From dc088b26ce39d8a4632d73e62e5440ae474a8cb5 Mon Sep 17 00:00:00 2001 From: Aleksey Kladov Date: Tue, 2 Jul 2019 11:06:01 +0300 Subject: [PATCH] refactor check_for_substitution No behavior change, just flatter and simpler code --- src/libsyntax/parse/lexer/mod.rs | 22 ---- src/libsyntax/parse/lexer/unicode_chars.rs | 117 +++++++++++++-------- 2 files changed, 72 insertions(+), 67 deletions(-) diff --git a/src/libsyntax/parse/lexer/mod.rs b/src/libsyntax/parse/lexer/mod.rs index ead5d543bec7d..2309ead55b296 100644 --- a/src/libsyntax/parse/lexer/mod.rs +++ b/src/libsyntax/parse/lexer/mod.rs @@ -84,28 +84,6 @@ impl<'a> StringReader<'a> { Ok(ret_val) } - /// Immutably extract string if found at current position with given delimiters - fn peek_delimited(&self, from_ch: char, to_ch: char) -> Option { - let mut pos = self.pos; - let mut idx = self.src_index(pos); - let mut ch = char_at(&self.src, idx); - if ch != from_ch { - return None; - } - pos = pos + Pos::from_usize(ch.len_utf8()); - let start_pos = pos; - idx = self.src_index(pos); - while idx < self.end_src_index { - ch = char_at(&self.src, idx); - if ch == to_ch { - return Some(self.src[self.src_index(start_pos)..self.src_index(pos)].to_string()); - } - pos = pos + Pos::from_usize(ch.len_utf8()); - idx = self.src_index(pos); - } - return None; - } - fn try_real_token(&mut self) -> Result { let mut t = self.try_next_token()?; loop { diff --git a/src/libsyntax/parse/lexer/unicode_chars.rs b/src/libsyntax/parse/lexer/unicode_chars.rs index 94ce6297fbefb..6a870685938a0 100644 --- a/src/libsyntax/parse/lexer/unicode_chars.rs +++ b/src/libsyntax/parse/lexer/unicode_chars.rs @@ -1,10 +1,11 @@ // Characters and their corresponding confusables were collected from // http://www.unicode.org/Public/security/10.0.0/confusables.txt -use syntax_pos::{Span, Pos, NO_EXPANSION}; -use errors::{Applicability, DiagnosticBuilder}; use super::StringReader; +use errors::{Applicability, DiagnosticBuilder}; +use syntax_pos::{Pos, Span, NO_EXPANSION}; +#[rustfmt::skip] // for line breaks const UNICODE_ARRAY: &[(char, &str, char)] = &[ ('
', "Line Separator", ' '), ('
', "Paragraph Separator", ' '), @@ -293,8 +294,8 @@ const UNICODE_ARRAY: &[(char, &str, char)] = &[ ('〉', "Right-Pointing Angle Bracket", '>'), ('〉', "Right Angle Bracket", '>'), ('》', "Right Double Angle Bracket", '>'), - ('＞', "Fullwidth Greater-Than Sign", '>'), ]; - + ('＞', "Fullwidth Greater-Than Sign", '>'), +]; const ASCII_ARRAY: &[(char, &str)] = &[ (' ', "Space"), @@ -321,46 +322,72 @@ const ASCII_ARRAY: &[(char, &str)] = &[ ('+', "Plus Sign"), ('<', "Less-Than Sign"), ('=', "Equals Sign"), - ('>', "Greater-Than Sign"), ]; - -crate fn check_for_substitution<'a>(reader: &StringReader<'a>, - ch: char, - err: &mut DiagnosticBuilder<'a>) -> bool { - UNICODE_ARRAY - .iter() - .find(|&&(c, _, _)| c == ch) - .map(|&(_, u_name, ascii_char)| { - let span = Span::new(reader.pos, reader.next_pos, NO_EXPANSION); - match ASCII_ARRAY.iter().find(|&&(c, _)| c == ascii_char) { - Some(&(ascii_char, ascii_name)) => { - // special help suggestion for "directed" double quotes - if let Some(s) = reader.peek_delimited('“', '”') { - let msg = format!("Unicode characters '“' (Left Double Quotation Mark) and \ - '”' (Right Double Quotation Mark) look like '{}' ({}), but are not", - ascii_char, ascii_name); - err.span_suggestion( - Span::new(reader.pos, reader.next_pos + Pos::from_usize(s.len()) + - Pos::from_usize('”'.len_utf8()), NO_EXPANSION), - &msg, - format!("\"{}\"", s), - Applicability::MaybeIncorrect); - } else { - let msg = - format!("Unicode character '{}' ({}) looks like '{}' ({}), but it is not", - ch, u_name, ascii_char, ascii_name); - err.span_suggestion( - span, - &msg, - ascii_char.to_string(), - Applicability::MaybeIncorrect); - } - true - }, - None => { - let msg = format!("substitution character not found for '{}'", ch); - reader.sess.span_diagnostic.span_bug_no_panic(span, &msg); - false - } + ('>', "Greater-Than Sign"), +]; + +crate fn check_for_substitution<'a>( + reader: &StringReader<'a>, + ch: char, + err: &mut DiagnosticBuilder<'a>, +) -> bool { + let (u_name, ascii_char) = match UNICODE_ARRAY.iter().find(|&&(c, _, _)| c == ch) { + Some(&(_u_char, u_name, ascii_char)) => (u_name, ascii_char), + None => return false, + }; + + let span = Span::new(reader.pos, reader.next_pos, NO_EXPANSION); + + let ascii_name = match ASCII_ARRAY.iter().find(|&&(c, _)| c == ascii_char) { + Some((_ascii_char, ascii_name)) => ascii_name, + None => { + let msg = format!("substitution character not found for '{}'", ch); + reader.sess.span_diagnostic.span_bug_no_panic(span, &msg); + return false + }, + }; + + // special help suggestion for "directed" double quotes + if let Some(s) = reader.peek_delimited('“', '”') { + let msg = format!( + "Unicode characters '“' (Left Double Quotation Mark) and \ + '”' (Right Double Quotation Mark) look like '{}' ({}), but are not", + ascii_char, ascii_name + ); + err.span_suggestion( + Span::new( + reader.pos, + reader.next_pos + Pos::from_usize(s.len()) + Pos::from_usize('”'.len_utf8()), + NO_EXPANSION, + ), + &msg, + format!("\"{}\"", s), + Applicability::MaybeIncorrect, + ); + } else { + let msg = format!( + "Unicode character '{}' ({}) looks like '{}' ({}), but it is not", + ch, u_name, ascii_char, ascii_name + ); + err.span_suggestion( + span, + &msg, + ascii_char.to_string(), + Applicability::MaybeIncorrect, + ); + } + true +} + +impl StringReader<'_> { + /// Immutably extract string if found at current position with given delimiters + fn peek_delimited(&self, from_ch: char, to_ch: char) -> Option<&str> { + let tail = &self.src[self.src_index(self.pos)..]; + let mut chars = tail.chars(); + let first_char = chars.next()?; + if first_char != from_ch { + return None; } - }).unwrap_or(false) + let last_char_idx = chars.as_str().find(to_ch)?; + Some(&chars.as_str()[..last_char_idx]) + } }