A pretty primitive custom scripting language implementation.
Making it according to Crafting Interpreters
Made with Java to learn concepts.
If I won't leave this idea, also there will be a cLox implementation in the future.
Run script with (must be executed with java >= 18)
java -jar jLox.jar [path/to/script]Lox scripts must have .lox extension.
If there is no script provided to interpreter a prompt will be started, and a user can type in code in interactive mode. All the variables will be stored for the time of interpreter's execution.
The Lox language is a c-style scripting language with an implementation in Java. Lox is a dynamically typed language and at moment it supports the most basic toolset such as arithmetic, logic operations and global variables.
Lox supports expressions with literals. The most basic expressions in lox will be
"hello";
10;
Also an important thing to remember is that semicolon IS mandatory on the end of each statement. Multiple statements can be placed on the same line making a
"hello"; "world";
a prefectly correct program.
Lox supports string, number, boolean literals and nil (instead of a null). Lox has no destiction between integer and double values, it's all number to it.
A variable can be declared with a var keyword. There are examples of correct variable declaration and initialization:
var a;
var a = 10;
var b = a;
var c = b = a = 12; // a, b and c all are equal to 12 at this point
Until variable is assigned a value it has nil as a value.
All the arithmetic operations are possible between any two numbers or expressions which are evaluated into a number. Also if some of the oprands in addition is a string, the second one will be casted to a string and the values will be concatenated. Negation is posible only with numbers.
Comparison is possible only between two numbers. Exception is != and == operators which can compare all types of expressions. There is no type casting in the process
Every expression with value different from nil, "", 0, false is truthy.
Lox has a print keyword. It will print into the console the expression to the reght of the print.
print a = 10; // Will print "10"
Lox supports oneline comments and block comments. Block comments can be nested.
// it's a one line comment
var a; // comment can be also here
/*
This is a block comment
*/
/**********************************
*
* This is also a block comment.
*
*********************************/
/* And this will be a nested comment block.
/* Outer
/* Inner */
*/
*/