Function parse_expression 

pub fn parse_expression(input: &str) -> ParseResult<Pairs<'_, Rule>>

Parses an expression.

Expressions are fundamental building blocks that compute or represent values. This parser handles a comprehensive range of expression types with proper operator precedence and associativity rules.

Supported Expression Types

• Literals: Integer, float, boolean, and string constants
• Identifiers: Variable and function names
• Binary Operations: Arithmetic, comparison, and logical operators
• Function Calls: Invocations with argument lists
• Parenthesized Expressions: For grouping and precedence control

Operator Precedence

Operators are evaluated in the following order (highest to lowest):

1. Parentheses: ( )
2. Unary operators
3. Multiplicative: *, /, %
4. Additive: +, -
5. Comparison: <, >, <=, >=
6. Equality: ==, !=
7. Logical AND: &&
8. Logical OR: ||

Arguments

• input - A string slice containing exactly one expression

Returns

Returns a ParseResult containing the parsed expression tree.

Grammar Rule

This function uses the expression grammar rule from carbon.pest.

Examples

Literals

use carbon_parser::parse_expression;

// Integer literal
assert!(parse_expression("42").is_ok());

// Float literal
assert!(parse_expression("3.14").is_ok());

// Boolean literals
assert!(parse_expression("true").is_ok());
assert!(parse_expression("false").is_ok());

// String literal
assert!(parse_expression(r#""Hello, World!""#).is_ok());

Identifiers

use carbon_parser::parse_expression;

let code = "variable_name";
let result = parse_expression(code);
assert!(result.is_ok());

Binary Operations

use carbon_parser::parse_expression;

// Addition
assert!(parse_expression("10 + 20").is_ok());

// Complex arithmetic with precedence
assert!(parse_expression("10 + 20 * 30 - 5").is_ok());

Function Calls

use carbon_parser::parse_expression;

let code = "calculate(x, y)";
let result = parse_expression(code);
assert!(result.is_ok());

Comparison Operators

use carbon_parser::parse_expression;

assert!(parse_expression("x == y").is_ok());
assert!(parse_expression("x != y").is_ok());
assert!(parse_expression("x < y").is_ok());
assert!(parse_expression("x > y").is_ok());