lci/main.c

/** \mainpage lci Documentation
  *
  * \section license License
  *
  * lci - a LOLCODE interpreter written in C.
  * Copyright (C) 2010-2011 Justin J. Meza
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
  * the Free Software Foundation, either version 3 of the License, or
  * (at your option) any later version.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  *
  * \section maintainer Maintainer
  *
  * The lead maintainer for this project is Justin J. Meza (justin.meza@gmail.com).
  * For more information, check this project's webpage at http://icanhaslolcode.org .
  *
  * \section about About
  *
  * lci is a LOLCODE interpreter written in C and is designed to be correct,
  * portable, fast, and precisely documented.
  *
  *   - correct: Every effort has been made to test lci's conformance to the
  *              LOLCODE language specification. Unit tests come packaged with
  *              the lci source code.
  *   - portable: lci follows the widely ported ANSI C specification allowing it
  *               to compile on a broad range of systems.
  *   - fast: Much effort has gone into producing simple and efficient code
  *           whenever possible to the extent that the above points are not
  *           compromized.
  *   - precisely documented: lci uses Doxygen to generate literate code
  *                           documentation, browsable here.
  *
  * \section organization Organization
  *
  * lci employs several different modules which each perform a specific task
  * during interpretation of code:
  *
  *   - \b lexer (lexer.c, lexer.h)- The lexer takes an array of characters and
  *   splits it up into individual \e lexemes.  Lexemes are divided by
  *   whitespace and other rules of the language.
  *   - \b tokenizer (tokenizer.c, tokenizer.h) - The tokenizer takes the
  *   output of the lexer and converts it into individual \e tokens.  Tokens
  *   are different from lexemes in that a single token may be made up of
  *   multiple lexemes.  Also, the contents of some tokens are evaluated (such
  *   as integers and floats) for later use.
  *   - \b parser (parser.c, parser.h) - The parser takes the output of the
  *   tokenizer and analyzes it semantically to turn it into a parse tree.
  *   - \b interpreter (interpreter.c, interpreter.h) - The interpreter takes
  *   the output of the parser and executes it.
  *
  * Each of these modules is contained within its own C header and source code
  * files of the same name.
  *
  * To handle the conversion of Unicode code points and normative names to
  * bytes, two additional files, unicode.c and unicode.h are used.
  * 
  * Finally, main.c ties all of these modules together and handles the initial
  * loading of input data for the lexer. */

/** \page varscope Variable Scope
  *
  * The specification states that variables are local to the scope of the main
  * block or any function they are contained within--except for temporary loop
  * variables which are local to the loop they are instantiated within.  This
  * behavior, combined with the fact that variables must be declared before
  * being used, means that variables may not be shadowed in different control
  * scopes (such as loops and conditional statements) and, more importantly,
  * programmers must keep track of whether variables have been previously
  * declared within conditionally executed code (for example, under this
  * scoping if a variable is declared in a conditional block it cannot be
  * safely used in later code).
  *
  * One advantage of a flat scoping scheme is that nearly everything can be
  * stored in a single structure, making lookups faster.  However, I believe
  * that this advantage is not worth the extra frustration transferred to the
  * programmer and so scoping in lci is done in a similar manner to other
  * programming languages, to wit, within
  *   - the main block of code,
  *   - the body of functions,
  *   - the body of loop statements, and
  *   - the bodies of conditional statements.
  *
  * This should alleviate any confusion which may have been caused by using a
  * completely local free-for-all scope.  Also, there seems to be a general
  * consensus on the LOLCODE forums that this is the way to go and flat scoping
  * causes too many problems for the programmer. */

#include <stdio.h>
#include <stdlib.h>
#include <getopt.h>

#include "lexer.h"
#include "tokenizer.h"
#include "parser.h"
#include "interpreter.h"

#define READSIZE 512

static char *program_name;

static char *shortopt = "hv";
static struct option longopt[] = {
	{ "help", no_argument, NULL, (int)'h' },
	{ "version", no_argument, NULL, (int)'v' },
	{ 0, 0, 0, 0 }
};

static void help(void) {
	fprintf(stderr, "\
Usage: %s [FILE] ... \n\
Interpret FILE(s) as LOLCODE. Let FILE be '-' for stdin.\n\
  -h, --help\t\toutput this help\n\
  -v, --version\t\tprogram version\n", program_name);
}

static void version (char *revision) {
	fprintf(stderr, "%s %s\n", program_name, revision);
}

int main(int argc, char **argv)
{
	unsigned int size = 0;
	unsigned int length = 0;
	char *buffer = NULL;
	LexemeList *lexemes = NULL;
	Token **tokens = NULL;
	MainNode *node = NULL;
	char *fname = NULL;
	FILE *file = NULL;
	int ch;

	char *revision = "v0.10.1";
	program_name = argv[0];

	while ((ch = getopt_long(argc, argv, shortopt, longopt, NULL)) != -1) {
		switch (ch) {
			default:
				fprintf (stderr, "Incorrect option '%c'\n", ch);
				help();
				exit(EXIT_FAILURE);
			case 'h':
				help();
				exit(EXIT_SUCCESS);
			case 'v':
				version(revision);
				exit(EXIT_SUCCESS);
		}
	}

	for (; optind < argc; optind++) {
		size = length = 0;
		buffer = fname = NULL;
		lexemes = NULL;
		tokens = NULL;
		node = NULL;
		file = NULL;

		if (!strncmp (argv[optind],"-\0",2)) {
			file = stdin;
			fname = "stdin";
		}
		else {
			file = fopen(argv[optind], "r");
			fname = argv[optind];
		}

		if (!file) {
			fprintf(stderr, "File does not exist.\n");
			return 1;
		}

		while (!feof(file)) {
			size += READSIZE;
			buffer = realloc(buffer, sizeof(char) * size);
			length += fread((buffer + size) - READSIZE, 1, READSIZE, file);
		}

		if (fclose(file) != 0) {
			fprintf(stderr, "Error closing file.\n");
			if (buffer) free(buffer);
			return 1;
		}
		if (!buffer) return 1;
		buffer[length] = '\0';

		/* Remove hash bang line if run as a standalone script */
		if (buffer[0] == '#' && buffer[1] == '!') {
			unsigned int n;
			for (n = 0; buffer[n] != '\n' && buffer[n] != '\r'; n++)
				buffer[n] = ' ';
		}

		/* Remove UTF-8 BOM if present and add it to the output stream (we
		 * assume here that if a BOM is present, the system will also expect
		 * the output to include a BOM). */
		if (buffer[0] == (char)0xef
				|| buffer[1] == (char)0xbb
				|| buffer[2] == (char)0xbf) {
			buffer[0] = ' ';
			buffer[1] = ' ';
			buffer[2] = ' ';
			printf("%c%c%c", 0xef, 0xbb, 0xbf);
		}

		/* Begin main pipeline */
		if (!(lexemes = scanBuffer(buffer, length, fname))) {
			free(buffer);
			return 1;
		}
		free(buffer);
		if (!(tokens = tokenizeLexemes(lexemes))) {
			deleteLexemeList(lexemes);
			return 1;
		}
		deleteLexemeList(lexemes);
		if (!(node = parseMainNode(tokens))) {
			deleteTokens(tokens);
			return 1;
		}
		deleteTokens(tokens);
		if (interpretMainNode(node)) {
			deleteMainNode(node);
			return 1;
		}
		deleteMainNode(node);
		/* End main pipeline */

	}

	return 0;
}