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Diffstat (limited to 'util/qlalr/examples/lambda/main.cpp')
-rw-r--r-- | util/qlalr/examples/lambda/main.cpp | 199 |
1 files changed, 199 insertions, 0 deletions
diff --git a/util/qlalr/examples/lambda/main.cpp b/util/qlalr/examples/lambda/main.cpp new file mode 100644 index 0000000000..6c45d48e69 --- /dev/null +++ b/util/qlalr/examples/lambda/main.cpp @@ -0,0 +1,199 @@ +/**************************************************************************** +** +** Copyright (C) 2012 Digia Plc and/or its subsidiary(-ies). +** Contact: http://www.qt-project.org/legal +** +** This file is part of the QLALR module of the Qt Toolkit. +** +** $QT_BEGIN_LICENSE:LGPL$ +** Commercial License Usage +** Licensees holding valid commercial Qt licenses may use this file in +** accordance with the commercial license agreement provided with the +** Software or, alternatively, in accordance with the terms contained in +** a written agreement between you and Digia. For licensing terms and +** conditions see http://qt.digia.com/licensing. For further information +** use the contact form at http://qt.digia.com/contact-us. +** +** GNU Lesser General Public License Usage +** Alternatively, this file may be used under the terms of the GNU Lesser +** General Public License version 2.1 as published by the Free Software +** Foundation and appearing in the file LICENSE.LGPL included in the +** packaging of this file. Please review the following information to +** ensure the GNU Lesser General Public License version 2.1 requirements +** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html. +** +** In addition, as a special exception, Digia gives you certain additional +** rights. These rights are described in the Digia Qt LGPL Exception +** version 1.1, included in the file LGPL_EXCEPTION.txt in this package. +** +** GNU General Public License Usage +** Alternatively, this file may be used under the terms of the GNU +** General Public License version 3.0 as published by the Free Software +** Foundation and appearing in the file LICENSE.GPL included in the +** packaging of this file. Please review the following information to +** ensure the GNU General Public License version 3.0 requirements will be +** met: http://www.gnu.org/copyleft/gpl.html. +** +** +** $QT_END_LICENSE$ +** +****************************************************************************/ + +#include "lambda.h" + +#include <cstdio> +#include <cstdlib> +#include <cstring> +#include "parser_table_p.h" + +class Parser: protected parser_table +{ +public: + union Value { + int ival; + // ### more... + }; + +public: + Parser(); + ~Parser(); + + bool parse(); + +protected: + inline void reallocateStack(); + + inline Value &sym(int index) + { return sym_stack [tos + index - 1]; } + + int nextToken(); + void consumeRule(int ruleno); + +protected: + int tos; + int stack_size; + Value *sym_stack; + int *state_stack; + int current_char; + unsigned in_tag: 1; +}; + +inline void Parser::reallocateStack() +{ + if (! stack_size) + stack_size = 128; + else + stack_size <<= 1; + + sym_stack = reinterpret_cast<Value*> (::realloc(sym_stack, stack_size * sizeof(Value))); + state_stack = reinterpret_cast<int*> (::realloc(state_stack, stack_size * sizeof(int))); +} + +Parser::Parser(): + tos(0), + stack_size(0), + sym_stack(0), + state_stack(0) +{ +} + +Parser::~Parser() +{ + if (stack_size) { + ::free(sym_stack); + ::free(state_stack); + } +} + +bool Parser::parse() +{ + const int INITIAL_STATE = 0; + + current_char = 0; + in_tag = 0; + + int yytoken = -1; + reallocateStack(); + + tos = 0; + state_stack[++tos] = INITIAL_STATE; + + while (true) + { + if (yytoken == -1 && - TERMINAL_COUNT != action_index [state_stack [tos]]) + yytoken = nextToken(); + + int act = t_action (state_stack [tos], yytoken); + + if (act == ACCEPT_STATE) { + return true; + } + + else if (act > 0) + { + if (++tos == stack_size) + reallocateStack(); + + sym_stack [tos].ival = current_char; // ### save the token value here + state_stack [tos] = act; + yytoken = -1; + } + + else if (act < 0) + { + int r = - act - 1; + + tos -= rhs [r]; + act = state_stack [tos++]; + consumeRule (r); + state_stack [tos] = nt_action (act, lhs [r] - TERMINAL_COUNT); + } + + else + break; + } + + return false; +} + + +int Parser::nextToken() +{ + static int tokens[] = { ID, ID, ID, EOF_SYMBOL }; + static int *tk = tokens; + + return *tk++; +} + +void Parser::consumeRule(int ruleno) +{ + switch (ruleno) { + case Symbol: + printf("symbol\n"); + break; + case SubExpression: + printf("sub-expr\n"); + break; + case Appl: + printf("appl\n"); + break; + case Abstr: + printf("abstr\n"); + break; + } +} + +///////////////////////////// +// entry point +///////////////////////////// +int main() +{ + Parser parser; + + if (parser.parse()) + printf ("OK\n"); + else + printf ("KO\n"); +} + + |