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ubasic.c
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/*
* Copyright (c) 2006, Adam Dunkels
* All rights reserved.
*
* Copyright (c) 2015, Alan Cox
* All rights reserved.
*
* Copyright (c) 2018, TK Chia
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the author nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
*/
#define DEBUG 0
#if DEBUG
#define DEBUG_PRINTF(...) printf(__VA_ARGS__)
#else
#define DEBUG_PRINTF(...)
#endif
#include <stdio.h> /* printf() */
#include <stdlib.h> /* exit() */
#include <stdint.h> /* Types */
#include <string.h>
#include <time.h>
#include <ctype.h>
#include <unistd.h>
#include "ubasic.h"
#include "tokenizer.h"
static char const *program_ptr;
#define MAX_GOSUB_STACK_DEPTH 10
static char const *gosub_stack[MAX_GOSUB_STACK_DEPTH];
static int gosub_stack_ptr;
struct for_state {
char const *resume_token; /* Token to resume execution at */
var_t for_variable;
value_t to;
value_t step;
};
#define MAX_FOR_STACK_DEPTH 4
static struct for_state for_stack[MAX_FOR_STACK_DEPTH];
static int for_stack_ptr;
struct line_index {
line_t line_number;
char const *program_text_position;
struct line_index *next;
};
struct line_index *line_index_head = NULL;
struct line_index *line_index_current = NULL;
#define MAX_VARNUM 26 * 11
#define MAX_SUBSCRIPT 2
#define MAX_STRING 26
#define MAX_ARRAY 26
static value_t variables[MAX_VARNUM];
static uint8_t *vararrays[MAX_ARRAY]; /* Could union with variables FIXME ?*/
static value_t variablesubs[MAX_ARRAY];
static value_t vardim[MAX_ARRAY][MAX_SUBSCRIPT];
static uint8_t *strings[MAX_STRING];
static value_t stringsubs[MAX_STRING];
static value_t stringdim[MAX_STRING][MAX_SUBSCRIPT];
static uint8_t nullstr[1] = { 0 };
static int ended;
static void expr(struct typevalue *val);
static void line_statements(void);
static void statements(void);
static uint8_t statementgroup(void);
static uint8_t statement(void);
static void index_free(void);
line_t line_num;
static const char *data_position;
static int data_seek;
static unsigned int array_base = 0;
#if defined(__linux__) || defined(__ia16__)
const char *_itoa(int v)
{
static char buf[16];
snprintf(buf, 16, "%d", v);
return buf;
}
const char *_uitoa(int v)
{
static char buf[16];
snprintf(buf, 16, "%u", v);
return buf;
}
#endif
/*---------------------------------------------------------------------------*/
void ubasic_init(const char *program)
{
int i;
program_ptr = program;
for_stack_ptr = gosub_stack_ptr = 0;
index_free();
tokenizer_init(program);
data_position = program_ptr;
data_seek = 1;
ended = 0;
for (i = 0; i < MAX_STRING; i++)
strings[i] = nullstr;
}
/*---------------------------------------------------------------------------*/
void ubasic_error(const char *err)
{
const char *p;
write(2, "\n", 1);
if (line_num) {
p = _uitoa(line_num);
write(2, p, strlen(p));
write(2, ": ", 2);
}
write(2, err, strlen(err));
write(2, " error.\n", 8);
exit(1);
}
static const char syntax[] = { "Syntax" };
static const char badtype[] = { "Type mismatch" };
static const char divzero[] = { "Division by zero" };
static const char outofmemory[] = { "Out of memory" };
static const char badsubscript[] = { "Subscript" };
static const char redimension[] = { "Redimension" };
static void syntax_error(void)
{
ubasic_error(syntax);
}
/* Call back from the tokenizer on error */
void ubasic_tokenizer_error(void)
{
syntax_error();
}
/*---------------------------------------------------------------------------*/
static uint8_t accept_tok(uint8_t token)
{
if(token != current_token) {
DEBUG_PRINTF("Token not what was expected (expected %d, got %d)\n",
token, current_token);
tokenizer_error_print();
exit(1);
}
DEBUG_PRINTF("Expected %d, got it\n", token);
tokenizer_next();
/* This saves lots of extra calls - return the new token */
return current_token;
}
/*---------------------------------------------------------------------------*/
static uint8_t accept_either(uint8_t tok1, uint8_t tok2)
{
uint8_t t = current_token;
if (t == tok2)
accept_tok(tok2);
else
accept_tok(tok1);
return t;
}
/*---------------------------------------------------------------------------*/
static int statement_end(void)
{
uint8_t t = current_token;
/* FIXME?? END OF FILE */
if (t == TOKENIZER_NL || t == TOKENIZER_COLON)
return 1;
return 0;
}
/*---------------------------------------------------------------------------*/
static void bracketed_expr(struct typevalue *v)
{
accept_tok(TOKENIZER_LEFTPAREN);
expr(v);
accept_tok(TOKENIZER_RIGHTPAREN);
}
/*---------------------------------------------------------------------------*/
static void typecheck_int(struct typevalue *v)
{
if (v->type != TYPE_INTEGER)
ubasic_error(badtype);
}
/*---------------------------------------------------------------------------*/
static void typecheck_string(struct typevalue *v)
{
if (v->type != TYPE_STRING)
ubasic_error(badtype);
}
/*---------------------------------------------------------------------------*/
static void typecheck_same(struct typevalue *l, struct typevalue *r)
{
if (l->type != r->type)
ubasic_error(badtype);
}
/*---------------------------------------------------------------------------*/
static void range_check(struct typevalue *v, value_t top)
{
typecheck_int(v);
if (v->d.i > top || v->d.i < array_base)
ubasic_error(badsubscript);
}
/*---------------------------------------------------------------------------*/
/* Temoporary implementation of string workspaces */
static uint8_t stringblob[512];
static uint8_t *nextstr;
static uint8_t *string_temp(int len)
{
uint8_t *p = nextstr;
if (len > 255)
ubasic_error("String too long");
nextstr += len + 1;
if (nextstr > stringblob + sizeof(stringblob))
ubasic_error("Out of temporary space");
*p = len;
return p;
}
/*---------------------------------------------------------------------------*/
static void string_temp_free(void)
{
nextstr = stringblob;
}
/*---------------------------------------------------------------------------*/
static void string_cut(struct typevalue *o, struct typevalue *t, value_t l, value_t n)
{
uint8_t *p = t->d.p;
int f = *p;
/* Strings start at 1 ... */
if (l > f) /* Nothing to cut */
o->d.p = string_temp(0);
else {
f -= l - 1;
if (f < n)
n = f;
o->d.p = string_temp(n);
memcpy(o->d.p+1, p + l, n);
}
o->type = TYPE_STRING;
}
/*---------------------------------------------------------------------------*/
static void string_cut_r(struct typevalue *o, struct typevalue *t, value_t r)
{
int f = *t->d.p;
f -= r;
if (f <= 0) {
o->d.p = string_temp(0);
o->type = TYPE_STRING;
} else
string_cut(o, t, f + 1, r);
}
/*---------------------------------------------------------------------------*/
static value_t string_val(struct typevalue *t)
{
uint8_t *p = t->d.p;
uint8_t l = *p++;
uint8_t neg = 0;
value_t n = 0;
if (*p == '-') {
neg = 1;
p++;
l--;
}
if (l == 0)
ubasic_error(badtype);
while(l) {
if (!isdigit(*p))
ubasic_error(badtype);
n = 10 * n + *p++ - '0';
l--;
}
return neg ? -n : n;
}
/*---------------------------------------------------------------------------*/
static value_t bracketed_intexpr(void)
{
struct typevalue v;
bracketed_expr(&v);
typecheck_int(&v);
return v.d.i;
}
/*---------------------------------------------------------------------------*/
static void funcexpr(struct typevalue *t, const char *f)
{
accept_tok(TOKENIZER_LEFTPAREN);
while(*f) {
expr(t);
if (*f != t->type)
ubasic_error(badtype);
if (*++f)
accept_tok(TOKENIZER_COMMA);
t++;
}
accept_tok(TOKENIZER_RIGHTPAREN);
}
/*---------------------------------------------------------------------------*/
static int parse_subscripts(struct typevalue *v)
{
accept_tok(TOKENIZER_LEFTPAREN);
expr(v);
if (accept_either(TOKENIZER_COMMA, TOKENIZER_RIGHTPAREN) == TOKENIZER_COMMA) {
expr(++v);
accept_tok(TOKENIZER_RIGHTPAREN);
return 2;
}
return 1;
}
/*---------------------------------------------------------------------------*/
static void varfactor(struct typevalue *v)
{
var_t var = tokenizer_variable_num();
struct typevalue s[MAX_SUBSCRIPT];
int n = 0;
/* Sinclair style A$(2 TO 5) would also need to be parsed here if added */
accept_either(TOKENIZER_INTVAR, TOKENIZER_STRINGVAR);
if (current_token == TOKENIZER_LEFTPAREN)
n = parse_subscripts(s);
ubasic_get_variable(var, v, n, s);
DEBUG_PRINTF("varfactor: obtaining %d from variable %d\n", v->d.i, tokenizer_variable_num());
}
/*---------------------------------------------------------------------------*/
static void factor(struct typevalue *v)
{
uint8_t t = current_token;
int len;
struct typevalue arg[3];
DEBUG_PRINTF("factor: token %d\n", current_token);
switch(t) {
case TOKENIZER_STRING:
v->type = TYPE_STRING;
len = tokenizer_string_len();
v->d.p = string_temp(len);
memcpy(v->d.p + 1, tokenizer_string(), len);
DEBUG_PRINTF("factor: string %p\n", v->d.p);
accept_tok(TOKENIZER_STRING);
break;
case TOKENIZER_NUMBER:
v->d.i = tokenizer_num();
v->type = TYPE_INTEGER;
DEBUG_PRINTF("factor: number %d\n", v->d.i);
accept_tok(TOKENIZER_NUMBER);
break;
case TOKENIZER_LEFTPAREN:
accept_tok(TOKENIZER_LEFTPAREN);
expr(v);
accept_tok(TOKENIZER_RIGHTPAREN);
break;
case TOKENIZER_INTVAR:
case TOKENIZER_STRINGVAR:
varfactor(v);
break;
default:
if (TOKENIZER_NUMEXP(t)) {
accept_tok(t);
switch(t) {
case TOKENIZER_PEEK:
funcexpr(arg,"I");
v->d.i = peek_function(arg[0].d.i);
break;
case TOKENIZER_ABS:
funcexpr(arg,"I");
v->d.i = arg[0].d.i;
if (v->d.i < 0)
v->d.i = -v->d.i;
break;
case TOKENIZER_INT:
funcexpr(arg,"I");
v->d.i = arg[0].d.i;
break;
case TOKENIZER_SGN:
funcexpr(arg,"I");
v->d.i = arg[0].d.i;
if (v->d.i > 1 ) v->d.i = 1;
if (v->d.i < 0) v->d.i = -1;
break;
case TOKENIZER_LEN:
funcexpr(arg,"S");
v->d.i = *arg[0].d.p;
break;
case TOKENIZER_CODE:
funcexpr(arg,"S");
if (*arg[0].d.p)
v->d.i = arg[0].d.p[1];
else
v->d.i = 0;
break;
case TOKENIZER_VAL:
funcexpr(arg,"S");
v->d.i = string_val(&arg[0]);
break;
default:
syntax_error();
}
v->type = TYPE_INTEGER;
}
else if (TOKENIZER_STRINGEXP(t)) {
accept_tok(t);
switch(t) {
case TOKENIZER_LEFTSTR:
funcexpr(arg, "SI");
string_cut(v, &arg[0], 1, arg[1].d.i);
break;
case TOKENIZER_RIGHTSTR:
funcexpr(arg, "SI");
string_cut_r(v, &arg[0], arg[1].d.i);
break;
case TOKENIZER_MIDSTR:
funcexpr(arg, "SII");
string_cut(v, &arg[0], arg[1].d.i, arg[2].d.i);
break;
case TOKENIZER_CHRSTR:
funcexpr(arg, "I");
v->d.p = string_temp(2);
v->d.p[1] = arg[0].d.i;
v->type = TYPE_STRING;
break;
default:
syntax_error();
}
}
else
syntax_error();
}
}
/*---------------------------------------------------------------------------*/
static void term(struct typevalue *v)
{
struct typevalue f2;
int op;
factor(v);
op = current_token;
DEBUG_PRINTF("term: token %d\n", op);
while(op == TOKENIZER_ASTR ||
op == TOKENIZER_SLASH ||
op == TOKENIZER_MOD) {
tokenizer_next();
factor(&f2);
typecheck_int(v);
typecheck_int(&f2);
DEBUG_PRINTF("term: %d %d %d\n", v->d.i, op, f2.d.i);
switch(op) {
case TOKENIZER_ASTR:
v->d.i *= f2.d.i;
break;
case TOKENIZER_SLASH:
if (f2.d.i == 0)
ubasic_error(divzero);
v->d.i /= f2.d.i;
break;
case TOKENIZER_MOD:
if (f2.d.i == 0)
ubasic_error(divzero);
v->d.i %= f2.d.i;
break;
}
op = current_token;
}
DEBUG_PRINTF("term: %d\n", v->d.i);
}
/*---------------------------------------------------------------------------*/
static void mathexpr(struct typevalue *v)
{
struct typevalue t2;
int op;
term(v);
op = current_token;
DEBUG_PRINTF("mathexpr: token %d\n", op);
while(op == TOKENIZER_PLUS ||
op == TOKENIZER_MINUS ||
op == TOKENIZER_BAND ||
op == TOKENIZER_BOR) {
tokenizer_next();
term(&t2);
if (op != TOKENIZER_PLUS)
typecheck_int(v);
typecheck_same(v, &t2);
DEBUG_PRINTF("mathexpr: %d %d %d\n", v->d.i, op, t2.d.i);
switch(op) {
case TOKENIZER_PLUS:
if (v->type == TYPE_INTEGER)
v->d.i += t2.d.i;
else {
uint8_t *p;
uint8_t l = *v->d.p;
p = string_temp(l + *t2.d.p);
memcpy(p + 1, v->d.p + 1, l);
memcpy(p + l + 1, t2.d.p + 1, *t2.d.p);
v->d.p = p;
}
break;
case TOKENIZER_MINUS:
v->d.i -= t2.d.i;
break;
case TOKENIZER_BAND:
v->d.i &= t2.d.i;
break;
case TOKENIZER_BOR:
v->d.i |= t2.d.i;
break;
}
op = current_token;
}
DEBUG_PRINTF("mathexpr: %d\n", v->d.i);
}
/*---------------------------------------------------------------------------*/
static void relation(struct typevalue *r1)
{
struct typevalue r2;
int op;
mathexpr(r1);
op = current_token;
DEBUG_PRINTF("relation: token %d\n", op);
/* FIXME: unclear the while is correct here. It's not correct in most
BASIC to write A > B > C, rather relations should be two part linked
with logic */
while(op == TOKENIZER_LT ||
op == TOKENIZER_GT ||
op == TOKENIZER_EQ ||
op == TOKENIZER_NE ||
op == TOKENIZER_LE ||
op == TOKENIZER_GE) {
tokenizer_next();
mathexpr(&r2);
typecheck_same(r1, &r2);
DEBUG_PRINTF("relation: %d %d %d\n", r1->d.i, op, r2.d.i);
if (r1->type == TYPE_INTEGER) {
switch(op) {
case TOKENIZER_LT:
r1->d.i = r1->d.i < r2.d.i;
break;
case TOKENIZER_GT:
r1->d.i = r1->d.i > r2.d.i;
break;
case TOKENIZER_EQ:
r1->d.i = r1->d.i == r2.d.i;
break;
case TOKENIZER_LE:
r1->d.i = r1->d.i <= r2.d.i;
break;
case TOKENIZER_GE:
r1->d.i = r1->d.i >= r2.d.i;
break;
case TOKENIZER_NE:
r1->d.i = r1->d.i != r2.d.i;
break;
}
} else {
int n =*r1->d.p;
if (*r2.d.p < n)
n = *r2.d.p;
n = memcmp(r1->d.p + 1, r2.d.p + 1, n);
if (n == 0) {
if (*r1->d.p > *r2.d.p)
n = 1;
else if (*r1->d.p < *r2.d.p)
n = -1;
}
switch(op) {
case TOKENIZER_LT:
n = (n == -1);
break;
case TOKENIZER_GT:
n = (n == 1);
break;
case TOKENIZER_EQ:
n = (n == 0);
break;
case TOKENIZER_LE:
n = (n != 1);
break;
case TOKENIZER_GE:
n = (n != -1);
break;
case TOKENIZER_NE:
n = (n != 0);
break;
}
r1->d.i = n;
}
op = current_token;
r1->type = TYPE_INTEGER;
}
}
/*---------------------------------------------------------------------------*/
static void expr(struct typevalue *r1)
{
struct typevalue r2;
int op;
relation(r1);
op = current_token;
DEBUG_PRINTF("logicrelation: token %d\n", op);
/* FIXME: unclear the while is correct here. It's not correct in most
BASIC to write A > B > C, rather relations should be two part linked
with logic */
while(op == TOKENIZER_AND ||
op == TOKENIZER_OR) {
tokenizer_next();
relation(&r2);
/* No type checks needed on relations */
DEBUG_PRINTF("logicrelation: %d %d %d\n", r1->d.i, op, r2.d.i);
switch(op) {
case TOKENIZER_AND:
r1->d.i = r1->d.i & r2.d.i;
break;
case TOKENIZER_OR:
r1->d.i = r1->d.i | r2.d.i;
break;
}
op = current_token;
r1->type = TYPE_INTEGER;
}
}
/*---------------------------------------------------------------------------*/
static value_t intexpr(void)
{
struct typevalue t;
expr(&t);
typecheck_int(&t);
return t.d.i;
}
/*---------------------------------------------------------------------------*/
static uint8_t *stringexpr(void)
{
struct typevalue t;
expr(&t);
typecheck_string(&t);
return t.d.p;
}
/*---------------------------------------------------------------------------*/
static void index_free(void) {
if(line_index_head != NULL) {
line_index_current = line_index_head;
do {
DEBUG_PRINTF("Freeing index for line %p.\n", (void *)line_index_current);
line_index_head = line_index_current;
line_index_current = line_index_current->next;
free(line_index_head);
} while (line_index_current != NULL);
line_index_head = NULL;
}
}
/*---------------------------------------------------------------------------*/
static char const *index_find(int linenum) {
#if DEBUG
int step = 0;
#endif
struct line_index *lidx;
lidx = line_index_head;
while(lidx != NULL && lidx->line_number != linenum) {
lidx = lidx->next;
#if DEBUG
if(lidx != NULL) {
DEBUG_PRINTF("index_find: Step %3d. Found index for line %d: %p.\n",
step, lidx->line_number,
lidx->program_text_position);
}
step++;
#endif
}
if(lidx != NULL && lidx->line_number == linenum) {
DEBUG_PRINTF("index_find: Returning index for line %d.\n", linenum);
return lidx->program_text_position;
}
DEBUG_PRINTF("index_find: Returning NULL.\n");
return NULL;
}
/*---------------------------------------------------------------------------*/
static void index_add(int linenum, char const* sourcepos) {
struct line_index *new_lidx;
if(line_index_head != NULL && index_find(linenum)) {
return;
}
new_lidx = malloc(sizeof(struct line_index));
new_lidx->line_number = linenum;
new_lidx->program_text_position = sourcepos;
new_lidx->next = NULL;
if(line_index_head != NULL) {
line_index_current->next = new_lidx;
line_index_current = line_index_current->next;
} else {
line_index_current = new_lidx;
line_index_head = line_index_current;
}
DEBUG_PRINTF("index_add: Adding index for line %d: %p.\n", linenum,
sourcepos);
}
/*---------------------------------------------------------------------------*/
static void
jump_linenum_slow(int linenum)
{
tokenizer_init(program_ptr);
while(tokenizer_num() != linenum) {
do {
do {
tokenizer_next();
} while(current_token != TOKENIZER_NL &&
current_token != TOKENIZER_ENDOFINPUT);
if(current_token == TOKENIZER_NL) {
tokenizer_next();
}
} while(current_token != TOKENIZER_NUMBER);
DEBUG_PRINTF("jump_linenum_slow: Found line %d\n", tokenizer_num());
}
}
/*---------------------------------------------------------------------------*/
static void
jump_linenum(int linenum)
{
char const* pos = index_find(linenum);
if(pos != NULL) {
DEBUG_PRINTF("jump_linenum: Going to line %d.\n", linenum);
tokenizer_goto(pos);
} else {
/* We'll try to find a yet-unindexed line to jump to. */
DEBUG_PRINTF("jump_linenum: Calling jump_linenum_slow %d.\n", linenum);
jump_linenum_slow(linenum);
}
}
/*---------------------------------------------------------------------------*/
static void go_statement(void)
{
int linenum;
uint8_t t;
t = accept_either(TOKENIZER_TO, TOKENIZER_SUB);
if (t == TOKENIZER_TO) {
linenum = intexpr();
DEBUG_PRINTF("go_statement: go to %d.\n", linenum);
if (!statement_end())
syntax_error();
DEBUG_PRINTF("go_statement: jumping.\n");
jump_linenum(linenum);
return;
}
linenum = intexpr();
if (!statement_end())
syntax_error();
if(gosub_stack_ptr < MAX_GOSUB_STACK_DEPTH) {
gosub_stack[gosub_stack_ptr] = tokenizer_pos();
gosub_stack_ptr++;
jump_linenum(linenum);
} else {
DEBUG_PRINTF("gosub_statement: gosub stack exhausted\n");
ubasic_error("Return without gosub");
}
}
/*---------------------------------------------------------------------------*/
static int chpos = 0;
static void charout(char c, void *unused)
{
#ifdef __ia16__
static char cr = '\r';
#endif
if (c == '\t') {
do {
charout(' ', NULL);
} while(chpos%8);
return;
}
#ifdef __ia16__
if (c == '\n')
write(1, &cr, 1);
#endif
/* FIMXE: line buffer ! */
write(1, &c, 1);
if ((c == 8 || c== 127) && chpos)
chpos--;
else if (c == '\r' || c == '\n')
chpos = 0;
else
chpos++;
}
static void charreset(void)
{
chpos = 0;
}
static void chartab(value_t v)
{
if (v < 1)
v = 1;
if (chpos >= v)
charout('\n', NULL);
while(chpos < v - 1)
charout(' ', NULL);
}
static void charoutstr(uint8_t *p)
{
int len =*p++;
while(len--)
charout(*p++, NULL);
}
static void intout(value_t v)
{
const char *p = _itoa(v);
while(*p)
charout(*p++, NULL);
}
static void print_statement(void)
{
uint8_t nonl;
uint8_t t;
uint8_t nv = 0;
do {
t = current_token;
nonl = 0;
DEBUG_PRINTF("Print loop\n");
if (nv == 0) {
if(t == TOKENIZER_STRING) {
/* Handle string const specially - length rules */
tokenizer_string_func(charout, NULL);
tokenizer_next();
nv = 1;
continue;
} else if(TOKENIZER_STRINGEXP(t)) {
charoutstr(stringexpr());
nv = 1;
continue;
} else if(TOKENIZER_NUMEXP(t)) {
intout(intexpr());
nv = 1;
continue;
} else if(t == TOKENIZER_TAB) {
nv = 1;
accept_tok(TOKENIZER_TAB);
chartab(bracketed_intexpr());
continue;
} else if(t == TOKENIZER_AT) {
int x,y;
nv = 1;
accept_tok(TOKENIZER_AT);
y = intexpr();
accept_tok(TOKENIZER_COMMA);
x = intexpr();
if (move_cursor(x,y))
chpos = x;
continue;
}
}
nv = 0;
if(t == TOKENIZER_COMMA) {
charout('\t', NULL);
nonl = 1;
tokenizer_next();
} else if(t == TOKENIZER_SEMICOLON) {
nonl = 1;
tokenizer_next();
} else if (!statement_end()) {
syntax_error();
break;
}
} while(!statement_end());
if (!nonl)
charout('\n', 0);
DEBUG_PRINTF("End of print\n");
}
/*---------------------------------------------------------------------------*/
static int if_statement(void)
{
struct typevalue r;
expr(&r);
DEBUG_PRINTF("if_statement: relation %d\n", r.d.i);
accept_tok(TOKENIZER_THEN);
if(r.d.i) {
if (current_token != TOKENIZER_NUMBER) {
statementgroup();
} else {
/* THEN number: Allow an arbitrary expression as a line number to
GO TO. Well, almost arbitrary --- require the expression to start
with a numeric token, otherwise the grammar becomes ambiguous.
-- tkchia 20180616 */
int linenum = intexpr();
if (!statement_end())
syntax_error();
jump_linenum(linenum);
return 0;
}
} else {
tokenizer_newline();
}
return 1;
}
/*---------------------------------------------------------------------------*/
static void let_statement(void)
{
var_t var;
struct typevalue v;
struct typevalue s[MAX_SUBSCRIPT];
int n = 0;
var = tokenizer_variable_num();
accept_either(TOKENIZER_INTVAR, TOKENIZER_STRINGVAR);
if (current_token == TOKENIZER_LEFTPAREN)
n = parse_subscripts(s);
accept_tok(TOKENIZER_EQ);
expr(&v);
DEBUG_PRINTF("let_statement: assign %d to %d\n", var, v.d.i);
ubasic_set_variable(var, &v, n, s);
}
/*---------------------------------------------------------------------------*/
static void return_statement(void)
{
if(gosub_stack_ptr > 0) {
gosub_stack_ptr--;
tokenizer_goto(gosub_stack[gosub_stack_ptr]);
} else {
DEBUG_PRINTF("return_statement: non-matching return\n");
}
}
/*---------------------------------------------------------------------------*/
static void next_statement(void)
{
int var;
struct for_state *fs;
struct typevalue t;
/* FIXME: support 'NEXT' on its own, also loop down the stack so if you
GOTO out of a layer of NEXT the right thing occurs */
var = tokenizer_variable_num();
accept_tok(TOKENIZER_INTVAR);
/* FIXME: make the for stack just use pointers so it compiles better */
fs = &for_stack[for_stack_ptr - 1];
if(for_stack_ptr > 0 &&
var == fs->for_variable) {
ubasic_get_variable(var, &t, 0, NULL);
t.d.i += fs->step;
ubasic_set_variable(var, &t, 0,NULL);
/* NEXT end depends upon sign of STEP */
if ((fs->step >= 0 && t.d.i <= fs->to) ||
(fs->step < 0 && t.d.i >= fs->to))
tokenizer_goto(fs->resume_token);
else
for_stack_ptr--;
} else
ubasic_error("Mismatched NEXT");
}