ELox

A Elixir port of jlox, the Lox language's AST interpreter (http://www.craftinginterpreters.com/). This is still a work in progress.

What has been done so far?

Lexical Analysis

Done!

Parsing/Interpreter:

Everything except classes and closures.

Grammar:

program      declaration* EOF ;

declaration  varDecl
            | funDecl
            | statement ;

statement    exprStmt
            | ifStmt
            | printStmt 
            | returnStmt
            | whileStmt
            | forStmt
            | block ;

funDecl   "fun" function ;
function  IDENTIFIER "(" parameters? ")" block ;

forStmt    "for" "(" ( varDecl | exprStmt | ";" )
                      expression? ";"
                      expression? ")" statement ;

block  "{" declaration* "}" ;

ifStmt     "if" "(" expression ")" statement ( "else" statement )? ;

varDecl  "var" IDENTIFIER ( "=" expression )? ";" ;

exprStmt   expression ";" ;
printStmt  "print" expression ";" ;

whileStmt  "while" "(" expression ")" statement ;

returnStmt  "return" expression? ";" ;

expression  assignment ;
assignment  identifier "=" assignment
           | equality
           | logic ;

logic    equality ( ( "or" | "and" ) logic )* ;

equality        comparison ( ( "!=" | "==" ) comparison )* ;
comparison      addition ( ( ">" | ">=" | "<" | "<=" ) addition )* ;
addition        multiplication ( ( "-" | "+" ) multiplication )* ;
multiplication  unary ( ( "/" | "*" ) unary )* ;

unary           ( "!" | "-" ) unary
               | call ;

call   primary ( "(" arguments? ")" )* ";" ;

arguments  expression ( "," expression )* ;

primary         NUMBER | STRING | "false" | "true" | "nil" | IDENTIFIER
               | "(" expression ")" ;

expression  literal
           | unary
           | binary
           | grouping ;

literal     NUMBER | STRING | "false" | "true" | "nil" | IDENTIFIER;
grouping    "(" expression ")" ;
unary       ( "-" | "!" ) expression ;
binary      expression operator expression ;
operator    "==" | "!=" | "<" | "<=" | ">" | ">="
           | "+"  | "-"  | "*" | "/" ;