Syntax of the Kimwitu input

In this section we present the syntax of the Kimwitu input. The notation is based on yacc, with the following extensions. Single quotes are used for string denotations, ordinary parentheses () denote grouping, square brackets [] denote zero or one instance, curly brackets {} denote zero or more instances.

Comments are in C style, e.g. enclosed between /* and */, but can be nested.

Some of the rules and conditions are expressed in prose, rather than by formal means. An identifier (ID) is a sequence of letters digits and underscores, not starting with a digit.

specification:          { phylumdeclaration | includedeclaration | functiondeclaration |
                          rwdeclaration | unparsedeclaration |
                          rviewdeclaration | uviewdeclaration | storageclassdeclaration } ;


phylumdeclaration:      ID [storage_option] ':' [productionblock] [Ccode] ';' ;


storage_option:         '{' ['!'] ID '}' ;


productionblock:        'list' ID | alternative_list ;


alternative_list:       [alternative_list '|'] ID '(' arguments ')' ;


arguments:              {ID} ; 


Ccode:                  '{' [Attributes] [Cbody] '}' ;


Attributes:             [Attributes] ID ID ['=' Cexpression] ';' ;


Cexpression:            /* arbitrary C expression without ';' and ',' with '$0' */


includedeclaration:     '%{' {ID} includes '%}' ; /* the tokens are at the beginning of a line */
                        /* ID's in {ID} are at the same line as '%{' */


includes:               /* arbitrary text */ ;


rwdeclaration:          outmostpatterns '->' rwclauses_or_term ';' ;


rwclauses_or_term:      {rewriteclause} | outmostterm ;


rewriteclause:          '<' rviewnames ':' outmostterm '>' ;


rviewnames:             {ID} ;


patternchains:          patternchain [',' patternchains] ;


patternchain:           patternchainitem ['&' patternchain] ;


patternchainitem:       outmostpattern
|                       '(' patternchains ')'
|                       '$' ID /* this rule is to be used only in 'patternchain' in foreach_statement */
;


outmostpatterns:        outmostpattern [',' outmostpatterns] ;


outmostpattern:         [ID '='] ID ['(' [patterns] ')']  | '*' | 'default' ;


patterns:               pattern [',' patterns] ;


pattern:                ID '=' pattern
|                       ID ['(' [patterns] ')']
|                       '"' /* any string of characters */ '"'
|                       /* a number */
|                       '*' | 'default'
;


outmostterm:            ID '(' [terms] ')' ;


term:                   ID ['(' [terms] ')'] 
|                       '"' /* any string of characters */ '"'
|                       /* a number */
;


terms:                  term [',' terms] ;


functiondeclaration:    decl_specifiers fn_declarator {declaration} MainCbody ;


decl_specifiers:        [stor_class_specifier] [type_qualifier] ID ;


stor_class_specifier:   'auto' | 'register' | 'static' | 'extern' | 'typedef' ;


type_qualifier:         'const' | 'volatile' ;


fn_declarator:          [pointer] direct_fn_declarator ;


direct_fn_declarator:   ID '(' [fnarguments] ')'
|                       ID '(' parameter_type_list ')'
;


fnarguments:            [fnarguments ','] ['$'] ID ;


parameter_type_list:    parameter_list [',' '...'] ;


parameter_list:         [parameter_list ','] parameter_decl ;


parameter_decl:         decl_specifiers declarator
|                       decl_specifiers abstract_declarator
;


declarator:             [pointer] direct_declarator ;


pointer:                '*' {type_qualifier} [pointer] ;


direct_declarator:      ['$'] ID
|                       '(' pointer direct_declarator ')'
|                       direct_declarator '[' [Cexpression] ']'
|                       direct_declarator '(' param_type_list ')'
|                       direct_declarator '(' [fnarguments] ')'
;


abstract_declarator:    pointer
|                       [pointer] direct_abstract_declarator
;


direct_abstract_declarator:'(' abstract_declarator ')'
|                       [direct_abstract_declarator] '[' [Cexpression] ']'
|                       [direct_abstract_declarator] '(' [parameter_type_list] ')'
;


declaration:            decl_specifiers [declarator_list] ;


declarator_list:        [declarator_list ','] declarator ;


MainCbody:              Cbody
|                       '{' with_clause '}' /* a with_clause if a fn argument has a $ prefix */
;


Cbody:                  '{' Ctext '}' ;


Ctext:                  /* arbitrary C text, with $0 through $n, 
                           with_statement and foreach_statement */ ;


foreach_statement:      'foreach' '(' patternchain ';' IDCexpressions ')' MainCbody
                        [ 'afterforeach' '(' patternchain ')' MainCbodyinC ]
;


IDCexpressions:         ID Cexpression [',' IDCexpressions] ;


with_statement:         'with' '(' Cexpressions ')' '{' with_clause '}' ;


Cexpressions:           Cexpression [',' Cexpressions] ;


with_clause:            patternchains ':' Cbody [with_clause] ;


unparsedeclaration:     outmostpatterns '->' {unparseclause} ';' ;


unparseclause:          '[' uviewnames ':' {unparseitem} ']' ;


uviewnames:             {ID} ;


unparseitem:            '"' /* any string of characters*/ '"'  [':' ID]
|                       ['(' ID ')']  ID  {'->' ID}  [':' ID]
|                       Cbody
|                       '${' {unparseitem} '$}'
;


rviewdeclaration:       '%rview' rviewnames ';' ;


uviewdeclaration:       '%uview' uviewnames ';' ;


storageclassdeclaration:'%storageclass' {ID} ';' ;