projects / ceph.git / blame
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1 | [/============================================================================== |
| 2 | Copyright (C) 2001-2011 Joel de Guzman | |
| 3 | Copyright (C) 2001-2011 Hartmut Kaiser | |
| 4 | ||
| 5 | Distributed under the Boost Software License, Version 1.0. (See accompanying | |
| 6 | file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) | |
| 7 | ===============================================================================/] | |
| 8 | ||
| 9 | This quick reference section is provided for convenience. You can use | |
| 10 | this section as a sort of a "cheat-sheet" on the most commonly used Lex | |
| 11 | components. It is not intended to be complete, but should give you an | |
| 12 | easy way to recall a particular component without having to dig through | |
| 13 | pages and pages of reference documentation. | |
| 14 | ||
| 15 | [/////////////////////////////////////////////////////////////////////////////] | |
| 16 | [section Common Notation] | |
| 17 | ||
| 18 | [variablelist Notation | |
| 19 | [[`L`] [Lexer type]] | |
| 20 | [[`l, a, b, c, d`] [Lexer objects]] | |
| 21 | [[`Iterator`] [The type of an iterator referring to the underlying | |
| 22 | input sequence]] | |
| 23 | [[`IdType`] [The token id type]] | |
| 24 | [[`Context`] [The lexer components `Context` type]] | |
| 25 | [[`ch`] [Character-class specific character (See __char_class_types__)]] | |
| 26 | [[`Ch`] [Character-class specific character type (See __char_class_types__)]] | |
| 27 | [[`str`] [Character-class specific string (See __char_class_types__)]] | |
| 28 | [[`Str`] [Character-class specific string type (See __char_class_types__)]] | |
| 29 | [[`Attrib`] [An attribute type]] | |
| 30 | [[`fa`] [A semantic action function with a signature: | |
| 31 | `void f(Iterator&, Iterator&, pass_flag&, Idtype&, Context&)`.]] | |
| 32 | ] | |
| 33 | ||
| 34 | [endsect] | |
| 35 | ||
| 36 | [/////////////////////////////////////////////////////////////////////////////] | |
| 37 | [section:lexers Primitive Lexer Components] | |
| 38 | ||
| 39 | [table | |
| 40 | [[Expression] [Attribute] [Description]] | |
| 41 | [[`ch`] [n/a] [Matches `ch`]] | |
| 42 | [[`char_(ch)`] [n/a] [Matches `ch`]] | |
| 43 | [[`str`] [n/a] [Matches regular expression `str`]] | |
| 44 | [[`string(str)`] [n/a] [Matches regular expression `str`]] | |
| 45 | [[`token_def<Attrib>`] [`Attrib`] [Matches the immediate argument]] | |
| 46 | [[`a | b`] [n/a] [Matches any of the expressions `a` or `b`]] | |
| 47 | [[`l[fa]`] [Attribute of `l`] [Call semantic action `fa` (after matching `l`).]] | |
| 48 | ] | |
| 49 | ||
| 50 | [note The column /Attribute/ in the table above lists the parser attribute | |
| 51 | exposed by the lexer component if it is used as a parser (see | |
| 52 | __attribute__). A 'n/a' in this columns means the lexer component is not | |
| 53 | usable as a parser.] | |
| 54 | ||
| 55 | [endsect] | |
| 56 | ||
| 57 | [/////////////////////////////////////////////////////////////////////////////] | |
| 58 | [section Semantic Actions] | |
| 59 | ||
| 60 | Has the form: | |
| 61 | ||
| 62 | l[f] | |
| 63 | ||
| 64 | where `f` is a function with the signatures: | |
| 65 | ||
| 66 | void f(); | |
| 67 | void f(Iterator&, Iterator&); | |
| 68 | void f(Iterator&, Iterator&, pass_flag&); | |
| 69 | void f(Iterator&, Iterator&, pass_flag&, Idtype&); | |
| 70 | void f(Iterator&, Iterator&, pass_flag&, Idtype&, Context&); | |
| 71 | ||
| 72 | You can use __boost_bind__ to bind member functions. For function | |
| 73 | objects, the allowed signatures are: | |
| 74 | ||
| 75 | void operator()(unused_type, unused_type, unused_type, unused_type, unused_type) const; | |
| 76 | void operator()(Iterator&, Iterator&, unused_type, unused_type, unused_type) const; | |
| 77 | void operator()(Iterator&, Iterator&, pass_flag&, unused_type, unused_type) const; | |
| 78 | void operator()(Iterator&, Iterator&, pass_flag&, Idtype&, unused_type) const; | |
| 79 | void operator()(Iterator&, Iterator&, pass_flag&, Idtype&, Context&) const; | |
| 80 | ||
| 81 | The `unused_type` is used in the signatures above to signify 'don't | |
| 82 | care'. | |
| 83 | ||
| 84 | For more information see __lex_actions__. | |
| 85 | ||
| 86 | [endsect] | |
| 87 | ||
| 88 | [/////////////////////////////////////////////////////////////////////////////] | |
| 89 | [section Phoenix] | |
| 90 | ||
| 91 | __boost_phoenix__ makes it easier to attach semantic actions. You just | |
| 92 | inline your lambda expressions: | |
| 93 | ||
| 94 | l[phoenix-lambda-expression] | |
| 95 | ||
| 96 | __lex__ provides some __boost_phoenix__ placeholders to access important | |
| 97 | information from the `Context` that are otherwise difficult to extract. | |
| 98 | ||
| 99 | [variablelist Spirit.Lex specific Phoenix placeholders | |
| 100 | [[`_start, _end`] [Iterators pointing to the begin and the end of the | |
| 101 | matched input sequence.]] | |
| 102 | [[`_pass`] [Assign `lex::pass_flags::pass_fail` to `_pass` to force the current match to fail.]] | |
| 103 | [[`_tokenid`] [The token id of the matched token.]] | |
| 104 | [[`_val`] [The token value of the matched token.]] | |
| 105 | [[`_state`] [The lexer state the token has been matched in.]] | |
| 106 | [[`_eoi`] [Iterator referring to the current end of the input sequence.]] | |
| 107 | ] | |
| 108 | ||
| 109 | [tip All of the placeholders in the list above (except `_eoi`) can be changed | |
| 110 | from the inside of the semantic action allowing to modify the lexer | |
| 111 | behavior. They are defined in the namespace `boost::spirit::lex`.] | |
| 112 | ||
| 113 | For more information see __lex_actions__. | |
| 114 | ||
| 115 | [endsect] | |
| 116 | ||
| 117 |