#ifndef S_EXPRESSION_H
#define S_EXPRESSION_H
+#include "main/core.h" /* for Elements */
+#include "strtod.h"
#include "list.h"
+/* Type-safe downcasting macros (also safe to pass NULL) */
#define SX_AS_(t,x) ((x) && ((s_expression*) x)->is_##t()) ? ((s_##t*) (x)) \
: NULL
#define SX_AS_LIST(x) SX_AS_(list, x)
#define SX_AS_NUMBER(x) SX_AS_(number, x)
#define SX_AS_INT(x) SX_AS_(int, x)
+/* Pattern matching macros */
+#define MATCH(list, pat) s_match(list, Elements(pat), pat, false)
+#define PARTIAL_MATCH(list, pat) s_match(list, Elements(pat), pat, true)
+
/* For our purposes, S-Expressions are:
* - <int>
* - <float>
* Read an S-Expression from the given string.
* Advances the supplied pointer to just after the expression read.
*
- * Any allocation will be performed with 'ctx' as the talloc owner.
+ * Any allocation will be performed with 'ctx' as the ralloc owner.
*/
static s_expression *read_expression(void *ctx, const char *&src);
void print();
private:
- char *str;
+ const char *str;
};
/* Lists of expressions: (expr1 ... exprN) */
s_list();
virtual bool is_list() const { return true; }
- unsigned length() const;
void print();
exec_list subexpressions;
};
+// ------------------------------------------------------------
+
+/**
+ * Part of a pattern to match - essentially a record holding a pointer to the
+ * storage for the component to match, along with the appropriate type.
+ */
+class s_pattern {
+public:
+ s_pattern(s_expression *&s) : p_expr(&s), type(EXPR) { }
+ s_pattern(s_list *&s) : p_list(&s), type(LIST) { }
+ s_pattern(s_symbol *&s) : p_symbol(&s), type(SYMBOL) { }
+ s_pattern(s_number *&s) : p_number(&s), type(NUMBER) { }
+ s_pattern(s_int *&s) : p_int(&s), type(INT) { }
+ s_pattern(const char *str) : literal(str), type(STRING) { }
+
+ bool match(s_expression *expr);
+
+private:
+ union {
+ s_expression **p_expr;
+ s_list **p_list;
+ s_symbol **p_symbol;
+ s_number **p_number;
+ s_int **p_int;
+ const char *literal;
+ };
+ enum { EXPR, LIST, SYMBOL, NUMBER, INT, STRING } type;
+};
+
+bool
+s_match(s_expression *top, unsigned n, s_pattern *pattern, bool partial);
+
#endif /* S_EXPRESSION_H */