From e4647f0ed4f48830f831f63a081a1df0725dabe2 Mon Sep 17 00:00:00 2001
From: Robin Jadoul <robin.jadoul@gmail.com>
Date: Tue, 31 Jan 2017 16:35:27 +0100
Subject: [PATCH] bf rewrite, fixes tests

---
 examples/brainfuck/generator.cpp |  51 +------------
 examples/brainfuck/generator.h   |  11 ++-
 examples/brainfuck/instruction.h | 120 ++++++++++++++++++++++++++++---
 examples/brainfuck/main.cpp      |   8 ++-
 examples/brainfuck/parser.cpp    |  76 +++++++++-----------
 examples/brainfuck/parser.h      |  10 +--
 6 files changed, 161 insertions(+), 115 deletions(-)

diff --git a/examples/brainfuck/generator.cpp b/examples/brainfuck/generator.cpp
index 82d3200..7afa64f 100644
--- a/examples/brainfuck/generator.cpp
+++ b/examples/brainfuck/generator.cpp
@@ -29,55 +29,10 @@
 namespace bf {
 
 void Generator::run() {
-	
-	counter = 0;
-	std::memset(array, 0, sizeof(array));
-	while (!lbrackets.empty())
-		lbrackets.pop();
-	
-	for (std::size_t instruct = 0; instruct < program.size(); instruct++) {
 
-		switch(program[instruct]) {
-		case Instruction::EMPTY: break;
-		case Instruction::PLUS: 
-			array[counter]++; 
-			break;
-		case Instruction::MINUS: 
-			array[counter]--; 
-			break;
-		case Instruction::GREATER: 
-			if (++counter == 30000) {
-				std::cout << "Tried to access unavailable memory" << std::endl;
-				return;
-			} break;
-		case Instruction::LESS:
-			if (--counter == -1) {
-				std::cout << "Tried to access unavailable memory" << std::endl;
-				return;
-			} break;
-		case Instruction::POINT:
-			std::cout << (char)array[counter];
-			break;
-		case Instruction::COMMA:
-			char c;
-			std::cin >> c; 
-			array[counter] = (int)c;
-			break;
-		case Instruction::LBRACKET: 
-			lbrackets.push(instruct);
-			if (array[counter] == 0) 
-				while (program[++instruct] != Instruction::RBRACKET) {}		
-			break;
-		case Instruction::RBRACKET: 
-			if (array[counter] != 0)  
-				instruct = lbrackets.top();
-			else 
-				lbrackets.pop();		
-			break;
-		default: // Won't happen
-			break;
-		}
-	} 
+    std::size_t data_ptr = 0;
+    for (auto& i : m_program)
+        i->execute(m_data, data_ptr);
 }
 
 
diff --git a/examples/brainfuck/generator.h b/examples/brainfuck/generator.h
index 9e93ed1..460d3c6 100644
--- a/examples/brainfuck/generator.h
+++ b/examples/brainfuck/generator.h
@@ -33,17 +33,14 @@ namespace bf {
 class Generator {
 
 public:
-	Generator(std::deque<Instruction> program) :
-		program(program) { }
+	Generator(std::deque<std::unique_ptr<Instruction>>&& program) :
+		m_program(std::move(program)) { }
 
 	void run();
 
 private:
-	std::deque<Instruction> program;
-	int array[30000];
-	int counter;
-	std::stack<int> lbrackets;
-
+	std::deque<std::unique_ptr<Instruction>> m_program;
+    std::array<int, 30000> m_data;
 };
 
 } // namespace bf
diff --git a/examples/brainfuck/instruction.h b/examples/brainfuck/instruction.h
index c658454..94ed838 100644
--- a/examples/brainfuck/instruction.h
+++ b/examples/brainfuck/instruction.h
@@ -25,18 +25,118 @@
 #ifndef INSTRUCTION_H
 #define INSTRUCTION_H
 
+#include <array>
+#include <deque>
+#include <iostream>
+#include <memory>
+
 namespace bf {
 
-enum class Instruction {
-    EMPTY,
-    PLUS,
-    MINUS,
-    GREATER,
-    LESS,
-    POINT,
-    COMMA,
-    LBRACKET,
-    RBRACKET
+using Data = std::array<int, 30000>;
+
+class Instruction {
+    public:
+        virtual void execute(Data& d, std::size_t& data_ptr) const = 0;
+        virtual void print() const = 0;
+};
+
+class InstructionRight : public Instruction {
+    public:
+        void execute(Data&, std::size_t& data_ptr) const {
+            data_ptr++;
+            if (data_ptr >= 30000) {
+                std::cerr << "Out of bounds" << std::endl;
+                std::exit(1);
+            }
+        };
+
+        void print() const {
+            std::cout << ">";
+        }
+};
+
+class InstructionLeft : public Instruction {
+    public:
+        void execute(Data&, std::size_t& data_ptr) const {
+            data_ptr--;
+            if (data_ptr >= 30000) { //wraps around when below 0
+                std::cerr << "Out of bounds" << std::endl;
+                std::exit(1);
+            }
+        };
+
+        void print() const {
+            std::cout << "<";
+        }
+};
+
+class InstructionInc : public Instruction {
+    public:
+        void execute(Data& d, std::size_t& ptr) const {
+            d[ptr]++;
+        }
+
+        void print() const {
+            std::cout << "+";
+        }
+};
+
+class InstructionDec : public Instruction {
+    public:
+        void execute(Data& d, std::size_t& ptr) const {
+            d[ptr]--;
+        }
+
+        void print() const {
+            std::cout << "-";
+        }
+};
+
+class InstructionOut : public Instruction {
+    public:
+        void execute(Data& d, std::size_t& ptr) const {
+            std::cout << static_cast<char>(d[ptr]);
+        }
+
+        void print() const {
+            std::cout << ".";
+        }
+};
+
+class InstructionIn : public Instruction {
+    public:
+        void execute(Data& d, std::size_t& ptr) const {
+            char c = -1;
+            if (!std::cin.eof())
+                std::cin.get(c);
+            d[ptr] = c;
+        }
+
+        void print() const {
+            std::cout << ",";
+        }
+};
+
+class InstructionLoop : public Instruction {
+    public:
+        InstructionLoop(std::deque<std::unique_ptr<Instruction>>&& body) : m_body(std::move(body)) {};
+
+        void execute(Data& d, std::size_t& ptr) const {
+            while (d[ptr] != 0) {
+                for (auto& b : m_body)
+                    b->execute(d, ptr);
+            }
+        }
+
+        void print() const {
+            std::cout << "[";
+            for (auto& b : m_body)
+                b->print();
+            std::cout << "]";
+        }
+
+    private:
+        std::deque<std::unique_ptr<Instruction>> m_body;
 };
 
 }
diff --git a/examples/brainfuck/main.cpp b/examples/brainfuck/main.cpp
index ed7a71f..392a55e 100644
--- a/examples/brainfuck/main.cpp
+++ b/examples/brainfuck/main.cpp
@@ -31,11 +31,15 @@ using namespace std;
 using namespace bf;
 
 int main(int argc, char** argv) {
-	
+    if (argc != 2) {
+        std::cerr << "Usage: bf <file.bf>" << std::endl;
+        std::exit(1);
+    }
+
 	ifstream file(argv[1]);	
     BfLexer lex(file);
     Parser parser(lex);
-	Generator gen(*(parser.parse()));
+	Generator gen(std::move(*(parser.parse().release())));
 	gen.run();
 
 	return 0;
diff --git a/examples/brainfuck/parser.cpp b/examples/brainfuck/parser.cpp
index 1d4f243..2c98d1e 100644
--- a/examples/brainfuck/parser.cpp
+++ b/examples/brainfuck/parser.cpp
@@ -29,55 +29,45 @@
 namespace bf {
 
 Parser::Parser(BfLexer lex) : 
-	bfParser<std::unique_ptr<std::deque<Instruction>>>(), m_lex(lex) {
+	bfParser<std::unique_ptr<std::deque<std::unique_ptr<Instruction>>>>(), m_lex(lex) {
 }
 
 Parser::Token Parser::lex() {
 	try {
 		
 		BfLexer::Token orig = m_lex.nextToken();
-		std::deque<Instruction> pm;
+        auto pm = std::make_unique<std::deque<std::unique_ptr<Instruction>>>();
 		switch(orig.type) {
 			case BfLexer::PLUS: {
-				pm.push_back(Instruction::PLUS);
-				std::unique_ptr<std::deque<Instruction>> p = std::make_unique<std::deque<Instruction>>(pm);
-				//std::cout << "PARSING: found PLUS " << (int)Instruction::PLUS << std::endl;
-				return Token{ bfParser_Symbol::T_PLUS, std::move(p) };
+				pm->push_back(std::make_unique<InstructionInc>());
+				//std::cout << "PARSING: found PLUS " << (int)std::unique_ptr<Instruction>::PLUS << std::endl;
+				return Token{ bfParser_Symbol::T_PLUS, std::move(pm) };
 			} case BfLexer::MINUS: {                  
-				pm.push_back(Instruction::MINUS);
-                std::unique_ptr<std::deque<Instruction>> p = std::make_unique<std::deque<Instruction>>(pm);
-				//std::cout << "PARSING: found MINUS" << (int)Instruction::MINUS << std::endl;
-                return Token{ bfParser_Symbol::T_MINUS, std::move(p) };
+				pm->push_back(std::make_unique<InstructionDec>());
+				//std::cout << "PARSING: found MINUS" << (int)std::unique_ptr<Instruction>::MINUS << std::endl;
+                return Token{ bfParser_Symbol::T_MINUS, std::move(pm) };
 			} case BfLexer::GREATER: {
-				pm.push_back(Instruction::GREATER);
-            	std::unique_ptr<std::deque<Instruction>> p = std::make_unique<std::deque<Instruction>>(pm);
-				//std::cout << "PARSING: found GREATER" << (int)Instruction::GREATER << std::endl;
-	    		return Token{ bfParser_Symbol::T_GREATER, std::move(p) };
+				pm->push_back(std::make_unique<InstructionRight>());
+				//std::cout << "PARSING: found GREATER" << (int)std::unique_ptr<Instruction>::GREATER << std::endl;
+	    		return Token{ bfParser_Symbol::T_GREATER, std::move(pm) };
 			} case BfLexer::LESS: {
-				pm.push_back(Instruction::LESS);
-                std::unique_ptr<std::deque<Instruction>> p = std::make_unique<std::deque<Instruction>>(pm);
-				//std::cout << "PARSING: found LESS" << (int)Instruction::LESS << std::endl;
-                return Token{ bfParser_Symbol::T_LESS, std::move(p) };
+				pm->push_back(std::make_unique<InstructionLeft>());
+				//std::cout << "PARSING: found LESS" << (int)std::unique_ptr<Instruction>::LESS << std::endl;
+                return Token{ bfParser_Symbol::T_LESS, std::move(pm) };
 			} case BfLexer::POINT: {
-				pm.push_back(Instruction::POINT);
-                std::unique_ptr<std::deque<Instruction>> p = std::make_unique<std::deque<Instruction>>(pm);
-				//std::cout << "PARSING: found POINT" << (int)Instruction::POINT << std::endl;
-                return Token{ bfParser_Symbol::T_POINT, std::move(p) };
+				pm->push_back(std::make_unique<InstructionOut>());
+				//std::cout << "PARSING: found POINT" << (int)std::unique_ptr<Instruction>::POINT << std::endl;
+                return Token{ bfParser_Symbol::T_POINT, std::move(pm) };
 			} case BfLexer::COMMA: {
-				pm.push_back(Instruction::COMMA);
-                std::unique_ptr<std::deque<Instruction>> p = std::make_unique<std::deque<Instruction>>(pm);
-				//std::cout << "PARSING: found COMMA" << (int)Instruction::COMMA << std::endl;
-                return Token{ bfParser_Symbol::T_COMMA, std::move(p) };
+				pm->push_back(std::make_unique<InstructionIn>());
+				//std::cout << "PARSING: found COMMA" << (int)std::unique_ptr<Instruction>::COMMA << std::endl;
+                return Token{ bfParser_Symbol::T_COMMA, std::move(pm) };
 			} case BfLexer::LBRACKET: {
-				pm.push_back(Instruction::LBRACKET);
-                std::unique_ptr<std::deque<Instruction>> p = std::make_unique<std::deque<Instruction>>(pm);
-				//std::cout << "PARSING: found LBRACKET" << (int)Instruction::LBRACKET << std::endl;
-                return Token{ bfParser_Symbol::T_LBRACKET, std::move(p) };
+				//std::cout << "PARSING: found LBRACKET" << (int)std::unique_ptr<Instruction>::LBRACKET << std::endl;
+                return Token{ bfParser_Symbol::T_LBRACKET, nullptr };
 			} case BfLexer::RBRACKET: {
-				pm.push_back(Instruction::RBRACKET);
-                std::unique_ptr<std::deque<Instruction>> p = std::make_unique<std::deque<Instruction>>(pm);
-				//std::cout << "PARSING: found RBRACKET" << (int)Instruction::RBRACKET << std::endl;
-                return Token{ bfParser_Symbol::T_RBRACKET, std::move(p) };
+				//std::cout << "PARSING: found RBRACKET" << (int)std::unique_ptr<Instruction>::RBRACKET << std::endl;
+                return Token{ bfParser_Symbol::T_RBRACKET, nullptr };
 			}
             default:
                 return Token { bfParser_Symbol::T_EOF, nullptr };
@@ -87,27 +77,27 @@ Parser::Token Parser::lex() {
 	}
 }
 
-std::unique_ptr<std::deque<Instruction>> Parser::reduce_PROGRAM(std::deque<Token> subparts) {
+std::unique_ptr<std::deque<std::unique_ptr<Instruction>>> Parser::reduce_PROGRAM(std::deque<Token> subparts) {
 	// <program> ::= <instruction> <program>
 	for(auto& instr : *(subparts[1].value))
-		subparts[0].value->push_back(instr);
+		subparts[0].value->push_back(std::move(instr));
 	return std::move(subparts[0].value);
 }
-std::unique_ptr<std::deque<Instruction>> Parser::reduce_EMPTY(std::deque<Token>) { 
+std::unique_ptr<std::deque<std::unique_ptr<Instruction>>> Parser::reduce_EMPTY(std::deque<Token>) { 
 	// <program> ::=
-	return std::make_unique<std::deque<Instruction>>();
+	return std::make_unique<std::deque<std::unique_ptr<Instruction>>>();
 }
-std::unique_ptr<std::deque<Instruction>> Parser::reduce_OPERATION(std::deque<Token> subparts) { 
+std::unique_ptr<std::deque<std::unique_ptr<Instruction>>> Parser::reduce_OPERATION(std::deque<Token> subparts) { 
 	// <instruction> ::= "PLUS" | "MINUS" | ... | "COMMA"
 	return std::move(subparts[0].value);
 }
-std::unique_ptr<std::deque<Instruction>> Parser::reduce_LOOP(std::deque<Token> subparts) {
+std::unique_ptr<std::deque<std::unique_ptr<Instruction>>> Parser::reduce_LOOP(std::deque<Token> subparts) {
 	// <instruction> ::= "LBRACKET" <program> "RBRACKET"
-	subparts[1].value->push_front(Instruction::LBRACKET);
-	subparts[1].value->push_back(Instruction::RBRACKET);
+    auto res = std::make_unique<std::deque<std::unique_ptr<Instruction>>>();
+	res->push_back(std::make_unique<InstructionLoop>(std::move(*subparts[1].value.release())));
+    return res;
 	//std::cout << "PARSING: found LOOP" << std::endl;	
 	//for(auto& s : *(subparts[1].value)) std::cout << "LOOP: " << (int)s << std::endl;
-	return std::move(subparts[1].value);
 }
 
 
diff --git a/examples/brainfuck/parser.h b/examples/brainfuck/parser.h
index 7e2b010..8c196a7 100644
--- a/examples/brainfuck/parser.h
+++ b/examples/brainfuck/parser.h
@@ -33,17 +33,17 @@
 
 namespace bf {
 
-class Parser : public bfParser<std::unique_ptr<std::deque<Instruction>>> {
+class Parser : public bfParser<std::unique_ptr<std::deque<std::unique_ptr<Instruction>>>> {
 public:
 	Parser(BfLexer lex);
 
 protected:
 	Token lex() override;
 	
-	std::unique_ptr<std::deque<Instruction>> reduce_PROGRAM(std::deque<Token> subparts) override;
-	std::unique_ptr<std::deque<Instruction>> reduce_EMPTY(std::deque<Token> subparts) override;
-	std::unique_ptr<std::deque<Instruction>> reduce_OPERATION(std::deque<Token> subparts) override;
-	std::unique_ptr<std::deque<Instruction>> reduce_LOOP(std::deque<Token> subparts) override;
+	std::unique_ptr<std::deque<std::unique_ptr<Instruction>>> reduce_PROGRAM(std::deque<Token> subparts) override;
+	std::unique_ptr<std::deque<std::unique_ptr<Instruction>>> reduce_EMPTY(std::deque<Token> subparts) override;
+	std::unique_ptr<std::deque<std::unique_ptr<Instruction>>> reduce_OPERATION(std::deque<Token> subparts) override;
+	std::unique_ptr<std::deque<std::unique_ptr<Instruction>>> reduce_LOOP(std::deque<Token> subparts) override;
 
 private:
 	BfLexer m_lex;