Python/pythonmain.c

/* Python interpreter main program */

#include "allobjects.h"

#include "grammar.h"
#include "node.h"
#include "parsetok.h"
#include "graminit.h"
#include "errcode.h"
#include "sysmodule.h"
#include "compile.h"
#include "ceval.h"
#include "pythonrun.h"
#include "import.h"

extern char *getpythonpath();

extern grammar gram; /* From graminit.c */

#ifdef DEBUG
int debugging; /* Needed by parser.c */
#endif

main(argc, argv)
	int argc;
	char **argv;
{
	char *filename = NULL;
	FILE *fp = stdin;
	
	initargs(&argc, &argv);
	
	if (argc > 1 && strcmp(argv[1], "-") != 0)
		filename = argv[1];
	
	if (filename != NULL) {
		if ((fp = fopen(filename, "r")) == NULL) {
			fprintf(stderr, "python: can't open file '%s'\n",
				filename);
			exit(2);
		}
	}
	
	initall();
	
	setpythonpath(getpythonpath());
	setpythonargv(argc-1, argv+1);
	
	goaway(run(fp, filename == NULL ? "<stdin>" : filename));
	/*NOTREACHED*/
}

/* Initialize all */

void
initall()
{
	static int inited;
	
	if (inited)
		return;
	inited = 1;
	
	initimport();
	
	/* Modules 'builtin' and 'sys' are initialized here,
	   they are needed by random bits of the interpreter.
	   All other modules are optional and should be initialized
	   by the initcalls() of a specific configuration. */
	
	initbuiltin(); /* Also initializes builtin exceptions */
	initsys();
	
	initcalls(); /* Configuration-dependent initializations */
	
	initintr(); /* For intrcheck() */
}

/* Parse input from a file and execute it */

int
run(fp, filename)
	FILE *fp;
	char *filename;
{
	if (filename == NULL)
		filename = "???";
	if (isatty(fileno(fp)))
		return run_tty_loop(fp, filename);
	else
		return run_script(fp, filename);
}

int
run_tty_loop(fp, filename)
	FILE *fp;
	char *filename;
{
	object *v;
	int ret;
	v = sysget("ps1");
	if (v == NULL) {
		sysset("ps1", v = newstringobject(">>> "));
		XDECREF(v);
	}
	v = sysget("ps2");
	if (v == NULL) {
		sysset("ps2", v = newstringobject("... "));
		XDECREF(v);
	}
	for (;;) {
		ret = run_tty_1(fp, filename);
#ifdef REF_DEBUG
		fprintf(stderr, "[%ld refs]\n", ref_total);
#endif
		if (ret == E_EOF)
			return 0;
		/*
		if (ret == E_NOMEM)
			return -1;
		*/
	}
}

int
run_tty_1(fp, filename)
	FILE *fp;
	char *filename;
{
	object *m, *d, *v, *w;
	node *n;
	char *ps1, *ps2;
	int err;
	v = sysget("ps1");
	w = sysget("ps2");
	if (v != NULL && is_stringobject(v)) {
		INCREF(v);
		ps1 = getstringvalue(v);
	}
	else {
		v = NULL;
		ps1 = "";
	}
	if (w != NULL && is_stringobject(w)) {
		INCREF(w);
		ps2 = getstringvalue(w);
	}
	else {
		w = NULL;
		ps2 = "";
	}
	err = parsefile(fp, filename, &gram, single_input, ps1, ps2, &n);
	XDECREF(v);
	XDECREF(w);
	if (err == E_EOF)
		return E_EOF;
	if (err != E_DONE) {
		err_input(err);
		print_error();
		return err;
	}
	m = add_module("__main__");
	if (m == NULL)
		return -1;
	d = getmoduledict(m);
	v = run_node(n, filename, d, d);
	flushline();
	if (v == NULL) {
		print_error();
		return -1;
	}
	DECREF(v);
	return 0;
}

int
run_script(fp, filename)
	FILE *fp;
	char *filename;
{
	object *m, *d, *v;
	m = add_module("__main__");
	if (m == NULL)
		return -1;
	d = getmoduledict(m);
	v = run_file(fp, filename, file_input, d, d);
	flushline();
	if (v == NULL) {
		print_error();
		return -1;
	}
	DECREF(v);
	return 0;
}

void
print_error()
{
	object *exception, *v;
	err_get(&exception, &v);
	fprintf(stderr, "Unhandled exception: ");
	printobject(exception, stderr, PRINT_RAW);
	if (v != NULL && v != None) {
		fprintf(stderr, ": ");
		printobject(v, stderr, PRINT_RAW);
	}
	fprintf(stderr, "\n");
	XDECREF(exception);
	XDECREF(v);
	printtraceback(stderr);
}

object *
run_string(str, start, globals, locals)
	char *str;
	int start;
	/*dict*/object *globals, *locals;
{
	node *n;
	int err;
	err = parse_string(str, start, &n);
	return run_err_node(err, n, "<string>", globals, locals);
}

object *
run_file(fp, filename, start, globals, locals)
	FILE *fp;
	char *filename;
	int start;
	/*dict*/object *globals, *locals;
{
	node *n;
	int err;
	err = parse_file(fp, filename, start, &n);
	return run_err_node(err, n, filename, globals, locals);
}

object *
run_err_node(err, n, filename, globals, locals)
	int err;
	node *n;
	char *filename;
	/*dict*/object *globals, *locals;
{
	if (err != E_DONE) {
		err_input(err);
		return NULL;
	}
	return run_node(n, filename, globals, locals);
}

object *
run_node(n, filename, globals, locals)
	node *n;
	char *filename;
	/*dict*/object *globals, *locals;
{
	if (globals == NULL) {
		globals = getglobals();
		if (locals == NULL)
			locals = getlocals();
	}
	else {
		if (locals == NULL)
			locals = globals;
	}
	return eval_node(n, filename, globals, locals);
}

object *
eval_node(n, filename, globals, locals)
	node *n;
	char *filename;
	object *globals;
	object *locals;
{
	codeobject *co;
	object *v;
	co = compile(n, filename);
	freetree(n);
	if (co == NULL)
		return NULL;
	v = eval_code(co, globals, locals, (object *)NULL);
	DECREF(co);
	return v;
}

/* Simplified interface to parsefile */

int
parse_file(fp, filename, start, n_ret)
	FILE *fp;
	char *filename;
	int start;
	node **n_ret;
{
	return parsefile(fp, filename, &gram, start,
				(char *)0, (char *)0, n_ret);
}

/* Simplified interface to parsestring */

int
parse_string(str, start, n_ret)
	char *str;
	int start;
	node **n_ret;
{
	int err = parsestring(str, &gram, start, n_ret);
	/* Don't confuse early end of string with early end of input */
	if (err == E_EOF)
		err = E_SYNTAX;
	return err;
}

/* Print fatal error message and abort */

void
fatal(msg)
	char *msg;
{
	fprintf(stderr, "Fatal error: %s\n", msg);
	abort();
}

/* Clean up and exit */

void
goaway(sts)
	int sts;
{
	flushline();
	
	/* XXX Call doneimport() before donecalls(), since donecalls()
	   calls wdone(), and doneimport() may close windows */
	doneimport();
	donecalls();
	
	err_clear();

#ifdef REF_DEBUG
	fprintf(stderr, "[%ld refs]\n", ref_total);
#endif

#ifdef THINK_C_3_0
	if (sts == 0)
		Click_On(0);
#endif

#ifdef TRACE_REFS
	if (askyesno("Print left references?")) {
#ifdef THINK_C_3_0
		Click_On(1);
#endif
		printrefs(stderr);
	}
#endif /* TRACE_REFS */

	exit(sts);
	/*NOTREACHED*/
}

static
finaloutput()
{
#ifdef TRACE_REFS
	if (!askyesno("Print left references?"))
		return;
#ifdef THINK_C_3_0
	Click_On(1);
#endif
	printrefs(stderr);
#endif /* TRACE_REFS */
}

/* Ask a yes/no question */

static int
askyesno(prompt)
	char *prompt;
{
	char buf[256];
	
	printf("%s [ny] ", prompt);
	if (fgets(buf, sizeof buf, stdin) == NULL)
		return 0;
	return buf[0] == 'y' || buf[0] == 'Y';
}

#ifdef THINK_C_3_0

/* Check for file descriptor connected to interactive device.
   Pretend that stdin is always interactive, other files never. */

int
isatty(fd)
	int fd;
{
	return fd == fileno(stdin);
}

#endif

/*	XXX WISH LIST

	- possible new types:
		- iterator (for range, keys, ...)
	- improve interpreter error handling, e.g., true tracebacks
	- save precompiled modules on file?
	- fork threads, locking
	- allow syntax extensions
*/

/* "Floccinaucinihilipilification" */