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Annotation of parser3/src/doc/string.dox, revision 1.6

1.1       paf         1: /**    @page String String
                      2: 
1.6     ! paf         3: In memory strings[String] are stored as letters[actually, cord objects from libgd cord library, see cord.h file] 
        !             4: plus list of fragments[String::Fragment] which contain language of fragment+it's length.
        !             5: 
        !             6: Fragments that are received from stdout of scripts are considered clean(String::Language ::L_CLEAN),
        !             7: but those from visitor - from stderr of scripts, from environment, from form, 
        !             8: from dist[table:load] or from sql server[table:sql] 
        !             9: are considered tainted(String::Language ::UL_TAINTED), 
        !            10: when string involved in different operations, it can be split, but all resulting parts 
        !            11: still remember languages of their fragments.
        !            12: String can be written to Request::wcontext, then part of fragments can change their language. 
        !            13: Language is set to those fragments, which were not in particular language, but just tainted[L_TAINTED], 
        !            14: they become "dirty, but we need what to do to make them clean, that is we know their language".
        !            15: Say,
1.1       paf        16: @verbatim
1.3       paf        17: ^void:sql{insert into news (title) values ('$form:title')]
1.1       paf        18: @endverbatim
1.6     ! paf        19: when parameter of sql is processed, with help of Temp_lang 
        !            20: we set "current language"[Request::flang],
        !            21: and when string got written[Request::write_assign_lang] 
        !            22: L_TAINTED string from $form:title part of parameter of sql-method, 
        !            23: the one in apostrophes, got assigned an L_SQL language.
        !            24: 
        !            25: String can be converted to normal Ñ-string by String::cstr().
        !            26: If it is called with this parameter String::cstr(String::L_UNSPECIFIED) then
        !            27: when it will be converted, fragment languages would be taken into consideration, and 
        !            28: corresponding cleansing performed.
        !            29: Particular language can also be specified String::cstr(String::Language) [by default =L_AS_IS], 
        !            30: then all string fragments would forcibly considered to be in that language, 
        !            31: regardles of the language inside fragment.
        !            32: 
        !            33: This is used, for instance, in work with file names
        !            34: [ATTENTION: never ever use this construction if you care about your secret files,
        !            35: it is used only as an example]:
1.1       paf        36: @verbatim
1.3       paf        37: $file[^table::load[$form:file_name]]
1.1       paf        38: @endverbatim
1.6     ! paf        39: here with normal $form:file_name processing would be L_HTML|L_OPTIMIZE_BIT, while we need L_FILE_SPEC,
        !            40: and it would be stupid everywhere to do like we do in table:sql, insisting on {} parameters.
        !            41: 
        !            42: Usual language of output is String::Language::L_HTML|String::Language::L_OPTIMIZE_BIT, 
        !            43: exception is CGI script, which got started outside of web-server,
        !            44: in that case language String::Language::L_AS_IS is used.
1.1       paf        45: 
1.6     ! paf        46: In fragments where language is marked as OPTIMIZED (String::Language::L_OPTIMIZE_BIT), 
        !            47: when they are converted into string String::cstr white spaces would be optimized:
        !            48: out of several consequent characters would be left only first, others would be wiped off the result.
1.1       paf        49: 
1.6     ! paf        50: When code works with char* it is assumed it is can never be 0.
        !            51: k
1.5       paf        52: */