static const char *atom_type_name (atom_type);
static struct expression *finish_expression (union any_node *,
struct expression *);
-static bool type_check (struct expression *, union any_node **,
- enum expr_type expected_type);
+static bool type_check (const union any_node *, enum val_type expected_type);
static union any_node *allocate_unary_variable (struct expression *,
const struct variable *);
\f
/* Public functions. */
-/* Parses an expression of the given TYPE.
- If DICT is nonnull then variables and vectors within it may be
- referenced within the expression; otherwise, the expression
- must not reference any variables or vectors.
- Returns the new expression if successful or a null pointer
- otherwise. */
+/* Parses an expression of the given TYPE. If DS is nonnull then variables and
+ vectors within it may be referenced within the expression; otherwise, the
+ expression must not reference any variables or vectors. Returns the new
+ expression if successful or a null pointer otherwise. If POOL is nonnull,
+ then destroying POOL will free the expression; otherwise, the caller must
+ eventually free it with expr_free(). */
struct expression *
-expr_parse (struct lexer *lexer, struct dataset *ds, enum expr_type type)
+expr_parse (struct lexer *lexer, struct pool *pool, struct dataset *ds,
+ enum val_type type)
{
- union any_node *n;
- struct expression *e;
+ assert (val_type_is_valid (type));
- assert (type == EXPR_NUMBER || type == EXPR_STRING || type == EXPR_BOOLEAN);
+ struct expression *e = expr_create (ds);
+ union any_node *n = parse_or (lexer, e);
+ if (!n || !type_check (n, type))
+ {
+ expr_free (e);
+ return NULL;
+ }
- e = expr_create (ds);
- n = parse_or (lexer, e);
- if (n != NULL && type_check (e, &n, type))
- return finish_expression (expr_optimize (n, e), e);
- else
+ e = finish_expression (expr_optimize (n, e), e);
+ if (pool)
+ pool_add_subpool (pool, e->expr_pool);
+ return e;
+}
+
+/* Parses a boolean expression, otherwise similar to expr_parse(). */
+struct expression *
+expr_parse_bool (struct lexer *lexer, struct pool *pool, struct dataset *ds)
+{
+ struct expression *e = expr_create (ds);
+ union any_node *n = parse_or (lexer, e);
+ if (!n)
{
expr_free (e);
return NULL;
}
+
+ atom_type actual_type = expr_node_returns (n);
+ if (actual_type == OP_number)
+ n = expr_allocate_binary (e, OP_NUM_TO_BOOLEAN, n,
+ expr_allocate_string (e, ss_empty ()));
+ else if (actual_type != OP_boolean)
+ {
+ msg (SE, _("Type mismatch: expression has %s type, "
+ "but a boolean value is required here."),
+ atom_type_name (actual_type));
+ expr_free (e);
+ return NULL;
+ }
+
+ e = finish_expression (expr_optimize (n, e), e);
+ if (pool)
+ pool_add_subpool (pool, e->expr_pool);
+ return e;
}
-/* Parses and returns an expression of the given TYPE, as
- expr_parse(), and sets up so that destroying POOL will free
- the expression as well. */
+/* Parses a numeric expression that is intended to be assigned to newly created
+ variable NEW_VAR_NAME. (This allows for a better error message if the
+ expression is not numeric.) Otherwise similar to expr_parse(). */
struct expression *
-expr_parse_pool (struct lexer *lexer,
- struct pool *pool,
- struct dataset *ds,
- enum expr_type type)
+expr_parse_new_variable (struct lexer *lexer, struct pool *pool, struct dataset *ds,
+ const char *new_var_name)
{
- struct expression *e = expr_parse (lexer, ds, type);
- if (e != NULL)
+ struct expression *e = expr_create (ds);
+ union any_node *n = parse_or (lexer, e);
+ if (!n)
+ {
+ expr_free (e);
+ return NULL;
+ }
+
+ atom_type actual_type = expr_node_returns (n);
+ if (actual_type != OP_number && actual_type != OP_boolean)
+ {
+ msg (SE, _("This command tries to create a new variable %s by assigning a "
+ "string value to it, but this is not supported. Use "
+ "the STRING command to create the new variable with the "
+ "correct width before assigning to it, e.g. STRING %s(A20)."),
+ new_var_name, new_var_name);
+ expr_free (e);
+ return NULL;
+ }
+
+ e = finish_expression (expr_optimize (n, e), e);
+ if (pool)
pool_add_subpool (pool, e->expr_pool);
return e;
}
converted to type EXPECTED_TYPE, inserting a conversion at *N
if necessary. Returns true if successful, false on failure. */
static bool
-type_check (struct expression *e,
- union any_node **n, enum expr_type expected_type)
+type_check (const union any_node *n, enum val_type expected_type)
{
- atom_type actual_type = expr_node_returns (*n);
+ atom_type actual_type = expr_node_returns (n);
switch (expected_type)
{
- case EXPR_BOOLEAN:
- case EXPR_NUMBER:
+ case VAL_NUMERIC:
if (actual_type != OP_number && actual_type != OP_boolean)
{
msg (SE, _("Type mismatch: expression has %s type, "
atom_type_name (actual_type));
return false;
}
- if (actual_type == OP_number && expected_type == EXPR_BOOLEAN)
- *n = expr_allocate_binary (e, OP_NUM_TO_BOOLEAN, *n,
- expr_allocate_string (e, ss_empty ()));
break;
- case EXPR_STRING:
+ case VAL_STRING:
if (actual_type != OP_string)
{
msg (SE, _("Type mismatch: expression has %s type, "
case T_LPAREN:
{
- union any_node *node;
- lex_get (lexer);
- node = parse_or (lexer, e);
- if (node != NULL && !lex_force_match (lexer, T_RPAREN))
+ /* Count number of left parentheses so that we can match them against
+ an equal number of right parentheses. This defeats trivial attempts
+ to exhaust the stack with a lot of left parentheses. (More
+ sophisticated attacks will still succeed.) */
+ size_t n = 0;
+ while (lex_match (lexer, T_LPAREN))
+ n++;
+
+ union any_node *node = parse_or (lexer, e);
+ if (!node)
return NULL;
+
+ for (size_t i = 0; i < n; i++)
+ if (!lex_force_match (lexer, T_RPAREN))
+ return NULL;
+
return node;
}
projects / pspp / blobdiff