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Jon Ross-PerkinsandChandler Carruth
ec182fb00d
Continuing with #3070. Just a dir and file rename (only prefix change is lexer_file_test). Everything in the lex dir should be marked as a move. Note, I think this closes #3070. There may still be further cleanup later, but the organizational changes suggested there are being completed. --------- Co-authored-by: Chandler Carruth <chandlerc@gmail.com>
77 lines
2.7 KiB
C++
77 lines
2.7 KiB
C++
// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
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// Exceptions. See /LICENSE for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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#ifndef CARBON_TOOLCHAIN_LEX_CHARACTER_SET_H_
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#define CARBON_TOOLCHAIN_LEX_CHARACTER_SET_H_
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#include "llvm/ADT/StringExtras.h"
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namespace Carbon::Lex {
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// TODO: These definitions need to be updated to match whatever Unicode lexical
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// rules we pick. The function interfaces will need to change to accommodate
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// multi-byte characters.
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// Is this an alphabetical character according to Carbon's lexical rules?
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//
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// Alphabetical characters are permitted at the start of identifiers. This
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// currently includes 'A'..'Z' and 'a'..'z'.
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inline auto IsAlpha(char c) -> bool { return llvm::isAlpha(c); }
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// Is this a decimal digit according to Carbon's lexical rules?
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//
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// This currently includes '0'..'9'.
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inline auto IsDecimalDigit(char c) -> bool { return llvm::isDigit(c); }
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// Is this an alphanumeric character according to Carbon's lexical rules?
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//
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// Alphanumeric characters are permitted as trailing characters in identifiers
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// and numeric literals. This includes alphabetical characters plus decimal
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// digits.
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//
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// Note that '_' is not considered alphanumeric, despite in most circumstances
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// being a valid continuation character of an identifier or numeric literal.
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inline auto IsAlnum(char c) -> bool { return llvm::isAlnum(c); }
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// Is this a hexadecimal digit according to Carbon's lexical rules?
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//
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// Hexadecimal digits are permitted in `0x`-prefixed literals, as well as after
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// a `\x` escape sequence.
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//
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// Note that lowercase 'a'..'f' are currently not considered hexadecimal digits
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// in any context.
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inline auto IsUpperHexDigit(char c) -> bool {
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return ('0' <= c && c <= '9') || ('A' <= c && c <= 'F');
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}
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// Is this a lowercase letter?
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//
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// Lowercase letters in numeric literals can be followed by `+` or `-` to
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// extend the literal.
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inline auto IsLower(char c) -> bool { return 'a' <= c && c <= 'z'; }
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// Is this character considered to be horizontal whitespace?
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//
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// Such characters can appear in the indentation of a line.
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inline auto IsHorizontalWhitespace(char c) -> bool {
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return c == ' ' || c == '\t';
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}
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// Is this character considered to be vertical whitespace?
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//
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// Such characters are considered to terminate lines.
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inline auto IsVerticalWhitespace(char c) -> bool { return c == '\n'; }
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// Is this character considered to be whitespace?
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//
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// Changes here will need matching changes in
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// `TokenizedBuffer::Lexer::SkipWhitespace`.
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inline auto IsSpace(char c) -> bool {
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return IsHorizontalWhitespace(c) || IsVerticalWhitespace(c);
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}
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} // namespace Carbon::Lex
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#endif // CARBON_TOOLCHAIN_LEX_CHARACTER_SET_H_
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