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https://github.com/carbon-language/carbon-lang.git
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Richard Smith
28602a87c2
Per [the design](https://docs.carbon-lang.dev/docs/design/lexical_conventions/), `x.1.2` should lex as `(x.1).2`, not as `x.(1.2)`.
77 lines
2.4 KiB
C++
77 lines
2.4 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_NUMERIC_LITERAL_H_
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#define CARBON_TOOLCHAIN_LEX_NUMERIC_LITERAL_H_
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#include <optional>
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#include <variant>
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#include "llvm/ADT/APInt.h"
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#include "llvm/ADT/StringRef.h"
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#include "toolchain/diagnostics/diagnostic_emitter.h"
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namespace Carbon::Lex {
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// A numeric literal token that has been extracted from a source buffer.
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class NumericLiteral {
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public:
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enum class Radix : int8_t { Binary = 2, Decimal = 10, Hexadecimal = 16 };
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// Value of an integer literal.
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struct IntValue {
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// An unsigned literal value.
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llvm::APInt value;
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};
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// Value of a real literal.
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struct RealValue {
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// The radix of the exponent, either Binary or Decimal.
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Radix radix;
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// The mantissa, represented as a variable-width unsigned integer.
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llvm::APInt mantissa;
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// The exponent, represented as a variable-width signed integer.
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llvm::APInt exponent;
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};
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struct UnrecoverableError {};
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using Value = std::variant<IntValue, RealValue, UnrecoverableError>;
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// Extract a numeric literal from the given text, if it has a suitable form.
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//
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// The supplied `source_text` must outlive the return value.
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static auto Lex(llvm::StringRef source_text, bool can_form_real_literal)
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-> std::optional<NumericLiteral>;
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// Compute the value of the token, if possible. Emit diagnostics to the given
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// emitter if the token is not valid.
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auto ComputeValue(DiagnosticEmitter<const char*>& emitter) const -> Value;
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// Get the text corresponding to this literal.
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auto text() const -> llvm::StringRef { return text_; }
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private:
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class Parser;
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NumericLiteral() = default;
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// The text of the token.
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llvm::StringRef text_;
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// The offset of the '.'. Set to text.size() if none is present.
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int radix_point_;
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// The offset of the alphabetical character introducing the exponent. In a
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// valid literal, this will be an 'e' or a 'p', and may be followed by a '+'
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// or a '-', but for error recovery, this may simply be the last lowercase
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// letter in the invalid token. Always greater than or equal to radix_point.
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// Set to text.size() if none is present.
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int exponent_;
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};
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} // namespace Carbon::Lex
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#endif // CARBON_TOOLCHAIN_LEX_NUMERIC_LITERAL_H_
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