CxCodeUnit

// Comment

using Usings.First;
using Usings.Second;
...

#pragma ... (ignored)

// ... (ignored)

namespace Namespace
{
  class Declaration
  {
    ...
  }
}

.   #                := w ;
.   root             := code-unit ;
.
.   !code-unit       := comment? usings? (comment-line | pragma-line)* namespace ;
.
.   !comment         := comment-line comment-line* ;
.   !namespace       := 'namespace' w+ (id .. '.') '{' decl '}' ;
.   !pragma-line     := '#pragma' ~lb* lb ;
.   usings           := using using* ;
.
.   !decl            := xmldoc? attribs? modifiers (class | delegate | enum | interface
.                       | struct) ;
.   !using           := 'using' w+ name ';' ;
.
.   !class           := 'class' w+ name-id type-params? base-types? constraints? regions ;
.   !delegate        := 'delegate' w+ var-decl type-params? params constraints? ';' ;
.   !enum            := 'enum' w+ name-id '{' (item .. comma) '}' ;
.   !interface       := 'interface' w+ name-id type-params? base-types? constraints?
.                       regions ;
.   !struct          := 'struct' w+ name-id type-params? base-types? constraints? regions ;
.
.   base-types       := ':' (type .. comma) ;
.   item             := xmldoc? name-id '=' expr ;
.   regions          := '{' region* '}' ;
.
.   region           := '#region' ws ~lb+ lb member* '#endregion' ;
.
.   member           := xmldoc? attribs? modifiers (constant | constructor | field
.                       | indexer | method | operator | property) ;
.
.   !constant        := 'const' w+ var-def ';' ;
.   !constructor     := name-id params (':' 'base' '(' (expr .. comma)? ')')? stat-block ;
.   !field           := var ';' ;
.   !indexer         := type 'this' '[' var-decl ']' '{' getter? setter? '}' ;
.   !method          := var-decl type-params? params constraints? (stat-block | ';') ;
.   modifiers        := ('public' w+)? ('protected' w+)? ('internal' w+)? ('new' w+)?
.                       ('abstract' w+)? ('virtual' w+)? ('override' w+)? ('sealed' w+)?
.                       ('static' w+)? ('readonly' w+)? ('volatile' w+)? ('partial' w+)? ;
.   !operator        := type 'operator' operator-op params stat-block ;
.   !property        := var-decl '{' getter? setter? '}' ;
.   !xmldoc          := (ws* xmldoc-line)+ ;
.
.   constraints      := constraint constraint* ;
.   getter           := 'get' (';' | stat-block) ;
.   operator-op      := '==' | '!=' | '>=' | '<=' | '<<' | '>>' | '&' | '/'
.                       | '>' | '~' | '<' | '%' | '*' | '-' | '!' | '|' | '+' | '^' ;
.   params           := '(' (param .. comma)? ')' ;
.   setter           := 'set' (';' | stat-block) ;
.   type-params      := '<' (type-param .. comma) '>' ;
.   xmldoc-line      := '///' (ws ~lb*)? lb ;
.
.   constraint       := 'where' w+ name-id ':' (constraint-item .. comma)? ;
.   param            := attribs? (('ref' | 'out' | 'this') w+)? var ;
.   type-param       := (('in' | 'out') w+)? name-id ;
.
.   attribs          := '[' (attrib .. comma) ']' ;
.   constraint-item  := 'class' | 'struct' | 'new()' | type-generic ;
.
.   attrib           := name-id ('(' (expr .. comma) ')')? ;
.
.   !arg             := (('out' | 'ref') w+)? expr ;
.   expr             := expr-assign ;
.   !expr-add        := expr-mul !> (expr-add-op expr-mul)+ ;
.   !expr-assign     := expr-cond !> (expr-assign-op expr-cond)+ ;
.   !expr-brace      := '(' expr ')' ;
.   !expr-cond       := expr-cond-or !> '?' expr-cond ':' expr-cond ;
.   !expr-cond-and   := expr-logic-or !> ('&&' expr-logic-or)+ ;
.   !expr-cond-or    := expr-cond-and !> ('||' expr-cond-and)+ ;
.   !expr-default    := 'default' '(' type ')' ;
.   !expr-equal      := expr-relate !> expr-equal-op expr-relate ;
.   !expr-generic    := expr-name !> '<' (type .. comma) '>' ;
.   !expr-logic-and  := expr-equal !> ('&' expr-equal)+ ;
.   !expr-logic-or   := expr-logic-xor !> ('|' expr-logic-xor)+ ;
.   !expr-logic-xor  := expr-logic-and !> ('^' expr-logic-and)+ ;
.   !expr-mul        := expr-unary !> (expr-mul-op expr-unary)+ ;
.   !expr-new        := 'new' w+ type (expr-new-object | expr-new-array1
.                       | expr-new-array2) ;
.   !expr-new-array1 := '{' (expr .. comma)? '}' ;
.   !expr-new-array2 := '[' expr ']' '[]'* ;
.   !expr-new-object := '(' (expr .. comma)? ')' ;
.   !expr-primary    := expr-brace | expr-new | expr-literal | expr-default
.                       | expr-generic ;
.   !expr-relate     := expr-shift !> expr-relate-op expr-shift ;
.   !expr-shift      := expr-add !> (expr-shift-op expr-add)+ ;
.   !expr-suffix     := expr-primary !> expr-suffix-op+ ;
.   expr-suffix-op   := '(' (arg .. comma)? ')' | '.' expr-generic | '[' expr ']' | '++'
.                       | '--' ;
.   !expr-unary      := expr-unary-op+ <! expr-suffix ;
.   expr-unary-op    := '++' | '+' | '--' | '-' \ literal-number | '!' | '~'
.                       | '(' type ')' <expr> ;
.   for-cond         := expr ;
.   for-next         := expr (comma expr)* ;
.   stat             := stat-block | stat-debug | stat-do | stat-foreach | stat-for
.                       | stat-if | stat-native | stat-return | stat-simple | stat-switch
.                       | stat-throw | stat-try | stat-while | stat-variable | stat-expr
.                       | stat-comment ;
.   !stat-block      := '{' stat* '}' ;
.   !stat-debug      := '#if' 'DEBUG' stat* '#endif' ;
.   !stat-do         := 'do' stat-block 'while' '(' expr ')' ';' ;
.   stat-expr        := expr ';' ;
.   !stat-for        := 'for' '(' var-def? ';' for-cond ';' for-next? ')' stat ;
.   !stat-foreach    := 'foreach' '(' var-decl 'in' expr ')' stat ;
.   !stat-if         := 'if' '(' expr ')' stat ('else' stat)? ;
.   !stat-return     := 'return' (w+ expr)? ';' ;
.   !stat-switch     := 'switch' '(' expr ')' '{' switch-case* switch-default? '}' ;
.   !stat-throw      := 'throw' (w+ expr)? ';' ;
.   !stat-try        := 'try' stat-block try-catch? try-finally? ;
.   !stat-variable   := ('using' w+)? var ';' (ws* '//' ws* '[' ws* ('!' ws*)? ('*' ws*)?
                        ']' ws* lb)? ;
.   !stat-while      := 'while' '(' expr ')' stat ;
.   switch-case      := 'case' w+ expr ':' stat* ;
.   switch-default   := 'default:' stat* ;
.   try-catch        := 'catch' '(' type (w+ name-id)? ')' stat-block ;
.   try-finally      := 'finally' stat-block ;
.   !type            := type-no-array !> '[]'+ ;
.   type-generic     := type-name !> '<' (type .. comma) '>' ;
.   type-no-array    := type-simple | type-generic ;
.   var              := type w+ name-id ('=' expr)? ;
.   var-decl         := type w+ name-id ;
.   var-def          := type w+ name-id '=' expr ;
.
.   !expr-literal    := literal ;
.
.   literal          := literal-simple | literal-string | literal-char | literal-hex
.                       | literal-number ;
.   !stat-comment    := comment-prefix (comment-tag | ws?) comment-text
.                       (ws* comment-line)* ;
.   type-name        := name ;
.
.   comment-tag      := ws* id ':' ws ;
.   !expr-name       := id ;
.   !literal-char    := '\'' (escape | ]'\\[) '\'' ;
.   !literal-string  := '"' (escape | ]"\\[ \ '\\"')* '"' | '@"' ('""' | ]"[)* '"' ;
.   name             := 'global::'? (id .. '.') ;
.   name-id          := id ;
.   !stat-native     := '#region' ws 'Native' ws '{' guid '}' lb ~native-end* native-end
.                       lb ;
.
.   comment-line     := comment-prefix ws? comment-text ;
.   escape           := '\\"' | '\\0' | '\\\'' | '\\\\' | '\\b' | '\\f' | '\\n' | '\\r'
.                       | '\\t' | '\\u' hex-digit[4] | '\\U' hex-digit[8] ;
.   !guid            := hex-digit[8] ('-' hex-digit[4])[3] '-' hex-digit[12] ;
.   !id              := letter id-char* ;
.   !literal-hex     := @'0x' hex-digit+ @'L'? ;
.   !literal-simple  := ('null' | 'this' | 'base' | 'true' | 'false') >id-char< ;
.   !type-simple     := ('bool' | 'sbyte' | 'char' | 'short' | 'int' | 'long' | 'float'
.                       | 'double' | 'string' | 'object' | 'void') >id-char< ;
.
.   comment-text     := ~lb* lb ;
.   hex-digit        := dec-digit | 'a'..'f' | 'A'..'F' ;
.   id-char          := letter | dec-digit ;
.   !literal-number  := '-'? dec-digit+ ('.' dec-digit+)? (@'E' ('-' | '+')? dec-digit+)?
.                       [FLfl]? ;
.   native-end       := lb ws* '#endregion' ;
.   w                := ws | lb ;
.
.   comma            := ',' ;
.   comment-prefix   := '//' \ '///' ;
.   dec-digit        := '0'..'9' ;
.   expr-add-op      := '+' | '-' ;
.   expr-assign-op   := '=' | '*=' | '/=' | '%=' | '+=' | '-=' | '<<=' | '>>='
.                       | '&=' | '^=' | '|=' ;
.   expr-equal-op    := '==' | '!=' ;
.   expr-mul-op      := '*' | '/' \ '//' | '%' ;
.   expr-relate-op   := '<=' | '<' | '>=' | '>' | 'is' | 'as' ;
.   expr-shift-op    := '<<' | '>>' ;
.   lb               := '\r' '\n'? | '\n' ;
.   letter           := 'a'..'z' | 'A'..'Z' | '_' ;
.   !stat-simple     := ('break' | 'continue') ';' ;
.   ws               := '\t' | ' ' ;