From cced0790f1f5a8bb7ac39bd14d83ceb4c4b9b64d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Martin=20Ko=C4=8Di=C4=8Dka?= <martin.kocicka@gmail.com>
Date: Wed, 11 May 2016 10:59:15 +0200
Subject: [PATCH] added SLR(1) action table generator
---
.../src/grammar/parsing/SLR1ParseTable.cpp | 72 +++++++++++++++++++
.../src/grammar/parsing/SLR1ParseTable.h | 31 ++++++++
2 files changed, 103 insertions(+)
create mode 100644 alib2algo/src/grammar/parsing/SLR1ParseTable.cpp
create mode 100644 alib2algo/src/grammar/parsing/SLR1ParseTable.h
diff --git a/alib2algo/src/grammar/parsing/SLR1ParseTable.cpp b/alib2algo/src/grammar/parsing/SLR1ParseTable.cpp
new file mode 100644
index 0000000000..0b3025d18b
--- /dev/null
+++ b/alib2algo/src/grammar/parsing/SLR1ParseTable.cpp
@@ -0,0 +1,72 @@
+/*
+ * SLR1ParseTable.cpp
+ *
+ * Created on: 4. 5. 2016
+ * Author: Martin Kocicka
+ */
+
+#include "SLR1ParseTable.h"
+
+#include "LRParser.h"
+#include "LR0Parser.h"
+#include "Follow.h"
+
+#include <exception/CommonException.h>
+#include <label/LR0ItemsLabel.h>
+
+namespace grammar {
+
+namespace parsing {
+
+void SLR1ParseTable::insertToActionTable ( LRActionTable & actionTable, LRActionTable::key_type key, LRActionTable::mapped_type value ) {
+ std::pair<LRActionTable::iterator, bool> result = actionTable.insert ( { key, value } );
+ if ( ! result.second ) {
+ throw exception::CommonException ( "Grammar is not SLR(1)!" );
+ }
+}
+
+LRActionTable SLR1ParseTable::getActionTable ( grammar::CFG originalGrammar ) {
+ LRActionTable actionTable;
+ grammar::CFG augmentedGrammar = LRParser::getAugmentedGrammar ( originalGrammar );
+ automaton::DFA parsingAutomaton = LR0Parser::getAutomaton ( originalGrammar );
+ for ( const automaton::State & state : parsingAutomaton.getStates ( ) ) {
+ LR0Items items = static_cast < const label::LR0ItemsLabel & > ( state.getName ( ) . getData ( ) ) . getItems ( );
+ std::map < std::pair < automaton::State, alphabet::Symbol >, automaton::State > transitionsFromCurrentState = parsingAutomaton.getTransitionsFromState ( state );
+ for ( const LR0Items::value_type & nonterminalItems : items ) {
+ alphabet::Symbol leftHandSide = nonterminalItems.first;
+ for ( const std::pair < unsigned, std::vector < alphabet::Symbol > > & item : nonterminalItems.second ) {
+ unsigned position = item.first;
+ std::vector < alphabet::Symbol > rightHandSide = item.second;
+
+ if ( position == rightHandSide.size ( ) ) {
+ if ( leftHandSide == augmentedGrammar.getInitialSymbol ( ) ) {
+ insertToActionTable(actionTable, { state, LRParser::getEndOfInputSymbol(augmentedGrammar) }, { LRAction::Accept, state } );
+ continue;
+ }
+
+ grammar::parsing::FollowResult2 followSet = grammar::parsing::Follow::follow ( augmentedGrammar, leftHandSide );
+ std::pair < alphabet::Symbol, std::vector < alphabet::Symbol > > currentRule = { leftHandSide, rightHandSide };
+ for ( const std::variant < alphabet::Symbol, string::Epsilon > & followSymbol : followSet ) {
+ if ( followSymbol.is < alphabet::Symbol > ( ) ) {
+ insertToActionTable(actionTable, { state, followSymbol.get < alphabet::Symbol > ( ) }, { LRAction::Reduce, currentRule } );
+ } else {
+ insertToActionTable(actionTable, { state, LRParser::getEndOfInputSymbol(augmentedGrammar) }, { LRAction::Reduce, currentRule } );
+ }
+ }
+ continue;
+ }
+
+ alphabet::Symbol currentSymbol = rightHandSide[position];
+ if ( originalGrammar.getTerminalAlphabet ( ) . find ( currentSymbol ) != originalGrammar.getTerminalAlphabet ( ) . end ( ) ) {
+ insertToActionTable(actionTable, { state, currentSymbol }, { LRAction::Shift, transitionsFromCurrentState.find ( { state, currentSymbol } )->second } );
+ }
+ }
+ }
+ }
+
+ return actionTable;
+}
+
+} /* namespace parsing */
+
+} /* namespace grammar */
diff --git a/alib2algo/src/grammar/parsing/SLR1ParseTable.h b/alib2algo/src/grammar/parsing/SLR1ParseTable.h
new file mode 100644
index 0000000000..3f4c6a4b5a
--- /dev/null
+++ b/alib2algo/src/grammar/parsing/SLR1ParseTable.h
@@ -0,0 +1,31 @@
+/*
+ * SLR1ParseTable.h
+ *
+ * Created on: 4. 5. 2016
+ * Author: Martin Kocicka
+ */
+
+#ifndef SLR_1_PARSE_TABLE_H_
+#define SLR_1_PARSE_TABLE_H_
+
+#include "LRParser.h"
+
+#include <grammar/ContextFree/CFG.h>
+#include <grammar/parsing/LRParserTypes.h>
+
+namespace grammar {
+
+namespace parsing {
+
+class SLR1ParseTable {
+ static void insertToActionTable ( LRActionTable & actionTable, LRActionTable::key_type key, LRActionTable::mapped_type value );
+
+public:
+ static LRActionTable getActionTable ( grammar::CFG originalGrammar );
+};
+
+} /* namespace parsing */
+
+} /* namespace grammar */
+
+#endif /* SLR_1_PARSE_TABLE_H_ */
--
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