Add a simple S-Expression reader and printer.
diff --git a/s_expression.cpp b/s_expression.cpp
new file mode 100644
index 0000000..4022dfa
--- /dev/null
+++ b/s_expression.cpp
@@ -0,0 +1,146 @@
+/* -*- c++ -*- */
+/*
+ * Copyright © 2010 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ */
+
+#include <cstdio>
+#include <cstdlib>
+#include <cstring>
+#include <assert.h>
+#include "s_expression.h"
+
+s_symbol::s_symbol(const char *tmp)
+{
+ this->str = new char [strlen(tmp) + 1];
+ strcpy(this->str, tmp);
+}
+
+s_symbol::~s_symbol()
+{
+ delete [] this->str;
+ this->str = NULL;
+}
+
+s_list::s_list()
+{
+}
+
+s_list::~s_list()
+{
+ exec_list_iterator it(this->subexpressions.iterator());
+ while (it.has_next())
+ it.remove();
+
+ assert(this->subexpressions.is_empty());
+}
+
+unsigned
+s_list::length() const
+{
+ unsigned i = 0;
+ foreach_iter(exec_list_iterator, it, this->subexpressions) {
+ i++;
+ }
+ return i;
+}
+
+static s_expression *
+read_atom(const char *& src)
+{
+ char buf[101];
+ int n;
+ if (sscanf(src, " %100[^( \v\t\r\n)]%n", buf, &n) != 1)
+ return NULL; // no atom
+ src += n;
+
+ // Check if the atom is a number.
+ char *float_end = NULL;
+ double f = strtod(buf, &float_end);
+ if (float_end != buf) {
+ char *int_end = NULL;
+ int i = strtol(buf, &int_end, 10);
+ // If strtod matched more characters, it must have a decimal part
+ if (float_end > int_end)
+ return new s_float(f);
+
+ return new s_int(i);
+ }
+ // Not a number; return a symbol.
+ return new s_symbol(buf);
+}
+
+s_expression *
+s_expression::read_expression(const char *&src)
+{
+ assert(src != NULL);
+
+ s_expression *atom = read_atom(src);
+ if (atom != NULL)
+ return atom;
+
+ char c;
+ int n;
+ if (sscanf(src, " %c%n", &c, &n) == 1 && c == '(') {
+ src += n;
+
+ s_list *list = new s_list;
+ s_expression *expr;
+
+ while ((expr = read_expression(src)) != NULL) {
+ list->subexpressions.push_tail(expr);
+ }
+ if (sscanf(src, " %c%n", &c, &n) != 1 || c != ')') {
+ printf("Unclosed expression (check your parenthesis).\n");
+ return NULL;
+ }
+ src += n;
+ return list;
+ }
+ return NULL;
+}
+
+void s_int::print()
+{
+ printf("%d", this->val);
+}
+
+void s_float::print()
+{
+ printf("%f", this->val);
+}
+
+void s_symbol::print()
+{
+ printf("%s", this->str);
+}
+
+void s_list::print()
+{
+ printf("(");
+ foreach_iter(exec_list_iterator, it, this->subexpressions) {
+ s_expression *expr = (s_expression*) it.get();
+ expr->print();
+ printf(" ");
+ }
+ printf(")");
+}
+