1 files changed, 178 insertions, 0 deletions
diff --git a/src/pim/Scanner.cpp b/src/pim/Scanner.cpp
new file mode 100644
index 0000000..32e64d0
--- /dev/null
+++ b/src/pim/Scanner.cpp
@@ -0,0 +1,178 @@
+//Lexical analyser
+#include <algorithm>
+#include "Scanner.h"
+
+namespace pim
+{
+	namespace compiler
+	{
+		Scanner::Scanner(std::stringstream & source_) :
+			source(source_)
+		{
+			nextCharacter();
+		}
+
+		Token Scanner::NextToken()
+		{
+			//Read whitespace, newlines and comments
+			while(
+				cChar == ' ' ||	cChar == '\t' ||
+				cChar == '\r' || cChar == '\n' ||
+				cChar == '/')
+			{
+				if(cChar == '/')
+				{
+					nextCharacter();
+					if(cChar == '/')
+					{
+						while(cChar != '\n' && cChar != '\r')
+							nextCharacter();
+					}
+					else
+						return Token(Token::DivideSymbol, "/", cLine);
+				}
+
+				if(cChar == '\r')
+				{
+					nextCharacter();
+					if(cChar == '\n')
+						cLine++;
+					else
+						continue;
+				}
+				else if(cChar == '\n')
+					cLine++;
+
+				nextCharacter();
+			}
+
+			if(std::isalpha(cChar))	//Read alphanumeric symbols
+			{
+				cToken.clear();
+				while(std::isalpha(cChar) || std::isdigit(cChar))
+				{
+					cToken.push_back(cChar);
+					nextCharacter();
+				}
+
+				std::transform(cToken.begin(), cToken.end(), cToken.begin(), ::tolower);
+
+				for(int i = 0; i < Token::SymbolNumber; i++)
+					if(Token::SymbolNames[i] == cToken)
+						return Token(i, cToken, cLine);
+				return Token(Token::Identifier, cToken, cLine);
+			}
+			else if(std::isdigit(cChar)) //Read numeric constants
+			{
+				bool decimal = false;
+				cToken.clear();
+				while(std::isdigit(cChar))
+				{
+					cToken.push_back(cChar);
+					nextCharacter();
+				}
+				if(cChar == '.')
+				{
+					decimal = true;
+					cToken.push_back(cChar);
+					nextCharacter();
+					while(std::isdigit(cChar))
+					{
+						cToken.push_back(cChar);
+						nextCharacter();
+					}
+				}
+				if(decimal)
+					return Token(Token::DecimalConstant, cToken, cLine);
+				return Token(Token::IntegerConstant, cToken, cLine);
+			}
+			else if(cChar == '=')
+			{
+				nextCharacter();
+				if(cChar == '=')
+				{
+					nextCharacter();
+					return Token(Token::EqualSymbol, "==", cLine);
+				}
+				return Token(Token::AssignSymbol, "=", cLine);
+			}
+			else if(cChar == '!')
+			{
+				nextCharacter();
+				if(cChar == '=')
+					return Token(Token::NotEqualSymbol, "==", cLine);
+			}
+			else if(cChar == '(')
+			{
+				nextCharacter();
+				return Token(Token::LeftBracket, "(", cLine);
+			}
+			else if(cChar == ')')
+			{
+				nextCharacter();
+				return Token(Token::RightBracket, ")", cLine);
+			}
+			else if(cChar == '/')
+			{
+				nextCharacter();
+				return Token(Token::DivideSymbol, "/", cLine);
+			}
+			else if(cChar == '*')
+			{
+				nextCharacter();
+				return Token(Token::MultiplySymbol, "*", cLine);
+			}
+			else if(cChar == '+')
+			{
+				nextCharacter();
+				return Token(Token::PlusSymbol, "+", cLine);
+			}
+			else if(cChar == '-')
+			{
+				nextCharacter();
+				return Token(Token::MinusSymbol, "-", cLine);
+			}
+			else if(cChar == '%')
+			{
+				nextCharacter();
+				return Token(Token::ModuloSymbol, "%", cLine);
+			}
+			else if(cChar == '<')
+			{
+				nextCharacter();
+				if(cChar == '=')
+				{
+					return Token(Token::LessEqualSymbol, "<=", cLine);
+				}
+				return Token(Token::LessSymbol, "<", cLine);
+			}
+			else if(cChar == '>')
+			{
+				nextCharacter();
+				if(cChar == '=')
+				{
+					return Token(Token::GreaterEqualSymbol, ">=", cLine);
+				}
+				return Token(Token::GreaterSymbol, ">", cLine);
+			}
+			else if(cChar == ',')
+			{
+				nextCharacter();
+				return Token(Token::CommaSymbol, ",", cLine);
+			}
+			else
+			{
+				nextCharacter();
+				return Token(Token::InvalidSymbol, std::string(1, cChar), cLine);
+			}
+		}
+
+		void Scanner::nextCharacter()
+		{
+			if(source.good())
+				cChar = source.get();
+			else
+				cChar = 0;
+		}
+	}
+}
+\ No newline at end of file