Bangla Script BNF Grammar

::= { <statement> }

::= <varDecl> ";"
                   | <assignment> ";"
                   | <ifStmt>
                   | <loopStmt>
                   | <ioStmt> ";"

::= "box" <ident> "=" <expr>

::= <ident> "=" <expr>

::= "if" "(" <expr> ")" "{" { <statement> } "}"
                   [ "else" "{" { <statement> } "}" ]

::= "loop" "(" <condList> ")" "{" { <statement> } "}"

::= <expr> { "," <expr> }

::= "output" "(" <expr> ")"
                   | "input" "(" <ident> ")"

::= <orExpr>

::= <andExpr> { ( "||" | "or" ) <andExpr> }

::= <compExpr> { ( "&&" | "and" ) <compExpr> }

::= <addExpr> [ ( "==" | "!=" | "<>" | "<" | ">" | "<=" | ">=" | "!<" | "!>" ) <addExpr> ]

::= <mulExpr> { ( "+" | "-" ) <mulExpr> }

::= <unaryExpr> { ( "*" | "/" | "%" ) <unaryExpr> }

::= ( "!" | "-" ) <unaryExpr> | <factor>

::= <number>
                   | <string>
                   | <ident>
                   | "(" <expr> ")"

::= <digits> [ "." <digits> ]

::= "\"" { <char> } "\"" | "'" { <char> } "'"

::= <letter> { <letter> | <digit> | "_" }

::= "A"–"Z" | "a"–"z"

::= "0"–"9"

– Open the runner page. Two boxes appear: the Code editor and the Scan Input field.
– The editor is pre­loaded with a sample program that shows variables, arithmetic, comparisons, loops, logic, and I/O.

– Declare with box name = expr; (numbers, strings, or expressions).
– Reassign with name = expr;.
– Arithmetic: +, -, *, /, %. Strings concatenate with +.

– Comparisons: ==, !=, <>, <, >, <=, >=, plus !< (>=) and !> (<=).
– Logic: ! for NOT, &&/and for AND, ||/or for OR.

– Conditional:
if (condition) { …   } else { …   }
– Loop:
- Fixed count: loop(5) { … } runs 5 times.
- While-style or combined conditions: loop(x < 5) or loop(x<3, y>0) repeats as long as all conditions are true.

– input(var); reads the next token from the Scan Input buffer (space-separated).
– output(expr); appends the value to the result area.

- Edit or replace the code in the editor.
- Provide any needed input tokens in Scan Input.
- Click Run. The interpreter will parse, evaluate, and display each output(...) result line by line.