* DEALINGS IN THE SOFTWARE.
*/
-#include <cstdio>
-#include <cstdlib>
-#include <cstring>
#include <assert.h>
+#include <limits>
#include "s_expression.h"
-s_symbol::s_symbol(const char *tmp, size_t n)
+s_symbol::s_symbol(const char *str, size_t n)
{
- this->str = talloc_strndup (this, tmp, n);
- assert(this->str != NULL);
+ /* Assume the given string is already nul-terminated and in memory that
+ * will live as long as this node.
+ */
+ assert(str[n] == '\0');
+ this->str = str;
}
s_list::s_list()
{
}
-unsigned
-s_list::length() const
+static void
+skip_whitespace(const char *&src, char *&symbol_buffer)
{
- unsigned i = 0;
- foreach_iter(exec_list_iterator, it, this->subexpressions) {
- i++;
+ size_t n = strspn(src, " \v\t\r\n");
+ src += n;
+ symbol_buffer += n;
+ /* Also skip Scheme-style comments: semi-colon 'til end of line */
+ if (src[0] == ';') {
+ n = strcspn(src, "\n");
+ src += n;
+ symbol_buffer += n;
+ skip_whitespace(src, symbol_buffer);
}
- return i;
}
static s_expression *
-read_atom(void *ctx, const char *& src)
+read_atom(void *ctx, const char *&src, char *&symbol_buffer)
{
s_expression *expr = NULL;
- // Skip leading spaces.
- src += strspn(src, " \v\t\r\n");
+ skip_whitespace(src, symbol_buffer);
- size_t n = strcspn(src, "( \v\t\r\n)");
+ size_t n = strcspn(src, "( \v\t\r\n);");
if (n == 0)
return NULL; // no atom
- // Check if the atom is a number.
- char *float_end = NULL;
- double f = strtod(src, &float_end);
- if (float_end != src) {
- char *int_end = NULL;
- int i = strtol(src, &int_end, 10);
- // If strtod matched more characters, it must have a decimal part
- if (float_end > int_end)
- expr = new(ctx) s_float(f);
- else
- expr = new(ctx) s_int(i);
+ // Check for the special symbol '+INF', which means +Infinity. Note: C99
+ // requires strtof to parse '+INF' as +Infinity, but we still support some
+ // non-C99-compliant compilers (e.g. MSVC).
+ if (n == 4 && strncmp(src, "+INF", 4) == 0) {
+ expr = new(ctx) s_float(std::numeric_limits<float>::infinity());
} else {
- // Not a number; return a symbol.
- expr = new(ctx) s_symbol(src, n);
+ // Check if the atom is a number.
+ char *float_end = NULL;
+ float f = glsl_strtof(src, &float_end);
+ if (float_end != src) {
+ char *int_end = NULL;
+ int i = strtol(src, &int_end, 10);
+ // If strtof matched more characters, it must have a decimal part
+ if (float_end > int_end)
+ expr = new(ctx) s_float(f);
+ else
+ expr = new(ctx) s_int(i);
+ } else {
+ // Not a number; return a symbol.
+ symbol_buffer[n] = '\0';
+ expr = new(ctx) s_symbol(symbol_buffer, n);
+ }
}
src += n;
+ symbol_buffer += n;
return expr;
}
-s_expression *
-s_expression::read_expression(void *ctx, const char *&src)
+static s_expression *
+__read_expression(void *ctx, const char *&src, char *&symbol_buffer)
{
- assert(src != NULL);
-
- s_expression *atom = read_atom(ctx, src);
+ s_expression *atom = read_atom(ctx, src, symbol_buffer);
if (atom != NULL)
return atom;
- // Skip leading spaces.
- src += strspn(src, " \v\t\r\n");
+ skip_whitespace(src, symbol_buffer);
if (src[0] == '(') {
++src;
+ ++symbol_buffer;
s_list *list = new(ctx) s_list;
s_expression *expr;
- while ((expr = read_expression(ctx, src)) != NULL) {
+ while ((expr = __read_expression(ctx, src, symbol_buffer)) != NULL) {
list->subexpressions.push_tail(expr);
}
- src += strspn(src, " \v\t\r\n");
+ skip_whitespace(src, symbol_buffer);
if (src[0] != ')') {
printf("Unclosed expression (check your parenthesis).\n");
return NULL;
}
++src;
+ ++symbol_buffer;
return list;
}
return NULL;
}
+s_expression *
+s_expression::read_expression(void *ctx, const char *&src)
+{
+ assert(src != NULL);
+
+ /* When we encounter a Symbol, we need to save a nul-terminated copy of
+ * the string. However, ralloc_strndup'ing every individual Symbol is
+ * extremely expensive. We could avoid this by simply overwriting the
+ * next character (guaranteed to be whitespace, parens, or semicolon) with
+ * a nul-byte. But overwriting non-whitespace would mess up parsing.
+ *
+ * So, just copy the whole buffer ahead of time. Walk both, leaving the
+ * original source string unmodified, and altering the copy to contain the
+ * necessary nul-bytes whenever we encounter a symbol.
+ */
+ char *symbol_buffer = ralloc_strdup(ctx, src);
+ return __read_expression(ctx, src, symbol_buffer);
+}
+
void s_int::print()
{
printf("%d", this->val);
foreach_iter(exec_list_iterator, it, this->subexpressions) {
s_expression *expr = (s_expression*) it.get();
expr->print();
- printf(" ");
+ if (!expr->next->is_tail_sentinel())
+ printf(" ");
}
printf(")");
}
+// --------------------------------------------------
+
+bool
+s_pattern::match(s_expression *expr)
+{
+ switch (type)
+ {
+ case EXPR: *p_expr = expr; break;
+ case LIST: if (expr->is_list()) *p_list = (s_list *) expr; break;
+ case SYMBOL: if (expr->is_symbol()) *p_symbol = (s_symbol *) expr; break;
+ case NUMBER: if (expr->is_number()) *p_number = (s_number *) expr; break;
+ case INT: if (expr->is_int()) *p_int = (s_int *) expr; break;
+ case STRING:
+ s_symbol *sym = SX_AS_SYMBOL(expr);
+ if (sym != NULL && strcmp(sym->value(), literal) == 0)
+ return true;
+ return false;
+ };
+
+ return *p_expr == expr;
+}
+
+bool
+s_match(s_expression *top, unsigned n, s_pattern *pattern, bool partial)
+{
+ s_list *list = SX_AS_LIST(top);
+ if (list == NULL)
+ return false;
+
+ unsigned i = 0;
+ foreach_iter(exec_list_iterator, it, list->subexpressions) {
+ if (i >= n)
+ return partial; /* More actual items than the pattern expected */
+
+ s_expression *expr = (s_expression *) it.get();
+ if (expr == NULL || !pattern[i].match(expr))
+ return false;
+
+ i++;
+ }
+
+ if (i < n)
+ return false; /* Less actual items than the pattern expected */
+
+ return true;
+}
projects / mesa.git / blobdiff