51 lines
2.8 KiB
Markdown
51 lines
2.8 KiB
Markdown
[lex.digraph]
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# 5 Lexical conventions [[lex]](./#lex)
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## 5.9 Alternative tokens [lex.digraph]
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[1](#1)
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[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/lex.tex#L815)
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Alternative token representations are provided for some operators and
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punctuators[.](#1.sentence-1)[10](#footnote-10 "These include âdigraphsâ and additional reserved words. The term âdigraphâ (token consisting of two characters) is not perfectly descriptive, since one of the alternative preprocessing-tokens is %:%: and of course several primary tokens contain two characters. Nonetheless, those alternative tokens that aren't lexical keywords are colloquially known as âdigraphsâ.")
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[2](#2)
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[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/lex.tex#L829)
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In all respects of the language, each alternative token behaves the
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same, respectively, as its primary token, except for its spelling[.](#2.sentence-1)[11](#footnote-11 "Thus the âstringizedâ values ([cpp.stringize]) of [ and <: will be different, maintaining the source spelling, but the tokens can otherwise be freely interchanged.")
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The set of alternative tokens is defined in
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Table [3](#tab:lex.digraph "Table 3: Alternative tokens")[.](#2.sentence-2)
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Table [3](#tab:lex.digraph) — Alternative tokens [[tab:lex.digraph]](./tab:lex.digraph)
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| [ð](#tab:lex.digraph-row-1)<br>**Alternative** | **Primary** | **Alternative** | **Primary** | **Alternative** | **Primary** |
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| --- | --- | --- | --- | --- | --- |
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| [ð](#tab:lex.digraph-row-2)<br><% | { | and | && | and_eq | &= |
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| [ð](#tab:lex.digraph-row-3)<br>%> | } | bitor | | | or_eq | |= |
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| [ð](#tab:lex.digraph-row-4)<br><: | [ | or | || | xor_eq | ^= |
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| [ð](#tab:lex.digraph-row-5)<br>:> | ] | xor | ^ | not | ! |
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| [ð](#tab:lex.digraph-row-6)<br>%: | # | compl | ~ | not_eq | != |
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| [ð](#tab:lex.digraph-row-7)<br>%:%: | ## | bitand | & | | |
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[10)](#footnote-10)[10)](#footnoteref-10)
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These include âdigraphsâ and additional reserved words[.](#footnote-10.sentence-1)
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The term
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âdigraphâ (token consisting of two characters) is not perfectly
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descriptive, since one of the alternative [*preprocessing-token*](lex.pptoken#nt:preprocessing-token "5.5 Preprocessing tokens [lex.pptoken]")*s* is%:%: and of course several primary tokens contain two
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characters[.](#footnote-10.sentence-2)
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Nonetheless, those alternative tokens that aren't lexical
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keywords are colloquially known as âdigraphsâ[.](#footnote-10.sentence-3)
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[11)](#footnote-11)[11)](#footnoteref-11)
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Thus the âstringizedâ values ([[cpp.stringize]](cpp.stringize "15.7.3 The # operator")) of[ and <: will be different, maintaining the source
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spelling, but the tokens can otherwise be freely interchanged[.](#footnote-11.sentence-1)
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