px4_autopilot/misc/pascal/doc/PascalGrammar.txt

PASCAL GRAMMAR:
The start symbol for this grammar is pascal.

   actual-parameter = expression | variable-access |
       procedure-identifier | function-identifier

   actual-parameter-list = '(' actual-parameter { ',' actual-parameter } ')'

   adding-operator = '+' | '-' | 'or' | 'or_else' | 'xor'

   array-type = 'array' '[' index-type-list ']' 'of' type-denoter

   array-variable = variable-access

   assignment-statement = assignment-statement-lhs ':=' expression

   assignment-statement-lhs = variable-access | function-identifier | property-designator

   binary-digit = '0' | '1'

   binary-digit-sequence = binary-digit { binary-digit }

   binary-integer = '%' binary-digit-sequence

   block = declaration-group compound-statement

   boolean-expression = expression

   buffer-variable = file-variable '^' | file-variable '@'

   c-string-type = 'cstring' [ max-string-length ]

   case-body = case-list-elements [ [ ';' ] case-statement-completer ] |
                       case-statement-completer

   case-constant = ordinal-constant

   case-constant-list = case-specifier { ',' case-specifier }

   case-index = ordinal-expression

   case-list-element = case-constant-list ':' statement

   case-list-elements = case-list-element { ';' case-list-element }

   case-specifier = case-constant [ '..' case-constant ]

   case-statement = 'case' case-index case-body [ ';' ] 'end'

   case-statement-completer = ( 'otherwise' | 'else' ) statement-sequence

   character-code = digit-sequence

   character-literal = ''' string-element-one ''' |
                            '"' string-element-two '"' |
                            '#' character-code

   component-variable = indexed-variable | field-designator

   compound-statement = 'begin' statement-sequence 'end'

   conditional-statement = if-statement | case-statement

   constant = [ sign ] integer-number |
                    [ sign ] real-number |
                    [ sign ] constant-identifier |
                               character-literal |
                               string-literal

   constant-definition = identifier '=' constant

   constant-definition-group = 'const' constant-definition ';' { constant-definition ';' }

   constant-identifier = identifier

   control-variable = entire-variable

   decimal-integer = digit-sequence

   declaration-group =
             label-declaration-group |
             constant-definition-group |
             type-definition-group |
             variable-declaration-group |
             function-declaration  | 
             procedure-declaration

   digit = '0' | '1' | '2' | '3' | '4' | '5' | '6' | '7' | '8' | '9'

   digit-sequence = digit { digit }

   directive = forward-directive | external-directive

   dllname = string-literal

   domain-type = type-identifier

   else-part = 'else' statement

   empty-statement =

   empty-string = '''' | '""'

   entire-variable = variable-identifier

   enumerated-constant = identifier

   enumerated-constant-list = enumerated-constant { ',' enumerated-constant }

   enumerated-type = '(' enumerated-constant-list ')'

   exponent = 'e' | 'E'

   exported-heading =  procedure-heading ';' [ directive ] | function-heading ';' [ directive ]

   expression = shift-expression [ relational-operator shift-expression ]

   external-directive = 'external' 'dll' '=' dllname [ 'name' '=' name ] [ 'stdcall' | 'cdecl' ]

   factor = [ sign ] unsigned-constant |
                [ sign ] variable-access |
                [ sign ] '(' expression ')' |
                [ sign ] function-designator |
                [ sign ] function-method-designator |
                [ sign ] 'not' factor |
                set-constructor

   field-designator = record-variable '.' field-specifier | field-designator-identifier

   field-designator-identifier = identifier

   field-identifier = identifier

   field-list = [
         fixed-part [ ';' ] variant-part [ ';' ] |
         fixed-part [ ';' ] |
         variant-part [ ';' ] |
      ]

   field-specifier = field-identifier

   file-type = 'file' 'of' type-denoter

   file-variable = variable-access

   final-value = ordinal-expression

   fixed-part = record-section { ';' record-section }

   for-statement = 'for' control-variable ':=' initial-value ( 'to' | 'downto' ) final-value
                  'do' statement

   formal-parameter-list = '(' formal-parameter-section { ';' formal-parameter-section } ')'

   formal-parameter-section = value-parameter-specification |
                  variable-parameter-specification |
                  procedure-parameter-specification |
                  function-parameter-specification

   forward-directive = 'forward'

   function-block = block

   function-declaration =
       function-heading ';' directive |
       function-heading ';' function-block

   function-designator = function-identifier [ actual-parameter-list ]

   function-heading = 'function' function-identifier [ formal-parameter-list ] ':' result-type

   function-identifier = identifier

   function-method-designator = object-variable '.' function-method-identifier [ actual-parameter-list ]

   function-method-identifier = identifier

   function-parameter-specification = function-heading

   goto-statement = 'goto' label

   hex-digit = digit | 'a' | 'b' | 'c' | 'd' | 'e' | 'f'
 
   hex-digit-sequence = hex-digit { hex-digit }

   hexadecimal-integer = '$' hex-digit-sequence

   identified-variable = pointer-variable '^' | pointer-variable '@'

   identifier = letter { letter | digit }

   identifier-list = identifier { ',' identifier }

   if-statement = 'if' boolean-expression 'then' statement [ else-part ]

   implementation-section = 'implementation' [ uses-section ] declaration-group

   index-expression = expression

   index-type = ordinal-type

   index-type-list = index-type { ',' index-type }

   indexed-variable = indexed-variable-array | indexed-variable-string

   indexed-variable-array = array-variable '[' index-expression { ',' index-expression } ']'

   indexed-variable-string = string-variable '[' integral-expression ']'

   initial-value = ordinal-expression

   init-section = 'initialization statement-sequence
       ['finalization' statement-sequence] 'end' |
       compound-statement | 'end'

   integer-number = decimal-integer | hexadecimal-integer | binary-integer

   integral-constant = constant

   integral-expression = expression

   interface-declaration = [ constant-definition-group ]
      [ type-definition-group ] [ variable-declaration-group ]
      exported-heading

   interface-section = 'interface' [ uses-section ] interface-declaration

   label = digit-sequence | identifier

   label-declaration-group = 'label' label { ',' label } ';'

   letter = 'a' | 'b' | 'c' | 'd' | 'e' | 'f' | 'g' | 'h' | 'i' | 'j' |
               'k' | 'l' | 'm' | 'n' | 'o' | 'p' | 'q' | 'r' | 's' | 't' |
               'u' | 'v' | 'w' | 'x' | 'y' | 'z' |
               '_'

   list-type = 'list' 'of' type-denoter

   list-variable = variable-access

   max-string-length = '[' integral-constant ']' | '(' integral-constant ')'

   member-designator = ordinal-expression [ '..' ordinal-expression ]

   multiplying-operator = '*' | '/' | 'div' | 'mod' | 'and' | 'and_then'

   name = identifier

   new-complex-type = new-structured-type | new-pointer-type

   new-ordinal-type = enumerated-type | subrange-type

   new-pointer-type = '^' domain-type | '@' domain-type

   new-structured-type =
      [ 'packed' ] array-type |
      [ 'packed' ] record-type |
      [ 'packed' ] set-type |
      [ 'packed' ] file-type |
      [ 'packed' ] list-type |
                         object-type |
                         string-type

   new-type = new-ordinal-type | new-complex-type

   non-empty-string =
       ''' string-element-one string-element-one { string-element-one } ''' |
       '"' string-element-two string-element-two { string-element-two } '"'

   object-type = 'object' | 'class'

   object-variable = variable-access

   ordinal-constant = constant

   ordinal-expression = expression

   ordinal-type = new-ordinal-type | ordinal-type-identifier

   ordinal-type-identifier = identifier

   pascal = program | unit

   pascal-string-type = 'string' [ max-string-length ]

   pointer-variable = variable-access

   printable-character = any character (including a space) that has a visual representation.

   procedure-block = block

   procedure-declaration =
       procedure-heading ';' directive |
       procedure-heading ';' procedure-block

   procedure-heading = 'procedure' procedure-identifier
      [ formal-parameter-list ]

   procedure-identifier = identifier

   procedure-method-identifier = identifier

   procedure-method-specifier = object-variable '.' procedure-method-identifier

   procedure-method-statement = procedure-method-specifier [ actual-parameter-list ]

   procedure-parameter-specification = procedure-heading

   procedure-statement = procedure-identifier (
         [ actual-parameter-list ] |
         read-parameter-list | readln-parameter-list |
         write-parameter-list | writeln-parameter-list
      )

   program = program-heading ';' [ uses-section ] block '.'

   program-heading = 'program' identifier [ '(' identifier-list ')' ]

   property-designator = object-variable '.' property-specifier

   property-identifier = identifier

   property-specifier = property-identifier | '(' property-string ')'

   property-string = string-expression

   read-parameter-list = '(' [ file-variable ',' ] variable-access { ',' variable-access } ')'

   readln-parameter-list = [ '(' ( file-variable | variable-access ) { ',' variable-access } ')' ]

   real-number =
       digit-sequence '.' [digit-sequence] [ exponent scale-factor ] |
       '.' digit-sequence [ exponent scale-factor ] |
       digit-sequence exponent scale-factor

   record-section = identifier-list ':' type-denoter

   record-type = 'record' field-list 'end'

   record-variable = variable-access

   record-variable-list = record-variable { ';' record-variable }

   relational-operator = '=' | '<>' | '<' | '<=' | '>' | '>=' | 'in'

   repeat-statement = 'repeat' statement-sequence 'until' boolean-expression

   repetitive-statement = repeat-statement | while-statement | for-statement

   result-type = type-identifier

   scale-factor = [ sign ] digit-sequence

   selected-variable = list-variable '[' index-expression { ',' index-expression } ']'

   set-constructor = '[' [ member-designator { ',' member-designator } ] ']'

   set-type = 'set' 'of' ordinal-type

   shift-expression = simple-expression [ shift-operator simple-expression ]

   shift-operator = 'shl' | 'shr'

   sign = '-' | '+'

   simple-expression = term { adding-operator term }

   simple-statement = empty-statement | assignment-statement |
              procedure-statement | procedure-method-statement |
              goto-statement

   statement = [ label ':' ] ( simple-statement | structured-statement )

   statement-sequence = statement { ';' statement }

   string-element-one = '''' | printable-character

   string-element-two = '""' | printable-character

   string-expression = expression

   string-literal = empty-string | non-empty-string

   string-type = pascal-string-type | c-string-type

   string-variable = variable-access

   structured-statement = compound-statement |
              conditional-statement |
              repetitive-statement |
              with-statement

   subrange-type = constant '..' constant

   term = factor { multiplying-operator factor }

   type-definition = identifier '=' type-denoter

   type-definition-group = 'type' type-definition ';' { type-definition ';' }

   type-denoter = type-identifier | new-type

   type-identifier = identifier

   unit = 'unit' identifer ';' interface-section implementation-section
      init-section '.'

   unit-import = identifier ['in' non-empty-string ]

   unit = unit-heading ';' interface-section implementation-section init-section

   unit-heading = 'unit' identifer

   unsigned-constant = integer-number | real-number |
         character-literal | string-literal | constant-identifier |
         'nil'

   uses-section = 'uses' [ uses-unit-list ] ';'

   uses-unit-list = unit-import {';' uses-unit-list }

   value-parameter-specification = identifier-list ':' type-identifier

   variable-access = entire-variable | component-variable | identified-variable |
              selected-variable | buffer-variable

   variable-declaration = identifier-list ':' type-denoter

   variable-declaration-group = 'var' variable-declaration { ';' variable-declaration }

   variable-identifier = identifier

   variable-parameter-specification = 'var' identifier-list ':' type-identifier

   variant = case-constant-list ':' '(' field-list ')'

   variant-body = variant-list [ [ ';' ] variant-part-completer ] | variant-part-completer

   variant-list = variant { ';' variant }

   variant-part = 'case' variant-selector 'of' variant-body

   variant-part-completer = ( 'otherwise' | 'else' ) ( field-list )

   variant-selector = [ identifier ':' ] ordinal-type-identifer

   while-statement = 'while' boolean-expression 'do' statement

   with-statement = 'with' record-variable-list 'do' statement

   write-parameter = expression [ ':' expression [ ':' expression ] ]

   write-parameter-list = '(' [ file-variable ',' ] write-parameter { ',' write-parameter } ')'

   writeln-parameter-list = [ '(' ( file-variable | write-parameter ) { ',' write-parameter } ')' ]