From fe3d4ce758822d65a0a5d617b7b77df2dbc972d8 Mon Sep 17 00:00:00 2001
From: Ben Longbons <b.r.longbons@gmail.com>
Date: Sun, 16 Mar 2014 14:55:57 -0700
Subject: Implement new magic frontend using sexpr

---
 src/sexpr/parser.cpp | 79 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 79 insertions(+)
 create mode 100644 src/sexpr/parser.cpp

(limited to 'src/sexpr/parser.cpp')

diff --git a/src/sexpr/parser.cpp b/src/sexpr/parser.cpp
new file mode 100644
index 0000000..2068565
--- /dev/null
+++ b/src/sexpr/parser.cpp
@@ -0,0 +1,79 @@
+#include "parser.hpp"
+//    parser.cpp - build a tree of S-expressions
+//
+//    Copyright © 2014 Ben Longbons <b.r.longbons@gmail.com>
+//
+//    This file is part of The Mana World (Athena server)
+//
+//    This program is free software: you can redistribute it and/or modify
+//    it under the terms of the GNU Affero General Public License as published by
+//    the Free Software Foundation, either version 3 of the License, or
+//    (at your option) any later version.
+//
+//    This program is distributed in the hope that it will be useful,
+//    but WITHOUT ANY WARRANTY; without even the implied warranty of
+//    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+//    GNU Affero General Public License for more details.
+//
+//    You should have received a copy of the GNU Affero General Public License
+//    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+#include "../poison.hpp"
+
+namespace sexpr
+{
+    bool token_is_int(ZString s, int64_t& out, bool& ok)
+    {
+        if (!s)
+            return false;
+        if (s.startswith('-') || s.xslice_h(1).is_digit10())
+        {
+            const char *z = s.c_str();
+            char *end = nullptr;
+            errno = 0;
+            out = strtoll(z, &end, 0);
+            if (errno)
+                ok = false;
+            return !*end;
+        }
+        return false;
+    }
+
+    bool parse(Lexer& lex, SExpr& out)
+    {
+        out._list.clear();
+        out._str = RString();
+
+        bool rv = true;
+        out._span.begin = lex.span().begin;
+        switch (lex.peek())
+        {
+        default:
+            return false;
+        case TOK_STRING:
+            out._type = STRING;
+            out._str = lex.val_string();
+            break;
+        case TOK_TOKEN:
+            out._type = TOKEN;
+            out._str = lex.val_string();
+            if (token_is_int(out._str, out._int, rv))
+                out._type = INT;
+            break;
+        case TOK_OPEN:
+            out._type = LIST;
+            lex.adv();
+            while (lex.peek() != TOK_CLOSE)
+            {
+                SExpr tmp;
+                if (!parse(lex, tmp))
+                    return false;
+                out._list.push_back(std::move(tmp));
+            }
+            break;
+        }
+        out._span.end = lex.span().end;
+        lex.adv();
+        return rv;
+    }
+} // namespace sexpr
-- 
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