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nora 2021-09-18 20:37:52 +02:00
parent 7506fc7478
commit 64baa7a749
4 changed files with 65 additions and 45 deletions
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35
src/stmt.rs
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@ -11,54 +11,57 @@ pub enum Stmt {
}
pub fn parse(text: &str) -> Result<Vec<Stmt>, String> {
text.lines().map(parse_line).collect()
text.lines()
.filter(|line| line.split_whitespace().next().is_some())
.map(parse_line)
.collect()
}
fn parse_line(line: &str) -> Result<Stmt, String> {
const NO_REGISTER: fn() -> String = || "No register".to_string();
const NO_LINE_NUMBER: fn() -> String = || "No line number".to_string();
const EMPTY_LINE: fn() -> String = || "Empty line not allowed".to_string();
const DISPLAY_ERR: fn(ParseIntError) -> String = |parse_err| parse_err.to_string();
let no_register = || "No register".to_string();
let no_line_number = || "No line number".to_string();
let empty_line = || "Empty line not allowed".to_string();
let display_err = |parse_err: ParseIntError| parse_err.to_string();
let mut iter = line.split_ascii_whitespace();
let first = iter.next().ok_or_else(EMPTY_LINE)?;
let first = iter.next().ok_or_else(empty_line)?;
Ok(match first {
"INC" => {
let register = iter
.next()
.ok_or_else(NO_REGISTER)?
.ok_or_else(no_register)?
.parse()
.map_err(DISPLAY_ERR)?;
.map_err(display_err)?;
Stmt::Inc(register)
}
"DEC" => {
let register = iter
.next()
.ok_or_else(NO_REGISTER)?
.ok_or_else(no_register)?
.parse()
.map_err(DISPLAY_ERR)?;
.map_err(display_err)?;
Stmt::Dec(register)
}
"IS_ZERO" => {
let register = iter
.next()
.ok_or_else(NO_REGISTER)?
.ok_or_else(no_register)?
.parse()
.map_err(DISPLAY_ERR)?;
.map_err(display_err)?;
let line_number = iter
.next()
.ok_or_else(NO_LINE_NUMBER)?
.ok_or_else(no_line_number)?
.parse()
.map_err(DISPLAY_ERR)?;
.map_err(display_err)?;
Stmt::IsZero(register, line_number)
}
"JUMP" => {
let line_number = iter
.next()
.ok_or_else(NO_LINE_NUMBER)?
.ok_or_else(no_line_number)?
.parse()
.map_err(DISPLAY_ERR)?;
.map_err(display_err)?;
Stmt::Jump(line_number)
}
"STOP" => Stmt::Stop,