Add parser

16 files changed, 179 insertions, 24 deletions

diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 89b60e6..9265ad8 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -11,7 +11,16 @@ target_include_directories(Pico-I2C-LCD INTERFACE ../libs/Pico-I2C-LCD/)
 target_include_directories(Pico-I2C-LCD PUBLIC ../libs/Pico-I2C-LCD/)
 
 # Main executable
-add_executable(pico-calc pico-calc.cpp calculator.cpp tokenizer.cpp)
+add_executable(pico-calc pico-calc.cpp
+  calculator.cpp
+  tokenizer.cpp
+  operand.cpp
+  syntax_tree.cpp
+  sum.cpp
+  substraction.cpp
+  product.cpp
+)
 target_link_libraries(pico-calc
   hardware_i2c Pico-I2C-LCD pico-keypad hardware_timer)
 target_include_directories(pico-calc PUBLIC include exceptions)
+pico_add_extra_outputs(pico-calc)
diff --git a/src/calculator.cpp b/src/calculator.cpp
index 5de706b..4dd8dcd 100644
--- a/src/calculator.cpp
+++ b/src/calculator.cpp
@@ -27,14 +27,20 @@ Calculator::~Calculator() {
 void Calculator::run() {
   while(true) {
     display->Clear();
-    std::string input;
-    short str_len = 0;
     char pressed_key = default_keypad->getKey();
     
     if(pressed_key == '\0')
       continue;
 
-    while(str_len <= 15) {
+    processInputs();
+}
+
+void Calculator::processInputs() {
+  char pressed_key;
+  short str_len = 0;
+  std::string input;
+  
+  while(str_len <= 15) {
       pressed_key = default_keypad->getKey();
 
       if(pressed_key != '\0' && pressed_key != '=') {
@@ -44,7 +50,7 @@ void Calculator::run() {
       }
 
       if(pressed_key == '=') {
-	std::array tokens = tokenizer.tokenize(input);
+	tokens = tokenizer.tokenize(input);
 	break;
       }
 
diff --git a/src/include/calculator.hpp b/src/include/calculator.hpp
index 8c5e97a..2362258 100644
--- a/src/include/calculator.hpp
+++ b/src/include/calculator.hpp
@@ -8,9 +8,11 @@
 
 class Calculator {
 private:
+  // Private attributes.
   LCD_I2C *display;
   Keypad *default_keypad;
   Tokenizer tokenizer = Tokenizer();
+  Token **tokens;
   char default_keypad_chars[4][4] = {
     {'1', '2', '3', '+'},
     {'4', '5', '6', '-'},
@@ -25,6 +27,10 @@ private:
   };
   uint keypad_col_pins[4] = {6, 7, 8, 9};
   uint keypad_row_pins[4] = {16, 17, 18, 19};
+  // End of private attributes.
+  // Private methods.
+  void processInputs();
+  // End of private methods.
 public:
   Calculator();
   ~Calculator();
diff --git a/src/include/operand.hpp b/src/include/operand.hpp
new file mode 100644
index 0000000..cc638de
--- /dev/null
+++ b/src/include/operand.hpp
@@ -0,0 +1,10 @@
+#pragma once
+#include "syntax_tree.hpp"
+
+
+class Operand: SyntaxTree {
+  int value;
+public:
+  Operand(int value);
+  float eval() const;
+};
diff --git a/src/include/parser.hpp b/src/include/parser.hpp
new file mode 100644
index 0000000..7bc7997
--- /dev/null
+++ b/src/include/parser.hpp
@@ -0,0 +1,24 @@
+/* Grammar
+ * Expression --> Term PrimeExpression
+ * PrimeExpression --> (+|-)Expression | Null
+ * Term --> Factor PrimeTerm
+ * PrimeTerm --> (*|/)Term | Null
+ * Factor --> -Expression | (Expression) | operand */
+#pragma once
+#include "tokenizer.hpp"
+#include "syntax_tree.hpp"
+
+
+class Parser {
+private:
+  // Private methods.
+  void parseExpression();
+  void parsePrimeExpression();
+  void parseTerm();
+  void parsePrimeTerm();
+  void parseFactor();
+  // End of private methods.
+public:
+  Parser();
+  const SyntaxTree *parse();
+};
diff --git a/src/include/product.hpp b/src/include/product.hpp
new file mode 100644
index 0000000..1a87f80
--- /dev/null
+++ b/src/include/product.hpp
@@ -0,0 +1,9 @@
+#pragma once
+#include "syntax_tree.hpp"
+
+
+class Product: SyntaxTree {
+public:
+  Product(SyntaxTree *left, SyntaxTree *right);
+  float eval() const;
+};
diff --git a/src/include/substraction.hpp b/src/include/substraction.hpp
new file mode 100644
index 0000000..4a5a8c7
--- /dev/null
+++ b/src/include/substraction.hpp
@@ -0,0 +1,8 @@
+#pragma once
+#include "syntax_tree.hpp"
+
+class Substraction: SyntaxTree {
+public:
+  Substraction(SyntaxTree *left, SyntaxTree *right);
+  float eval() const;
+};
diff --git a/src/include/sum.hpp b/src/include/sum.hpp
new file mode 100644
index 0000000..35d6736
--- /dev/null
+++ b/src/include/sum.hpp
@@ -0,0 +1,8 @@
+#pragma once
+#include "syntax_tree.hpp"
+
+class Sum: SyntaxTree {
+public:
+  Sum(SyntaxTree *left, SyntaxTree *right);
+  float eval() const;
+};
diff --git a/src/include/syntax_tree.hpp b/src/include/syntax_tree.hpp
new file mode 100644
index 0000000..9edf23c
--- /dev/null
+++ b/src/include/syntax_tree.hpp
@@ -0,0 +1,12 @@
+#pragma once
+#include "tokenizer.hpp"
+
+class SyntaxTree {
+protected:
+  const SyntaxTree *left {};
+  const SyntaxTree *right {};
+public:
+  SyntaxTree(SyntaxTree *left = nullptr, SyntaxTree *right = nullptr);
+  virtual ~SyntaxTree();
+  virtual float eval() const = 0;
+};
diff --git a/src/include/tokenizer.hpp b/src/include/tokenizer.hpp
index a3f9998..7d00055 100644
--- a/src/include/tokenizer.hpp
+++ b/src/include/tokenizer.hpp
@@ -1,7 +1,7 @@
 #pragma once
 #include <regex>
 #include <string>
-#include <array>
+#define TOKENS_ARRAY_LEN 16
 
 enum Type {
   operand,
@@ -11,7 +11,8 @@ enum Type {
   division,
   left_parens,
   right_parens,
-  equals
+  equals,
+  nil
 };
 
 struct Token {
@@ -22,14 +23,14 @@ struct Token {
 class Tokenizer {
 private:
   // Private attributes
-  std::array<Token *, 16> tokens;
+  Token *tokens[17];
   const std::string *to_tokenize;
   size_t current_char_index;
   short tokens_head;
   // Regexes
-  std::regex operand_regex = std::regex("^0{1}|\\d+");
-  std::regex operation_regex = std::regex("\\+|-|/|\\*");
-  std::regex parens_regex = std::regex("(|)");
+  std::regex operand_regex = std::regex("^0{1}|^\\d+");
+  std::regex operation_regex = std::regex("^\\+|^-|/|^\\*");
+  std::regex parens_regex = std::regex("^\\(|^\\)");
   // End of private attributes
   // Private methods
   void clearTokens();
@@ -42,6 +43,6 @@ private:
 public:
   Tokenizer();
   ~Tokenizer();
-  const std::array<Token *, 16> &tokenize(const std::string &operation);
-  const std::array<Token *, 16> &getTokens();
+  Token **tokenize(const std::string &operation);
+  Token **getTokens();
 };
diff --git a/src/operand.cpp b/src/operand.cpp
new file mode 100644
index 0000000..67654f0
--- /dev/null
+++ b/src/operand.cpp
@@ -0,0 +1,13 @@
+#include "include/operand.hpp"
+#include "include/syntax_tree.hpp"
+#include "include/tokenizer.hpp"
+
+
+Operand::Operand(int value)
+  : SyntaxTree{nullptr, nullptr}
+  ,value{value}
+{}
+
+float Operand::eval() const {
+  return value;
+}
diff --git a/src/product.cpp b/src/product.cpp
new file mode 100644
index 0000000..093aff1
--- /dev/null
+++ b/src/product.cpp
@@ -0,0 +1,11 @@
+#include "include/product.hpp"
+#include "include/syntax_tree.hpp"
+
+
+Product::Product(SyntaxTree *left, SyntaxTree *right)
+  : SyntaxTree{left, right}
+{}
+
+float Product::eval() const {
+  return left->eval() * right->eval();
+}
diff --git a/src/substraction.cpp b/src/substraction.cpp
new file mode 100644
index 0000000..ba995b5
--- /dev/null
+++ b/src/substraction.cpp
@@ -0,0 +1,10 @@
+#include "include/substraction.hpp"
+#include "include/syntax_tree.hpp"
+
+
+Substraction::Substraction(SyntaxTree *left, SyntaxTree *right)
+  : SyntaxTree{left, right} {}
+
+float Substraction::eval() const {
+  return left->eval() - right->eval();
+}
diff --git a/src/sum.cpp b/src/sum.cpp
new file mode 100644
index 0000000..aa77d4e
--- /dev/null
+++ b/src/sum.cpp
@@ -0,0 +1,9 @@
+#include "include/sum.hpp"
+#include "include/syntax_tree.hpp"
+
+
+Sum::Sum(SyntaxTree *left, SyntaxTree *right) : SyntaxTree{left, right} {}
+
+float Sum::eval() const {
+  return left->eval() + left->eval();
+}
diff --git a/src/syntax_tree.cpp b/src/syntax_tree.cpp
new file mode 100644
index 0000000..83b5d60
--- /dev/null
+++ b/src/syntax_tree.cpp
@@ -0,0 +1,13 @@
+#include "include/syntax_tree.hpp"
+
+SyntaxTree::SyntaxTree(SyntaxTree *left,
+		       SyntaxTree *right)
+  : left{left}, right{right} {}
+
+SyntaxTree::~SyntaxTree() {
+  if(left != nullptr)
+    delete left;
+
+  if(right != nullptr)
+    delete right;
+}
diff --git a/src/tokenizer.cpp b/src/tokenizer.cpp
index a156000..783803e 100644
--- a/src/tokenizer.cpp
+++ b/src/tokenizer.cpp
@@ -1,11 +1,11 @@
 #include <string>
-#include <array>
 #include "include/tokenizer.hpp"
 #include "exceptions/tokenizer_exception.hpp"
 
 Tokenizer::Tokenizer() {
-  tokens.fill(nullptr);
   tokens_head = 0;
+  for(int i = 0; i < TOKENS_ARRAY_LEN; ++i)
+    tokens[i] = nullptr;
 }
 
 Tokenizer::~Tokenizer() {
@@ -13,10 +13,14 @@ Tokenizer::~Tokenizer() {
 }
 
 void Tokenizer::clearTokens() {
-  for(auto token{ tokens.begin() }; *token != nullptr; ++token)
-    delete token;
-
-  tokens.fill(nullptr);
+  tokens_head = 0;
+  
+  for(int i = 0; i < TOKENS_ARRAY_LEN; ++i) {
+    if(tokens[i] != nullptr) {
+      delete tokens[i];
+      tokens[i] = nullptr;
+    }
+  }
 }
 
 void Tokenizer::insertToken(Type type, int value = 0) {
@@ -27,8 +31,8 @@ void Tokenizer::insertToken(Type type, int value = 0) {
 }
 
 
-const std::array<Token *, 16>
-&Tokenizer::tokenize(const std::string &operation) {
+Token **Tokenizer::tokenize(const std::string &operation) {
+  clearTokens();
   to_tokenize = &operation;
   current_char_index = 0;
   
@@ -44,6 +48,8 @@ const std::array<Token *, 16>
       throw TokenizerException("Invalid character detected.");
   }
 
+  // "Nil" terminated array. Intended to be the epsilon terminal in the grammar.
+  tokens[tokens_head] = new Token { .type = nil, .value = 0 };
   return getTokens();
 }
 
@@ -72,7 +78,7 @@ void Tokenizer::matchParens(const std::string &operation) {
 
   std::string remaining(operation.substr(current_char_index)); 
   bool result = std::regex_search(remaining, match,
-				  operand_regex);
+				  parens_regex);
 
   if(!result)
     return;
@@ -97,7 +103,7 @@ void Tokenizer::matchOperation(const std::string &operation) {
 
   std::string remaining(operation.substr(current_char_index)); 
   bool result = std::regex_search(remaining, match,
-				  operand_regex);
+				  operation_regex);
 
   if(!result)
     return;
@@ -120,6 +126,6 @@ void Tokenizer::matchOperation(const std::string &operation) {
   current_char_index += 1;
 }
 
-const std::array<Token *, 16> &Tokenizer::getTokens() {
+Token **Tokenizer::getTokens() {
   return tokens;
 }