Function parse_assignment_expression

crates/gitql-parser/src/parser.rs:1362–1397

(
    context: &mut ParserContext,
    env: &mut Environment,
    tokens: &[Token],
    position: &mut usize,
)

}

fn parse_assignment_expression(
    context: &mut ParserContext,
    env: &mut Environment,
    tokens: &[Token],
    position: &mut usize,
) -> Result<Box<dyn Expr>, Box<Diagnostic>> {
    let expression = parse_regex_expression(context, env, tokens, position)?;
    if is_current_token(tokens, position, TokenKind::ColonEqual) {
        if expression.kind() != ExprKind::GlobalVariable {
            return Err(Diagnostic::error(
                "Assignment expressions expect global variable name before `:=`",
            )
            .with_location(tokens[*position].location)
            .as_boxed());
        }

        let expr = expression
            .as_any()
            .downcast_ref::<GlobalVariableExpr>()
            .unwrap();

        let variable_name = expr.name.to_string();

        // Consume `:=` operator
        *position += 1;

        let value = parse_regex_expression(context, env, tokens, position)?;
        env.define_global(variable_name.clone(), value.expr_type());

        return Ok(Box::new(AssignmentExpr {
            symbol: variable_name.clone(),
            value,
        }));
    }
    Ok(expression)
}

pub(crate) fn parse_is_null_expression(
    context: &mut ParserContext,