+++ /dev/null
-use rustc_ast::ast::{Lit, LitFloatType, LitIntType, LitKind};
-
-#[derive(Debug, PartialEq, Copy, Clone)]
-pub enum Radix {
- Binary,
- Octal,
- Decimal,
- Hexadecimal,
-}
-
-impl Radix {
- /// Returns a reasonable digit group size for this radix.
- #[must_use]
- fn suggest_grouping(self) -> usize {
- match self {
- Self::Binary | Self::Hexadecimal => 4,
- Self::Octal | Self::Decimal => 3,
- }
- }
-}
-
-/// A helper method to format numeric literals with digit grouping.
-/// `lit` must be a valid numeric literal without suffix.
-pub fn format(lit: &str, type_suffix: Option<&str>, float: bool) -> String {
- NumericLiteral::new(lit, type_suffix, float).format()
-}
-
-#[derive(Debug)]
-pub struct NumericLiteral<'a> {
- /// Which radix the literal was represented in.
- pub radix: Radix,
- /// The radix prefix, if present.
- pub prefix: Option<&'a str>,
-
- /// The integer part of the number.
- pub integer: &'a str,
- /// The fraction part of the number.
- pub fraction: Option<&'a str>,
- /// The exponent separator (b'e' or b'E') including preceding underscore if present
- /// and the exponent part.
- pub exponent: Option<(&'a str, &'a str)>,
-
- /// The type suffix, including preceding underscore if present.
- pub suffix: Option<&'a str>,
-}
-
-impl<'a> NumericLiteral<'a> {
- pub fn from_lit(src: &'a str, lit: &Lit) -> Option<NumericLiteral<'a>> {
- NumericLiteral::from_lit_kind(src, &lit.kind)
- }
-
- pub fn from_lit_kind(src: &'a str, lit_kind: &LitKind) -> Option<NumericLiteral<'a>> {
- if lit_kind.is_numeric() && src.chars().next().map_or(false, |c| c.is_digit(10)) {
- let (unsuffixed, suffix) = split_suffix(&src, lit_kind);
- let float = matches!(lit_kind, LitKind::Float(..));
- Some(NumericLiteral::new(unsuffixed, suffix, float))
- } else {
- None
- }
- }
-
- #[must_use]
- pub fn new(lit: &'a str, suffix: Option<&'a str>, float: bool) -> Self {
- // Determine delimiter for radix prefix, if present, and radix.
- let radix = if lit.starts_with("0x") {
- Radix::Hexadecimal
- } else if lit.starts_with("0b") {
- Radix::Binary
- } else if lit.starts_with("0o") {
- Radix::Octal
- } else {
- Radix::Decimal
- };
-
- // Grab part of the literal after prefix, if present.
- let (prefix, mut sans_prefix) = if let Radix::Decimal = radix {
- (None, lit)
- } else {
- let (p, s) = lit.split_at(2);
- (Some(p), s)
- };
-
- if suffix.is_some() && sans_prefix.ends_with('_') {
- // The '_' before the suffix isn't part of the digits
- sans_prefix = &sans_prefix[..sans_prefix.len() - 1];
- }
-
- let (integer, fraction, exponent) = Self::split_digit_parts(sans_prefix, float);
-
- Self {
- radix,
- prefix,
- integer,
- fraction,
- exponent,
- suffix,
- }
- }
-
- pub fn is_decimal(&self) -> bool {
- self.radix == Radix::Decimal
- }
-
- pub fn split_digit_parts(digits: &str, float: bool) -> (&str, Option<&str>, Option<(&str, &str)>) {
- let mut integer = digits;
- let mut fraction = None;
- let mut exponent = None;
-
- if float {
- for (i, c) in digits.char_indices() {
- match c {
- '.' => {
- integer = &digits[..i];
- fraction = Some(&digits[i + 1..]);
- },
- 'e' | 'E' => {
- let exp_start = if digits[..i].ends_with('_') { i - 1 } else { i };
-
- if integer.len() > exp_start {
- integer = &digits[..exp_start];
- } else {
- fraction = Some(&digits[integer.len() + 1..exp_start]);
- };
- exponent = Some((&digits[exp_start..=i], &digits[i + 1..]));
- break;
- },
- _ => {},
- }
- }
- }
-
- (integer, fraction, exponent)
- }
-
- /// Returns literal formatted in a sensible way.
- pub fn format(&self) -> String {
- let mut output = String::new();
-
- if let Some(prefix) = self.prefix {
- output.push_str(prefix);
- }
-
- let group_size = self.radix.suggest_grouping();
-
- Self::group_digits(
- &mut output,
- self.integer,
- group_size,
- true,
- self.radix == Radix::Hexadecimal,
- );
-
- if let Some(fraction) = self.fraction {
- output.push('.');
- Self::group_digits(&mut output, fraction, group_size, false, false);
- }
-
- if let Some((separator, exponent)) = self.exponent {
- output.push_str(separator);
- Self::group_digits(&mut output, exponent, group_size, true, false);
- }
-
- if let Some(suffix) = self.suffix {
- output.push('_');
- output.push_str(suffix);
- }
-
- output
- }
-
- pub fn group_digits(output: &mut String, input: &str, group_size: usize, partial_group_first: bool, pad: bool) {
- debug_assert!(group_size > 0);
-
- let mut digits = input.chars().filter(|&c| c != '_');
-
- let first_group_size;
-
- if partial_group_first {
- first_group_size = (digits.clone().count() - 1) % group_size + 1;
- if pad {
- for _ in 0..group_size - first_group_size {
- output.push('0');
- }
- }
- } else {
- first_group_size = group_size;
- }
-
- for _ in 0..first_group_size {
- if let Some(digit) = digits.next() {
- output.push(digit);
- }
- }
-
- for (c, i) in digits.zip((0..group_size).cycle()) {
- if i == 0 {
- output.push('_');
- }
- output.push(c);
- }
- }
-}
-
-fn split_suffix<'a>(src: &'a str, lit_kind: &LitKind) -> (&'a str, Option<&'a str>) {
- debug_assert!(lit_kind.is_numeric());
- lit_suffix_length(lit_kind).map_or((src, None), |suffix_length| {
- let (unsuffixed, suffix) = src.split_at(src.len() - suffix_length);
- (unsuffixed, Some(suffix))
- })
-}
-
-fn lit_suffix_length(lit_kind: &LitKind) -> Option<usize> {
- debug_assert!(lit_kind.is_numeric());
- let suffix = match lit_kind {
- LitKind::Int(_, int_lit_kind) => match int_lit_kind {
- LitIntType::Signed(int_ty) => Some(int_ty.name_str()),
- LitIntType::Unsigned(uint_ty) => Some(uint_ty.name_str()),
- LitIntType::Unsuffixed => None,
- },
- LitKind::Float(_, float_lit_kind) => match float_lit_kind {
- LitFloatType::Suffixed(float_ty) => Some(float_ty.name_str()),
- LitFloatType::Unsuffixed => None,
- },
- _ => None,
- };
-
- suffix.map(str::len)
-}
projects / rustc.git / blobdiff