From f746b783b1d06dc72c8fe16ad88b26929e65350d Mon Sep 17 00:00:00 2001
From: dos-reis <gdr@axiomatics.org>
Date: Tue, 4 Oct 2011 08:04:07 +0000
Subject: 	* interp/lexing.boot: New. 	* interp/metalex.lisp: Include
 it.  Use new stack datatype support. 	* interp/parsing.lisp: Use new stack
 datatype support. 	* interp/Makefile.in: Adjust.

---
 src/interp/lexing.boot | 88 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 88 insertions(+)
 create mode 100644 src/interp/lexing.boot

(limited to 'src/interp/lexing.boot')

diff --git a/src/interp/lexing.boot b/src/interp/lexing.boot
new file mode 100644
index 00000000..506e22c6
--- /dev/null
+++ b/src/interp/lexing.boot
@@ -0,0 +1,88 @@
+-- Copyright (C) 2011, Gabriel Dos Reis.
+-- All rights reserved.
+--
+-- Redistribution and use in source and binary forms, with or without
+-- modification, are permitted provided that the following conditions are
+-- met:
+--
+--     - Redistributions of source code must retain the above copyright
+--       notice, this list of conditions and the following disclaimer.
+--
+--     - Redistributions in binary form must reproduce the above copyright
+--       notice, this list of conditions and the following disclaimer in
+--       the documentation and/or other materials provided with the
+--       distribution.
+--
+--     - Neither the name of OpenAxiom. nor the names of its contributors
+--       may be used to endorse or promote products derived from this
+--       software without specific prior written permission.
+--
+-- THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
+-- IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+-- TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
+-- PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
+-- OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+-- EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+-- PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+-- PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+-- LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+-- NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+-- SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+--
+
+--%
+--% Author: Gabriel Dos Reis
+--%
+
+import sys_-utility
+
+namespace BOOT
+
+module lexing
+
+--%
+--% Stack abstract datatype.
+--%  Operational semantics:
+--%     structure Stack ==
+--%         Record(store: List T, size: Integer, top: T, updated?: Boolean)
+
+++ Construct a new stack
+makeStack() ==
+  [nil,0,nil,false]
+
+macro stackStore st ==
+  first st
+
+macro stackSize st ==
+  second st
+
+macro stackTop st ==
+  third st
+
+macro stackUpdated? st ==
+  fourth st
+
+stackLoad!(l,st) ==
+  stackStore(st) := l
+  stackSize(st) := #l
+  stackTop(st) := first l
+
+stackClear! st ==
+  stackStore(st) := nil
+  stackSize(st) := 0
+  stackTop(st) := nil
+  stackUpdate?(st) := false
+
+stackPush!(x,st) ==
+  stackStore(st) := [x,:stackStore st]
+  stackTop(st) := x
+  stackSize(st) := stackSize st + 1
+  stackUpdated?(st) := true
+
+stackPop! st ==
+  y := first stackStore st
+  stackStore(st) := rest stackStore st
+  stackSize(st) := stackSize st - 1
+  if stackStore st ~= nil then
+    stackTop(st) := first stackStore st
+  y
-- 
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