30 lines
1.3 KiB
Rust
30 lines
1.3 KiB
Rust
use nom::{complete, named, tag, take_while, tuple, IResult};
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use crate::commands::{Command, RollCommand};
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use crate::dice::parser::parse_element_expression;
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use crate::parser::eat_whitespace;
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// Parse a roll expression.
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fn parse_roll(input: &str) -> IResult<&str, Box<dyn Command>> {
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let (input, _) = eat_whitespace(input)?;
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let (input, expression) = parse_element_expression(input)?;
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Ok((input, Box::new(RollCommand(expression))))
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}
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/// Potentially parse a command expression. If we recognize the command, an error should be raised
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/// if the command is misparsed. If we don't recognize the command, ignore it and return none
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pub fn parse_command(original_input: &str) -> IResult<&str, Option<Box<dyn Command>>> {
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let (input, _) = eat_whitespace(original_input)?;
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named!(command(&str) -> (&str, &str), tuple!(complete!(tag!("!")), complete!(take_while!(char::is_alphabetic))));
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let (input, command) = match command(input) {
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// Strip the exclamation mark
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Ok((input, (_, result))) => (input, result),
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Err(_e) => return Ok((original_input, None)),
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};
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match command {
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"r" | "roll" => parse_roll(input).map(|(input, command)| (input, Some(command))),
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// No recognized command, ignore this.
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_ => Ok((original_input, None)),
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}
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}
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