A Parser is a program that reads the tokens and converts it into an abstract syntax tree (AST). It is the second part of an interpreter. What the usage looks like // for an input `let five = 5;` input := `let five = 5;` l := lexer.New(input) p := parser.New(l) // result is a list of statements result := []ast.Statement{ &ast.LetStatement{ Token: token.Token{Type: token.LET, Literal: "let"}, Name: &ast.Identifier{ Token: token....
A Lexer is a program that reads the code and converts it into tokens. It is the first part of an interpreter. What the usage looks like // for an input `let five = 5;` input := `let five = 5;` l := lexer.New(input) // result is a list of tokens result := []tokens.Token{ {Type: tokens.LET, Literal: "let"}, {Type: tokens.IDENT, Literal: "five"}, {Type: tokens.ASSIGN, Literal: "="}, {Type: tokens.INT, Literal: "5"}, {Type: tokens....
An interpreter is a program that reads and executes code. It is a way to execute code without compiling it. It is a great way to execute code on the fly. It is used in many places like scripting languages, command line tools, etc. Parts of an Interpreter ( Simplified ) A minimal interpreter can be represented in 3 parts: lexer: It reads the code and converts it into tokens. parser: It reads the tokens and converts it into an abstract syntax tree (AST)....
Grammer in computer science is a set of rules that defines the structure of a language. It defines a language in a structured way and parsers are built based on it. BNF Backus-Naur Form, or BNF, is a notation technique used to express context-free grammars. It is used to define syntax of programming languages, datastructures, etc. EBNF Extended Backus-Naur Form, or EBNF, is a notation technique used to express context-free grammars....