andrew/piquant
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Added the ability to parse commands as well as expressions.

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Added basic PRINT and REM commands.
Added solver tests which had been around for a while and not committed.
All execution is still immediate mode.
This commit is contained in:
Andrew Kesterson
2024-05-06 15:12:12 -04:00
parent ef53041427
commit a428b905da
6 changed files with 247 additions and 68 deletions
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190
src/basic.c
View File

@@ -11,6 +11,62 @@ char _tokenizer_value[BASIC_TOKENIZER_MAX_LENGTH];
char *_tokenizer_prev;
char *_tokenizer_prev_next;
void basic_report_error()
{
char decimal[2];
decimal[0] = 0;
decimal[1] = 0;
_cputs("Error: ");
decimal[0] = dtoa(basic_errno);
_cputs((char *)&decimal);
_cputs("\n");
}
/***************************************************************
*
* Basic Commands
*
***************************************************************/
void basic_cmd_rem(void *expr)
{
return;
}
void basic_cmd_print(void *data)
{
struct basic_variable result;
basic_expr *expr;
if ( data == NULL ) {
basic_errno = BASIC_ERR_INTERNAL_NULLPOINTER;
return;
}
_cputs("PRINT(");
_cputs((char *)data);
_cputs(")\n");
expr = basic_parse_expr((char *)data);
if ( expr == NULL ) {
basic_errno = BASIC_ERR_INTERNAL_NULLPOINTER;
return;
}
memset((void *)&result, 0x00, sizeof(struct basic_variable));
basic_solve_expr(expr, &result);
if ( basic_errno != 0 ) {
return;
} else {
basic_print_var(&result);
}
}
/***************************************************************
*
* Basic Tokenizer
*
***************************************************************/
void _tokenizer_init(void)
{
_tokenizer_prev = NULL;
@@ -64,11 +120,17 @@ _tokenize_copy:
return ptr;
}
char *_token_get(void)
char *tokenizer_token(void)
{
return (char *)&_tokenizer_value;
}
/***************************************************************
*
* Basic Interpreter
*
***************************************************************/
int basic_solve_expr(struct basic_expr *expr, struct basic_variable *result)
{
if ( expr == NULL || result == NULL ) {
@@ -77,9 +139,18 @@ int basic_solve_expr(struct basic_expr *expr, struct basic_variable *result)
}
switch (expr->type) {
case BASIC_OPTP_NONE:
if ( expr->lval_type == BASIC_LVAL_CONST_INT ) {
result->flags = (result->flags | BASIC_VARFLAG_TINT | BASIC_VARFLAG_INIT);
result->value.i = expr->lval.i;
} else {
basic_errno = BASIC_ERR_INTERNAL_UNIMPLEMENTED;
return 0;
}
break;
case BASIC_OPTP_ADD:
if ( expr->lval_type != BASIC_LVAL_CONST ||
( expr->rval_type != BASIC_RVAL_CONST ) ) {
if ( expr->lval_type != BASIC_LVAL_CONST_INT ||
( expr->rval_type != BASIC_RVAL_CONST_INT ) ) {
basic_errno = BASIC_ERR_INVALID_ARGUMENTS;
return 0;
}
@@ -87,8 +158,8 @@ int basic_solve_expr(struct basic_expr *expr, struct basic_variable *result)
result->value.i = expr->lval.i + expr->rval.i;
break;
case BASIC_OPTP_SUB:
if ( expr->lval_type != BASIC_LVAL_CONST ||
( expr->rval_type != BASIC_RVAL_CONST ) ) {
if ( expr->lval_type != BASIC_LVAL_CONST_INT ||
( expr->rval_type != BASIC_RVAL_CONST_INT ) ) {
basic_errno = BASIC_ERR_INVALID_ARGUMENTS;
return 0;
}
@@ -96,8 +167,8 @@ int basic_solve_expr(struct basic_expr *expr, struct basic_variable *result)
result->value.i = expr->lval.i - expr->rval.i;
break;
case BASIC_OPTP_MUL:
if ( expr->lval_type != BASIC_LVAL_CONST ||
( expr->rval_type != BASIC_RVAL_CONST ) ) {
if ( expr->lval_type != BASIC_LVAL_CONST_INT ||
( expr->rval_type != BASIC_RVAL_CONST_INT ) ) {
basic_errno = BASIC_ERR_INVALID_ARGUMENTS;
return 0;
}
@@ -105,8 +176,8 @@ int basic_solve_expr(struct basic_expr *expr, struct basic_variable *result)
result->value.i = expr->lval.i * expr->rval.i;
break;
case BASIC_OPTP_DIV:
if ( expr->lval_type != BASIC_LVAL_CONST ||
( expr->rval_type != BASIC_RVAL_CONST ) ) {
if ( expr->lval_type != BASIC_LVAL_CONST_INT ||
( expr->rval_type != BASIC_RVAL_CONST_INT ) ) {
basic_errno = BASIC_ERR_INVALID_ARGUMENTS;
return 0;
}
@@ -118,8 +189,8 @@ int basic_solve_expr(struct basic_expr *expr, struct basic_variable *result)
result->value.i = expr->lval.i / expr->rval.i;
break;
case BASIC_OPTP_MOD:
if ( expr->lval_type != BASIC_LVAL_CONST ||
( expr->rval_type != BASIC_RVAL_CONST ) ) {
if ( expr->lval_type != BASIC_LVAL_CONST_INT ||
( expr->rval_type != BASIC_RVAL_CONST_INT ) ) {
basic_errno = BASIC_ERR_INVALID_ARGUMENTS;
return 0;
}
@@ -131,8 +202,8 @@ int basic_solve_expr(struct basic_expr *expr, struct basic_variable *result)
result->value.i = (expr->lval.i) - ((expr->lval.i / expr->rval.i)*expr->rval.i);
break;
case BASIC_OPTP_EQL:
if ( expr->lval_type != BASIC_LVAL_CONST ||
( expr->rval_type != BASIC_RVAL_CONST ) ) {
if ( expr->lval_type != BASIC_LVAL_CONST_INT ||
( expr->rval_type != BASIC_RVAL_CONST_INT ) ) {
basic_errno = BASIC_ERR_INVALID_ARGUMENTS;
return 0;
}
@@ -169,37 +240,60 @@ struct basic_expr *basic_parse_expr(char *expbuf)
continue;
}
expbuf = _tokenize(expbuf, BASIC_TOKENIZER_TOKENS);
token = _token_get();
expbuf = _tokenize(expbuf, " ");
token = tokenizer_token();
if ( isdigit(*token) == 1 ) {
if ( (ret->type == 0) && (flags & BASIC_PARSE_FOUND_LVAL) == BASIC_PARSE_FOUND_LVAL ) {
basic_errno = BASIC_ERR_SYNTAX_MULTIPLE_LVALUES;
return NULL;
} else if ( ret->type == 0x0 ) {
ret->lval.i = atoi(token);
ret->lval_type = BASIC_LVAL_CONST;
ret->lval_type = BASIC_LVAL_CONST_INT;
flags = (flags | BASIC_PARSE_FOUND_LVAL);
} else if ( ret->type != 0x0 && ((flags & BASIC_PARSE_FOUND_RVAL) == BASIC_PARSE_FOUND_RVAL)) {
basic_errno = BASIC_ERR_SYNTAX_MULTIPLE_RVALUES;
return NULL;
} else if ( ret->type != 0x0 ) {
ret->rval.i = atoi(token);
ret->rval_type = BASIC_RVAL_CONST;
ret->rval_type = BASIC_RVAL_CONST_INT;
}
} else if ( token != NULL && ret->type == 0x0 ) {
if ( *token == '+' ) {
ret->type = BASIC_OPTP_ADD;
} else if ( *token == '*' ) {
ret->type = BASIC_OPTP_MUL;
} else if ( *token == '-' ) {
ret->type = BASIC_OPTP_SUB;
} else if ( *token == '/' ) {
ret->type = BASIC_OPTP_DIV;
} else if ( *token == '%' ) {
ret->type = BASIC_OPTP_MOD;
} else {
basic_errno = BASIC_ERR_SYNTAX_GENERAL;
return NULL;
switch ( *token ) {
case '+':
ret->type = BASIC_OPTP_ADD;
break;
case '*':
ret->type = BASIC_OPTP_MUL;
break;
case '-':
ret->type = BASIC_OPTP_SUB;
break;
case '/':
ret->type = BASIC_OPTP_DIV;
break;
case '%':
ret->type = BASIC_OPTP_MOD;
break;
default:
/* see if a command will claim this token */
if ( strcmp(token, "REM") == 0 ) {
ret->type = BASIC_OPTP_CMD;
ret->lval_type = BASIC_LVAL_CMDPTR;
ret->lval.cmd_ptr = basic_cmd_rem;
ret->rval_type = BASIC_RVAL_NONE;
return ret;
} else if ( strcmp(token, "PRINT") == 0 ) {
ret->type = BASIC_OPTP_CMD;
ret->lval_type = BASIC_LVAL_CMDPTR;
ret->lval.cmd_ptr = basic_cmd_print;
ret->rval_type = BASIC_RVAL_PTR;
ret->rval.ptr = expbuf;
return ret;
} else {
basic_errno = BASIC_ERR_SYNTAX_GENERAL;
return NULL;
break;
}
}
} else {
basic_errno = BASIC_ERR_SYNTAX_GENERAL;
@@ -209,6 +303,12 @@ struct basic_expr *basic_parse_expr(char *expbuf)
return ret;
}
/***************************************************************
*
* Basic REPL
*
***************************************************************/
void basic_print_var(struct basic_variable *var)
{
char decimal[32];
@@ -229,20 +329,14 @@ void basic_repl(basic_program *program)
{
char keybuff[512];
char outbuff[128];
char decimal[2];
struct basic_expr *expr;
struct basic_variable result;
decimal[0] = 0;
decimal[1] = 0;
blankScreen();
setCursorPosition(0, 0);
_cputs("Piquant Basic v0.1\n\n");
while ( 1 ) {
memset((void *)&result, 0x00, sizeof(struct basic_variable));
expr = NULL;
_cputs("> ");
@@ -256,23 +350,17 @@ void basic_repl(basic_program *program)
/* Evaluate */
expr = basic_parse_expr((char *)&keybuff);
if ( expr == NULL ) {
_cputs("Error: ");
decimal[0] = dtoa(basic_errno);
_cputs((char *)&decimal);
_cputs("\n");
basic_report_error();
basic_errno = 0;
continue;
}
basic_solve_expr(expr, &result);
if ( basic_errno != 0 ) {
_cputs("Error: ");
decimal[0] = dtoa(basic_errno);
_cputs((char *)&decimal);
_cputs("\n");
} else {
/* Print */
basic_print_var(&result);
if ( expr->lval_type == BASIC_LVAL_CMDPTR ) {
if ( expr->lval.cmd_ptr == NULL ) {
basic_errno = BASIC_ERR_INTERNAL_NULLPOINTER;
basic_report_error();
basic_errno = 0;
} else {
(*expr->lval.cmd_ptr)(expr->rval.ptr);
}
}
}
}

37
src/basic.h
View File

@@ -1,25 +1,30 @@
#ifndef _BASIC_H_
#define _BASIC_H_
#define BASIC_MAX_LINES 1000
#define BASIC_MAX_LINE_LENGTH 256
/* Per MS BASIC-80 ref page 1-2 */
#define BASIC_MAX_LINES sizeof(int)
#define BASIC_MAX_LINE_LENGTH 255
#define BASIC_OPTP_ADD 1 /* Add */
#define BASIC_OPTP_SUB 2 /* Subtract */
#define BASIC_OPTP_MUL 3 /* Multiply */
#define BASIC_OPTP_DIV 4 /* Divide */
#define BASIC_OPTP_MOD 5 /* Modulus */
#define BASIC_OPTP_EQL 6 /* Equality test */
#define BASIC_OPTP_ASN 7 /* Assignment */
#define BASIC_OPTP_STOR 8 /* Store line for later */
#define BASIC_OPTP_NONE 0 /* No operation (only valid when LVAL is CONST and no RVAL) */
#define BASIC_OPTP_ADD 1 /* Add */
#define BASIC_OPTP_SUB 2 /* Subtract */
#define BASIC_OPTP_MUL 3 /* Multiply */
#define BASIC_OPTP_DIV 4 /* Divide */
#define BASIC_OPTP_MOD 5 /* Modulus */
#define BASIC_OPTP_EQL 6 /* Equality test */
#define BASIC_OPTP_ASN 7 /* Assignment */
#define BASIC_OPTP_STOR 8 /* Store line for later */
#define BASIC_OPTP_CMD 9 /* BASIC command (PRINT, FOR, REM, etc)*/
#define BASIC_LVAL_EXPR 0
#define BASIC_LVAL_VAR 1
#define BASIC_LVAL_CONST 2
#define BASIC_LVAL_CONST_INT 2
#define BASIC_LVAL_CMDPTR 3
#define BASIC_RVAL_EXPR 3
#define BASIC_RVAL_VAR 4
#define BASIC_RVAL_CONST 5
#define BASIC_RVAL_CONST_INT 5
#define BASIC_RVAL_PTR 6 /* Only used internally */
#define BASIC_RVAL_NONE 7
#define BASIC_PARSE_FOUND_LVAL 1
#define BASIC_PARSE_FOUND_RVAL 2
@@ -62,6 +67,7 @@ union basic_value {
*/
char *str;
void *ptr;
void (*cmd_ptr)(void *data);
};
typedef union basic_value basic_value;
@@ -94,5 +100,12 @@ extern int basic_errno;
void basic_repl(basic_program *program);
basic_expr *basic_parse_expr(char *);
int basic_solve_expr(struct basic_expr *expr, struct basic_variable *result);
char *tokenizer_token(void);
void basic_cmd_rem(void *data);
void basic_cmd_print(void *data);
void basic_print_var(basic_variable *var);
void basic_report_error();
#endif /* _BASIC_H_ */