; Source: http://www.fit.vutbr.cz/study/courses/APR/public/ebnf.html#string-character

; Programs and Blocks

program
    program-heading block "." 
program-heading
    program identifier "(" identifier-list ")" ";" 
block
    declaration-part statement-part 
declaration-part
    [ label-declaration-part ]
    [ constant-definition-part ]
    [ type-definition-part ]
    [ variable-declaration-part ]
    procedure-and-function-declaration-part 
label-declaration-part
    label label { "," label } ";" 
constant-definition-part
    const constant-definition ";" { constant-definition ";" } 
constant-definition
    identifier "=" constant 
type-definition-part
    type type-definition ";" { type-definition ";" } 
type-definition
    identifier "=" type 
variable-declaration-part
    var variable-declaration ";" { variable-declaration ";" } 
variable-declaration
    identifier-list ":" type 
procedure-and-function-declaration-part
    { (procedure-declaration | function-declaration) ";" } 
procedure-declaration
    procedure-heading ";" procedure-body |
    procedure-heading ";" directive |
    procedure-identification ";" procedure-body 
procedure-body
    block 
function-declaration
    function-heading ";" function-body |
    function-heading ";" directive |
    function-identification ";" function-body 
function-body
    block 
directive
    forward | compiler-defined-directives 
statement-part
    begin statement-sequence end 

; Procedure and Function Definitions

procedure-heading
    procedure identifier [ formal-parameter-list ] 
function-heading
    function identifier [ formal-parameter-list ] ":" result-type 
result-type
    type-identifier 
procedure-identification
    procedure procedure-identifier 
function-identification
    function function-identifier 
formal-parameter-list
    "(" formal-parameter-section { ";" formal-parameter-section } ")" 
formal-parameter-section
    value-parameter-section |
    variable-parameter-section |
    procedure-parameter-section |
    function-parameter-section 
value-parameter-section
    identifier-list ":" parameter-type 
variable-parameter-section
    var identifier-list ":" parameter-type 
procedure-parameter-section
    procedure-heading 
function-parameter-section
    function-heading 
parameter-type
    type-identifier | conformant-array-schema 
conformant-array-schema
    packed-conformant-array-schema |
    unpacked-conformant-array-schema 
packed-conformant-array-schema
    packed array "[ " bound-specification " ]" of type-idnetifier 
unpacked-conformant-array-schema
    array "[ " bound-specification { ";" bound-specification } " ]"
    of (type-identifier | conformant-array-schema) 
bound-specification
    identifier ".." identifier ":" ordinal-type-identifier 
ordinal-type-identifier
    type-identifier 

; Statements

statement-sequence
    statement { ";" statement } 
statement
    [ label ":" ] (simple-statement | structured-statement) 
simple-statement
    [ assignment-statement | procedure-statement | goto-statement ] 
assignment-statement
    (variable | function-identifier) ":=" expression 
procedure-statement
    procedure-identifier [ actual-parameter-list ] 
goto-statement
    goto label 
structured-statement
    compound-statement | repetitive-statement | conditional-statement | with-statement 
compound-statement
    begin statement-sequence end 
repetitive-statement
    while-statement | repeat-statement | for-statement 
while-statement
    while expression do statement 
repeat-statement
    repeat statement-sequence until expression 
for-statement
    for variable-identifier ":=" initial-expression (to | downto) final-expression do statement 
initial-expression
    expression 
final-expression
    expression 
conditional-statement
    if-statement | case-statement 
if-statement
    if expression then statement [ else statement ] 
case-statement
    case expression of
    case-limb { ";" case-limb } [ ";" ]
    end 
case-limb
    case-label-list ":" statement 
case-label-list
    constant { "," constant } 
with-statement
    with record-variable { "," record-variable } do statement 
actual-parameter-list
    "(" actual-parameter { "," actual-parameter } ")" 
actual-parameter
    actual-value | actual-variable | actual-procedure | actual-function 
actual-value
    expression 
actual-procedure
    procedure-identifier 
actual-function
    function-identifier 

; Expressions

expression
    simple-expression [ relational-operator simple-expression ] 
simple-expression
    [ sign ] term { addition-operator term } 
term
    factor { multiplication-operator factor } 
factor
    variable | number | string | set | nil | constant-identifier | bound-identifier | function-designator | "(" expression ")" | not factor 
relational-operator
    "=" | "<>" | "<" | "<=" | ">" | ">=" | "in" 
addition-operator
    "+" | "-" | or 
multiplication-operator
    "*" | "/" | div | mod | and 
variable
    entire-variable | component-variable | referenced-variable 
entire-variable
    variable-identifier | field-identifier 
component-variable
    indexed-variable | field-designator | file-buffer 
indexed-variable
    array-variable "[ " expression-list " ]" 
field-designator
    record-variable "." field-identifier 
set
    "[ " element-list " ]" 
element-list
    [ expression { "," expression } ] 
function-designator
    function-identifier [ actual-parameter-list ] 
file-buffer
    file-variable "^" 

; Types

type
    simple-type | structured-type | pointer-type | type-identifier 
simple-type
    subrange-type | enumerated-type 
enumerated-type
    "(" identifier-list ")" 
subrange-type
    lower-bound ".." upper-bound 
lower-bound
    constant 
upper-bound
    constant 
structured-type
    [ packed ] unpacked-structured-type 
unpacked-structured-type
    array-type | record-type | set-type | file-type 
array-type
    array "[ " index-type { "," index-type } " ]" of element-type 
index-type
    simple-type 
element-type
    type 
record-type
    record field-list end 
set-type
    set of base-type 
base-type
    type 
file-type
    file of file-component-type 
file-component-type
    type 
pointer-type
    "^" type-identifier 

; Record Fields

field-list
    [ (fixed-part [ ";" variant-part ] | variant-part) [ ";" ] ] 
fixed-part
    record-section { ";" record-section } 
record-section
    identifier-list ":" type 
variant-part
    case tag-field type-identifier of variant { ";" variant } 
tag-field
    [ identifier ":" ] 
variant
    case-label-list ":" "(" field-list ")" 

; Input/Output

output-list
    output-value { "," output-value } 
output-value
    expression [ ";" field-width [ ":" fraction-length ] ] 
field-width
    expression 
fraction-length
    expression 

; Variable and Identifier Categories

identifier
    letter { letter | digit } 
file-variable
    variable 
referenced-variable
    pointer-variable "^" 
record-variable
    variable 
pointer-variable
    variable 
actual-variable
    variable 
array-variable
    variable 
field-identifier
    identifier 
constant-identifier
    identifier 
variable-identifier
    identifier 
type-identifier
    identifier 
procedure-identifier
    identifier 
function-identifier
    identifier 
bound-identifier
    identifier 

; Low Level Definitions

variable-list
    variable { "," variable } 
identifier-list
    identifier { "," identifier } 
expression-list
    expression { "," expression } 
number
    integer-number | real-number 
integer-number
    digit-sequence 
real-number
    digit-sequence "." [ digit-sequence ] [ scale-factor ] |
    digit-sequence scale-factor 
scale-factor
    ("E" | "e") [ sign ] digit-sequence 
unsigned-digit-sequence
    digit { digit } 
digit-sequence
    [ sign ] unsigned-digit-sequence 
sign
    "+" | "-" 
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" | "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" 
digit
    "0" | "1" | "2" | "3" | "4" | "5" | "6" | "7" | "8" | "9" 
string
    "'" string-character { string-character } "'" 
string-character
    any-character-except-quote | "''" 
label
    integer-number 
constant
    [ sign ] (constant-identifier | number) | string