Robot Programming Language

Complete Formal Specification (BNF)

Version 1.0

This document defines the complete formal syntax and static semantic rules of the Robot Programming Language.
The grammar is expressed using Backus–Naur Form (BNF) with minimal EBNF extensions.

1. NOTATIONAL CONVENTIONS

2. Non-terminals are enclosed in angle brackets:

3. Terminals are written as literal strings: "int"
4. | denotes alternation
5. { X } denotes zero or more repetitions
6. [ X ] denotes an optional element

BNF defines syntax only. Semantic constraints are defined separately.

1. LEXICAL STRUCTURE

2.1 Character Classes

::= "A" | ... | "Z" | "a" | ... | "z"

::= "0" | "1" | "2" | "3" | "4" | "5" | "6" | "7" | "8" | "9"

::= "_"

2.2 Identifiers

::= { | | }

Rules:

• Case-sensitive
• MUST NOT begin with a digit
• MUST NOT match a reserved keyword

2.3 Integer Literals

::= { }

Only unsigned decimal integers are supported.

2.4 Reserved Keywords

int void if else while return

Reserved keywords MUST NOT be used as identifiers.

1. PROGRAM STRUCTURE

::= { } { }

Constraints:

• Exactly one MUST exist.

1. DECLARATIONS

4.1 Global Declaration

::=

4.2 Variable Declaration

::= "int" [ "=" ] ";"

Rules:

• Variables MUST be declared before use.
• Only type "int" is allowed for variables.

1. FUNCTION DEFINITIONS

5.1 Main Function

::= "int" "main" "(" ")"

Constraints:

• MUST appear exactly once
• MUST have no parameters
• MUST return type int

5.2 User Function Definition

::= "(" [ ] ")"

::= "int" | "void"

5.3 Parameter List

::= { "," }

::= "int"

Rules:

• Only int parameters are allowed.
• Parameter names MUST be unique within the function.

1. STATEMENTS

::= | | | | |

6.1 Compound Statement

::= "{" { } "}"

6.2 Expression Statement

::= [ ] ";"

6.3 Selection Statement

::= "if" "(" ")" | "if" "(" ")" "else"

6.4 Iteration Statement

::= "while" "(" ")"

The language does not support "for" or "do-while".

6.5 Return Statement

::= "return" [ ] ";"

Rules:

• Functions declared as int MUST return a value.
• Functions declared as void MUST NOT return a value.

1. EXPRESSIONS

::=

7.1 Assignment

::= | "="

7.2 Logical OR

::= | "||"

7.3 Logical AND

::= | "&&"

7.4 Equality

::= | "==" | "!="

7.5 Relational

::= | "<" | ">" | "<=" | ">="

7.6 Additive

::= | "+" | "-"

7.7 Multiplicative

::= | "*" | "/" | "%"

7.8 Unary

::= | "!" | "-"

7.9 Primary

::= | | "(" ")" |

7.10 Function Call

::= "(" [ ] ")"

::= { "," }

Rules:

• Argument count MUST match parameter count.
• Argument types MUST match declared types.

1. BUILT-IN FUNCTION IDENTIFIERS

The following identifiers are reserved as runtime functions:

drive scan cannon loc_x loc_y damage speed rand

They follow normal grammar but are semantically defined by the runtime engine.

1. STATIC SEMANTIC CONSTRAINTS

The following rules are mandatory and not enforced by BNF:

1. Exactly one main function MUST exist.
2. main MUST have signature: int main().
3. All identifiers MUST be declared before use.
4. No duplicate global variable names.
5. No duplicate function names.
6. Function return types MUST match return statements.
7. No implicit type conversion is allowed.
8. Only types int and void exist.
9. Arrays are not supported.
10. Pointers are not supported.
11. Dynamic memory allocation is not supported.
12. Recursion is allowed syntactically but execution limits are implementation-defined.

1. UNDEFINED BEHAVIOR

The following produce undefined behavior:

• Division by zero
• Use of uninitialized variables
• Integer overflow beyond implementation limits
• Calling built-in functions with invalid parameter ranges
• Stack overflow due to deep recursion

End of Specification