307 lines
8.7 KiB
Rust
307 lines
8.7 KiB
Rust
use crate::units::{NonMetric, NonMetricQuantity};
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enum Expect {
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Number,
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Unit,
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}
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#[derive(Debug, PartialEq)]
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pub enum ParseError {
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NotValidNumber(String),
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UnexpectedUnit(String),
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UnknownUnit(String),
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ExpectedUnit,
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}
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pub fn parse(input: &str) -> Result<Vec<NonMetricQuantity>, ParseError> {
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let mut quantities = Vec::new();
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let mut state = Expect::Number;
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let mut amount = None;
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for token in tokenize(input) {
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match (&state, token) {
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(Expect::Number, Token::Number(number)) => {
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let number = parse_number(number)?;
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amount = Some(number);
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state = Expect::Unit;
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}
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(Expect::Number, Token::Unit(unit)) => {
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return Err(ParseError::UnexpectedUnit(unit));
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}
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(Expect::Unit, Token::Number(_)) => {
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unreachable!("token stream can't contain two numbers in a row");
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}
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(Expect::Unit, Token::Unit(unit)) => {
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let unit = parse_unit(unit)?;
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let quantity = NonMetricQuantity {
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amount: amount.take().expect("must have read a number to be in this state"),
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unit: unit,
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};
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quantities.push(quantity);
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state = Expect::Number;
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}
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}
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}
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match state {
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Expect::Number => {}
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Expect::Unit => {
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return Err(ParseError::ExpectedUnit);
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}
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}
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Ok(quantities)
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}
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fn parse_number(input: String) -> Result<f64, ParseError> {
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let no_whitespace: String = input.chars().filter(|c| !c.is_whitespace()).collect();
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no_whitespace.parse().or_else(|_| Err(ParseError::NotValidNumber(input)))
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}
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fn parse_unit(input: String) -> Result<NonMetric, ParseError> {
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match input.as_str() {
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// Length
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"inch" => Ok(NonMetric::Inch),
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"inches" => Ok(NonMetric::Inch),
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"in" => Ok(NonMetric::Inch),
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"\"" => Ok(NonMetric::Inch),
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"″" => Ok(NonMetric::Inch),
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"foot" => Ok(NonMetric::Foot),
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"feet" => Ok(NonMetric::Foot),
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"ft" => Ok(NonMetric::Foot),
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"'" => Ok(NonMetric::Foot),
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"′" => Ok(NonMetric::Foot),
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"yard" => Ok(NonMetric::Yard),
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"yards" => Ok(NonMetric::Yard),
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"yd" => Ok(NonMetric::Yard),
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"mile" => Ok(NonMetric::Mile),
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"miles" => Ok(NonMetric::Mile),
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"mi" => Ok(NonMetric::Mile),
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"m" => Ok(NonMetric::Mile),
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// Weight
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"ounce" => Ok(NonMetric::Ounce),
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"ounces" => Ok(NonMetric::Ounce),
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"oz" => Ok(NonMetric::Ounce),
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"pound" => Ok(NonMetric::Pound),
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"pounds" => Ok(NonMetric::Pound),
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"lb" => Ok(NonMetric::Pound),
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"lbs" => Ok(NonMetric::Pound),
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"#" => Ok(NonMetric::Pound),
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"stone" => Ok(NonMetric::Stone),
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"stones" => Ok(NonMetric::Stone),
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"st" => Ok(NonMetric::Stone),
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// Temperature
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"°F" => Ok(NonMetric::Fahrenheit),
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"F" => Ok(NonMetric::Fahrenheit),
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_ => Err(ParseError::UnknownUnit(input)),
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}
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}
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#[derive(Debug, PartialEq)]
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enum Token {
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Number(String),
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Unit(String),
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}
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enum TokState {
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Neutral,
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Number,
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Unit,
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}
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fn tokenize(input: &str) -> Vec<Token> {
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let mut tokens = Vec::new();
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let mut token = String::new();
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let mut state = TokState::Neutral;
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for c in input.chars() {
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match state {
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TokState::Neutral => {
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if c.is_ascii_digit() || c == '-' {
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token.push(c);
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state = TokState::Number;
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} else if !c.is_whitespace() {
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token.push(c);
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state = TokState::Unit;
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}
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}
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TokState::Number => {
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if c.is_ascii_digit() ||
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c.is_whitespace() ||
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c == '.' {
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token.push(c);
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} else {
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tokens.push(Token::Number(token.trim().to_string()));
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state = TokState::Unit;
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token = String::new();
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token.push(c);
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}
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}
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TokState::Unit => {
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if c.is_ascii_digit() || c == '-' {
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tokens.push(Token::Unit(token));
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state = TokState::Number;
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token = String::new();
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token.push(c);
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} else if !c.is_whitespace() {
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token.push(c);
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} else {
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tokens.push(Token::Unit(token));
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state = TokState::Neutral;
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token = String::new();
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}
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}
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}
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}
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match state {
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TokState::Neutral => { assert!(token.len() == 0); }
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TokState::Number => { tokens.push(Token::Number(token.trim().to_string())); }
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TokState::Unit => { tokens.push(Token::Unit(token)); }
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}
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tokens
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}
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#[cfg(test)]
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mod test {
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use super::*;
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#[test]
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fn parsing() {
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assert_eq!(parse(""), Ok(vec![]));
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assert_eq!(parse("5 ft"), Ok(vec![
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NonMetricQuantity { amount: 5.0, unit: NonMetric::Foot },
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]));
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assert_eq!(parse("5 ft 8 in"), Ok(vec![
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NonMetricQuantity { amount: 5.0, unit: NonMetric::Foot },
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NonMetricQuantity { amount: 8.0, unit: NonMetric::Inch },
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]));
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assert_eq!(parse("20 000 lbs"), Ok(vec![
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NonMetricQuantity { amount: 20_000.0, unit: NonMetric::Pound },
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]));
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assert_eq!(parse("12.0."), Err(ParseError::NotValidNumber("12.0.".to_string())));
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assert_eq!(parse("ft"), Err(ParseError::UnexpectedUnit("ft".to_string())));
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assert_eq!(parse("5 tf"), Err(ParseError::UnknownUnit("tf".to_string())));
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assert_eq!(parse("12"), Err(ParseError::ExpectedUnit));
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}
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#[test]
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fn numbers() {
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assert_eq!(parse_number("".to_string()), Err(ParseError::NotValidNumber("".to_string())));
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assert_eq!(parse_number("1".to_string()), Ok(1.0));
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assert_eq!(parse_number("1.0".to_string()), Ok(1.0));
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assert_eq!(parse_number("0.1".to_string()), Ok(0.1));
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assert_eq!(parse_number("0.1.".to_string()), Err(ParseError::NotValidNumber("0.1.".to_string())));
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assert_eq!(parse_number("-10".to_string()), Ok(-10.0));
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assert_eq!(parse_number("10\t00\u{1680}000".to_string()), Ok(10_00_000.0));
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}
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#[test]
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fn units() {
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// Length
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assert_eq!(parse_unit("inch".to_string()), Ok(NonMetric::Inch));
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assert_eq!(parse_unit("inches".to_string()), Ok(NonMetric::Inch));
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assert_eq!(parse_unit("in".to_string()), Ok(NonMetric::Inch));
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assert_eq!(parse_unit("\"".to_string()), Ok(NonMetric::Inch));
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assert_eq!(parse_unit("″".to_string()), Ok(NonMetric::Inch));
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assert_eq!(parse_unit("foot".to_string()), Ok(NonMetric::Foot));
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assert_eq!(parse_unit("feet".to_string()), Ok(NonMetric::Foot));
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assert_eq!(parse_unit("ft".to_string()), Ok(NonMetric::Foot));
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assert_eq!(parse_unit("'".to_string()), Ok(NonMetric::Foot));
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assert_eq!(parse_unit("′".to_string()), Ok(NonMetric::Foot));
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assert_eq!(parse_unit("yard".to_string()), Ok(NonMetric::Yard));
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assert_eq!(parse_unit("yards".to_string()), Ok(NonMetric::Yard));
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assert_eq!(parse_unit("yd".to_string()), Ok(NonMetric::Yard));
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assert_eq!(parse_unit("mile".to_string()), Ok(NonMetric::Mile));
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assert_eq!(parse_unit("miles".to_string()), Ok(NonMetric::Mile));
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assert_eq!(parse_unit("mi".to_string()), Ok(NonMetric::Mile));
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assert_eq!(parse_unit("m".to_string()), Ok(NonMetric::Mile));
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// Weight
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assert_eq!(parse_unit("ounce".to_string()), Ok(NonMetric::Ounce));
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assert_eq!(parse_unit("ounces".to_string()), Ok(NonMetric::Ounce));
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assert_eq!(parse_unit("oz".to_string()), Ok(NonMetric::Ounce));
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assert_eq!(parse_unit("pound".to_string()), Ok(NonMetric::Pound));
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assert_eq!(parse_unit("pounds".to_string()), Ok(NonMetric::Pound));
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assert_eq!(parse_unit("lb".to_string()), Ok(NonMetric::Pound));
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assert_eq!(parse_unit("lbs".to_string()), Ok(NonMetric::Pound));
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assert_eq!(parse_unit("#".to_string()), Ok(NonMetric::Pound));
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assert_eq!(parse_unit("stone".to_string()), Ok(NonMetric::Stone));
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assert_eq!(parse_unit("stones".to_string()), Ok(NonMetric::Stone));
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assert_eq!(parse_unit("st".to_string()), Ok(NonMetric::Stone));
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// Temperature
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assert_eq!(parse_unit("°F".to_string()), Ok(NonMetric::Fahrenheit));
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assert_eq!(parse_unit("F".to_string()), Ok(NonMetric::Fahrenheit));
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// Unknown unit
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assert_eq!(parse_unit("hutenosa".to_string()), Err(ParseError::UnknownUnit("hutenosa".to_string())));
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}
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#[test]
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fn tokens() {
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assert_eq!(tokenize(""), vec![]);
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assert_eq!(tokenize("10"), vec![Token::Number("10".to_string())]);
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assert_eq!(tokenize(" 10 "), vec![Token::Number("10".to_string())]);
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assert_eq!(tokenize("10 000"), vec![Token::Number("10 000".to_string())]);
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assert_eq!(tokenize("10\t000"), vec![Token::Number("10\t000".to_string())]);
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assert_eq!(tokenize("10\u{1680}000"), vec![Token::Number("10\u{1680}000".to_string())]);
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assert_eq!(tokenize("10.0.1"), vec![Token::Number("10.0.1".to_string())]);
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assert_eq!(tokenize("ft"), vec![Token::Unit("ft".to_string())]);
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assert_eq!(
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tokenize("10 ft"),
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vec![
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Token::Number("10".to_string()),
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Token::Unit("ft".to_string()),
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]
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);
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assert_eq!(
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tokenize("ft in"),
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vec![
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Token::Unit("ft".to_string()),
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Token::Unit("in".to_string()),
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]
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);
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assert_eq!(
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tokenize("5 ft 7 in"),
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vec![
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Token::Number("5".to_string()),
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Token::Unit("ft".to_string()),
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Token::Number("7".to_string()),
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Token::Unit("in".to_string()),
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]
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);
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assert_eq!(
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tokenize("5\"7'"),
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vec![
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Token::Number("5".to_string()),
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Token::Unit("\"".to_string()),
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Token::Number("7".to_string()),
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Token::Unit("'".to_string()),
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]
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);
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assert_eq!(
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tokenize(" 2.2lbs "),
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vec![
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Token::Number("2.2".to_string()),
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Token::Unit("lbs".to_string()),
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]
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);
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}
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}
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