SEEK_SET);
    }
    exit(status);
}

/*
 *----------------------------------------------------------------------
 *
 * DoMacro --
 *
 *	This procedure is called to handle a macro invocation.
 *	It parses the arguments to the macro and generates a
 *	Tcl command to handle the invocation.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	A Tcl command is written to stdout.
 *
 *----------------------------------------------------------------------
 */

static void
DoMacro(line)
    char *line;			/* The line of text that contains the
				 * macro invocation. */
{
    char *p, *end;

    /*
     * If there is no macro name, then just skip the whole line.
     */

    if ((line[1] == 0) || (isspace(line[1]))) {
	return;
    }

    if (writeOutput) {
	printf("macro");
    }
    if (*line != '.') {
	if (writeOutput) {
	    printf("2");
	}
    }

    /*
     * Parse the arguments to the macro (including the name), in order.
     */

    p = line+1;
    while (1) {
	if (writeOutput) {
	    putc(' ', stdout);
	}
	if (*p == '"')  {
	    /*
	     * The argument is delimited by quotes.
	     */

	    for (end = p+1; *end != '"'; end++) {
		if (*end == 0) {
		    fprintf(stderr,
			"Unclosed quote in macro call on line %d.\n",
			lineNumber);
		    status = 1;
		    break;
		}
	    }
	    QuoteText(p+1, (end-(p+1)));
	} else {
	    for (end = p+1;  (*end != 0) && !isspace(*end); end++) {
		/* Empty loop body. */
	    }
	    QuoteText(p, end-p);
	}
	if (*end == 0) {
	    break;
	}
	p = end+1;
	while (isspace(*p)) {
	    /*
	     * Skip empty space before next argument.
	     */

	    p++;
	}
	if (*p == 0) {
	    break;
	}
    }
    if (writeOutput) {
	putc('\n', stdout);
    }
}

/*
 *----------------------------------------------------------------------
 *
 * DoText --
 *
 *	This procedure is called to handle a line of troff text.
 *	It parses the text, generating Tcl commands for text and
 *	for formatting stuff such as font changes.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Tcl commands are written to stdout.
 *
 *----------------------------------------------------------------------
 */

static void
DoText(line)
    char *line;			/* The line of text. */
{
    char *p, *end;

    /*
     * Divide the line up into pieces consisting of backslash sequences,
     * tabs, and other text.
     */

    p = line;
    while (*p != 0) {
	if (*p == '\t') {
	    if (writeOutput) {
		printf("tab\n");
	    }
	    p++;
	} else if (*p != '\\') {
	    /*
	     * Ordinary text.
	     */

	    for (end = p+1; (*end != '\\') && (*end != 0); end++) {
		/* Empty loop body. */
	    }
	    if (writeOutput) {
		printf("text ");
	    }
	    QuoteText(p, end-p);
	    if (writeOutput) {
		putc('\n', stdout);
	    }
	    p = end;
	} else {
	    /*
	     * A backslash sequence.  There are particular ones
	     * that we understand;  output an error message for
	     * anything else and just ignore the backslash.
	     */

	    p++;
	    if (*p == 'f') {
		/*
		 * Font change.
		 */

		if (writeOutput) {
		    printf("font %c\n", p[1]);
		}
		p += 2;
	    } else if (*p == '-') {
		if (writeOutput) {
		    printf("dash\n");
		}
		p++;
	    } else if (*p == 'e') {
		if (writeOutput) {
		    printf("text \\\\\n");
		}
		p++;
	    } else if (*p == '.') {
		if (writeOutput) {
		    printf("text .\n");
		}
		p++;
	    } else if (*p == '&') {
		p++;
	    } else if (*p == '(') {
		if ((p[1] == 0) || (p[2] == 0)) {
		    fprintf(stderr, "Bad \\( sequence on line %d.\n",
			    lineNumber);
		    status = 1;
		} else {
		    if (writeOutput) {
			printf("char {\\(%c%c}\n", p[1], p[2]);
		    }
		    p += 3;
		}
	    } else if (*p != 0) {
		if (writeOutput) {
		    printf("char {\\%c}\n", *p);
		}
		p++;
	    }
	}
    }
    if (writeOutput) {
	printf("newline\n");
    }
}

/*
 *----------------------------------------------------------------------
 *
 * QuoteText --
 *
 *	Copy the "string" argument to stdout, adding quote characters
 *	around any special Tcl characters so that they'll just be treated
 *	as ordinary text.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Text is written to stdout.
 *
 *----------------------------------------------------------------------
 */

static void
QuoteText(string, count)
    char *string;		/* The line of text. */
    int count;			/* Number of characters to write from string. */
{
    if (count == 0) {
	if (writeOutput) {
	    printf("{}");
	}
	return;
    }
    for ( ; count > 0; string++, count--) {
	if ((*string == '$') || (*string == '[') || (*string == '{')
		|| (*string == ' ') || (*string == ';') || (*string == '\\')
		|| (*string == '"') || (*string == '\t')) {
	    if (writeOutput) {
		putc('\\', stdout);
	    }
	}
	if (writeOutput) {
	    putc(*string, stdout);
	}
    }
}
