Build a Complete Programming Language

This video shows you how to install the Gold Parser. Visit this link to download it http://www.goldparser.org/

In this lecture you will start writing your first line of your own programming language using BNF mate language provided by Gold parser

After this lecture you will be able to write the grammar for Expressions and how is it describe in most programming languages.

The if statement here will be like most programming language but instead of else if I put elif

In this lecture I will define some of the known data types 

Today lecture I'll do method declaration with single parameter and multi-parameter.

After declaring function we need to call them when ever we need them. So, today I try to show how to call them. 

In this lecture I will show you how to write the grammar of the Array, but I will not do the implementation of it because it takes ages to do it. So, try it yourself.

Input function is our second build in function in our language which reads the input from the user. In this section we'll write only the grammar the implementation will be in the next section.

This tour it will be useful for you guys because I will show you how to download grammars of any existing programming language and you can see their syntax. 

This is nothing more than a summary of the section. I'll discuss with you what we have done in the section.

this you can visit python.org to download the python shell. If you not familiar with it you feel free to use java , c# ,c++ or any other.

After teaching the lexer how to recognize the print in this lecture I'll parse the print statement and show the result on screen.

Here I will show to run python file in many different way and how you can debug it using Visual Studio.  

First w should make the lexer distinguish between the number and expression. So, if the lexer sees just number it will return number. On other hand if it sees number followed by +,-,*,or / it will return expression. 

In order to evaluate expression we need to use stack to push tokens into it and then pop them and parse each tokens, but this process takes ages to do. So, we will use a build in function in python we'll pass it the expression and it evaluate it and return the result. 

We said that variable starts with ($) then name of the variable. This how we can recognize them.

We will store the value of the variable in symbol table. what is symbol table? symbol table is connect to lexer and parser. We store the value in it and when ever the variable's value needed we can retrieve the value.

To implement greater and less than we need to add any number or variable we see before adding greater or less than. How? we will sit a flag when ever lexer sees a number the flag will be 1. Next step is add the number before check if the next token is > or <. Then add the operator.