tenebrous-dicebot/src/variables.rs

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use crate::error::BotError;
use combine::parser::char::{digit, letter, spaces};
use combine::{many1, Parser};
use thiserror::Error;
enum ParsedValue {
Valid(i32),
Invalid,
}
#[derive(Error, Debug)]
pub enum VariableParsingError {
#[error("invalid variable value, must be a number")]
InvalidValue,
#[error("unconsumed input")]
UnconsumedInput,
}
pub fn parse_set_variable(input: &str) -> Result<(String, i32), BotError> {
let name = many1(letter()).map(|value: String| value);
let value = many1(digit()).map(|value: String| match value.parse::<i32>() {
Ok(num) => ParsedValue::Valid(num),
_ => ParsedValue::Invalid,
});
let mut parser = name.skip(spaces().silent()).and(value);
let (result, rest) = parser.parse(input)?;
if rest.len() == 0 {
match result {
(variable_name, ParsedValue::Valid(value)) => Ok((variable_name, value)),
_ => Err(BotError::VariableParsingError(
VariableParsingError::InvalidValue,
)),
}
} else {
Err(BotError::VariableParsingError(
VariableParsingError::UnconsumedInput,
))
}
}