From 314482b95ff83f1f88e41d45fadd05a7e625bb0c Mon Sep 17 00:00:00 2001
From: David Robillard <d@drobilla.net>
Date: Mon, 29 Jun 2009 00:28:50 +0000
Subject: Split code up further.

git-svn-id: http://svn.drobilla.net/resp/tuplr@165 ad02d1e2-f140-0410-9f75-f8b11f17cedd
---
 src/lex.cpp | 95 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 95 insertions(+)
 create mode 100644 src/lex.cpp

(limited to 'src/lex.cpp')

diff --git a/src/lex.cpp b/src/lex.cpp
new file mode 100644
index 0000000..81dbe19
--- /dev/null
+++ b/src/lex.cpp
@@ -0,0 +1,95 @@
+/* Tuplr: A programming language
+ * Copyright (C) 2008-2009 David Robillard <dave@drobilla.net>
+ *
+ * Tuplr 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.
+ *
+ * Tuplr 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 Tuplr.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/** @file
+
+ * @brief Lexing (build a SExp from a string)
+ */
+
+#include <stack>
+#include "tuplr.hpp"
+
+using namespace std;
+
+inline int
+readChar(Cursor& cur, istream& in)
+{
+	int ch = in.get();
+	switch (ch) {
+	case '\n': ++cur.line; cur.col = 0; break;
+	default:   ++cur.col;
+	}
+	return ch;
+}
+
+SExp
+readExpression(Cursor& cur, istream& in)
+{
+#define PUSH(s, t)  { if (t != "") { s.top().push_back(SExp(loc, t)); t = ""; } }
+#define YIELD(s, t) { if (s.empty()) { return SExp(loc, t); } else PUSH(s, t) }
+	stack<SExp> stk;
+	string      tok;
+	Cursor      loc; // start of tok
+	while (int c = readChar(cur, in)) {
+		switch (c) {
+		case EOF:
+			THROW_IF(!stk.empty(), cur, "unexpected end of file")
+			return SExp(cur);
+		case ';':
+			while ((c = readChar(cur, in)) != '\n') {}
+		case '\n': case ' ': case '\t':
+			if (tok != "") YIELD(stk, tok);
+			break;
+		case '"':
+			loc = cur;
+			do { tok.push_back(c); } while ((c = readChar(cur, in)) != '"');
+			YIELD(stk, tok + '"');
+			break;
+		case '(':
+			stk.push(SExp(cur));
+			break;
+		case ')':
+			switch (stk.size()) {
+			case 0:
+				throw Error(cur, "unexpected `)'");
+			case 1:
+				PUSH(stk, tok);
+				return stk.top();
+			default:
+				PUSH(stk, tok);
+				SExp l = stk.top();
+				stk.pop();
+				stk.top().push_back(l);
+			}
+			break;
+		case '#':
+			if (in.peek() == '|') {
+				while (!(readChar(cur, in) == '|' && readChar(cur, in) == '#')) {}
+				break;
+			}
+		default:
+			if (tok == "") loc = cur;
+			tok += c;
+		}
+	}
+	switch (stk.size()) {
+	case 0:  return SExp(loc, tok);
+	case 1:  return stk.top();
+	default: throw  Error(cur, "missing `)'");
+	}
+	return SExp(cur);
+}
-- 
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